Application of biotechnology to high yield aquaculture systems

Joseph A. Hankins

The Conservation Fund Freshwater Institute

Shepherdstown, WV 25443

j.hankins@freshwaterinstitute.org

Abstract

The aquaculture industry is currently faced with solving the simultaneous problems of developing economically viable production systems, reducing the impact on the environment and improving public perception. Significant progress has been made in understanding and design of production systems. Improvement in cultured stocks has not kept pace with productivity demands. The benefits of advancing aquaculture capability, driven by investments into biotechnology research, may allow rapid progress in fish farming productivity if those advances do not create additional environmental or economic liabilities.

Keywords: GMO, controlled environment aquaculture, system productivity

Introduction

The promising application of biotechnology to aquaculture production has stimulated heated debate around the issues of potential human health impacts, environmental risks, toxicity, economic efficacy and even morality. Many of the issues must and will be debated in the arenas of public policy, politics and, one hopes, in the scientific literature. A continuing theme is the concern over the risk of interaction between GM crops and constructs and the natural ecology. Critics have drawn parallels to the early use of pesticides justified for the green revolution and have added the new fear of escaped GMO crops multiplying uncontrollably and with unintended effect.

One solution that appeals to both sides is the idea of closed or secure production systems specifically designed to maximize the advantage of GM technology and minimize the interaction risk with the external environment.

Status of Controlled Environment Aquaculture

On first examination the match up of GM technology and high yield controlled systems seems to be logical and ideal. Currently the design philosophy of such systems provides for consistent, stable culture conditions that are continuously in the optimum range for the minimization of growth limiting factors. Through substantial progress in the field of aquaculture engineering, we can now design and technically operate finfish production systems that operate at standing crop densities of 150 kg/m³ and annually produce biomass that exceeds the standing crop by a factor of five or more. Over the last decade, the design of the biofilter has progressed from a black art to an act of predictable unit process engineering. Our understanding of the importance of gas exchange and bio-solids removal has led to reliable designs to control factors that often caused earlier systems to fail. The explosion in industrial electronics technology has given aquaculture the ability to measure, monitor and control the environment in real time, providing ever more cost effective reliability and operation robustness.

Advantages to closing and controlling the aquaculture production environment are numerous and compelling. The simple act of enclosure provides an increase in crop and food product biosecurity that can reduce or eliminate the risk of certain diseases, predation, contamination, weather and theft. Enclosure and intensification can provide new opportunities for culture in non-traditional locations and remove dependence on unique natural resources. Intensification with appropriate technology can economically minimize the quantity of waste products that leave the facility and provide opportunities for sustainable reuse. Controlled environment aquaculture can dramatically increase productivity through the precision selection of optimum environmental conditions that allow rapid, near non-limiting growth.

Controlled environment aquaculture has been criticized as impractical and unsustainable, largely on the basis of the capital and operational cost for the complexity. In simple terms the advantages of control and intensity can be outweighed by the cost of achievement, when practical markets and products are considered.

We Need a Better Fish

It could be argued that a clear solution to the impracticality of intensification is to produce a product that provides greater production efficiency and provides greater economy to the farmer. While there have been substantive advances made in rearing system design and environmental control, for all practical purposes the fish now being cultured has changed very little from the fish available to farmers over the last two decades. Aquaculture is coming late to the table when compared with the performance superiority and generations of selection in other animal and plant crop systems. With the exception of catfish and trout, fish farmers are working with strains that are often still more wild than domesticated. Fish farmers are writing production stories with ink quill on parchment technology while the poultry and corn farmers get to use a PC and a word processing application. Should aquaculture be forced to use obsolete tools like offset printing and typewriters because their agricultural forefathers did? In truth, it seems reasonable that the largest return on immediate state-of-the-art technological investment would come from the agriculture production sector that is furthest behind, and from which so much is expected in the future.

The wish list for attributes that might be found in a better fish might be categorized into areas of metabolic efficiency, disease resistance, morphological conformation, behavior, harvestability, product yield and quality.

It can be demonstrated that the growth rate of fish cultured in any rearing system has a large and controlling impact on annual productivity, on the standing crop biomass required to generate a given level of annual productivity and by extension the capital and operational cost to support that biomass (Hankins et al., 1995). In simple terms, relatively small increases in growth rate (10-20%) have disproportionately large impact on the economic productivity of production systems. The projections for increases in GM salmonid growth rates of 200% to even 400% present the kind of disruptive technological impact that could revolutionize and immediately legitimize intensive controlled production system aquaculture.

Application of Soft Biotechnology to High Yield Intensive Systems Operation

Biotechnology applications need not be limited to the cultured product. There is growing interest and credible evidence that the presence of probiotics can have a significant impact on survival and disease resistance . Biologically reactive sensors may be developed that allow the direct measurement of stress, metabolic or reproductive condition or environmental chemistry (Delwiche et al., 2000). Biofilters could be seeded with specially selected microbial populations that would reduce the size and cost of filter construction (Libman et al. 2000; Vanotti and Hunt, 2000). Sentinel fish might be created to detect the presence of a pathogen or toxic threat before it could impact the larger normal population. Microbial systems might produce feedstock ingredients that are superior to wild harvest materials such as fishmeals and fish oils.

Complications Created by Biotechnology that are Relevant to

Aquaculture Production System Design

Over the last half century of aquaculture research and development, most of the progress has been internal to the production process, examining culture practices and systems, feeds and nutrition, species choice and other husbandry considerations. Over the last decade an increased awareness and urgency has developed regarding certain external factors or constraints involving industry sustainability and environmental interactions. In some cases these concerns are driven by the aquaculture industry’s recognition that some practices or key production inputs currently utilized to maintain productivity are no longer assuring future profitability. In other cases, a maturing aquaculture industry has found itself increasingly scrutinized by regulatory and private sectors no longer willing to automatically accept aquaculture as alternative "green" agriculture.

The introduction of biotechnology into the mix of technologies available in production system design and application choice provides dramatic and appealing options for increased productivity, product quality and management. This new technology will only be effective and welcomed if the new choices can be integrated into cost effective systems and do not bring a large baggage of external factors that must be internalized at the farm level. A faster growing fish is a panacea for increasing return on capital investment, but only if additional new investment is not required making the production system 100% escape proof. GM products may be welcomed at the farm level, but not if the potential market for the products is severely limited, or traceability and labeling requirements create large liabilities and risks. GMO candidates for culture must have attributes that improve robustness, reliability and efficiency, potentially reducing production system cost; rather than requirements for narrow and refined environments that increase management complexity.

Next Steps

The U.S. and European aquaculture industries, and to some extent the general public, has mixed feelings about intensification of production and the appropriate application of high-yield technology to increase productivity (Kilman 1999; Urch 1999). Other sectors of the global aquaculture community may have made more pragmatic decisions (Leggett and Johnson 2000) and these sectors will be our global competitors in the future. One can clearly argue that for terrestrial agriculture (Avery 1999a,b; Huber 1999) and specifically for aquaculture (Bergheim, Kristiansen et al. 1993; Summerfelt 1998), that intensification provides the only foreseeable solution to meeting the at odds imperatives of conserving natural resources and meeting the food production requirements of a growing global population. Low yield aquaculture will not get us where we need to go. We simply must get smart enough to create and use the tools technology provides in a sustainable manner.

Short-term (1-3 years)

• Increase multi-disciplinary research investment with a production systems focus
• Leverage non-agriculture/aquaculture R&D and make cross-cutting applications
• Develop criteria for research needs that recognize the importance of precaution and fully realized application cost at the farm level
• Establish stakeholder driven mechanism for identification of traits and characteristics that benefit from improvement
• Fully explore newly emerging soft biotechnologies such as biosensing, probiotics, bioremediation