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![](https://webarchive.library.unt.edu/eot2008/20081109093507im_/http://www.ars.usda.gov/incme/images/Research_head.gif) |
Research Project:
NOVEL APPROACHES FOR IMPROVING PERCH GROWTH IN RAS SYSTEMS
Project Number: 3655-31000-020-02
Project Type:
Specific Cooperative Agreement
Start Date: Apr 28, 2006
End Date: Jun 30, 2009
Objective:
The yellow perch (Perca flavescens) is an important social and economic species in the Great Lakes, however, populations have plummeted. Given strong consumer demand, and high fillet value ($12.00/lb.- $15.00/lb retail), there is an urgent need to develop a sustainable yellow perch aquaculture industry that can deliver a high-quality cultivar year-round. Northern Aquaculture Research (NADF) will focus on a portion of the objectives that form the research initiative being conducted by ARS/USDA/Great Lakes Aquaculture Center (GLAC) at the University of Wisconsin-Milwaukee Great Lakes Water Institute (GLWI). The objective is to assist with developing/adapting recirculating aquaculture system(s) technology for year-round production and enhanced grow-out. This will be accomplished by examining the effects of diel temperature fluctuations on juvenile perch growth, over a 6-month interval, in commercial-scale recirculating aquaculture systems (RAS), and to repeat the findings of this initial study. We expect to show that underutilized capabilities (temperature control) of RAS systems can be used to improve yellow perch growth, in an environmentally compatible and sustainable manner, for year-round production of this cool water species.
Approach:
The goal of this project is to evaluate growth (linear and mass) and feed conversion efficiency of perch exposed to fluctuating thermal regimes in commercial-scale recirculating aquaculture systems. Due to system limitations, there will only be two treatments (constant vs. fluctuating temperatures). It will be necessary to repeat the study to ensure that the findings will stand up to peer-review for publication in a mainstream aquaculture journal.
Each system will be stocked with juvenile perch that have been habituated to the indoor RAS systems at NADF. Prior to each experiment, each lot of fish used will undergo the fish health certification procedures developed by the Wisconsin Department of Agriculture aquaculture veterinarian, and no unhealthy fish will be used. The six-month time frame for each proposed experiment necessitates that each experiment begin with fish that are at least several months old (100 mm in mean length and 10g in mean weight). For the grow-out study, one system will be held at a constant temperature of 20 C and constant photoperiod, whereas the second system should experience diel fluctuations (cooling to approximately 18 C during the scotophase and warming to approximately 22 C during the photophase, temperatures should be gradually ramped up or down) around a mean temperature of 20 C. NADF personnel will determine the stocking densities of juvenile fish in each system and replication.
In addition to routine daily maintenance of the RAS systems, water chemistry measurements to be done on a daily basis include pH, temperature, and oxygen. Ammonia, nitrite, and nitrate will also be measured on a regular basis. Careful assessments of feed intake will also be determined on a daily basis so that feed conversion efficiency can be estimated. To obtain maximum growth and careful feed estimates, fish will be fed to apparent satiation each day. Every three weeks, a random sample of 300-400 fish (from each system) will be weighed (grams) and measured (length in mm); adjustments in feed will be made accordingly. The amount of uneaten food will also be observed and quantified.
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Last Modified: 11/08/2008
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