Perspective And Opinion AQM 43 4

Aquaculture Research Needs

By Dallas Weaver, Ph.D.*

There is an inherent food conversion efficiency advantage of aquaculture over terrestrial meat production, based upon the fact that aquatic animals don’t have to expend energy to stand up or keep warm.

This fact, combined with the coming 3 billion more people, as well as the already present 2 billion people on this planet who desire more edible protein sources, means that the world will be forced by finite agriculture area to grow “feed stuff” to produce meat. This will result in an inevitable shift towards drastically increasing aquaculture production of meat. Therefore, research will be required in all areas of aquaculture production — ranging from “nut and bolt” research into practical culture systems, genetics, and nutrition, to advanced ecological genetic research necessary to obtain some control over microbiological ecologies associated with aquaculture.

At the present time, this world wide shift to aquaculture to obtain these meat production efficiency advantages of 2 to 3 more meat per unit of “feed stuff” is occurring outside the U.S. Our regulatory systems and other factors are preventing our development of aquaculture. We are even falling behind the rest of the world in aquaculture technology as they develop off-shore aquaculture systems and massive high intensity production with a growth rate in the range of 9 %/year, while aquaculture is actually shrinking in the U.S. If this trend continues, all the jobs associated with meat production by chickens and pigs in the U.S. will lose market share to imported aquaculture production from countries ranging from Norway to Bangladesh and India and everywhere in between. The continued technological evolution of aquaculture will make fish/shrimp a cheaper meat than pigs and chickens, which have higher food energy demands per unit of meat. Unless policy changes, the U.S. will not be part of that evolution.

This being left out of the party is unnecessary. The U.S. could utilize its technological leading position in biotechnology to regain a top position and prevent the above massive job losses to aquaculture imports. One area would be GMO animals, however, this is a politically loaded area and probably a non-starter in the “Land of Activist Veto” of any implementation by any miscellaneous anti-science nut group with good PR desires. However another area has to do with the external and internal micro-biomes associated with aquaculture, where the relevant biological games deal with viruses, phages, bacteria, fungi, algal organisms and their complex interactions that activists don’t understand and can’t even imagine. To most activists, “ecology” is just a buzz word with no understanding of the real complexity of the interactions implies in this word.

Except for flow-through aquaculture and systems with massive water exchanges (net pens, raceways and fast exchange ponds on rivers, etc.), most aquaculture systems, including all pond culture and recycle aquaculture systems, depend upon microbiological ecology to handle, detoxify and recycle the waste products. This complex ecology contains thousands of species of viruses (phages), bacteria, fungi, algae, protozoans, zooplankton, pathogens, etc. whose complexity and dynamics are poorly understood.

Crude attempts are being made to influence these microbiological ecologies using “probiotic” and “prebiotic” formulations which are being utilized around the world. However the results are neither consistent nor reproducible. In the natural world, we know that the structure and composition of many of these aquatic microbiological ecologies depend upon the entire ecology down to the phage level. The phage (virus) level can determine which strain of algae will be dominant and whether that is a toxic strain or a non-toxin producing strain.

If we could control these microbiological ecologies in pond and recycle aquaculture systems, we could control the water chemistry, energy flows and the performance of our target species. To control these system, we need basic research to define the systems down to the DNA/RNA level and all their interactions. Modern biological technology is now on the exponential cost-decreasing curve, long associated with microelectronics. This is an area where the U.S. is a dominant player and the spillovers from this area could be utilized to make the U.S. a top aquaculture producer.

Basically, all pond and recycle aquacultural systems are really “polyculture” systems of thousands of interacting species, which presently only sell one or a few species. Opportunities are present to capture more of the internal energy flows into sellable products or to shift the energy flows away from detrimental outcomes that limit production. For example, in conventional pond aquaculture with fish being fed by the farmer, the nutrients are being recycled in the algal ecology, which maintains the water quality of the system. If this algal production were then used to feed a filter feeding species or harvested for sale, the net production of sellable product can be increased without increased resource usage (increased sustainability). However, such systems are unstable in an open environment, where new microbiological species/strains can be introduced. For example, an algal species that can’t be harvested by the filter feeder species can have an advantage and become dominant at the expense of a more desirable, nutritious, digestible (i.e., sellable) algal species.

In order to create stability in an inherently unstable environment, a true understanding of the ecology becomes critical. For example, if a species/strain of toxic algae becomes dominant, it is theoretically possible to introduce a mix of specific phage (a virus) that will selectively kill/control those algae. With cheap enough DNA analysis to determine what strains of what organisms make up the microbiological ecology and a library of lytic phages, we could, in theory, stabilize the ecology in a structure that is beneficial to the farmer as the system shifts from one species of profitable algae to another species by killing unwanted toxic algae with specific phage additions. With enough information on the status of the microbiological ecology and enough control tools, the problem of stability becomes a standard control theory problem through which an unstable system is made stable by active feedback control.

Research in this direction will be tightly coupled with basic research into natural microbiological ecologies, biotechnology and the rapidly changing area of bioinformatics. To accomplish this necessitates support of very basic research along with support of the more applied practical research and increasing the communication between the two complimentary research areas.

Future aquaculture will of necessity be tightly coupled with biotechnology. Consequently research efforts should be concentrated in biotechnology. Initially, the amount of money devoted to research will represent a high percentage of sales, because the amount of resources devoted to aquaculture R&D needs to be based upon what the industry will be two decades from now, not on what it is today.

Dallas Weaver, PhD, started designing and building closed aquaculture systems in 1973 and worked for several engineering/consulting companies in the fields of air pollution, liquid wastes, and solid wastes until 1980. Today, he’s the Owner/President of Scientific Hatcheries.
e-mail: deweaver@mac.com

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