RESEARCH - Research Summary

Environmental Integrity Theme

Research Summary

The release of solids, nitrogen and phosphorus from aquaculture operations into the surrounding waters may lead to environmental degradation. Phosphorus waste output is a greater concern in freshwater, since it is generally the most limiting factor for plant (algae) growth in that environment. Nitrogen waste output is generally a greater concern in the marine environment for the same reason. Solid wastes settling to the sediment can negatively impact fresh water and marine benthic ecosystems by creating anoxic conditions. Reduction of all these types of wastes is key to ensuring the long-term sustainability of fish culture in Canada. Since all these wastes (solid, nitrogen, phosphorus) are ultimately from biological and dietary origins, efforts to reduce waste outputs should concentrate on these sources, either through improvement of the cultured animals themselves (e.g. through genetic improvements), or the feeds and feeding strategies.

This project brings together investigators and partners from Canada, France, Mexico, Norway, Portugal and the U.S.A. with complimentary strengths and interests (nutrition, genetic, physiology, growth modeling and environmental impact assessment). The investigators are conducting a series of trials to improve our understanding of factors that have a determinant effect on solid, nitrogen and phosphorus waste outputs of fish. This improved knowledge will then be translated into the development of approaches, such as feed formulae, models, software, genetic selection strategies and waste signatures that will help mitigate the environmental impact of fish culture in Canada.

A series of feeding trials have been conducted to examine the effects of different diet compositions, blood meal feeds, ingredients such as soybean meal, and additives such as exogenous enzyme, on feed utilization, digestibility, fish species, fish size, and solid waste output. A dataset of energy-yielding nutrient utilization by salmonids is currently being constructed. The research findings will help Canadian feed manufacturers to improve feed formulae and production models and help establish guidelines for aquaculture wastes.

Network Investigators

Dominique P. Bureau, Department of Animal and Poultry Science, University of Guelph, Guelph, ON
C. F. M. de Lange, Department of Animal and Poultry Science, University of Guelph, Guelph, ON
Richard D. Moccia, Department of Animal and Poultry Science, University of Guelph, Guelph, ON
Stephen Birkett, Dept. of Systems Design Engineering, University of Waterloo, Waterloo, ON
Muriel Mambrini, Institut National de Recherche Agronomiques (INRA), Jouy-en-josas, France
Barbara Grisdale-Helland, AKVAFORSK (Institute of Aquaculture Research AS), Sunndalsora, Norway
Stale J. Helland, AKVAFORSK (Institute of Aquaculture Research AS), Sunndalsora, Norway
Patricia Wright, Department of Integrative Biology, University of Guelph, Guelph, ON

Publications

Azevedo, P.A., S. Leeson, C.Y. Cho, and D. P. Bureau. 2004. Growth, nitrogen, and energy utilization by four juvenile salmonid species: Diet, species, and size effects. Aquaculture. (In Press)

Encarnacao, P.M., C.F.M. de Lange, M. Rodehutscord, D. Hoehler, W. Bureau and D. P. Bureau. 2004. Diet digestible energy content affects lysine utilization, but not dietary lysine requirement of rainbow trout (Oncorhynchus mykiss) for maximum growth. Aquaculture. (In Press)

Bureau, D.P., S. Gunther and C.Y. Cho. 2003. Chemical composition and preliminary theoretical estimates of waste outputs of rainbow trout reared on commercial cage culture operations in Ontario. North American Journal of Aquaculture 65: 33-38.