Thanks to recent funds from an NSERC-SPG grant we are beginning to study food web dynamics and nutrient recycling in mussel aquaculture in Quebec. AquaMaN is our catchy internal acronym for the project but its real title is “Integrating across scales in marine aquaculture: the role of trophic dynamics and nutrient recycling for mussel production.”
The primary goal of aquaculture is to produce animals which occupy higher trophic levels in aquatic food webs. Aquaculture systems are complex trophic systems; their dynamics and productivity are the result of numerous interactions between nutrients and organisms in the food web and the net effect of these interactions is difficult to predict. If aquaculture is to fulfill its role as an environmentally sustainable alternative to large-scale commercial fisheries, the management of animal production needs to be increasingly based on the flows of energy and material supplied by the target organisms' natural food webs.
Bivalve aquaculture is especially amenable to this approach:
- Unlike fish cultures, bivalve mariculture is typically non-enclosed, with intensive cultures growing in their natural marine environment (although at unnaturally high densities).
- Bivalve culture ultimately relies on autochthonous primary production, i.e. cultures are not being enriched to enhance growth.
- Marine bivalves are suspension-feeders which occupy a lower trophic level than most other economically important species in aquaculture farms. This decreases the potential complexity of the food webs to consider and increases the ecological efficiency of energy flow from the base to the top of the food web.
Our research project explores the potential of a food-web-based approach to managing suspended bivalve aquaculture across trophic levels. We focus on experimental investigations spanning a wide range of spatial scales and combine these with mathematical food web modelling approaches.
The ultimate question: Can marine mussel aquaculture be managed in a more efficient and, at the same time, more sustainable way than is presently commonly practiced?
What is the importance of qualitative differences within and among food types for mussel production?
What is the role of food web structure and dynamics, in particular, the differential effect of absence and presence of microbial heterotrophs and zooplankton?
How can we prevent loss of nutrients to the benthic compartment by “shortcircuiting” nutrient recycling on the aquaculture structure?
How do mussel-related food web dynamics change at different scales?
We investigate aquaculture-related processes at scales ranging from individual mussels to whole experimental ecosystems. The experimental units range from beakers/chemostats (volume ≈ 1L) over larger in-door mesocosms (≈ 1,000L) to sections of in-situ aquaculture facilities (> 100 m3); or in ecological terms, from the individual over the population and community level to the ecosystem level. The rationale of this approach is to assess the validity of a reductionist approach with respect to spatial scale and to reveal the importance of higher-order processes within the mussel aquaculture framework.
We combine experimental and theoretical approaches, i.e., food web models with coupled ordinary differential equations. These models help us to understand the dynamic processes that occur across the ecological interfaces that we identified and to predict system behaviour for scenarios that cannot be experimentally investigated.
Our experimental approaches focus on the blue mussel (Mytilus edulis, which is a commercially important species and widely cultured in commercial aquaculture in Eastern Canada) and the pelagic and benthic ecosystem acssociated with mussel cultures. Experiments take place at the Institut Maurice Lamontagne of Fisheries and Oceans Canada and at our field site in the Magdalen Islands.
This is a collaborative research project between McGill University (Prof. Gregor Fussmann, lead-PI), Université de Québec à Rimouski (Prof. Philippe Archambault, Prof. Réjean Tremblay), Université Laval (Prof. Connie Lovejoy), Fisheries and Oceans Canada (Senior scientists Dr. Christopher McKindsey and Dr. Stéphane Plourde), MAPAQ (Dr. Bruno Myrand) and the aquaculture industry in the Magdalen Islands (Moules de Culture des Îles).
Mehdi Cherif is the postdoctoral fellow on this project.
Graduate students on the project are Sean Duffy (McGill), Lisandre Gilmore-Solomon (UQAR), Monica Granados, Vani Mohit (Laval), Pauline Robert (UQAR), Bérangère Paquin (Laval) and Nicolas Toupoint (UQAR).
NSERC Strategic Partnership Grant (PIs: Fussmann, Archambault, Lovejoy, Tremblay; collaborators: McKindsey, Myrand, Plourde).
We acknowledge generous financial support by the Réseau Aquaculture Québec (RAQ) and by the Société de développement de l'industrie maricole inc. (SODIM).
We acknowledge generous in-kind contributions by Moules de Culture des Îles, MAPAQ and Fisheries and Oceans Canada.