RESEARCH - Research Summary

Research Summary

According to the Canadian Fisheries Act, aquaculture facilities must not give rise to “the harmful alteration, disruption or destruction of fish habitat”. This essentially means that the productivity of the sites must be maintained. Despite the evidence that aquaculture sites may impact benthic communities (i.e. alter their structure because of an increased deposition of organic matter) little work has examined the actual productivity of the benthos - what the law is based on. Similarly, little research has been directed at examining interactions between bivalve aquaculture (e.g. mussels) and the abundance and productivity of macrobenthic invertebrates (lobster and crabs) and fishes.

This research project tests the general hypothesis that the abundance and productivity of fish and large invertebrates is enhanced in mussel culture sites. An increase in the productivity of this component of the ecosystem may offset some of that productivity commonly believed to be lost due to the presence of aquaculture. Work will include surveys and a determination of the productivity of these organisms. Work will include surveys of fish and invertebrates and determination of the productivity of these organisms. The work will be replicated both temporally and spatially to ensure generality of the results.

Several lines of evidence suggest that an increased abundance of several species at mussel aquaculture sites may also lead to an increase in the productivity of these species through a complex cascading effect of aquaculture on the local environment. For example, winter flounder is one of the dominant fish species in the lagoons of the Magdalen Islands and seems to have increased abundances within mussel farms there. Winter flounder shift their diet with their size, the smallest ones feeding mostly on small worms that often dominate under mussel aquaculture sites, as they do in the Magdalen Islands. Thus an abundance of food for this species may increase their growth rate, allowing them to more quickly attain a size that is less susceptible to predation and have a larger reproductive output, increasing their productivity. Other arguments may also be made for the productivity of lobster and crabs in mussel aquaculture sites based on the abundance of mussels that fall from the mussel lines and are a food source for these two species.

The proposed research will help to better understand the mechanisms that increase the productivity of fishes and macroinvertrebrates, justifying the evaluation of their abundances as a key tool for environmental assessments and monitoring of aquaculture sites.

Network Investigators

Chris McKindsey, Fisheries and Oceans Canada, Institut Maurice Lamontage; Institut des sciences de la mer de Rimouski (ISMER), Université de Quebec à Rimouski (UQAR), Mont-Joli, QC
Philippe Archambault, Fisheries and Oceans Canada, Institut Maurice Lamontage, Institut des sciences de la mer de Rimouski (ISMER), UQAR, Mont-Joli, QC,
Guglielmo Tita, Station technologique maricole, Ministère de l’Agriculture, des Pêcheries et de l’Alimentation, UQAR, Cap-aux-Meules, QC
Thomas Landry, Fisheries and Oceans Canada, Université de Moncton, Moncton, NB