I was reading again(and again) a simple report in January-February 2009 issue of Global Aquaculture Advocate on trials of advance low-salinity culture of Cobia, Pompano and other species. The report was on successful collaborative efforts between Agricultural Research Service (ARS) of the United States Department of Agriculture and Harbor Branch Oceanographic Institute of Florida Atlantic University to develop and improve technologies for rearing marine fish in low cost, energy-efficient, low salinity and recirculating aquaculture system for various species. The broad issues in the aquaculture industry were addressed in holistic and integrated approach by bringing in diverse researchers of multi disciplines to address the bottleneck of the industry.
What attract my attention to this particular report was on how research organisations and multi discipline researchers of broad based skills were gathered to improve the aquaculture technologies in USA. I love that kind of arrangements for solving and improving the aquaculture technologies. Reading from the report, it covers multi aquaculture species such as Cobia, Pompano, Southern Flounder, Summer Flounder and hybrid between Striped Bass and Black Sea Bass. By having multiple species will require different skills and knowledge in the research team. The researches of multiple disciplines to improve multiple issues at one time are efforts which require good centralised command. The issues covered from eggs to market.
Farming Protocols
Among the achievements from the studies are the protocols on predictable spawning pattern throughout the year using hormone inducement for pompano as well as black seabass and mass production of juveniles in RAS (re-circulating aquaculture system) for pompano which helps in better growth, survival rate and shorter time for metamorphosis. The study also successfully documented the fecundity, fertilization rates and hatching success during numerous spawning trials conducted over the last four years. The ongoing research was designed to determine the optimal broodstock sex ratios, photothermal regimes and environmental cues to achieve natural spawning on a year-round basis for pompano. Should you interested to know more about RAS, I will recommend you to read in detail about it in this book: Recirculating Aquaculture.
The study of such environmental stimulants is very interesting and I believe can be use as a basic knowledge to be use for our grouper hatching technique. Although hormonal inducement are now a well known technique in fish breeding, I personally paying more attention to the environmental stimulants that can be manipulated to induce the natural spawning activities among the grouper species because I believe such stimulation that actually trigger the spawning behaviour of most of the fishes in thier wild natural habitat.
Feeding Regimes
Come back to that particular research, the team also manage to find the way to short cut the enrichment process of live feed from 12 hours to 3 hours which directly will reduce cost in preparing the better quality live feed. Cofeeding of artemia with microparticulate as soon as possible can coincide with metamorphosis at 16 to 18 DAH (days after hatching) plus the usage of certain attractant to increase growth and survival of early postmetamorphic larvae of pompano. Since the usage of live feed is one of my subject of interest (in reducing the fry production cost), I hope to be able to benefit from this study in my own trial production. Perhaps the usage of algae and certain macrophytes could be the answer in reducing the grouper seed production costs. If you interested in this subject, I would like to recommend you this book: Use of Algae and Aquatic Macrophytes As Feed In Small Scale Aquaculture for your reading (you can download it for free).
Nutrition
The particular researches manage to determine the protein level in the diet for their targeted species. Black seabass achieve optimal growth with 45% dietary protein and 10% lipid. Pompano give optimal growth result at 48% protein (37% digestible protein) and 18% lipid in their diet. They found out that the diet for black seabass give the best result for the fish reared in decreasing salinity down to 10 ppt but give the different result to pompano when reared below 1 ppt. This indicate that the diet does not meet the pompano requirement at that salinity and the researchers now working to determine the amino acid requirements for pompano.
They found that fish meal diet give the best result for pompano and black seabass (and other carnivorous species) but still studying the best alternative to fishmeal from soy products, corn gluten meal, meat and bone meal, distiller's dried grain, poultry by-products (PBP) and blended meals in order to reduce the cost of feed in high and low salinity culturing regimes. The research manage to determine the amount of isolated soy protein that could replace the fishmeal for pompano and black seabass, which shown that 80% replacement of fishmeal is possible but the growth will significantly affected after 40% replacement. They evaluated 5 poultry processing co-products for fish meal replacement and found that pompano grow well in 10 weeks farming period using 75% replaced fishmeal by poultry by products.
Well, we not exposed to such knowledge on effect of salinity to growth to grouper fishes although some observations shown the lower in salinity may help to reduce the cannibalism among the tiger grouper fishes. How ever about the fishmeal replacement, I was so pleased to read some reports from University Malaysia Sabah (UMS) on their success of developing diet for mouse and tiger groupers using poultry by-products which suppose to reduce the feed cost of grouper farming although we not yet see such feed in our market.
Engineering Aspects
In these aspects, the said research targeting to reduce the energy consumption to move the water in RAS. Pumping is the way of moving the water in RAS and normally using centrifugal pump. They found that using airlift pumps is a better alternative and lower in initial and operating costs. Airlift pumping system use the buoyancy of the entrained air bubbles to lift up and move the water.
Their study using 7.9 cubic meters tank with 1 meter depth shown that water moved by gravity down a PVC pipe to a 10 cm diameter airlift riser pipe and lifted back into the tank using air from air blower. The submergence:lift ratio greater than 80% with the water velocity in the approach pipe was at least 61 cm/second while at the riser pipe the velocity was recorded at least 30.5 cm/second. They also found that the dynamic head increased with increasing water flow and a greater freeboard in the tank increased the airlift need and off course, greater air flow was required to maintain a steady flow rate in the tank. By placing the air injection lower in the riser pipe, a greater flow per unit was achieved. By applying such information, they manage to reduce 30% of their energy usage in a juvenile nursery. They evaluated airlift techniques for aeration either for the fish, filter and degassing needs in RAS. At the same time, they also evaluated total ammonia nitrogen (TAN) and solid waste removal, and water, energy and oxygen supplement in a low head system.
To most of us, RAS is still new and know-how on the subject still at a very infant stage. I do not know such engineering aspect being taught at our universities or not, either as part of their hydro-engineering or aquaculture engineering subject. Hopefully, our graduates in fisheries from UPM, UMS, UMT and UNISZA have equipped themselves in such technology before they come out into fisheries / aquaculture sector.
Production
Using 3m diameter tanks in RAS system, (complete with solid removal using swirl separators and rotating drum filter, with each system supplied with two floating biofilters equipped with automatic back washing controller, oxygen contactor, degassing column and ultraviolet sterilizer) the studies evaluated the grow out of hybrid striped bass, pompano and cobia from juveniles to marketable size. In 110 days trial, juvenile from 259g were stocked in 2 different densities at 5 ppt end up 632g and 570g respectively. Although food conversion ratio (FCR) were still relatively poor the results shown that pompano can be cultured in low salinity using RAS. In similar study, cobia with initial weight 322g were reared using RAS shown growth to 2.1kg in 119 days with excellent FCR, survival and 42% fillet yield. Both studies shown that both species can achieve a marketable size within a short period of time provided they were given right treatment and proper food.
I must say that I love that conclusion. To those who are still skeptical about RAS as a viable and commercial way in aquaculture investment, I sincerely suggest for them to look at all major seafood export countries such as Norway, Scotland, Denmark, Chile and study their way of doing their business. No doubt that you will find some still doing cage and pond culture, but at the same time most of the successful ventures done using RAS system.
Malaysian Groupers: Need For Concerted Efforts
My actual point in highlighting the studies done by ARS of USDOA and Harbor Branch Oceanic Institute of Florida Atlantic University is that our grouper farming industry also in the need for such broad based and multi disciplines researches which should be done in a very concerted efforts. I do not know who should lead the team nor who should become the member of the study team(s). However, from my personal communications with friends at various institutions that somehow related with aquaculture and fisheries activities, I can sincerely conclude that we do have expertise in that multi disciplines studies.
Maybe I can stress one simple point should such studies taken place. Please find the appropriate technology that suit us and easily adaptable to our farmers. Please don't show us the multi million Ringgit RAS system which non of us can afford to build or perhaps only few can afford to invest. I stress again the word appropriate, please find the APPROPRIATE technology for us. Another point, please, please, please and please make the finding available to all interested parties and stake holders. Please don't keep it as a secret to the researchers only, after a lot of public fund being used to fund such projects. Can we have such broad studies, multi disciplines, multi expertise and multi institutions in grouper farming in Malaysia taken place and answering the real business need? My answer, always, Malaysia Boleh!
Farming Protocols
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| Stripping the eggs from matured broodstock of Mouse Grouper C. altivelis |
The study of such environmental stimulants is very interesting and I believe can be use as a basic knowledge to be use for our grouper hatching technique. Although hormonal inducement are now a well known technique in fish breeding, I personally paying more attention to the environmental stimulants that can be manipulated to induce the natural spawning activities among the grouper species because I believe such stimulation that actually trigger the spawning behaviour of most of the fishes in thier wild natural habitat. |
| What trigger the spawning activities of grouper fishes in their natural habitat such as in coral area of Tun Sakaran Marine Park, Semporna, Sabah? Photo: Sim See Hong. |
Come back to that particular research, the team also manage to find the way to short cut the enrichment process of live feed from 12 hours to 3 hours which directly will reduce cost in preparing the better quality live feed. Cofeeding of artemia with microparticulate as soon as possible can coincide with metamorphosis at 16 to 18 DAH (days after hatching) plus the usage of certain attractant to increase growth and survival of early postmetamorphic larvae of pompano. Since the usage of live feed is one of my subject of interest (in reducing the fry production cost), I hope to be able to benefit from this study in my own trial production. Perhaps the usage of algae and certain macrophytes could be the answer in reducing the grouper seed production costs. If you interested in this subject, I would like to recommend you this book: Use of Algae and Aquatic Macrophytes As Feed In Small Scale Aquaculture for your reading (you can download it for free).
Nutrition
The particular researches manage to determine the protein level in the diet for their targeted species. Black seabass achieve optimal growth with 45% dietary protein and 10% lipid. Pompano give optimal growth result at 48% protein (37% digestible protein) and 18% lipid in their diet. They found out that the diet for black seabass give the best result for the fish reared in decreasing salinity down to 10 ppt but give the different result to pompano when reared below 1 ppt. This indicate that the diet does not meet the pompano requirement at that salinity and the researchers now working to determine the amino acid requirements for pompano.
They found that fish meal diet give the best result for pompano and black seabass (and other carnivorous species) but still studying the best alternative to fishmeal from soy products, corn gluten meal, meat and bone meal, distiller's dried grain, poultry by-products (PBP) and blended meals in order to reduce the cost of feed in high and low salinity culturing regimes. The research manage to determine the amount of isolated soy protein that could replace the fishmeal for pompano and black seabass, which shown that 80% replacement of fishmeal is possible but the growth will significantly affected after 40% replacement. They evaluated 5 poultry processing co-products for fish meal replacement and found that pompano grow well in 10 weeks farming period using 75% replaced fishmeal by poultry by products.
Well, we not exposed to such knowledge on effect of salinity to growth to grouper fishes although some observations shown the lower in salinity may help to reduce the cannibalism among the tiger grouper fishes. How ever about the fishmeal replacement, I was so pleased to read some reports from University Malaysia Sabah (UMS) on their success of developing diet for mouse and tiger groupers using poultry by-products which suppose to reduce the feed cost of grouper farming although we not yet see such feed in our market.
Engineering Aspects
In these aspects, the said research targeting to reduce the energy consumption to move the water in RAS. Pumping is the way of moving the water in RAS and normally using centrifugal pump. They found that using airlift pumps is a better alternative and lower in initial and operating costs. Airlift pumping system use the buoyancy of the entrained air bubbles to lift up and move the water.
Their study using 7.9 cubic meters tank with 1 meter depth shown that water moved by gravity down a PVC pipe to a 10 cm diameter airlift riser pipe and lifted back into the tank using air from air blower. The submergence:lift ratio greater than 80% with the water velocity in the approach pipe was at least 61 cm/second while at the riser pipe the velocity was recorded at least 30.5 cm/second. They also found that the dynamic head increased with increasing water flow and a greater freeboard in the tank increased the airlift need and off course, greater air flow was required to maintain a steady flow rate in the tank. By placing the air injection lower in the riser pipe, a greater flow per unit was achieved. By applying such information, they manage to reduce 30% of their energy usage in a juvenile nursery. They evaluated airlift techniques for aeration either for the fish, filter and degassing needs in RAS. At the same time, they also evaluated total ammonia nitrogen (TAN) and solid waste removal, and water, energy and oxygen supplement in a low head system.
To most of us, RAS is still new and know-how on the subject still at a very infant stage. I do not know such engineering aspect being taught at our universities or not, either as part of their hydro-engineering or aquaculture engineering subject. Hopefully, our graduates in fisheries from UPM, UMS, UMT and UNISZA have equipped themselves in such technology before they come out into fisheries / aquaculture sector.
Production
Using 3m diameter tanks in RAS system, (complete with solid removal using swirl separators and rotating drum filter, with each system supplied with two floating biofilters equipped with automatic back washing controller, oxygen contactor, degassing column and ultraviolet sterilizer) the studies evaluated the grow out of hybrid striped bass, pompano and cobia from juveniles to marketable size. In 110 days trial, juvenile from 259g were stocked in 2 different densities at 5 ppt end up 632g and 570g respectively. Although food conversion ratio (FCR) were still relatively poor the results shown that pompano can be cultured in low salinity using RAS. In similar study, cobia with initial weight 322g were reared using RAS shown growth to 2.1kg in 119 days with excellent FCR, survival and 42% fillet yield. Both studies shown that both species can achieve a marketable size within a short period of time provided they were given right treatment and proper food.
I must say that I love that conclusion. To those who are still skeptical about RAS as a viable and commercial way in aquaculture investment, I sincerely suggest for them to look at all major seafood export countries such as Norway, Scotland, Denmark, Chile and study their way of doing their business. No doubt that you will find some still doing cage and pond culture, but at the same time most of the successful ventures done using RAS system.
Malaysian Groupers: Need For Concerted Efforts
My actual point in highlighting the studies done by ARS of USDOA and Harbor Branch Oceanic Institute of Florida Atlantic University is that our grouper farming industry also in the need for such broad based and multi disciplines researches which should be done in a very concerted efforts. I do not know who should lead the team nor who should become the member of the study team(s). However, from my personal communications with friends at various institutions that somehow related with aquaculture and fisheries activities, I can sincerely conclude that we do have expertise in that multi disciplines studies.
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| A simple RAS system for nursing of Seabass and Grouper juveniles in inland area of Bukit Beruntung, Selangor which only cost the owner less than RM50,000 to set up. Photo: Mahmud Ismail |
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