Early life stage research…a new opportunity for US aquaculture

John Nickum
August 22, 2017
By John Nickum

The Foundation for Food and Agriculture Research (FFAR) is a nonprofit organization established by the United States’ Congress in the 2014 Farm Bill. Remarkably for these times, there was bipartisan congressional support for the organization and the activities it supports, which include aquaculture.

The FFAR announced a competitive, matching grant research program in early June (2017), designed to stimulate innovative research on farmed production of fish and shellfish. One of the focus areas identified in the announcement was research to identify best practices for early stage life cycle production of commercial fish.

Studies to identify additional species with potential for commercial production are another focus area. And studies to analyze the potential for expansion of presently cultured species into additional geographic areas will also be encouraged.

These types of research and development studies are complicated and difficult, but they are important, perhaps essential, if the United States is to become competitive in international aquaculture production.

Financial constraints

The financial capabilities of the aquaculture community for research and development studies are very limited, essentially non-existent; so, it is encouraging to obtain support from an organization such as FFAR.

Research focused on production of “new” species and, especially on early life stage production methods, is rarely a priority for commercial farmers, or even managers of state and federal facilities.

When current methods are considered to be satisfactory (good enough?) and produce satisfactory survival and growth of the species under production there is little, or no, incentive to investigate new methods and/or culture of additional species.

Budgets are always lean, so exploring new horizons is pretty much an unaffordable luxury for most farmers and managers. If new methods are to be developed, or production of “new” species explored, funds will have to come from government programs, or non-profit foundations. 

  Difference of opinion

There is a long-standing argument among fish culturists concerning the preferred approach for culturing early life stage fishes. Those who prefer to maximize control of the entire process want predictable feeding regimens based on formulated feeds. The other, traditional, side of the “discussion” argues that it is unrealistic to design feeds that the young fish will eat and satisfy all of their survival and growth needs. These culturists contend that offering live food items, similar to those the fish would eat in a natural environment is more realistic.

However, the live food approach requires additional culture operations; production of an array of invertebrates and/or algae. Extra culture units and/or natural pond environments are required for live feed production. Those who prefer formulated feeds argue that adding facilities and operations for these live food items increases costs and the possibilities for failure… one more chance to screw up. Conversely, developing formulated feeds and feeding systems that meet all the requirements needed by the newly hatched fish can be costly and complicated… very complicated.

The walleye challenge

My own research, many years ago, provides an example of the challenges involved with the culture of early life stage fish, especially species that have not been hatchery-reared previously.

My students, research associates, and I focused on developing intensive culture systems for walleyes; systems to rear them from first-feeding early life stage through to market size.

Walleyes, and other fish similar to them, such as striped bass, are especially difficult because the newly hatched fish are very small (7-8 mm), have small mouths, and very small yolk sacs. The energy and nutrient reserves in their yolk sac are extremely limited. They must begin feeding within 3 to 4 days, at the longest, or they “sink” into energy and nutrient deficits from which they cannot recover.

Adding to the problems in the case of walleyes is the fact that first-feeding larvae lack several gut enzymes; therefore, digestibility of feeds was a major issue. We designed initial feeds on formulas designed to replicate the nutrient and energy composition of walleye eggs, but with lower fat content. Feeds with full equivalent fats had the consistency of peanut butter.

Tank/trough culture of first-feeding fish requires solutions to an array of culture conditions in addition to a satisfactory feed. Water temperatures, light conditions, water movement, and aeration systems all must be controlled within narrow limits similar to those experienced by each species in its natural habitat.

In the case of walleyes, and similar carnivorous species, control of cannibalism adds to the challenges. All these challenges notwithstanding, it is technically possible to rear walleyes from hatching to market size fish (~ 4 kg) under intensive culture conditions. However, price competition from wild-caught fish captured primarily from large Canadian lakes, has prevented the development of economically feasible walleye farming.

Creative farmers

The research support offered by FFAR will provide creative farmers, managers, and researchers with incentives to identify species with market potential, and design research plans to address the myriad challenges inherent in the culture of early life stages that suit the needs of “new” species in new geographic areas.

Given the reality that the United States currently imports almost 90% of the seafood consumed domestically, half of which comes from foreign aquaculture sources, it is vitally important for American producers to accept and meet these challenges.

John Nickum

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