WO2010017172A2

WO2010017172A2 - Marine aquaculture system

Info

Publication number: WO2010017172A2
Application number: PCT/US2009/052658
Authority: WO
Inventors: Nicholas P. Brown; Peter Harvey; Stephen Eddy
Original assignee: University Of Maine System Board Of Trustees
Priority date: 2008-08-07
Filing date: 2009-08-04
Publication date: 2010-02-11
Also published as: WO2010017172A3

Abstract

A marine aquaculture system (10) for growing marine organisms is provided. The marine aquaculture system includes a media tank (14) having an inlet (32) and a substrate (34) positioned above the inlet. The substrate is suitable for growing the marine organisms. A supply conduit (16) is connected to the inlet. The supply conduit contains a foodstuff (34c) flowing in a direction toward the inlet. The marine aquaculture system is characterized in that the foodstuff flows through the inlet and through the substrate in an upwelling fashion.

Description

MARINE AQUACULTURE SYSTEM

Inventors: Nicholas P. Brown, Peter Harvey, Stephen Eddy

TECHNICAL FIELD

[0001] This invention relates to the farming of marine organisms, such as for example marine worms and marine invertebrates. More particularly, this invention relates to the farming of marine organisms in an engineered system.

BACKGROUND OF THE INVENTION

[0002] Marine organisms, such as for example the marine worms and marine invertebrates, are used for a variety of purposes including bait for fishing, for bioremediation, for scientific purposes including medical research, and for foodstuffs for commercial aquaculture. Marine worms, for example, can be harvested from natural sources, such as for example mudflats, saltwater marshes and lagoons. Marine worms can also be grown in captivity through the use of marine aquaculture systems. [0003] Typical marine aquaculture systems for growing marine worms involve the use of large, shallow tanks in which the marine worms are held. The shallow tanks contain a shallow layer of growing media, typically sand, which is used by the marine worms as a substrate during the growth process. After the marine worms are stocked into the media, flowing water is pumped over the surface of the media. Feed is presented to the marine worms from above the tank and the marine worms come to the surface of the media to take the feed. It would be advantageous if marine aquaculture systems could be improved to make them more efficient and easier to use. SUMMARY OF THE INVENTION

[0004] The above objects as well as other objects not specifically enumerated are achieved by a marine aquaculture system for growing marine organisms. The marine aquaculture system includes a media tank having an inlet and a substrate positioned above the inlet. The substrate is suitable for growing the marine organisms. A supply conduit is connected to the inlet. The supply conduit contains a foodstuff flowing in a direction toward the inlet. The marine aquaculture system is characterized in that the foodstuff flows through the inlet and through the substrate in an upwelling fashion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 is a side view in elevation of a marine aquaculture system.

[0006] Figure 2 is a side view in elevation of a media tank of the marine aquaculture system of Figure 1.

[0007] Figure 3 is a plan view in elevation of a screen of the media tank of

Figure 2.

[0008] Figure 4 is an enlarged side view in elevation of a portion of the media segment of the marine aquaculture system of Figure 1.

[0009] Figure 5 is a chart illustrating the percentage change of biomass of marine worms held in the marine aquaculture system of Figure 1 for a period of two months.

[00010] Figure 6 is a chart illustrating the percentage change of average weight of marine worms held in the marine aquaculture system of Figure 1 for a period of two months.

[00011] Figure 7 is a chart illustrating the survival percentage of marine worms held in the marine aquaculture system of Figure 1 for a period of two months. [00012] Figure 8 is a side view in elevation of a 2^nd embodiment of the marine aquaculture system.

[00013] Figure 9 is a side view in elevation of a 3^rd embodiment of the marine aquaculture system.

[00014] Figure 10 is a side view in elevation of a 4^th embodiment of the marine aquaculture system.

DETAILED DESCRIPTION OF THE INVENTION

[00015] The description and drawings disclose a marine aquaculture system 10 for growing marine organisms, such as for example marine worms and marine invertebrates. In the illustrated embodiment, the marine worms are polychaetes, such as for example Nereis Virens. In other embodiments, the marine organisms can be other types of marine worms or marine organisms.

[00016] As shown in Fig. 1, the marine aquaculture system 10 includes a header tank 12 and a plurality of media tanks 14. While the embodiment shown in Fig. 1 illustrates a single header tank 12 and four media tanks 14, it should be understood that more than one header tank 12 and more or less than four media tanks 14 can be used.

[00017] Referring again to Fig. 1, the header tank 12 is configured to contain a supply of water mixed with feed and oxygen and convey the water mixed with feed and oxygen to the media tanks 14. The header tank 12 includes a vessel segment 18, a conical segment 20 and an outlet portion 22. In the illustrated embodiment, water is mixed with feed and oxygen within the header tank 12 to form a foodstuff. The term "foodstuff as used herein, is defined to mean a mixture of water, feed and oxygen. In other embodiments, a pre-mixed foodstuff containing water, feed and oxygen can be supplied to the header tank 12. The header tank 12 can be made of any suitable material, such as for example steel, aluminum or plastic, sufficient to contain a supply of foodstuff to the media tanks 14. Optionally, any suitable device or mechanism, such as for example a mixer (not shown) can be used to mix the water, feed and oxygen within the header tank 12.

[00018] In the embodiment shown in Fig. 1, the header tank 12 has a volumetric capacity in a range of from about 1,000 gallons (3,784 liters) to about 10,000 gallons (37,843 liters). In other embodiments, the volumetric capacity of the header tank 12 can be less than 1,000 gallons (3,784 liters) or more than 10,000 gallons (37,843 liters).

[00019] Referring again to Fig. 1, the vessel segment 18 of the header tank 12 has a cylindrical shape. In other embodiments, the vessel segment 18 of the header tank 12 can have any shape sufficient to contain the desired volumetric capacity of the header tank 12.

[00020] As mentioned above, the header tank 12 has a conical segment 20 positioned at the bottom of the vessel segment 18. The conical segment 20 is configured to funnel the foodstuff from the vessel segment 18 to the outlet portion 22 such that suspended feed within the foodstuff does not settle and remain at the bottom of the header tank 12. The conical segment 20 can have any geometric dimensions sufficient to funnel the foodstuff to the outlet portion 22 such that suspended feed within the foodstuff does not settle and remain at the bottom of the header tank 12. In other embodiments, the header tank 12 can have other shapes and structures sufficient that suspended feed within the foodstuff does not settle and remain at the bottom of the header tank 12.

[00021] As mention above, the header tank 12 is configured to contain a supply of foodstuff containing water mixed with feed and oxygen and convey the supply of foodstuff to the media tanks 14. The feed can be any suitable worm food. Examples of suitable worm food includes formulated feeds, dry, moist or wet feeds, plant based feeds, fishmeal based feeds, terrestrial based feeds and various types of bacteria. In other embodiments, suitable worm food can include solid or liquid wastes from a production system for other marine organisms including fish. In the illustrated embodiment, the water is sea water from the ocean and has salinity in a range of from about 30-35 parts per thousand. In other embodiments, the salinity of the water can be higher than about 35 parts per thousand or lower than about 30 parts per thousand depending on the tolerance of the marine organisms.

[00022] As shown in Fig. 1, the outlet portion 22 connects the header tank 12 with a supply conduit 16. The outlet portion 22 is configured to allow a flow of foodstuff from the header tank 12 to the supply conduit 16 in the direction indicated by the arrow Dl . Optionally, feed may be introduced to the flow of foodstuff in the supply conduit 16 downstream from the header tank 12 by an auxiliary feeder 24. The auxiliary feeder 24 can be any mechanism or device or combination of mechanisms and devices suitable to supply feed to the flow of foodstuff in the supply conduit 16. [00023] In the embodiment shown in Fig. 1, the header tank 12 has a configuration and a capacity to provide sufficient head pressure to enable the flow of foodstuff to the media tanks 14 by the force of gravity as indicated by the arrow Fg. Optionally, a supply pump 26 may be positioned downstream from the header tank 12 to provide additional pressure to the flow of foodstuff within the supply conduit 16. The optional pump 26 can be any suitable pump sufficient to provide additional pressure to the flow of foodstuff within the supply conduit 16. [00024] As shown in Fig. 1, the header tank 12 and the media tanks 14 are connected by a supply conduit 16. The supply conduit 16 is configured to convey the foodstuff contained in the header tank 12 from the header tank 12 to the media tanks 14. In the illustrated embodiment, the supply conduit 16 is made of plastic pipe having an inside diameter in a range of from about 3.0 inches to about 6.0 inches. In other embodiments, the supply conduit 16 can be made of other suitable materials, such as for example high density polyethylene (HDPE) or glass reinforced plastic (GRP), and the supply conduit 16 can have an inside diameter of more than about 6.0 inches or less than about 3.0 inches. In yet other embodiments, the supply conduit 16 can have a non-round cross-sectional shape.

[00025] Referring now to Fig. 2, a single media tank 14 is illustrated for purposes of clarity. Generally, the media tank 14 is configured to provide an environment suitable to promote optimum growth of the marine worms. The media tank 14 includes a media segment 28, a manifold segment 30, an inlet 32 and a screen

36. As will be explained in more detail below, in operation, foodstuff flows in an upwelling fashion from the supply conduit 16 beneath the media tank 14, vertically up through the inlet 32, through the manifold segment 30 and the screen, and into the media segment 28 of media tank 14.

[00026] In the embodiment shown in Fig. 2, the media tank 14 has a volumetric capacity in a range of from about 1,000 gallons (3,784 liters) to about 10,000 gallons

(37,843 liters). In other embodiments, the volumetric capacity of the media tank 14 can be less than 1,000 gallons (3,784 liters) or more than 10,000 gallons (37,843 liters).

[00027] The media tank 12 can be made of any suitable material, such as for example stainless steel, glass reinforced plastic or plastic, sufficient to provide an environment suitable to promote optimum growth of the marine worms.

[00028] The media segment 28 of the media tank 14 contains a substrate 34 and has a substantially cylindrical shape. In other embodiments, the media segment 28 of the media tank 14 can have any shape sufficient to hold the substrate 34 and the desired volumetric capacity of the media tank 14.

[00029] As shown in Fig. 2, the substrate 34 is configured to provide a structure within which the marine organisms can live and grow. As will be explained in more detail below, the structure of the substrate 34 allows the movement of the marine organisms and also provides a structure within which the foodstuff is trapped and available to the marine organisms. In the illustrated embodiment, the substrate 34 comprises individual substrate elements 34a, having a substantially spherical shape. Referring now to Fig. 4, the relative placement of the substrate elements 34a defines a plurality of interstices 34b. The interstices 34b provide spaces among and between the substrate elements 34b sufficient to trap foodstuff 34c from the flow of foodstuff in the upwelling direction Dl. The trapped foodstuff 34c within the interstices 34b of the substrate elements 34a is available to the marine organisms. [00030] Referring again to Fig. 4, each of the substrate elements 34a has an exterior surface 35. The exterior surface 35 of the substrate elements 34a provides a surface for bacteria to locate. The bacteria located on the exterior surface 35 of the substrate elements 34a is configured to act as a biofilter and assist in the breakdown of waste products produced by the marine organisms. In other embodiments, the substrate 34 can comprise elements having other shapes, such as for example cubic or polygonal shapes, sufficient to provide a surface for bacteria to locate. [00031] Referring again to Fig. 2, the substrate elements 34a have a diameter that corresponds to the size of marine organisms. In the illustrated embodiment, the substrate elements 34a have a diameter in a range of from about lmm to about 3mm corresponding to marine organisms having a cross-sectional diameter of approximately 4 mm. In other embodiments, the substrate elements 34a can have other suitable diameters corresponding to marine organisms having other cross-sectional diameters. In yet other embodiments, the substrate elements 34a can have a diameter that does not correspond to the size of the marine organism.

[00032] Referring again to the embodiment shown in Fig. 2, the substrate elements 34a have a specific gravity of approximately 1.4. Accordingly, the substrate elements 34a are configured to sink to the bottom of the media segment 28 and rest on the top surface of the screen 36 within the media segment 28 of the media tank 14. In other embodiments, the substrate elements 34a can have any specific gravity sufficient to sink to the bottom of the media segment and rest on the top surface of the screen within the media segment of the media tank 14. In yet other embodiments, the substrate elements 34a can have a specific gravity of less than the water used within the media tank 14. In this embodiment, a screen (not shown) is positioned at the top of the media segment 28 and is configured to retain the substrate elements 34a within the media segment 28 of the media tank 14.

[00033] In the embodiment shown in Fig. 2, the substrate elements 34a are made of a plastic material. In other embodiments, the substrate elements 34a can be other suitable materials or a combination of materials, such as for example glass, perlite, and vermiculite. In other embodiments, the substrate elements 34a can be made of absorbent materials, such as for example water absorbent polymers. In yet other embodiments, the substrate 34 can have other structures and can be made of other materials, such as for example a matrix made from polymeric material or natural materials, sufficient to provide a structure within which the marine organisms can live and grow.

[00034] As shown in Fig. 2, the screen 36 is positioned between the media segment 28 and the manifold segment 30. The screen 36 is configured to maintain separation between the substrate 34 in the media segment 28 and the manifold segment 30. Referring now to Fig. 3, the screen 36 comprises a plate 38 and a plurality of perforations 40. The plate 38 is configured to seal against the media segment 28 thereby retaining the substrate 34 within the media segment. In the illustrated embodiment, the plate 38 has a round shape corresponding to the circular cross- sectional shape of the media segment 28. In other embodiments, the plate 38 can have other shapes sufficient to seal the media segment 28. The plate 38 can be made of any suitable material, such as for example plastic, glass reinforced plastic or stainless steel. [00035] As shown in Fig. 3, the plate 38 includes a plurality of perforations 40. The perforations 40 allow a desirable flow of upwelling foodstuff to flow from the manifold segment 30 to the media segment 28 while simultaneously retaining the marine organisms within the media segment 28. In the illustrated embodiment, the perforations 40 have a round cross-sectional shape. In other embodiments, the perforations 40 can have other suitable cross-sectional shapes. The perforations 40 have a diameter configured to prevent the marine organisms from exiting the media tank 14 through the perforations 40 in the screen 36. In the illustrated embodiment, the perforations 40 have a diameter in a range of from about lmm to about 3mm corresponding to marine organisms having a diameter of approximately 4 mm. In other embodiments, the perforations 40 can have other suitable diameters corresponding to marine organisms having other diameters. [00036] While the screen 36 illustrated in Figs. 2 and 3 comprises a plate 38 having a plurality of perforations 40, it should be understood that other suitable structures, such as for example nylon mesh, sufficient to maintain separation between the substrate 34 in the media segment 28 and the manifold segment 30, can be used. [00037] As shown in Fig. 3, the plate 38 is substantially covered with the perforations 40. In other embodiments, the perforations 40 can arranged in patterns producing advantageous flows through the screen 36.

[00038] Referring again to Fig. 2, the media tank 14 is illustrated without a cover at the top of the media segment 28. In other embodiments, the media tank 14 may comprise a cover at the top of the media segment 28 for purposes including varying the amount of light entering the top of the media tank 14.

[00039] As mentioned above, the media tank 14 includes a manifold segment 30 positioned under the screen 36 at the bottom of the media segment 28. The manifold segment 30 is configured to provide foodstuff from the supply conduit 16 to the media segment 28 in an upwelling fashion. The term "upwelling" as used herein, is defined to mean the rising of the foodstuff through the media tank 14 from a lower source or location. The manifold segment 30 can have any geometric dimensions sufficient to provide foodstuff from the supply conduit 16 to the media segment 28 in an upwelling fashion.

[00040] As shown in Fig. 2, the inlet 32 connects the manifold segment 30 of the media tank 14 with the supply conduit 16. The inlet 32 is configured to allow a flow of foodstuff from the supply conduit 16 to the manifold segment 30 in the direction indicated by the arrow Dl.

[00041] Referring again to Fig. 2, an outlet filter 42 is positioned at the top of the media segment 28 and is connected to the outlet conduit 44. The outlet filter 42 is configured to allow upwelling outlet water to enter the outlet conduit 44 while simultaneously preventing the marine organisms and the substrate 34 from entering the outlet conduit 44. The term "outlet water" as used herein, is defined to mean water containing organism waste and unconsumed foodstuff that is exiting the media tank 14. The outlet filter 42 can be any suitable structure or device sufficient to allow upwelling outlet water to enter the outlet conduit 44 while simultaneously preventing the marine organisms and the substrate 34 from entering the outlet conduit 44. [00042] As shown in Fig. 2, the outlet water leaves the media tank 14 through the outlet filter in direction D2 and flows in the outlet conduit 44 in direction D2. Referring again to Fig. 1, the outlet water flows in direction D2 and collects in a sump tank 50. The outlet conduit 44 is configured to convey the outlet water from the media tank 14 to the sump tank 50. In the illustrated embodiment, the outlet conduit 44 is made of plastic pipe having an inside diameter in a range of from about 3.0 inches to about 6.0 inches. In other embodiments, the outlet conduit 44 can be made of other suitable materials, such as for example high density polyethylene (HDPE) or glass reinforced plastic, and the outlet conduit 44 can have an inside diameter of more than about 6.0 inches or less than about 3.0 inches. In yet other embodiments, the outlet conduit 44 can have a non-round cross-sectional shape.

[00043] Referring again to Fig. 1, the sump tank 50 has a sump inlet 52, a sump outlet 54 and a header tank overflow inlet 56. The sump tank 50 is configured to collect the outlet water flowing through the outlet conduits 44 into the sump inlet 52 and to collect excess foodstuff flowing from the header tank 12 through overflow conduit 58 into the header tank overflow inlet 56. While the marine aquaculture system 10 shown in Fig. 1 illustrates a single sump tank 50, it should be appreciated that more than one sump tank 50 can be used. The sump tank 50 can be made of any suitable material, such as for example stainless steel, glass reinforced plastic or plastic, sufficient to collect the outlet water flowing through the outlet conduits 44 into the sump inlet 52 and to collect excess foodstuff flowing from the header tank 12 through overflow conduit 58 into the header tank overflow inlet 56. [00044] As shown in Fig. 1, a circulating pump 60 is positioned downstream from the sump outlet 54. The circulating pump 60 is configured to pump the water collected in the sump tank 50 back to the header tank 12 through the recycling conduit 62. Any suitable pump sufficient to pump the water collected in the sump tank 50 back to the header tank 12 can be used.

[00045] While not shown in Fig. 1, it should be understood that the water pumped back to the header tank 12 by the circulating pump 60 can be treated by other devices and systems. One example of water treatment is an ultra violet sterilizer configured to destroy harmful or unwanted microorganisms from the water. Other examples of water treatment devices include devices for the removal of solids and carbon dioxide, and for protein skimming.

[00046] In operation, the marine worms may be introduced to the substrate 34 within the media tanks 14 at any stage of development including the larval stages. Foodstuff flows in direction Dl from the header tank 12 to the inlet 32 of the media tank 14. The combination of an adequate flow rate of the foodstuff, with the desired size of the perforation 40 of the screen, serves to prevent the clogging of the perforations 40 of the screen 36. In the illustrated embodiment, the flow rate of the foodstuff is 2 liters per minute and the perforation size is approximately 1-3 mm. In other embodiments, other combinations of flow rate of the foodstuff and perforation size can be used, sufficient to prevent clogging of the screen. [00047] As the foodstuff flows in an upwelling fashion through the manifold segment 30 and the through the media segment 28, the foodstuff 34c is trapped within the interstices 34b between the substrate elements 34a. The marine organisms feed directly on the foodstuff 34c. This mode of feeding by the marine organisms allows for the delivery of liquefied forms of feed, including waste sludge from other marine organism production systems.

[00048] The marine organisms can be harvested from the media tanks 14 in any suitable manner. As an example of one embodiment, the marine organisms can be separated from the substrate 34 by the force of gravity. In other embodiments, a pressurized gas, such as for example air, can be introduced or water flow increased to disrupt the substrate 34 to loosen the marine organisms from the substrate 34. [00049] Referring now to Figs. 5-7, the results of the marine aquaculture system 10, shown using different materials for the substrate 34, provide excellent results. Figs. 5-7 illustrate trials using vermiculite, perlite and three different sizes of plastic elements 34a. Fig. 5 illustrates the percentage change in biomass of the marine worms held in the marine aquaculture system 10 for two months and fed waste sludge from a halibut recirculation system.

[00050] Referring now to Fig. 6, the percentage of growth in average weight of the marine worms over a two months period is illustrated. The marine worms were fed foodstuff comprising waste sludge from a halibut recirculation system. [00051] Figure 7 illustrates the percentage survival rate of the marine worms held in the marine aquaculture system 10 for two months and fed waste sludge from a halibut recirculation system.

[00052] While the marine aquaculture system 10 described above has been illustrated as a stand alone system for marine organisms, in other embodiments the marine aquaculture system 10 can be incorporated into other polyculture systems for other aquatic species, such as fish or shellfish or terrestrial organisms. [00053] Summarizing the above discussion, a marine aquaculture system 10 illustrated in Figs. 1-4 includes a flow of a foodstuff through a substrate, wherein the flow of the foodstuff enters the substrate from a source positioned outside the substrate. In the embodiment illustrated in Figs. 1-4, the source of the flow of foodstuff entering the substrate was positioned below the substrate, thereby resulting in an upwelling flow through the substrate. In other embodiments, the source of the flow of foodstuff entering the substrate can be positioned in other locations, sufficient to provide a flow of foodstuff through the substrate. As one example, Fig. 8 illustrates a source of foodstuff positioned horizontally adjacent to the substrate. As shown in Fig. 8, a media tank 114 includes a media segment 128 bounded on both horizontal sides by screens 136a and 136b. In turn, the screens 136a and 136b are horizontally bounded on one side by the inlet manifold 130 and on the other horizontal side by the outlet manifold 131. In a fashion similar to the screen 36 illustrated in Fig. 2, the screens, 136a and 136b, are configured to maintain separation between a substrate 134 positioned within the media segment 128 and the inlet and outlet manifolds, 130 and 131. Each of the screens, 136a and 136b, comprise a plate and a plurality of perforations. A supply conduit 116 is connected to the inlet manifold 130 and an outlet conduit 144 is connected to the outlet manifold 131. [00054] In operation, the marine worms are introduced to the substrate 134 within the media segment 128. Foodstuff flows in direction DlOl from a header tank (not shown), through the supply conduit 116 and through the inlet manifold 130 to the screen 136a. The foodstuff continues to flow through the screen 136a and through the substrate 134 contained within the media segment 128. The foodstuff continues flowing through the screen 136b and through the outlet manifold 131 to the outlet conduit 144. The foodstuff exits the media tank 114 through the outlet conduit 144 in direction D102. In the embodiment shown in Fig. 8, the foodstuff flows in a substantially horizontal direction. In other embodiments, the foodstuff can flow in directions other than substantially horizontal. As the foodstuff flows in a substantially horizontal direction through the inlet manifold segment 130 and the through the media segment 128, the foodstuff is trapped within interstices formed within the substrate 134. The marine organisms feed directly on the trapped foodstuff. [00055] As another example, Fig. 9 illustrates a source of foodstuff positioned above the substrate. As shown in Fig. 9, a media tank 214 includes a media segment 228 bounded on the top by screen 236a and on the bottom by screen 236b. In turn, screen 236a is bounded on the top by inlet manifold 230 and screen 236b is bounded on the bottom by outlet manifold 231. In a fashion similar to the screen 36 illustrated in Fig. 2, the screens, 236a and 236b, are configured to maintain separation between a substrate 234 positioned within the media segment 228 and the inlet and outlet manifolds, 230 and 231. Each of the screens, 236a and 236b, comprise a plate and a plurality of perforations. A supply conduit 216 is connected to the inlet manifold 230 and an outlet conduit 244 is connected to the outlet manifold 231. [00056] In operation, the marine worms are introduced to the substrate 234 within the media segment 228. Foodstuff flows in a substantially downwelling direction D201 from a header tank (not shown), through the supply conduit 216 and through the inlet manifold 230 to the screen 236a. The foodstuff continues to flow through the screen 236a and through the substrate 234 contained within the media segment 228. The foodstuff continues flowing through the screen 236b and through the outlet manifold 231 to the outlet conduit 244. The foodstuff exits the media tank 214 through the outlet conduit 244 in direction D202. In the embodiment shown in Fig. 9, the foodstuff flows in a substantially vertical downward direction. In other embodiments, the foodstuff can flow in directions other than substantially vertically downward. As the foodstuff flows in a substantially vertical downward direction through the inlet manifold segment 230 and the through the media segment 228, the foodstuff is trapped within interstices formed within the substrate 234. The marine organisms feed directly on the trapped foodstuff.

[00057] Referring now to Fig. 10, another embodiment of the marine aquaculture system 310 is illustrated. In this embodiment, there is no header tank 12. Instead, water and excess foodstuff is returned directly from the sump tank 350, through the recycling conduit 362, to the supply conduit 316. A circulating pump 360 is positioned downstream from the sump tank 350 and is configured to pump the water and excess foodstuff through the recycling conduit 362 to the supply conduit 316. Any suitable circulating pump 360 can be used. Additional foodstuff can be added to the water and foodstuff collected in the sump tank by any suitable device or mechanism (not shown). In other embodiments, additional foodstuff can be added by an auxiliary feeder (not shown) positioned downstream from the sump tank 350. The recycled water and foodstuff flows in an upwelling fashion through the media tanks 314 in an upwelling fashion as described above.

[00058] While the embodiment of the marine aquaculture system 10 described above provides an aquaculture system for marine organisms, it is within the contemplation of this invention that the marine aquaculture system 10 could be used for fresh water organisms.

[00059] The principle and mode of operation of this marine aquaculture system have been described in its preferred embodiments. However, it should be noted that the marine aquaculture system may be practiced otherwise than as specifically illustrated and described without departing from its scope.

Claims

CLAIMSWhat is claimed is:

1. A marine aquaculture system (10) for growing marine organisms comprising: a media tank (14) having an inlet (32) and a substrate (34) positioned above the inlet (32), the substrate (34) being suitable for growing the marine organisms; and a supply conduit (16) connected to the inlet (32), the supply conduit (16) containing a foodstuff (34c) flowing in a direction toward the inlet (32); characterized in that the foodstuff (34c) flows through the inlet (32) and through the substrate (34) in an upwelling fashion.

2. The marine aquaculture system (10) of claim 1 wherein the substrate (34) includes substrate elements (34a) made of a water absorbent polymer material.

3. The marine aquaculture system (10) of claim 2 wherein the substrate elements (34a) have a substantially spherical shape.

4. The marine aquaculture system (10) of claim 2 wherein the substrate elements (34a) define a plurality of interstices (34b), wherein the interstices (34c) provide spaces among and between the substrate elements (34a) sufficient to trap the foodstuff (34c) from the flow of foodstuff (34c) in the upwelling fashion.

5. The marine aquaculture system (10) of claim 2 wherein the substrate elements (34a) have a diameter in a range of from about 1 mm to about 3 mm.

6. The marine aquaculture system (10) of claim 2 wherein the substrate elements (34a) have a specific gravity of approximately 1.4.

7. The marine aquaculture system (10) of claim 2 wherein the substrate elements (34a) have an exterior surface (35), the exterior surface (35) being configured as a location for bacteria, wherein the bacteria are configured to act as a biofilter and assist in the breakdown of waste products produced by the marine organisms.

8. The marine aquaculture system (10) of claim 1 wherein a screen (36) is positioned between the substrate (34) and the inlet (32) and configured to maintain separation between the substrate (34) and the inlet (32).

9. The marine aquaculture system (10) of claim 8 wherein the screen (36) includes perforations (40) configured to allow a desired flow of upwelling foodstuff (34c) from the inlet (32) to the media tank (14), wherein the perforations (40) have a circular cross-sectional shape.

10. The marine aquaculture system (10) of claim 9 wherein the perforations (40) have a diameter in a range of from about 1 mm to about 3 mm.

11. The marine aquaculture system (10) of claim 1 wherein a manifold segment (30) is positioned between the screen (36) and the inlet (32).

12. The marine aquaculture system (10) of claim 1 wherein an outlet filter (42) is positioned between a top of the media tank (14) and an outlet conduit (44), wherein the outlet filter (42) is configured to allow upwelling outlet water to enter the outlet conduit (44) while simultaneously preventing the marine organisms and the substrate (34) from entering the outlet conduit (44), wherein outlet water includes water containing organism waste and unconsumed foodstuff (34c).

13. The marine aquaculture system (10) of claim 12 wherein the outlet water is recycled through the media tank (14).

14. The marine aquaculture system (10) of claim 1 wherein a header tank (12) is configured to contain a supply of water mixed with feed and oxygen and convey the water mixed with feed and oxygen to the media tank (14).

15. The marine aquaculture system of claim 14 wherein the header tank (12) includes a conical segment (20) positioned at the bottom of the header tank (12) and configured to funnel the supply of water mixed with feed and oxygen from the header tank (12) to the media tank (14).