CA2460246A1 - Method and apparatus for controlling, removing, preventing and/or inhibiting the accumulation, colonizing or otherwise fouling of aquaculture fish farm pen nets with marine organisms, plankton and algae - Google Patents
Method and apparatus for controlling, removing, preventing and/or inhibiting the accumulation, colonizing or otherwise fouling of aquaculture fish farm pen nets with marine organisms, plankton and algae Download PDFInfo
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- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01K—ANIMAL HUSBANDRY; CARE OF BIRDS, FISHES, INSECTS; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
- A01K75/00—Accessories for fishing nets; Details of fishing nets, e.g. structure
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Abstract
This patent is to protect the method and apparatus for controlling, removing, preventing and/or inhibiting the accumulation, colonization or otherwise fouling of aquaculture fish farm pen nets with marine organisms, plankton and algae. The method and apparatus whereby this is accomplished involves the formation of a copper ion plume in and around the aquaculture fish farm pen nets. In general, the copper must be in an ionic form to be most effective in controlling, removing and inhibiting marine growth (fouling) on aquaculture fish pen nets.
The mechanism is, believed to be, attributed to the positively charged ions that attach to the negatively charged cell wall of the microorganism and destroy cell wall permeability.
The apparatus by which this ionic plume is generated is through an electrolysis process.
Although electrolysis can be made to work under a variety of methods and for different applications, this patent provides an optimal method for creating a copper ionic concentration that is specific and unique to the aquaculture fish farms industry. The method of using electrolysis has been used in the marine environment for many years and all over the world to protect vessels and to protect the marine water-intakes from fouling with marine organisms.
However, the method and application of using electrolysis to create a copper ion plume to protect aquaculture fish farm pen nets is unique, this method and application has never been done before.
The electrolysis method uses two dissimilar metal electrodes. The cathodic electrode is stainless steel (but can be a graphite rod or other equivalent material). The anodic electrodes are copper and aluminum, where the aluminum provides corrosion protection. The oxidation of the anodes is by electron loss. The positive metal atoms of the metal electrodes oxidize to form positive metal ions, which form a plume (within the electrolyte or sea water) that may range in size and shape depending on the input variables such as voltage, electrical current, size of electrodes, but will also be dependent on ambient conditions such as temperature and salinity of the marine environment. Because the variables for creating the copper ionic plume can range so drastically, the scope of the protection afforded by the patent is specifically for the application, as it applies to the protection of aquaculture fish farm pen nets.
The electrodes are connected to a DC electrical power source of 2.2Volts using an electrical current of 160mAmps (although this may vary depending on the desired plume size and ionic concentrations). The copper concentration of the ionic plume will range from less than ( < ) 0.01 ppm to 0.1 ppm. These concentrations are sufficient for controlling, removing, preventing and/or inhibiting the accumulation of marine growth (fouling) on aquaculture fish farm nets
The mechanism is, believed to be, attributed to the positively charged ions that attach to the negatively charged cell wall of the microorganism and destroy cell wall permeability.
The apparatus by which this ionic plume is generated is through an electrolysis process.
Although electrolysis can be made to work under a variety of methods and for different applications, this patent provides an optimal method for creating a copper ionic concentration that is specific and unique to the aquaculture fish farms industry. The method of using electrolysis has been used in the marine environment for many years and all over the world to protect vessels and to protect the marine water-intakes from fouling with marine organisms.
However, the method and application of using electrolysis to create a copper ion plume to protect aquaculture fish farm pen nets is unique, this method and application has never been done before.
The electrolysis method uses two dissimilar metal electrodes. The cathodic electrode is stainless steel (but can be a graphite rod or other equivalent material). The anodic electrodes are copper and aluminum, where the aluminum provides corrosion protection. The oxidation of the anodes is by electron loss. The positive metal atoms of the metal electrodes oxidize to form positive metal ions, which form a plume (within the electrolyte or sea water) that may range in size and shape depending on the input variables such as voltage, electrical current, size of electrodes, but will also be dependent on ambient conditions such as temperature and salinity of the marine environment. Because the variables for creating the copper ionic plume can range so drastically, the scope of the protection afforded by the patent is specifically for the application, as it applies to the protection of aquaculture fish farm pen nets.
The electrodes are connected to a DC electrical power source of 2.2Volts using an electrical current of 160mAmps (although this may vary depending on the desired plume size and ionic concentrations). The copper concentration of the ionic plume will range from less than ( < ) 0.01 ppm to 0.1 ppm. These concentrations are sufficient for controlling, removing, preventing and/or inhibiting the accumulation of marine growth (fouling) on aquaculture fish farm nets
Description
Provisional Patent January 16. 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae Page 4 of 20 ANALYSIS OF AUUACULTURE FISH FARM NET FOULING
Prior to describing the application and benefits of this invention, the background of the industry and the challenges of the industry must be explained. As the problem is described, the benefits and usefulness of the invention will become prevalent.
The aquaculture fish farm industry uses nets that are typically made of nylon.
These nets form large open "bags" in which fish are kept secure for a period of approximately eighteen months.
During this period of time, the fish "grow-out" to maturity. The fish are not allowed to escape and must be monitored on a continual basis. The fish have specific feeding times and the environment in which they live is carefully monitored. The purpose of using nets as opposed to sealed bags is to provide a continual supply of oxygen rich water to the fish and to allow waste products to continually flush from the pen nets. The farm nets are formed into pens that typically measure 3l.Sm in length and 3l.Sm in width and are typically 20m deep. These are approximate dimensions and are used to illustrate a typical fish farm.
As the pen nets become fouled with marine growth, the water supply is restricted. This essentially limits the oxygen supply to the fish and prevents the waste from leaving the pen nets.
The result of pen net fouling is an increase in farm fish stress levels. This results is poor production levels, increased mortality and disease. Aquaculture fish farms that treat their nets with a chemical biocide (antifouling) must do so on a continual basis to keep the nets clean. This is both expensive and toxic to the environment.
This invention is unique in that it specifically addresses the issue of ongoing accumulation, colonization or otherwise fouling of aquaculture fish farm pen nets with marine organisms, plankton and algae. Marine organisms including (but not limited to) algae, mussels, oysters and barnacles typically attach (colonize) to aquaculture fish farm pen nets. Over the typical lifecycle of eighteen (18) months these marine organisms will accumulate and "foul" the nets, thus restricting the oxygen rich water flow to the fish and preventing waste products to flush out of the pen nets.
Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and.'or Inhibiting the Accumulation, Colonizing or Otherwise Fouling ofAquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae of 20 Although this invention specifically addresses the issue of marine growth on the pen nets, there are other beneficial erects that result from the copper ion plume that must be mentioned. The copper ionic plume that is created around the fish farm pen nets will create environmental conditions that are less opportunistic for other plankton. Specifically, the copper ion plume will disrupt the sea louse Lepeophtheirus salmonis at the early free living planktonic naupliar stage of its lifecycle. Although this invention does not claim that it will eliminate sea lice, it does claim to have an impact on the early stages of the sea lice lifecycle that will reduce the opportunistic environment for the sea lice to develop to the copepodid stage within the fish farm pen nets.
This invention is used to create a low concentration of copper ions in and around the vicinity of the aquaculture fish farm pen nets. The copper ions are an effective in controlling, removing (but not cleaning), preventing and inhibiting the accumulation, growth and/or attachment (colonization) of marine organisms on the aquaculture fish farm pen nets.
There are a number of benefits to this invention. The primary objective is to assist the aquaculture fish farm industry in the following ways:
1. Keep the pen nets clean of marine fouling using copper ions 2. Reduce the need for treating nets 3. Maintain maximum water flow through the nets (over time) for better oxygenation and therefore reduced stress on the farm fish 4. Reduce the need for cleaning the nets 5. Increase the life expectancy of the nets 6. Reduce the need for inspecting the marine substrate 7. Low cost alternative 8. Keep nets from becoming too heavy and thereby reducing the potential for fish escape 9. Create an environment that is less opportunistic for plankton to live and grow.
1. The application of this invention will keep the aquaculture fish farm pen nets clean of marine fouling a. It is not the intention of the patent to guarantee that this method and application will forever keep an aquaculture fish net from being fouled by marine organisms, however Provisional Patent January 16, 2004 Title: Method and Apparatus for (:onirolling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 6 orao there will be a significant reduction or elimination of marine organisms in areas where the functioning electrodes are placed. The limiting factor is the number of units deposited per fish pen net. There will always be a minimum number of electrodes required to adequately protect a fish farm. Most of these electrodes will be at a constant depth of 2m but there may be conditions where additional electrodes will be required at different depths. Electrodes have a limited life expectancy of two years and must be upgraded or the electrodes will not work.
b. The number of electrodes to adequately protect a single pen net measuring 3l.Sm by 31. Sm by l Om deep will depend on the size of the electrode, the voltage used in creating the electrolysis, the electrical current (amperage) of the DC power source, the tidal fluctuation, temperature and salinity of the marine water.
c. Under normal conditions the number of electrodes units required per pen net is eight (8). The same electrode units will impact adjacent nets and therefore the number of electrode units will decrease where nets multiple pen nets are used.
d. The cost savings is estimated to be significant.
2. Reduce the need for treating nets a. The length and width of a typical aquaculture fish farm net is 31. Sm square. The depth of these nets (pens) is typically 20m. Each net or fish pen is custom made so the size and dimensions may range from site to site. Factors that may influence the net size and dimensions may include (but are not limited to) the physical location of the fish farm, the depth of water, the current, the number of fish and fish species per pen.
b. The depth at which fouling typically occurs is within the top lOm from the surface.
Photosynthesis typically occurs within this range and as a result the primary growth of marine organisms on the nets occurs within this depth.
c. Nets are not always treated. There are areas where brackish water flow and growth or fouling is minimal. In these locations the nets are monitored and cleaned by hauling the nets up on to the floats and washed with a high-pressure water unit. This is however very labor intensive and has been reported to be one of the factors in employee back related injuries.
d. The treated nets are typically dipped in a latex based (or equivalent) paint to which a chemical biocide (antifouling) has been added. These biocides, however, gradually are Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling ofAquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae Page 7 of 20 released into the water and are very harmful for the water fauna and flora.
These biocides may also have an erect on the health of the farm fish. Nets that are treated have a limited lifecycle before they must be cleaned and retreated. This is both cumbersome, labor intensive and is relatively expensive. In addition, the entire fish net is treated as opposed to just the area of the net that is constantly fouled.
e. Some aquaculture fish farms will choose not to treat the nets. This may be a cost saving or environmental reasons. The result of not treating is that marine organisms will eventually colonize the nets. The nets become very heavy and may sink. As the nets become fouled with marine growth, the water flow through the nets decreases and the farm fish become more stressed due to a lack of available oxygen. In addition there is a higher potential for the fish net to sink, resulting in a loss of farm fish to the environment.
f. If the growth (over an eighteen month period) of marine organisms on one square meter of net is equal to 2.Skg, then a net measuring 3l.Sm square by lOm deep will weigh as much as 3000kg. At a fish farm with 12 pen nets this may equate to 36,OOOkg of waste. If the net is cleaned on site, all of the waste will end up in the marine environment, mostly under the fish farm.
3. Maintain maximum water flow through the nets (over time) for better oxygenation and therefore reduced stress on the farm fish a. Over a typical eighteen (18) month cycle, an aquaculture fish farm net will be exposed to a constant attack of marine organisms. There are certain periods of time when the lifecycle of mussels and other marine organisms will want to attach or colonize onto the nets. At the same time there is the continuous attack of algae.
b. Nets that are not treated are much more susceptible to the fouling by marine organisms. When these marine organisms attach, they gradually fill the mesh holes of the nets. This in turn reduces the amount of water flow through the nets.
c. As the water flow through the nets is restricted, so is the availability of oxygen to the fish. The more water that passes through the nets, the more oxygen the fish are exposed to. The water within the fish pen needs to be flushed as much as possible for more than just oxygen. Oxygen availability is believed to be one of the primary factors relating the fish to stress. The more oxygen, the less stress on the fish.
Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae Page 8 of ZO
4. Reduce the need for cleaning the nets a. Aquaculture fish farm nets that are not treated may last 6 weeks before signs of marine growth are evident. This of course is dependent on a number of factors of which the predominant one is location. Some aquaculture fish farms have reported a three to four month period where fouling of marine organisms were minimal. This would likely be during the mid winter months.
b Aquaculture fish farm nets that have been treated may be free of marine growth for a period of eight to eighteen months. This is dependent on the treatment method such as latex or wax based, environmental conditions such as location and seasonal conditions such as winter vs. summer months.
c. The cleaning methods vary from fish farm but there are some standard methods worth mentioning.
i. Some aquaculture fish farms will not clean their nets. The nets are basically allowed to foul with marine organisms until they are no longer useful. The fish are eventually removed and the net is allowed to sink the bottom. These nets undergo a "composting" period. This leaves a lot of debris on the bottom of the marine environment and has the potential to build-up over time. Not all environments are suitable for this type of "cleansing" and will require pre-approval.
ii. Some aquaculture fish farms will "tramp" the nets. This involves pulling the nets above the water and suspending the net above the water. The marine organisms die and are pressure washed oil The debris that is washed oi~the net will eventually sink to the bottom of the marine environment.
iii. Some aquaculture fish farms will pressure wash the nets in-situ. This involves a diver, pressure washing equipment and support staff. The marine environment is clouded by the debris and also ends up sinking to the bottom of the marine environment.
iv. Some aquaculture fish farms will manually haul a section of the net up onto the float and pressure-wash the net. This is very labor-intensive work and has been linked to back injuries: The advantage of pressure washing the nets on Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae Page 9 of 20 the floats is that no divers axe required. The wash water and waste debris from the nets are released into the marine environment.
d. At the end of the eighteen ( 18) month cycle, the aquaculture fish pens (nets) are typically shipped from the site far washing, repairs and optional treatment. A
typical net that is untreated may go through three (3) or four (4) cycles while a treated net may go through five (5) or six (6) cycles before being replaced.
5. Increase the life expectancy of the nets a. The life cycle of an aquaculture fish farm is carefully monitored and well documented.
It is well known that the on-site and ofd site cleaning processes, the treatment process and handling all impact the life of a typical aquaculture fish farm pen net.
b. The use of this invention, to use electrolysis as an antifouling system, will reduce the number of times that the aquaculture fish farm nets will require cleaning, although they will still require some mending and other forms of maintenance. The focus is to increase the cycle of eighteen months or increase the number of cycles. There are a number of factors that will ai~ect this eighteen (18) month cycle, however the overall lifecycle is expected to increase when using the electrolysis antifouling system because there will be less impact from cleaning and handling.
6. Reduce the need for inspecting the marine substrate a. Currently video cameras are used to monitor the bottom substrate below aquaculture fish farms. The regulatory agencies require continual monitoring of the bottom substrate because of the potential build-up of debris released from net cleaning activities on-site. Although there are other sources (i.e. food pellets, fish waste) that rnay impact the bottom substrate most agencies believe that the primary source is from net cleaning activities on-site.
b. Although monitoring of the bottom substrate by way of video surveillance may never be eliminated, it is possible that this form of monitoring may be re-negotiated if the primary source of contamination was eliminated.
7. Keep nets from becoming too heavy and thereby reducing the potential for fish escape a. One of the associated problems of net fouling (with marine organisms) is the gradual submersion of the nets. As the weight (upwards of 3000kg) of the net increases, it is more difficult to keep top of the nets above water.
Provisional Patent January 16, 2004 Title: Method and Apparatus for C.'ontrolling, Removing, Preventing andior Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae l0 of 20 b. The accidental release of farm fish into the "wild" marine environment as a result of a sinking net is a serious problem. There is the immediate loss of revenue due to the loss of product and there is the loss of time and investment that went into raising the fish.
c. The loss of any farm fish from the aquaculture industry produces a significant public relations issue. The public relations issue surrounding accidental escapement has been one of the most controversial debates surrounding the aquaculture fish farms in the marine environment.
d. Any potential to reduce the escapement of farm fish to the wild is a progressive step forward in the aquaculture industry.
8. Low cost and environmentally friendly alternative a. In general the cost of doing business is increasing as a result of more stringent environmental regulations that often reflect the need to ensure that the impacts of the business do not alter or impact the environment.
b. There are many environmental issues to consider when operating an aquaculture fish farm. Most of these will significantly increase the cost of business.
c. This invention has the potential to significantly lower both the short term and long-term cost of operating an aquaculture fish farm and at the same time, reduce the impacts of the operation is having on the environment.
d. The initial electrode units cost approximately $750.00 (Canadian Funds) per unit and last, on average, two years. Thus a standard size aquaculture fish farm with 6 pens will require an estimated 34 units. This amounts to an estimated $12,750.00 (Canadian Funds) per year or $2,125.00 per pen net per year to protect. After two years the replacernent/upgrades units cost approximately $550.00 (Canadian Funds).
This reduces the annual cost (for the following two years) to $9,350.00 for the six-pen fish farm or $1,558.00 per pen net per year.
9. Create an environment that is less opportunistic for plankton to live and grow.
a. Some marine organisms such as parasitic copepods may not colonize the pen nets but live within the fish farm. There are numerous species of crustaceans that live on a host salmon for a period of their lifecycle. In particular, the sea louse Lepeophtheirus salmonis is known to be parasitic during the Chalimus I-IV stages of its life cycle.
Provisional Patent January 16, 2004 Tide: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaeulture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 11 or2o Under normal circumstances, the parasite and host can coexist. Under the opportunistic conditions of a fish farm, where fish are kept in close proximity to each other, sea lice numbers can increase rapidly as a result of the high density of available hosts.
b. During the larval stages or the Nauplius I & II stages of their lifecycle, the sea lice Lepeophtheirus salmonis are free living, non-feeding and positive phototactic.
At this early stage of development the Lepeophtheirus salmonis are free-living plankton.
Their typical migration is towards the surface light during the day and in deeper water at night.
c. The creation of a copper ion plume within the pen net will create an environment less suitable for plankton to live and grow.
d. At temperatures ranging from 5°C to 15°C the nauplii I stage is typically 9 - 52 hours and the nauplii II stage is 17 - 35 hours. It is during this short time of its lifecycle that the environmental conditions must be unsuitable for the development or migration of the Lepeophtheirus salmonis. These conditions will result in the free-living plankton moving away from the copper ion plume and away from the fish farm pen nets.
OTHER INDUSTRIAL USES
In Canada, the provincial (British Columbia) Crown Corporation (BC Ferry Services) for the coastal fernes uses their own unique electrolysis system to create a copper ion plume that protects the vessels and docks from marine growth. These electrolysis units are suspended over the bottom substrate at each docking berth. The voltage is significantly higher than what is considered optimal for aquaculture fish farms. The protection of the docking berth ensures that the vessels do not become fouled with marine organisms. The benefits include:
(a) Vessels do not slow down as a result of excess drag caused by marine growth.
(b) Minimize the long-term maintenance and antifouling paint required.
Just about every marine vessel has some form of electrolysis protection within their cooling water intake. A very high voltage is required to ensure that the ionic copper concentrations are sufficient to prevent marine growth from accumulating within the water intake pipes and tank.
Provisional Fatent January 16, 2004 Title: Method and Apparatus for (,'ontrolling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling orAquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 13 of 20 How this Invention Works:
Brief Overview of Apparatus:
This invention is based on the principles of electrolysis. We know that we can create copper ions by using a copper anode and a stainless steel cathode (see diagram). By operating the electrolysis continually, we create a plume that is detected approximately 6m to lOm from the electrodes. The copper ions form a concentration plume that can be detected with a conductivity meter.
Electrolysis begins when the electrodes are submerged in seawater (marine environment) and connected to a DC electrical power source. The voltage of the DC electrical power source may vary, however we found that using 2.2Volt at 160mAmp produced an 8m radius plume with a copper ion concentration of less than 0.01 ppm. The variables for creating the copper ion plume included: voltage, electrical current, water temperature, salinity, the size of the electrodes and the water quality criteria for ionic copper.
Detailed Overview: Description of Invention and How to Use I~
1. Objective: Creating a copper ion plume a. The primary objective of this invention is to create a copper ion plume in and around the aquaculture fish farm pen net that will protect it from the fouling of marine organisms and/or marine growth. The method and apparatus for controlling, removing and inhibiting marine growth on aquaculture fish farm nets is accomplished by: submerging a series of electrodes copper, aluminum and stainless steel around the aquaculture fish farm; applying a l.2Volts to 7.SVolts with a current that may range from 70mAmps to S.SAmps;
b. Because this is a DC power source the negative pole on the DC power source (battery) must be connected to the anode and the positive pole must be connected to the cathode to creating an electrical circuit that will create a copper ion plume in and around the aquaculture fish net pens. The ionic plume typically creates a detectable plume of up to 16m (diameter) around each electrode unit. Under ideal conditions, the plume would be in the shape of a sphere.
Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing ana'r'or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae Page 14 of 20 c. Electrolysis is an electrochemical process by which electrical energy is used to promote chemical reactions that occur on the surface of functionally cooperating electrodes. One electrode, called the anode, involves the oxidation process where chemical species lose electrons. A second electrode, called the cathode, involves the reduction process where electrons are gained. The process of creating a copper ionic plume can be accomplished in so many difrerent ways that to try and patent the electrolysis unit would be ineffective. There are however some general parameters that are unique to this patent that need to be addressed.
d. Parameters that are unique and are addressed, include:
i. The size of the copper ion plume or the concentration of copper ions that are detected in a three-dimensional radius around the electrode unit. This copper concentration is dependent on a voltage, electrical current and the size of the electrodes. It is also dependent on environmental conditions including water temperature, salinity and water current (tidal).
ii. An available and dependable DC electrical power source is required to maintain electrolysis and therefore a constant source of copper ions;
iii. A constant voltage output that the farm fish will become adapted to. Too much fluctuation in voltage will typically stress farm fish;
iv. The allowable concentration of copper ions within the marine environment.
e. The size and concentration of the copper ion plume must be large enough to protect the entire perimeter of the pen net, not just one section. The copper ion plume must be an ongoing process to continually protect the pen nets.
i. An estimated eight (8) standard electrode units (as described in this patent) would be required to protect a typical aquaculture fish farm pen net. This area being approximately 31. Sm by 31. Sm to a depth of l Om.
ii. Each of the electrodes will require 2.2 volts at 160mAmps. The copper ion concentration will create a plume size that may ranges from 12m to ZOm depending on the variable and the electrolysis unit.
iii. Other variable that will be considered when developing a protection strategy for a particular aquaculture fish farm will be tidal influences, salinity and number of fish pens.
Provisional Patent January 16, 2004 Title: Method and Apparatus,for (.'ontrolling, Removing, Preventing and/or Inhihiting the Accumulation, Colonizing or Otherwise Fouling ojAquaeulture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 15 01'20 iv. In addition to protecting the pen net perimeter, one (possibly two) electrode units) positioned in the centre of the pen net will assist in creating the environmental conditions that are unsuitable for the development or migration of the Lepeophtheirus salmonis at the larval or planktonic stage of its lifecycle.
f. The concentration of copper ions within the plume should be less than (<) O.lppm.
The concentrations for a typical electrode is less than (<) O.Olppm for total copper in marine (salt) water, this is less than the analytical (laboratory) detection limit.
g. The impact from the electrolysis circuit is negligible. At a constant 2.2 volt and 160mAmps there is not enough electrical impact to stress the fish.
2. Copper Source: Electrodes a. As discussed, the electrolysis unit could be made in several ways and still work.
The electrolysis unit, as described below is therefore only one of numerous ways to create copper ions.
b. The copper and aluminum electrodes are standard 32 mm (1 '/4 inch) diameter rods.
i. Each rod measures 648mm (25 '/2 inches) in length and is fitted into a sleeve of non-conductive material such as PVC or Nylon.
ii. The electrodes are connected with an 18-gauge waterproof power cable.
This is accomplished by drilling the electrodes at the ends and securing the copper wire with glue (or equivalent cement) such as SikaFlex~.
c. The stainless steel electrode, which functions as the cathode measures 25 mm ( 1 inch) in diameter. The stainless steel cathode ring is made of tubular 316-stainless alloy. The stainless tube is bent, full circle, so that it has a diameter of 685 mm (27 inches). The stainless steel tubing has four holes in it for the nylon fitting to slide into and for the wire (connected to the electrode) to go through.
d. Assembly of electrode is complete by fitting the copper and aluminum electrodes ends (tapered nylon fittings) into the stainless steel tubing. The stainless steel ends are secured with sleeve fitting. The wires from the electrodes and a wire secured to the stainless steel are tied together and extend to the surface (see diagram). It is important to note the copper, aluminum and stainless steel all be insulated from each other.
Provisional Patent January 16, 2004 Title: Method and Apparatus for C.'ontrolling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 16 of 20 e. The copper rod acts as the antifouling for the pen net, the aluminum rod acts as a corrosion protection.
f. The typical life expectancy of each electrode is dependent on the voltage, electrical current, and the size of the electrodes, the water temperature and the salinity.
Using the above mentioned electrode unit at 2.2Volts, 160mAmps in typical marine waters, the life expectancy is around 2 years.
g. The replacement of the electrodes can be done on-site and should be in timely fashion to continue the antifouling process.
3. Power Source: Voltage and Electrical Current a. As discussed, the voltage, and electrical current could change within a given range and the electrolysis system would still work. This patent is specifically for the application of using electrolysis to create copper ions (that will form an ionic plume), which in-turn will protect the aquaculture fish farm pen nets from the continual growth (fouling) caused by marine organisms. It will also create an environment that is unsuitable for the development and migration of other organisms such as the Lepeophtheirus salmonis during its free-living plankton lifecycle stage.
b. The available DC electrical power source at any given aquaculture fish farm will vary. Typically the aquaculture fish farms do not have a reliable or consistent source of continuous DC electrical power. Because the power supply is critical for electrolysis to occur, and the power requirements are so small, the power supply will likely be from a battery source. Although it could be from a number of other sources such as a power generator, a DC electrical power source, such as a battery, will be a more reliable source of consistent voltage and current.
c. The means by which a battery is recharged may also vary and may include a diesel power generator with an alternator, solar panels or other reliable charging mechanism.
d. As discussed, the DC electrical power source may range from l.2Volts to 7.5Volts and the electrical current may range from 70mAmps to 5.5Amps. Although this patent sets a range of voltage that is considered optimal, electrolysis will occur at higher voltages.
Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling ofAquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 17 of 20 e. Aquaculture fish farms that have reliable source of shore power (110Vo1t) can simply plug the electrode directly into a 1 lOVolt power supply. These units must be fitted with a 1 lOVolt input and 2.2Volt output converter (see diagram:
Power Supply Box).
f. The optimum voltage will range from l.BVolts to 2.6Volts while the electrical current will range from 90mAmps to 210mAmps. The voltage used on the electrodes will have specific consequences.
i. The higher the voltage/current: the less number of electrodes required.
(a) However, the higher voltage/current, the greater the copper ion concentration. The copper concentration must remain below 0.1 ppm.
(b) To create a higher voltage, the more DC electrical power supply (more batteries) required and therefore the more solar panels or charging times.
(c) More significantly, the greater the voltage/current, the more likely that electrical current will impact (stress) the farm fish.
ii. The lower the voltage, the lower the copper ionic concentration and therefore the more electrode units that will be required to protect the aquaculture fish farm pen nets.
g. The optimal voltage range that is expected to be most efficient for battery power supply, low or negligible impact on electrical current in water, and for the least number of electrodes required to create and effective copper ion plume will range from l.8volts to 2.6 volts. The optimal voltage for a single electrode unit should be around 2.2volts, with the electrical current around 160mAmps.
h. One of the main impacts of constantly cycling a battery is the life expectancy. A
battery is expected to be replaced every 2 years.
4. Electrolyte Solution: Seawater a. Electrolysis requires an electrolyte to create the electrical circuit. The electrolyte will allow the electrons to flow from the anode to the cathode at relatively low voltage. If the water is too brackish or the surface striation is almost all fresh-water, the electrolysis will not function as intended.
Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling ofAquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 78 of20 b. The salinity of seawater is typically around 28 parts per thousand. The salinity at this concentration is optimal. Electrolysis will function as intended and the copper ion concentration will create a 16m-diameter plume.
c. There is no set range for salinity, however it should be noted that if the salinity is less than (<) 20ppt the aqueous environment is not optimal for the electrolysis.
d. The temperature of the seawater is another variable affecting electrolysis and therefore the size of the copper ion plume. As the seawater temperature increases (during spring and summer), the plume size will increase (given the same salinity).
e. There is no intention of limiting the application of this invention, therefore marine environment may include all tidal and non-tidal areas including marine estuaries, inlets, fjords, etc. where the salinity is high enough for the electrolysis to work.
5. Application: Effects on marine organisms a. Phytoplankton along the west coast of Canada are unicellular algae that burst into productivity around the end of February and early March. This is primarily due to the calmer spring weather, more sunlight and most importantly when the nutrient rich surface water from the winter runoff starts to stratify the water creating layers of warm, nutrient rich surface water and the colder water below. This is a perfect environment for plankton. By March, a single plankton is able to divide itself every 24 hours creating exponential growth. At this rate it may only take about 20 days to reproduce itself a million times. Within a month or two the coastal waters are typically saturated with plankton, such as diatoms. The diatom concentrations peak in March in some protected waters, April within the straights and outer islands and May along the outer west coast of Canada.
b. By summer, the nitrate levels begin to drop and the zooplankton take over (they also eat the phytoplankton/ diatoms). By now another group of phytoplankton known as the flagellates begin to dominate the brackish waters. These however have mobility and use it to their advantage. They can move approximately Sm up and down, so that during the daytime they migrate up for sun and nutrients and at night they go down to hide. The dinoflagellates grow best in warm, strongly stratified waters of summer. The exponential growth of these algae may lead to algae blooms. The species known as Alexandrium causes paralytic shellfish Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaeulture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 19 of 20 poisoning. The species known as Heterosigma is known to have such high densities that they become toxic to inshore fish and to fish constrained in aquaculture fish farm net pens.
c. The copper ions can eliminate and control algae, for example, by inhibiting photosynthesis d. The controlled release of copper ions is a more effective inhibitor to marine growth than the latex based chemical biocide paint used to impregnate nets. Chemical biocides have been known to be toxic to the marine environment, expensive and requiring continual reapplication. Washing and cleaning nets that have been treated with a chemical biocide will create a toxic waste discharge. As a result, the nets must be washed and cleaned at an off site approved facility.
e. The aquaculture industry has stated that over the next ten (10) years it would like to improve its environmental practices and eliminate the use of copper treated nets.
f The advantage of using copper ions is that, even at very low concentrations, they are more effective in preventing marine growth, than copper treated nets.
g. Copper ions are not harmful to farm fish and do not create a residual that is considered a waste product. There is a significant cost savings to the fish farm industry and a progressive move towards more environmentally conscious practices.
h. In order to protect the aquaculture fish farm pen nets there are an optimum number of electrode units that need to be placed around the pen net. For a standard (3l.Sm by 3l.Sm) size net the optimum number of electrodes is approximately eight (8) with an additional one (or two) in the centre if copepods (sea lice) are a problem.
i. The recommended spacing should be 8m from each pen net corner. The number of electrode units may vary with the water salinity, the water current and number of pen nets. The electrodes will typically produce a copper ion plume of 8m in radius or 16m in diameter. To ensure the pen net is adequately protected the plume of each electrode must overlap. To ensure this, the electrodes should be spaced around the perimeter of the pen so that the maximum distance is not more than 16m.
Provisional Patent January lfi, 2004 Title: Method and Apparatus for Controlling, Removing, Preveming and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling ofAquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 20 of 20 j. The depth at which the electrode hangs should be 2m. The marine growth decreases with depth. The limiting factor is light. The typical depth at which photosynthesis occurs is l Om. The growth of most marine organisms on pen nets will be from the surface to a depth of lOm. To ensure full protection, additional electrodes could be hung at lower depths.
k. The toxicity of copper to aquatic organisms is well established although the exact mechanism is not well defined. In general, the copper must be in an ionic form to be most effective in controlling, removing and inhibiting marine growth (fouling) on aquaculture fish pen nets. The mechanism is, believed to be, attributed to the positively charged ions that attach to the negatively charged cell wall of the microorganism and destroy cell wall permeability.
1. To continually protect the aquaculture fish farm pen nets the ionic plume must be continuous to minimize the possibility of re-colonization of the marine organisms.
m. In addition to protecting the pen nets from marine growth (fouling), one (or two) electrode units) positioned in the centre of the pen net will assist in creating the environmental conditions that are unsuitable for the growth/development or migration of the Lepeophtheirus salmonis at the larval or planktonic stage of its lifecycle n. In summary the advantage of using copper ionization compared to copper impregnated nets is the relatively low cost, straightforward installation, easy maintenance, and the presence of residual antifouling throughout the aquaculture fish farm pens.
~~Wloa~D ~VL ~~o~I.~Ne~
Prior to describing the application and benefits of this invention, the background of the industry and the challenges of the industry must be explained. As the problem is described, the benefits and usefulness of the invention will become prevalent.
The aquaculture fish farm industry uses nets that are typically made of nylon.
These nets form large open "bags" in which fish are kept secure for a period of approximately eighteen months.
During this period of time, the fish "grow-out" to maturity. The fish are not allowed to escape and must be monitored on a continual basis. The fish have specific feeding times and the environment in which they live is carefully monitored. The purpose of using nets as opposed to sealed bags is to provide a continual supply of oxygen rich water to the fish and to allow waste products to continually flush from the pen nets. The farm nets are formed into pens that typically measure 3l.Sm in length and 3l.Sm in width and are typically 20m deep. These are approximate dimensions and are used to illustrate a typical fish farm.
As the pen nets become fouled with marine growth, the water supply is restricted. This essentially limits the oxygen supply to the fish and prevents the waste from leaving the pen nets.
The result of pen net fouling is an increase in farm fish stress levels. This results is poor production levels, increased mortality and disease. Aquaculture fish farms that treat their nets with a chemical biocide (antifouling) must do so on a continual basis to keep the nets clean. This is both expensive and toxic to the environment.
This invention is unique in that it specifically addresses the issue of ongoing accumulation, colonization or otherwise fouling of aquaculture fish farm pen nets with marine organisms, plankton and algae. Marine organisms including (but not limited to) algae, mussels, oysters and barnacles typically attach (colonize) to aquaculture fish farm pen nets. Over the typical lifecycle of eighteen (18) months these marine organisms will accumulate and "foul" the nets, thus restricting the oxygen rich water flow to the fish and preventing waste products to flush out of the pen nets.
Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and.'or Inhibiting the Accumulation, Colonizing or Otherwise Fouling ofAquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae of 20 Although this invention specifically addresses the issue of marine growth on the pen nets, there are other beneficial erects that result from the copper ion plume that must be mentioned. The copper ionic plume that is created around the fish farm pen nets will create environmental conditions that are less opportunistic for other plankton. Specifically, the copper ion plume will disrupt the sea louse Lepeophtheirus salmonis at the early free living planktonic naupliar stage of its lifecycle. Although this invention does not claim that it will eliminate sea lice, it does claim to have an impact on the early stages of the sea lice lifecycle that will reduce the opportunistic environment for the sea lice to develop to the copepodid stage within the fish farm pen nets.
This invention is used to create a low concentration of copper ions in and around the vicinity of the aquaculture fish farm pen nets. The copper ions are an effective in controlling, removing (but not cleaning), preventing and inhibiting the accumulation, growth and/or attachment (colonization) of marine organisms on the aquaculture fish farm pen nets.
There are a number of benefits to this invention. The primary objective is to assist the aquaculture fish farm industry in the following ways:
1. Keep the pen nets clean of marine fouling using copper ions 2. Reduce the need for treating nets 3. Maintain maximum water flow through the nets (over time) for better oxygenation and therefore reduced stress on the farm fish 4. Reduce the need for cleaning the nets 5. Increase the life expectancy of the nets 6. Reduce the need for inspecting the marine substrate 7. Low cost alternative 8. Keep nets from becoming too heavy and thereby reducing the potential for fish escape 9. Create an environment that is less opportunistic for plankton to live and grow.
1. The application of this invention will keep the aquaculture fish farm pen nets clean of marine fouling a. It is not the intention of the patent to guarantee that this method and application will forever keep an aquaculture fish net from being fouled by marine organisms, however Provisional Patent January 16, 2004 Title: Method and Apparatus for (:onirolling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 6 orao there will be a significant reduction or elimination of marine organisms in areas where the functioning electrodes are placed. The limiting factor is the number of units deposited per fish pen net. There will always be a minimum number of electrodes required to adequately protect a fish farm. Most of these electrodes will be at a constant depth of 2m but there may be conditions where additional electrodes will be required at different depths. Electrodes have a limited life expectancy of two years and must be upgraded or the electrodes will not work.
b. The number of electrodes to adequately protect a single pen net measuring 3l.Sm by 31. Sm by l Om deep will depend on the size of the electrode, the voltage used in creating the electrolysis, the electrical current (amperage) of the DC power source, the tidal fluctuation, temperature and salinity of the marine water.
c. Under normal conditions the number of electrodes units required per pen net is eight (8). The same electrode units will impact adjacent nets and therefore the number of electrode units will decrease where nets multiple pen nets are used.
d. The cost savings is estimated to be significant.
2. Reduce the need for treating nets a. The length and width of a typical aquaculture fish farm net is 31. Sm square. The depth of these nets (pens) is typically 20m. Each net or fish pen is custom made so the size and dimensions may range from site to site. Factors that may influence the net size and dimensions may include (but are not limited to) the physical location of the fish farm, the depth of water, the current, the number of fish and fish species per pen.
b. The depth at which fouling typically occurs is within the top lOm from the surface.
Photosynthesis typically occurs within this range and as a result the primary growth of marine organisms on the nets occurs within this depth.
c. Nets are not always treated. There are areas where brackish water flow and growth or fouling is minimal. In these locations the nets are monitored and cleaned by hauling the nets up on to the floats and washed with a high-pressure water unit. This is however very labor intensive and has been reported to be one of the factors in employee back related injuries.
d. The treated nets are typically dipped in a latex based (or equivalent) paint to which a chemical biocide (antifouling) has been added. These biocides, however, gradually are Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling ofAquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae Page 7 of 20 released into the water and are very harmful for the water fauna and flora.
These biocides may also have an erect on the health of the farm fish. Nets that are treated have a limited lifecycle before they must be cleaned and retreated. This is both cumbersome, labor intensive and is relatively expensive. In addition, the entire fish net is treated as opposed to just the area of the net that is constantly fouled.
e. Some aquaculture fish farms will choose not to treat the nets. This may be a cost saving or environmental reasons. The result of not treating is that marine organisms will eventually colonize the nets. The nets become very heavy and may sink. As the nets become fouled with marine growth, the water flow through the nets decreases and the farm fish become more stressed due to a lack of available oxygen. In addition there is a higher potential for the fish net to sink, resulting in a loss of farm fish to the environment.
f. If the growth (over an eighteen month period) of marine organisms on one square meter of net is equal to 2.Skg, then a net measuring 3l.Sm square by lOm deep will weigh as much as 3000kg. At a fish farm with 12 pen nets this may equate to 36,OOOkg of waste. If the net is cleaned on site, all of the waste will end up in the marine environment, mostly under the fish farm.
3. Maintain maximum water flow through the nets (over time) for better oxygenation and therefore reduced stress on the farm fish a. Over a typical eighteen (18) month cycle, an aquaculture fish farm net will be exposed to a constant attack of marine organisms. There are certain periods of time when the lifecycle of mussels and other marine organisms will want to attach or colonize onto the nets. At the same time there is the continuous attack of algae.
b. Nets that are not treated are much more susceptible to the fouling by marine organisms. When these marine organisms attach, they gradually fill the mesh holes of the nets. This in turn reduces the amount of water flow through the nets.
c. As the water flow through the nets is restricted, so is the availability of oxygen to the fish. The more water that passes through the nets, the more oxygen the fish are exposed to. The water within the fish pen needs to be flushed as much as possible for more than just oxygen. Oxygen availability is believed to be one of the primary factors relating the fish to stress. The more oxygen, the less stress on the fish.
Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae Page 8 of ZO
4. Reduce the need for cleaning the nets a. Aquaculture fish farm nets that are not treated may last 6 weeks before signs of marine growth are evident. This of course is dependent on a number of factors of which the predominant one is location. Some aquaculture fish farms have reported a three to four month period where fouling of marine organisms were minimal. This would likely be during the mid winter months.
b Aquaculture fish farm nets that have been treated may be free of marine growth for a period of eight to eighteen months. This is dependent on the treatment method such as latex or wax based, environmental conditions such as location and seasonal conditions such as winter vs. summer months.
c. The cleaning methods vary from fish farm but there are some standard methods worth mentioning.
i. Some aquaculture fish farms will not clean their nets. The nets are basically allowed to foul with marine organisms until they are no longer useful. The fish are eventually removed and the net is allowed to sink the bottom. These nets undergo a "composting" period. This leaves a lot of debris on the bottom of the marine environment and has the potential to build-up over time. Not all environments are suitable for this type of "cleansing" and will require pre-approval.
ii. Some aquaculture fish farms will "tramp" the nets. This involves pulling the nets above the water and suspending the net above the water. The marine organisms die and are pressure washed oil The debris that is washed oi~the net will eventually sink to the bottom of the marine environment.
iii. Some aquaculture fish farms will pressure wash the nets in-situ. This involves a diver, pressure washing equipment and support staff. The marine environment is clouded by the debris and also ends up sinking to the bottom of the marine environment.
iv. Some aquaculture fish farms will manually haul a section of the net up onto the float and pressure-wash the net. This is very labor-intensive work and has been linked to back injuries: The advantage of pressure washing the nets on Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae Page 9 of 20 the floats is that no divers axe required. The wash water and waste debris from the nets are released into the marine environment.
d. At the end of the eighteen ( 18) month cycle, the aquaculture fish pens (nets) are typically shipped from the site far washing, repairs and optional treatment. A
typical net that is untreated may go through three (3) or four (4) cycles while a treated net may go through five (5) or six (6) cycles before being replaced.
5. Increase the life expectancy of the nets a. The life cycle of an aquaculture fish farm is carefully monitored and well documented.
It is well known that the on-site and ofd site cleaning processes, the treatment process and handling all impact the life of a typical aquaculture fish farm pen net.
b. The use of this invention, to use electrolysis as an antifouling system, will reduce the number of times that the aquaculture fish farm nets will require cleaning, although they will still require some mending and other forms of maintenance. The focus is to increase the cycle of eighteen months or increase the number of cycles. There are a number of factors that will ai~ect this eighteen (18) month cycle, however the overall lifecycle is expected to increase when using the electrolysis antifouling system because there will be less impact from cleaning and handling.
6. Reduce the need for inspecting the marine substrate a. Currently video cameras are used to monitor the bottom substrate below aquaculture fish farms. The regulatory agencies require continual monitoring of the bottom substrate because of the potential build-up of debris released from net cleaning activities on-site. Although there are other sources (i.e. food pellets, fish waste) that rnay impact the bottom substrate most agencies believe that the primary source is from net cleaning activities on-site.
b. Although monitoring of the bottom substrate by way of video surveillance may never be eliminated, it is possible that this form of monitoring may be re-negotiated if the primary source of contamination was eliminated.
7. Keep nets from becoming too heavy and thereby reducing the potential for fish escape a. One of the associated problems of net fouling (with marine organisms) is the gradual submersion of the nets. As the weight (upwards of 3000kg) of the net increases, it is more difficult to keep top of the nets above water.
Provisional Patent January 16, 2004 Title: Method and Apparatus for C.'ontrolling, Removing, Preventing andior Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae l0 of 20 b. The accidental release of farm fish into the "wild" marine environment as a result of a sinking net is a serious problem. There is the immediate loss of revenue due to the loss of product and there is the loss of time and investment that went into raising the fish.
c. The loss of any farm fish from the aquaculture industry produces a significant public relations issue. The public relations issue surrounding accidental escapement has been one of the most controversial debates surrounding the aquaculture fish farms in the marine environment.
d. Any potential to reduce the escapement of farm fish to the wild is a progressive step forward in the aquaculture industry.
8. Low cost and environmentally friendly alternative a. In general the cost of doing business is increasing as a result of more stringent environmental regulations that often reflect the need to ensure that the impacts of the business do not alter or impact the environment.
b. There are many environmental issues to consider when operating an aquaculture fish farm. Most of these will significantly increase the cost of business.
c. This invention has the potential to significantly lower both the short term and long-term cost of operating an aquaculture fish farm and at the same time, reduce the impacts of the operation is having on the environment.
d. The initial electrode units cost approximately $750.00 (Canadian Funds) per unit and last, on average, two years. Thus a standard size aquaculture fish farm with 6 pens will require an estimated 34 units. This amounts to an estimated $12,750.00 (Canadian Funds) per year or $2,125.00 per pen net per year to protect. After two years the replacernent/upgrades units cost approximately $550.00 (Canadian Funds).
This reduces the annual cost (for the following two years) to $9,350.00 for the six-pen fish farm or $1,558.00 per pen net per year.
9. Create an environment that is less opportunistic for plankton to live and grow.
a. Some marine organisms such as parasitic copepods may not colonize the pen nets but live within the fish farm. There are numerous species of crustaceans that live on a host salmon for a period of their lifecycle. In particular, the sea louse Lepeophtheirus salmonis is known to be parasitic during the Chalimus I-IV stages of its life cycle.
Provisional Patent January 16, 2004 Tide: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaeulture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 11 or2o Under normal circumstances, the parasite and host can coexist. Under the opportunistic conditions of a fish farm, where fish are kept in close proximity to each other, sea lice numbers can increase rapidly as a result of the high density of available hosts.
b. During the larval stages or the Nauplius I & II stages of their lifecycle, the sea lice Lepeophtheirus salmonis are free living, non-feeding and positive phototactic.
At this early stage of development the Lepeophtheirus salmonis are free-living plankton.
Their typical migration is towards the surface light during the day and in deeper water at night.
c. The creation of a copper ion plume within the pen net will create an environment less suitable for plankton to live and grow.
d. At temperatures ranging from 5°C to 15°C the nauplii I stage is typically 9 - 52 hours and the nauplii II stage is 17 - 35 hours. It is during this short time of its lifecycle that the environmental conditions must be unsuitable for the development or migration of the Lepeophtheirus salmonis. These conditions will result in the free-living plankton moving away from the copper ion plume and away from the fish farm pen nets.
OTHER INDUSTRIAL USES
In Canada, the provincial (British Columbia) Crown Corporation (BC Ferry Services) for the coastal fernes uses their own unique electrolysis system to create a copper ion plume that protects the vessels and docks from marine growth. These electrolysis units are suspended over the bottom substrate at each docking berth. The voltage is significantly higher than what is considered optimal for aquaculture fish farms. The protection of the docking berth ensures that the vessels do not become fouled with marine organisms. The benefits include:
(a) Vessels do not slow down as a result of excess drag caused by marine growth.
(b) Minimize the long-term maintenance and antifouling paint required.
Just about every marine vessel has some form of electrolysis protection within their cooling water intake. A very high voltage is required to ensure that the ionic copper concentrations are sufficient to prevent marine growth from accumulating within the water intake pipes and tank.
Provisional Fatent January 16, 2004 Title: Method and Apparatus for (,'ontrolling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling orAquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 13 of 20 How this Invention Works:
Brief Overview of Apparatus:
This invention is based on the principles of electrolysis. We know that we can create copper ions by using a copper anode and a stainless steel cathode (see diagram). By operating the electrolysis continually, we create a plume that is detected approximately 6m to lOm from the electrodes. The copper ions form a concentration plume that can be detected with a conductivity meter.
Electrolysis begins when the electrodes are submerged in seawater (marine environment) and connected to a DC electrical power source. The voltage of the DC electrical power source may vary, however we found that using 2.2Volt at 160mAmp produced an 8m radius plume with a copper ion concentration of less than 0.01 ppm. The variables for creating the copper ion plume included: voltage, electrical current, water temperature, salinity, the size of the electrodes and the water quality criteria for ionic copper.
Detailed Overview: Description of Invention and How to Use I~
1. Objective: Creating a copper ion plume a. The primary objective of this invention is to create a copper ion plume in and around the aquaculture fish farm pen net that will protect it from the fouling of marine organisms and/or marine growth. The method and apparatus for controlling, removing and inhibiting marine growth on aquaculture fish farm nets is accomplished by: submerging a series of electrodes copper, aluminum and stainless steel around the aquaculture fish farm; applying a l.2Volts to 7.SVolts with a current that may range from 70mAmps to S.SAmps;
b. Because this is a DC power source the negative pole on the DC power source (battery) must be connected to the anode and the positive pole must be connected to the cathode to creating an electrical circuit that will create a copper ion plume in and around the aquaculture fish net pens. The ionic plume typically creates a detectable plume of up to 16m (diameter) around each electrode unit. Under ideal conditions, the plume would be in the shape of a sphere.
Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing ana'r'or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae Page 14 of 20 c. Electrolysis is an electrochemical process by which electrical energy is used to promote chemical reactions that occur on the surface of functionally cooperating electrodes. One electrode, called the anode, involves the oxidation process where chemical species lose electrons. A second electrode, called the cathode, involves the reduction process where electrons are gained. The process of creating a copper ionic plume can be accomplished in so many difrerent ways that to try and patent the electrolysis unit would be ineffective. There are however some general parameters that are unique to this patent that need to be addressed.
d. Parameters that are unique and are addressed, include:
i. The size of the copper ion plume or the concentration of copper ions that are detected in a three-dimensional radius around the electrode unit. This copper concentration is dependent on a voltage, electrical current and the size of the electrodes. It is also dependent on environmental conditions including water temperature, salinity and water current (tidal).
ii. An available and dependable DC electrical power source is required to maintain electrolysis and therefore a constant source of copper ions;
iii. A constant voltage output that the farm fish will become adapted to. Too much fluctuation in voltage will typically stress farm fish;
iv. The allowable concentration of copper ions within the marine environment.
e. The size and concentration of the copper ion plume must be large enough to protect the entire perimeter of the pen net, not just one section. The copper ion plume must be an ongoing process to continually protect the pen nets.
i. An estimated eight (8) standard electrode units (as described in this patent) would be required to protect a typical aquaculture fish farm pen net. This area being approximately 31. Sm by 31. Sm to a depth of l Om.
ii. Each of the electrodes will require 2.2 volts at 160mAmps. The copper ion concentration will create a plume size that may ranges from 12m to ZOm depending on the variable and the electrolysis unit.
iii. Other variable that will be considered when developing a protection strategy for a particular aquaculture fish farm will be tidal influences, salinity and number of fish pens.
Provisional Patent January 16, 2004 Title: Method and Apparatus,for (.'ontrolling, Removing, Preventing and/or Inhihiting the Accumulation, Colonizing or Otherwise Fouling ojAquaeulture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 15 01'20 iv. In addition to protecting the pen net perimeter, one (possibly two) electrode units) positioned in the centre of the pen net will assist in creating the environmental conditions that are unsuitable for the development or migration of the Lepeophtheirus salmonis at the larval or planktonic stage of its lifecycle.
f. The concentration of copper ions within the plume should be less than (<) O.lppm.
The concentrations for a typical electrode is less than (<) O.Olppm for total copper in marine (salt) water, this is less than the analytical (laboratory) detection limit.
g. The impact from the electrolysis circuit is negligible. At a constant 2.2 volt and 160mAmps there is not enough electrical impact to stress the fish.
2. Copper Source: Electrodes a. As discussed, the electrolysis unit could be made in several ways and still work.
The electrolysis unit, as described below is therefore only one of numerous ways to create copper ions.
b. The copper and aluminum electrodes are standard 32 mm (1 '/4 inch) diameter rods.
i. Each rod measures 648mm (25 '/2 inches) in length and is fitted into a sleeve of non-conductive material such as PVC or Nylon.
ii. The electrodes are connected with an 18-gauge waterproof power cable.
This is accomplished by drilling the electrodes at the ends and securing the copper wire with glue (or equivalent cement) such as SikaFlex~.
c. The stainless steel electrode, which functions as the cathode measures 25 mm ( 1 inch) in diameter. The stainless steel cathode ring is made of tubular 316-stainless alloy. The stainless tube is bent, full circle, so that it has a diameter of 685 mm (27 inches). The stainless steel tubing has four holes in it for the nylon fitting to slide into and for the wire (connected to the electrode) to go through.
d. Assembly of electrode is complete by fitting the copper and aluminum electrodes ends (tapered nylon fittings) into the stainless steel tubing. The stainless steel ends are secured with sleeve fitting. The wires from the electrodes and a wire secured to the stainless steel are tied together and extend to the surface (see diagram). It is important to note the copper, aluminum and stainless steel all be insulated from each other.
Provisional Patent January 16, 2004 Title: Method and Apparatus for C.'ontrolling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 16 of 20 e. The copper rod acts as the antifouling for the pen net, the aluminum rod acts as a corrosion protection.
f. The typical life expectancy of each electrode is dependent on the voltage, electrical current, and the size of the electrodes, the water temperature and the salinity.
Using the above mentioned electrode unit at 2.2Volts, 160mAmps in typical marine waters, the life expectancy is around 2 years.
g. The replacement of the electrodes can be done on-site and should be in timely fashion to continue the antifouling process.
3. Power Source: Voltage and Electrical Current a. As discussed, the voltage, and electrical current could change within a given range and the electrolysis system would still work. This patent is specifically for the application of using electrolysis to create copper ions (that will form an ionic plume), which in-turn will protect the aquaculture fish farm pen nets from the continual growth (fouling) caused by marine organisms. It will also create an environment that is unsuitable for the development and migration of other organisms such as the Lepeophtheirus salmonis during its free-living plankton lifecycle stage.
b. The available DC electrical power source at any given aquaculture fish farm will vary. Typically the aquaculture fish farms do not have a reliable or consistent source of continuous DC electrical power. Because the power supply is critical for electrolysis to occur, and the power requirements are so small, the power supply will likely be from a battery source. Although it could be from a number of other sources such as a power generator, a DC electrical power source, such as a battery, will be a more reliable source of consistent voltage and current.
c. The means by which a battery is recharged may also vary and may include a diesel power generator with an alternator, solar panels or other reliable charging mechanism.
d. As discussed, the DC electrical power source may range from l.2Volts to 7.5Volts and the electrical current may range from 70mAmps to 5.5Amps. Although this patent sets a range of voltage that is considered optimal, electrolysis will occur at higher voltages.
Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling ofAquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 17 of 20 e. Aquaculture fish farms that have reliable source of shore power (110Vo1t) can simply plug the electrode directly into a 1 lOVolt power supply. These units must be fitted with a 1 lOVolt input and 2.2Volt output converter (see diagram:
Power Supply Box).
f. The optimum voltage will range from l.BVolts to 2.6Volts while the electrical current will range from 90mAmps to 210mAmps. The voltage used on the electrodes will have specific consequences.
i. The higher the voltage/current: the less number of electrodes required.
(a) However, the higher voltage/current, the greater the copper ion concentration. The copper concentration must remain below 0.1 ppm.
(b) To create a higher voltage, the more DC electrical power supply (more batteries) required and therefore the more solar panels or charging times.
(c) More significantly, the greater the voltage/current, the more likely that electrical current will impact (stress) the farm fish.
ii. The lower the voltage, the lower the copper ionic concentration and therefore the more electrode units that will be required to protect the aquaculture fish farm pen nets.
g. The optimal voltage range that is expected to be most efficient for battery power supply, low or negligible impact on electrical current in water, and for the least number of electrodes required to create and effective copper ion plume will range from l.8volts to 2.6 volts. The optimal voltage for a single electrode unit should be around 2.2volts, with the electrical current around 160mAmps.
h. One of the main impacts of constantly cycling a battery is the life expectancy. A
battery is expected to be replaced every 2 years.
4. Electrolyte Solution: Seawater a. Electrolysis requires an electrolyte to create the electrical circuit. The electrolyte will allow the electrons to flow from the anode to the cathode at relatively low voltage. If the water is too brackish or the surface striation is almost all fresh-water, the electrolysis will not function as intended.
Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling ofAquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 78 of20 b. The salinity of seawater is typically around 28 parts per thousand. The salinity at this concentration is optimal. Electrolysis will function as intended and the copper ion concentration will create a 16m-diameter plume.
c. There is no set range for salinity, however it should be noted that if the salinity is less than (<) 20ppt the aqueous environment is not optimal for the electrolysis.
d. The temperature of the seawater is another variable affecting electrolysis and therefore the size of the copper ion plume. As the seawater temperature increases (during spring and summer), the plume size will increase (given the same salinity).
e. There is no intention of limiting the application of this invention, therefore marine environment may include all tidal and non-tidal areas including marine estuaries, inlets, fjords, etc. where the salinity is high enough for the electrolysis to work.
5. Application: Effects on marine organisms a. Phytoplankton along the west coast of Canada are unicellular algae that burst into productivity around the end of February and early March. This is primarily due to the calmer spring weather, more sunlight and most importantly when the nutrient rich surface water from the winter runoff starts to stratify the water creating layers of warm, nutrient rich surface water and the colder water below. This is a perfect environment for plankton. By March, a single plankton is able to divide itself every 24 hours creating exponential growth. At this rate it may only take about 20 days to reproduce itself a million times. Within a month or two the coastal waters are typically saturated with plankton, such as diatoms. The diatom concentrations peak in March in some protected waters, April within the straights and outer islands and May along the outer west coast of Canada.
b. By summer, the nitrate levels begin to drop and the zooplankton take over (they also eat the phytoplankton/ diatoms). By now another group of phytoplankton known as the flagellates begin to dominate the brackish waters. These however have mobility and use it to their advantage. They can move approximately Sm up and down, so that during the daytime they migrate up for sun and nutrients and at night they go down to hide. The dinoflagellates grow best in warm, strongly stratified waters of summer. The exponential growth of these algae may lead to algae blooms. The species known as Alexandrium causes paralytic shellfish Provisional Patent January 16, 2004 Title: Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaeulture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 19 of 20 poisoning. The species known as Heterosigma is known to have such high densities that they become toxic to inshore fish and to fish constrained in aquaculture fish farm net pens.
c. The copper ions can eliminate and control algae, for example, by inhibiting photosynthesis d. The controlled release of copper ions is a more effective inhibitor to marine growth than the latex based chemical biocide paint used to impregnate nets. Chemical biocides have been known to be toxic to the marine environment, expensive and requiring continual reapplication. Washing and cleaning nets that have been treated with a chemical biocide will create a toxic waste discharge. As a result, the nets must be washed and cleaned at an off site approved facility.
e. The aquaculture industry has stated that over the next ten (10) years it would like to improve its environmental practices and eliminate the use of copper treated nets.
f The advantage of using copper ions is that, even at very low concentrations, they are more effective in preventing marine growth, than copper treated nets.
g. Copper ions are not harmful to farm fish and do not create a residual that is considered a waste product. There is a significant cost savings to the fish farm industry and a progressive move towards more environmentally conscious practices.
h. In order to protect the aquaculture fish farm pen nets there are an optimum number of electrode units that need to be placed around the pen net. For a standard (3l.Sm by 3l.Sm) size net the optimum number of electrodes is approximately eight (8) with an additional one (or two) in the centre if copepods (sea lice) are a problem.
i. The recommended spacing should be 8m from each pen net corner. The number of electrode units may vary with the water salinity, the water current and number of pen nets. The electrodes will typically produce a copper ion plume of 8m in radius or 16m in diameter. To ensure the pen net is adequately protected the plume of each electrode must overlap. To ensure this, the electrodes should be spaced around the perimeter of the pen so that the maximum distance is not more than 16m.
Provisional Patent January lfi, 2004 Title: Method and Apparatus for Controlling, Removing, Preveming and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling ofAquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae 20 of 20 j. The depth at which the electrode hangs should be 2m. The marine growth decreases with depth. The limiting factor is light. The typical depth at which photosynthesis occurs is l Om. The growth of most marine organisms on pen nets will be from the surface to a depth of lOm. To ensure full protection, additional electrodes could be hung at lower depths.
k. The toxicity of copper to aquatic organisms is well established although the exact mechanism is not well defined. In general, the copper must be in an ionic form to be most effective in controlling, removing and inhibiting marine growth (fouling) on aquaculture fish pen nets. The mechanism is, believed to be, attributed to the positively charged ions that attach to the negatively charged cell wall of the microorganism and destroy cell wall permeability.
1. To continually protect the aquaculture fish farm pen nets the ionic plume must be continuous to minimize the possibility of re-colonization of the marine organisms.
m. In addition to protecting the pen nets from marine growth (fouling), one (or two) electrode units) positioned in the centre of the pen net will assist in creating the environmental conditions that are unsuitable for the growth/development or migration of the Lepeophtheirus salmonis at the larval or planktonic stage of its lifecycle n. In summary the advantage of using copper ionization compared to copper impregnated nets is the relatively low cost, straightforward installation, easy maintenance, and the presence of residual antifouling throughout the aquaculture fish farm pens.
~~Wloa~D ~VL ~~o~I.~Ne~
Claims
The claims that are made, include:
This invention will benefit the aquaculture fish farm industry by reducing or eliminating the marine growth of organisms such as algae, plankton, mussels and other marine organisms that typically adhere or colonize onto fish pen nets at marine (tidal or coastal) water aquaculture fish farms.
The instant benefits (of the claims) of this invention include (but are not limited) to:
.cndot. A significant reduction or elimination of the requirement to continually clean untreated pen nets. This invention will allow pen nets to remain in the water during the entire grow-out period without the need to continually remove the accumulated growth of marine organisms that colonize and re-colonize on the pen nets. An estimated 3000kg of accumulated marine growth is washed off each untreated pen net over an eighteen (18) month period.
.cndot. A reduction of waste debris that typically builds up under the fish farm net pens from manual or mechanical cleaning of the pen nets. Under a twelve-pen aquaculture fish farm, the accumulation of growth on untreated nets from marine organisms such as mussels, barnacles, algae, etc. would be equal to 36,000 kg over an eighteen-month grow-out period.
.cndot. Providing a more consistent and continual (uninhibited) flow of water through the nets due to the reduction or elimination of marine growth on the nets. This will ensure that farm fish are Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae not oxygen deprived as a result of fouled nets and that waste from the farm fish can easily flush from the nets, .cndot. Providing a more continuous water flow through the nets will ensure less stress on the fish due to more available oxygen rich water, .cndot. The elimination or significant reduction in the use of antifouling (chemical biocides) used to impregnate/dip (or otherwise treat) fish farm nets. The advantages include:
cost savings and a reduction on environmental impact of these treated nets. For example: copper treated nets must be cleaned off-site (at a special waste facility) due to the toxic waste discharge that must be collected and treated, .cndot. A potentially longer life expectancy for each fish farm pen net due to the continual protection it receives and the reduction of manual or mechanical cleaning (otherwise required), .cndot. A reduction or elimination of the cost and man-hours (including physical stress) required to manually-clean the marine growth from the pen nets. This would include less diving time to pressure wash the nets and a potential reduction in physical injuries, specifically back related.
.cndot. The copper ionic plume that is created around the fish farm pen nets will create environmental conditions that are less opportunistic for other plankton species. As a result, the copper ion plume will disrupt the sea louse Lepeophtheirus salmonis at the early, free living, planktonic naupliar stage of its lifecycle. This invention does not claim that it will eliminate sea lice, however it does claim to have an impact on the early stages of the sea lice lifecycle that will reduce the opportunistic environment for the sea lice to develop to the copepodid stage. Ongoing environmental impact studies on the lifecycle of sea lice will help to verify this claim.
This invention will benefit the aquaculture fish farm industry by reducing or eliminating the marine growth of organisms such as algae, plankton, mussels and other marine organisms that typically adhere or colonize onto fish pen nets at marine (tidal or coastal) water aquaculture fish farms.
The instant benefits (of the claims) of this invention include (but are not limited) to:
.cndot. A significant reduction or elimination of the requirement to continually clean untreated pen nets. This invention will allow pen nets to remain in the water during the entire grow-out period without the need to continually remove the accumulated growth of marine organisms that colonize and re-colonize on the pen nets. An estimated 3000kg of accumulated marine growth is washed off each untreated pen net over an eighteen (18) month period.
.cndot. A reduction of waste debris that typically builds up under the fish farm net pens from manual or mechanical cleaning of the pen nets. Under a twelve-pen aquaculture fish farm, the accumulation of growth on untreated nets from marine organisms such as mussels, barnacles, algae, etc. would be equal to 36,000 kg over an eighteen-month grow-out period.
.cndot. Providing a more consistent and continual (uninhibited) flow of water through the nets due to the reduction or elimination of marine growth on the nets. This will ensure that farm fish are Method and Apparatus for Controlling, Removing, Preventing and/or Inhibiting the Accumulation, Colonizing or Otherwise Fouling of Aquaculture Fish Farm Pen Nets with Marine Organisms, Plankton and Algae not oxygen deprived as a result of fouled nets and that waste from the farm fish can easily flush from the nets, .cndot. Providing a more continuous water flow through the nets will ensure less stress on the fish due to more available oxygen rich water, .cndot. The elimination or significant reduction in the use of antifouling (chemical biocides) used to impregnate/dip (or otherwise treat) fish farm nets. The advantages include:
cost savings and a reduction on environmental impact of these treated nets. For example: copper treated nets must be cleaned off-site (at a special waste facility) due to the toxic waste discharge that must be collected and treated, .cndot. A potentially longer life expectancy for each fish farm pen net due to the continual protection it receives and the reduction of manual or mechanical cleaning (otherwise required), .cndot. A reduction or elimination of the cost and man-hours (including physical stress) required to manually-clean the marine growth from the pen nets. This would include less diving time to pressure wash the nets and a potential reduction in physical injuries, specifically back related.
.cndot. The copper ionic plume that is created around the fish farm pen nets will create environmental conditions that are less opportunistic for other plankton species. As a result, the copper ion plume will disrupt the sea louse Lepeophtheirus salmonis at the early, free living, planktonic naupliar stage of its lifecycle. This invention does not claim that it will eliminate sea lice, however it does claim to have an impact on the early stages of the sea lice lifecycle that will reduce the opportunistic environment for the sea lice to develop to the copepodid stage. Ongoing environmental impact studies on the lifecycle of sea lice will help to verify this claim.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2460246 CA2460246A1 (en) | 2004-03-11 | 2004-03-11 | Method and apparatus for controlling, removing, preventing and/or inhibiting the accumulation, colonizing or otherwise fouling of aquaculture fish farm pen nets with marine organisms, plankton and algae |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2460246 CA2460246A1 (en) | 2004-03-11 | 2004-03-11 | Method and apparatus for controlling, removing, preventing and/or inhibiting the accumulation, colonizing or otherwise fouling of aquaculture fish farm pen nets with marine organisms, plankton and algae |
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| Publication Number | Publication Date |
|---|---|
| CA2460246A1 true CA2460246A1 (en) | 2005-09-11 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2460246 Abandoned CA2460246A1 (en) | 2004-03-11 | 2004-03-11 | Method and apparatus for controlling, removing, preventing and/or inhibiting the accumulation, colonizing or otherwise fouling of aquaculture fish farm pen nets with marine organisms, plankton and algae |
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| CA (1) | CA2460246A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111285469A (en) * | 2020-03-02 | 2020-06-16 | 陈华 | Method for controlling and recycling blue algae |
-
2004
- 2004-03-11 CA CA 2460246 patent/CA2460246A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111285469A (en) * | 2020-03-02 | 2020-06-16 | 陈华 | Method for controlling and recycling blue algae |
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