CA1292919C - Arrangement for farming of fish, shellfish and other marine beings - Google Patents

Abstract

ABSTRACT

Arrangement for enhanced farming of fish and other similar species, comprising a formed enclosure such as a bag having preferrably circular cross-section submerged in water with an upper edge of the bag defining an opening at the water surface and fastened to floats or disposed in a land base arrangement. The cloth of the bag is preferably watertight, and a hose and pump arrangement is provided to suction water from a depth having a favorable water temperature, and expell the water within the bag by means of an outlet at the water surface, the outlet being oriented tangential to the horizontal cross-section of the bag.

Description

02 This invention relates to an arrangement for 03 farming fish, shell fish and other marine beings, and 04 more particularly to a formed enclosure such as a bag of 05 preferrably circular cross-section in the horizontal 06 plane, which is submerged into surrounding water with an 07 open edge of the bag supported at the water surface.
08 Prior art arrangements for fish farming can be 09 divided into two categories: open water-based 1~ enclosures, and closed land-based plants. Open 11 enclosures are used mostly for farming consumer fish 12 while land-based plants are filled with fresh water and 13 are used mostly for farming fry. Open water enclosures 14 are far less expensive than land-based plants, and are also cheaper to operate since the land-based plants 16 typically require large, costly and power consuming 17 pumps for conveying water into an on-shore basin.
18 Prior art open water enclosures are typically 19 formed from bags comprised of net cloth which are ~ubmerged in the ocean. Natural water currents cause 21 the water within the bags to circulate. Open water 22 enclosures are very popular in Norway since the Gulf 23 Stream carries relatively warm water up along the coast 24 in the we~tern and northern part of the country, and relatively strong tides provide sufficient current to 26 facilitate constant circulation of water.
27 One disadvantage of prior art open enclosures 2~ is that the farmed fish are subject to contamination by 29 contagious matter and parasites which may be carried by the circulating water. Another disadvantage is that the 31 net cloth has a tendency to become clogged over time, 32 thus requiring frequent cleaning. In order to clean the 33 cloth, the fish are emptied and the cloth is hoisted 34 above the water and manually scrubbed. It has been discovered that this time consuming net cleaning 36 procedure is responsible for a major portion of the 37 expenses incurred in the operation of prior art open 38 enclosure fish farming installations.

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01 An additional disadvantage of open water 02 enclosures is that it is difficult to adjust and control 03 the water temperature, which typically conforms to the 04 ambient temperature of the water surrounding and 05 infiltrating the bag. Hence, open water enclosures 06 cannot be used in coastal districts where the water is 07 too cold during the winter, or where the surface water 08 is contaminated or contain~ damaging algae or similar Og matter. Nor can such prior art open water enclosures be used in districts where the surface water is too warm.
11 Furthermore, it has been found that fish 12 excrement and unconsumed food particles tend to fall to 13 the bottom of the net where they decay, causing bubbles 14 of H2S and methane gas to rise within the nets. These gases are very harmful to the farmed fish and may in 16 some ca~es cause death.
17 There have been instances reported of large 18 school# of jelly fish carried by natural currents, 19 becoming entangled in the nets and causing the farmed fi~h to sufocate due to a lack of circulated fre~h 21 water.
22 In the event that fish ~armed by means of an 23 open water enclosure become infected with disease or 24 parasites, the disease can spread quickly to neighboring enclosures which are usually placed relatively close 26 by. Administering medicine to the farmed fish in such 27 prior art open water enclo~ures has also been found to 28 be problematic since the medicine dissipates and washes 29 away quickly as a result of the natural water currents.
SUMMARY OF THE INVENTION
31 It is an object of the present invention to 32 provide an open water enclosure designed to maximize the 33 yield of farmed fish or other marine animals.
34 R further object of the invention is to provide an open water enclosure which can be used in 36 area~ whe~e the surface water is either too cold or too 3? warm during particular seasons of the year, or where the 38 surface water contains matter damaging to the fish.

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lZ~25~:~9 01 Yet another object of the pre~ent invention is 02 to provide means in an open water enclosure to 03 effectively administer medicine to the farmed fish and 04 to shorten the working time required to periodically 05 clean the enclosure.
06 According to the present invention, there is 07 provided a fish farming arrangement characterized by a 08 watertight enclosure, such as a bag, in combination with~
09 a pump and hose for drawing water from a depth at which the water temperature is favorable for fish farming, and 11 introducing the water through an upper edge of the side 12 wall of the bag, tangential to the side wall in relation 13 to the horizontal cross-section of the bag.
14 A further characteristic of the present invention is that the side walls of the bag are kept 16 above the water surface, and an overflow hose is 17 provided in the centre of the bag extending slightly 18 above the water surface.
19 Accor~ing to a further aspect of the invention, the pump includes apparatu~ or adding air 21 and/or oxygen to the water being drawn through the hose.
22 According to a preferred embodiment of the 23 invention, the hose is comprised of a ver~ically 24 oriented pipe, and a plurality of small openings are provided in the pipe at a distance of approximately 3 26 meters below water level for blowing air or oxygen into 27 the pipe in the form of a stream of small air bubbles.
28 The lower part of the pipe is made flexible, and the 29 upper portion of the pipe bends toward the outlet which extends substantially horizontally through the bag and 31 tangentially to the side wall of the bag.
32 According to a successful prototype of the 33 invention, a roof or cover of light impervious material 34 such as black plastic c}oth, is provided over the upper edge of the bag, in order that at least the surface 36 water is kept dark. The bag wall is preferably made 37 tran-clucent in a lower submexged portion thereof to 38 allow light to pass therethrough.

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01 A number of advantages are obtained over 02 prior art open water enclosures through use of the 03 arrangement according to the present invention. By 04 virtue o~ the dense watertight construction of the bag 05 and use of a water pump and flexible hose, the 06 temperature and circulation of water can be accurately 07 controlled within the enclosure. In particular, water 08 can be supplied to the enclosure from a depth where the 09 temperature is most favorable. ThUS, for sea-based enclosures which are used in countries having very cold 11 winters (e.g. Norway), where the water at the surface 12 level during the winter is typically so cold as to Xill 13 the fish on contact, the arrangement of the present 14 invention can be used to draw water into the bag from a depth of, for instance, 20 to 30 meters where the 16 temperature may vary from 5C to 7C, even in the middle 17 of winter.
18 By using a pump according to the arrangement 19 o the present invention, air or oxygen enriched water ma~ be ed continuously to the inner part of the 21 enclosure, 22 One ~pecial advantage of the fish farming 23 arrangement according to the present invention over that 24 of the prior art, is the provision of a constant circulating current within the watertight bag 26 enclosure. It has been found that the ish within the 27 bag will position themselves against the current 80 as 28 to remain parallel with one another, all heading in the 29 same direction, and thereby arranging themselves in a school formation. In the school formation, the fish can 31 swim tightly together without stress.
32 By way of contra~t, in prior art open water 33 enclosures, the fish swim in all directions during 34 periods when there is no current. As a result, the fish become aggressive, and attack one another as a result of 36 lack of space. Thi~ phenomenon is known a~ eyebiting, 37 and imposes a strict limit to ~he amount of ~ish that 38 can be accommodated within SUch conventional 39 installations.

lZ~Z~19 01 Fish farmed in the arrangement according 02 to the present invention gain weight and strength at a 03 faster rate than those farmed in prior art open water 04 enclosures, as a result of being provided with 05 constant current, favorable temperature and a rich 06 addition of air and/or oxygen.
07 Furthermore, better utilization of the 08 feed is provided than in prior art open water 09 enclosures since the circulating current keeps the feed floating for a long perod of time during which it 11 can be eaten.
12 Fish raised according to the arrangement 13 of the present inventon are also characterized by a 14 low frequency of disease since the fish are isolated from contagious matter in the surrounding waters.
16 Medicine can be administered in a controlled manner, 17 minimizing the amount used since the medicine is not 18 carried out of the enclosure by water currents, as in 19 the prior art, Furthermore, any ~ick fish in a particular armlng in~tallation will not infect the 21 fi~h in adjacent enclo~ures.
22 The watertight bag used in the arrangment 23 of the present invention can be simply replaced in the 24 event of excessive ~hell growth, etc., or alternatively the fish can be emptied from the bag and 26 the bag can be cleaned.
27 In general, an embodiment of the invention 28 is a fish farming arrangment comprised of a liquid 29 impervious enclosure for containing marine life, the enclosure being submerged in surrounding water.
31 Apparatus i9 attached to a side wall of the enclosure 32 for supporting the enclosure submerged within the 33 surrounding water. Apparatus is included for pumping - ~Z~2~19 water at a predetermined depth from the surrounding water into an upper portion of the enclosure tangentially to the side wall and in a horizontal plane.
The pumping apparatus is comprised of a pump connected to a hose having an inlet in the surrounding water and an outlet connected to the sidewall. A diffuser injects one or both of air and oxygen into water flowing within the hose.
According to another embodiment, a fish farming arrangement is comprised of a liquid impervious enclosure for containing marine life, the enclosure being submerged in surrounding water, apparatus attached to a curved side wall of the enclosure for supporting the enclosure submerged within the surrounding water, and apparatus for pumping water at a predetermined depth from the surrounding water into an upper portion of the enclosure tangentially to the curved side wall and in a horizontal plane, such that within the enclosure a constant circulating current is maintained against which the fi~h ~wim and position themselves in parallel formation, the apparatu~ for pumping watér being comprised of a pump connected to a vertically-oriented hose having an inlet in a flexible end in the surrounding water and an outlet connected to the side wall, and a diffuser for injecting one or both of air and oxygen into water flowing within the hose, and further comprised of apparatus disposed at the bottom of the enclosure for collecting debris and pumping the debris to a cleaning station for purification.
Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description.

3s - 5a -1;2~?2919 DESCRIPTION OF_THE DRAWINGS
The description refers to the accompanying drawings in which like reference characters refer to like parts throughout the several views, and in which:
Figure 1 shows a fish farming arrangement according to the present invention shown from the side, Figure 2 shows the arrangement of Figure 1 from above, and Figure 3 is a side view of an alternative embodiment of the fish farming arrangement according to : 35 - 5b -19' 01 the present invention.

03 Referring to Figure 1, a sea based fish 04 farming enclosure is illustrated comprising a bag 1 05 submerged in water such as in a fjord, lake or ocean, 06 etc. The side walls 2 and bottom 3 of the bag 1 are 07 comprised of watertight material, such as plastic. The 08 bottom 3 is shaped in the form o a funnel, and 09 terminates in an outlet 4 for receiving matter 5 collected at the very bottom of the bag. The outlet 4 11 receives the matter 5 which is conveyed through a pipe 12 or hose 6 by means of a pump 7, to a place of deposit, 13 or cleaning station for dirt.
14 A further pump 13 is connected to a vertical pipe 8 which is provided at a predetermined depth (e.g.
16 3 meters under the water surface) with a diffuser 10 17 comprised of a plurality of small openings 11. Air 18 and/or oxygen are pumped through a line 12 to the 19 diffuser 10. The pump 13 can be any form of inexpensive low pre~ure pump, 21 A flex~ble s~ctlon plpe or hose 14 i8 fastened 22 to the end of the pipe 8, and can be formed of, for 23 instance, corregated plastic pipe. Flexibility in the 24 ho~e 14 results in the ability to direct the inlet 14' of the pipe to any required depth within the water by 26 means of a string or cord 15 fa~tened from the end of 27 the pipe up to the water surface.
28 The pipe 8 i5 provided with a deflection or 29 bend at 16 leading to the inside of the side wall 2 of the bag 1.
31 As seen from Figure 2, the outlet 17 from the 32 pipe bend 16 is made tangential to the side wall 2.
33 When air i~ blown into the pipe 8 through the difuser 34 11, the air bubbles draw the water upwardly through the pipe and into the bag 1, re~ulting in a circulating 36 current, as ~hown by the direction of arrows 18. The 37 current moves in a spiral toward the center of the bag, 38 and at the same time downwardly along the side wall~, as d~'!

12~29i9 shown by the direction of arrows 19 in Figure 1.
As discussed above, this current results in the fish assuming a tight school formation against the current.
S Also, feed is carried with the current and circulates around the bag and is kept a float for a long time.
Fish excrement and unconsumed food particles eventually travel along the wa}l 2 of the bag in the direction of the current 19, and are collected at the bottom 5 and removed via the outlet 4.
In the center of the bag is an overflow pipe 21 (not shown in Figure 2) having an edge 22 extending slightly (preferably 5-10 cm) above the water surface.
Thus, a somewhat higher water level is maintained inside the enclosure than outside, which serves two purposes.
Firstly, water which overflows into the pipe 21 spills through the outlet 23 into the surrounding water by mean~ of gravity. Thi~ overflowing water iB typically quite clean, since excrement and food particles travel to the bottom of the bag. If required, outlet 23 can be connected to a cleaning station, etc. Secondly, a small difference in the water level between the inside and the outside of the bag l results in the bag Rtretching in such a way that it iB kept tight, thereby resisting deformation of the walls due to currents in the surrounding water.
The entire arrangement is supported by floats 23A, or alternatively may be supported by a land based arrangem~nt, such as an outrigger, etc. A fence 24 is fastened to the upper edge of the side wall 2, for preventing fish from leaping over the edge. A roof or cover 25 of preferably opaque material, such a~ pla~tic cloth, i9 stretched over the entire arrangement, and can be supported by means of 11quid air pressure within the bag (i.e. above the water level). The roof is tightly connected to the fence 24 by means of appropriate airtight sealing material. A portion of the bag 26 l~Z919 01 shown between the dashed lines in ~igure 1, forms a 02 window and is fabricated from translucent material 03 through which light is allowed to penetrate. The 04 preferred arrangement of an opaque roof and a 05 translucent lower portion of the bag has been found to 06 result in increased fish yield.
07 According to the arrangement of the present 08 invention, as illustrated in Figures 1 and 2, a complete 09 closed system is provided in which the environment inside the enclosure can be accurately controlled. By 11 use of the pump 13, the system can be operated year 12 round with favorable water temperatures. The fish are 13 less agressive as a result of the constant current.
14 Thus, increased utilization of the fish farming arrangement and better economy are provided over prior 16 art open water enclosures, yielding a greater amount of 17 larger and healthier fish. Greater efficiency in feed 18 utilization and low frequency of disease is obtained due 19 to constant circulation of fresh water and a plentiful supply of air or oxygen, 21 As a result of u~ing watertight or liquid 22 impervious material in forming the bag 1, poisonous 23 planctum algae are prevented from entering, and bacteria 24 is prevented from spreading to neighboring fi~h farming -works. Alqo, medicine introduced within the-bag can be 26 retained therein by ~imply shutting off the pump 13.
27 Contamination of the sea floor i5 28 substantially prevented a~ a re~ult of excrement and 29 unconsumed food particles being removed at the bottom of the bag by means of the pipe 4 in combination with pump 31 7. Hence, the incidence of rising H2S and methane gases 32 formed by rotting excrement and feed at the bottom, ls 33 ~ubstantially prevented.
34 As discu~sed above, the bag may be disposed of or cleaned in the event of exces~ive ~hell growth, etc.
36 A preferred manner of exchanging a new bag for an old 37 bag is to thread the new bag ou~side the old one and 12~29i9 01 fasten it to the floats 23A, and thereafter cut loose 02 the old bag from the fastenings and remove the bag while 03 simultaneously allowing the fish to spill into the new 04 bag.
OS With reference to Figure 3, an alternative 06 embodiment is shown wherein a plurality of fish farming 07 works 1 are submerged in water within the cargo hold or 08 tank 28 of a ~loating vessel 29. Such a vessel may be 09 for instance, a retired tanker or other combined vessel such as an obo-ship having open holds without cumbersome 11 bulk heads. Water is drawn through the pipe 8 and 12 ~lexible hose 14 from a suitable depth in the 13 surrounding sea as discussed above with reference to 14 Figure 1, and circulates within each of the farming bags 1 as discussed above with reference to Figure 2. An 16 outlet 23 passes through the side o~ the vessel 29 and 17 out into the surrounding water, for overflow. The 18 suction line 6 is connected ~o the bottom of each of the 19 bags 1 or pumping dlrt and excrement to on board cleaning ~tation~ ~not ~hown).
21 By using such an alternative embodiment, the 22 farming o fish may be pursued at locations where it 23 would otherwise be prohibited, such as in narrow fjords 24 where there is the hazard of water pollution. By utilizing the arrangement according to the present 26 invention, the ish farming proprietor has full control 27 over pollution to the surrounding waters since the 28 effluent can, if necessary, be purified~
29 The alternative embodiment has been found to be advantageous since retired vessels are quickly sold 31 at scrap iron prices on the world marXet, and can be 32 sold after some years of use for fi~h farming, at 33 practically the same price.
34 A person skilled in the art may conceive of other embodiments or variations of the pre~ent invention 36 without departing from the sphere and ~cope as defined 37 by the claims appended hereto.
38 _ 9 _ ~. ~

Claims (17)

1. A fish farming arrangement comprised of a liquid impervious enclosure for containing marine life, said enclosure being submerged in surrounding water, means attached to a side wall of said enclosure for supporting such enclosures submerged within the surrounding water, means for pumping water at a predetermined depth from said surrounding water into an upper portion of said enclosure tangentially to said side wall and in a horizontal plane, said means for pumping water being comprised of a pump connected to a hose having an inlet in said surrounding water and an outlet connected to said side wall, and a diffuser for injecting one or both of air and oxygen into water flowing within said hose.

2. The arrangement according to claim 1 further including means for supporting said side wall above the surface of said surrounding water, and means for maintaining the level of said water within the enclosure slightly higher than the level of said surrounding water.

3. The arrangement according to claim 2 in which the level maintaining means includes overflow means disposed centrally within said enclosure and having an inlet disposed slightly higher than the level of the surrounding water.

4. The arrangement according to claim 3 wherein said inlet of the overflow means is from five to ten centimeters higher than the level of said surrounding water.

5. The arrangement according to claim 1 wherein said pump is connected by means of said diffuser to a substantially vertical pipe, said diffuser being provided with apertures for injecting a stream of small air bubbles into water flowing through said pipe, a lower end of said pipe being arranged with a flexible suction inlet, and an upper portion of said pipe leading to an outlet connected tangentially to said side wall of the enclosure in an approximately horizontal plane.

6. The arrangement according to claim 1 further including a cover of opaque material connected to and supported above said upper portion of the enclosure and translucent means for transmitting light through a predetermined portion of said side wall below water level.

7. The arrangement according to claim 6 wherein said opaque cover is comprised of a black plastic sheet.

8. The arrangement according to claim 2 comprised of a plurality of said enclosures submerged in water within a cargo hold of a floating vessel, wherein water is pumped from outside the vessel and said overflow means dumps water outside the vessel by means of gravity feed.

9. The arrangement according to claim 1 further comprised of means disposed at the bottom of said enclosure for collecting debris and pumping said debris to a cleaning station for purification.

10. The arrangement according to claim 1 wherein said enclosure is comprised of a bag.

11. The arrangement according to claim 10, wherein said bag is fabricated from plastic.

12. A fish farming arrangement comprised of a liquid impervious enclosure for containing marine life, said enclosure being submerged in surrounding water, means attached to a curved side wall of said enclosure for supporting said enclosure submerged within the surrounding water, and means for pumping water at a predetermined depth from said surrounding water into an upper portion of said enclosure tangentially to said curved side wall and in a horizontal plane, such that within said enclosure a constant circulating current is maintained against which said fish swim and position themselves in parallel formation, said means for pumping water being comprised of a pump connected to a vertically-oriented hose having an inlet in a flexible end in said surrounding water and an outlet connected to said side wall, and a diffuser for injecting one or both of air and oxygen into water flowing within said hose, and further comprised of means disposed at the bottom of said enclosure for collecting debris and pumping said debris to a cleaning station for purification.

13. The arrangement according to claim 12, wherein said means for pumping is further comprised of a substantially vertical pipe connecting said hose to said outlet and said pump via said diffuser, said diffuser being provided with apertures for injecting a stream of small air bubbles into the water flowing through said hose.

14. The arrangement according to claim 13, comprised of a plurality of said enclosures submerged in water within a cargo hold of a floating vessel, wherein water is pumped from outside the vessel and overflow means are provided for dumping water outside the vessel via gravity feed.

15. The arrangement according to claim 12, further including a cover of opaque material connected to and supported above said upper portion of the enclosure and translucent means for transmitting light through a predetermined portion of said side wall below water level.

16. The arrangement according to claim 15, wherein said opaque cover is comprised of a black plastic sheet.

17. The arrangement according to claim 12, wherein said outlet is connected tangentially to said side wall of the enclosure in an approximately horizontal plane.