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Bibliographie de l'Institut Maurice-Lamontagne

Annelidés - Polychètes / Pectinaria granulata / 

WEISE, A.M., C.J. CROMEY, M.D. CALLIER, P. ARCHAMBAULT, J. CHAMBERLAIN, C.W. McKINDSEY, 2009. Shellfish-DEPOMOD : modelling the biodeposition from suspended shellfish aquaculture and assessing benthic effects. Aquaculture, 288(3-4): 239-253.

[Résumé disponible seulement en anglais]
By predicting the dispersal of particulate aquaculture wastes around farm sites, numerical modelling can provide an effective tool to assess the spatial extent of environmental effects. The present paper describes how the aquaculture waste model DEPOMOD (Cromey, C.J., Nickell, T.D., Black, K.D. 2002a. DEPOMOD – modelling the deposition and biological effects of waste solids from marine cage farms. Aquaculture 214, 211-239.), originally developed for finfish aquaculture sites, was adapted and validated for suspended shellfish aquaculture. Field data were collected for species-specific model input parameters (mussel biodeposition rates and particle settling velocities) and several finfish model parameters (farm representation and calculation of aquaculture wastes) were adjusted for the shellfish scenario. Shellfish-DEPOMOD was tested at three coastal mussel Mytilus edulis farms with differing hydrodynamic regimes in Quebec, Canada. For each site, model predictions were compared to observed deposition measured in situ with sediment traps. Sedimentation rates under the three mussel culture sites were ca. Two to five times those observed at corresponding reference sites. Mussel biodeposits were predicted to accumulate within 30 m of the farms in the shallow depositional sites while being dispersed more than 90 m in the deeper dispersive site. At the farm site in Great-Entry Lagoon, model predictions agreed well with field data for the 0+ and 1+ mussel cohorts when the maximum biodeposit production parameter was used. At the farm site in House-Harbour Lagoon, model predictions did not agree with observed sedimentation rates, due most likely to the resuspension and advection of non farm-derived material and complex hydrodynamics. The model correctly predicted the pattern of waste dispersal at the third farm site in Cascapedia Bay, although it underestimated biodeposition. Predicted fluxes may have been underestimated at this site because biodeposits from biofouling communities were not included in the calculation of aquaculture wastes. The relationship between modelled long-term biodeposition and benthic descriptors was assessed for the three farms. Alterations to the benthic community were observed at high biodeposition rates (>15 g m-2d-1). At the most disturbed site, predicted fluxes were best correlated with the Infaunal Trophic Index (ITI) (R=-0.79, P<0.001), followed by AZTI's marine disturbance index (AMBI) (R=0.64, Pb0.001). The potential application of Shellfish-DEPOMOD in terms of the management of shellfish aquaculture sites is discussed.©2008 Elsevier B.V.

CALLIER, M.D., C.W. McKINDSEY, G. DESROSIERS, 2008. Evaluation of indicators used to detect mussel farm influence on the benthos : two case studies in the Magdalen Islands, Eastern Canada. Aquaculture, 278(1-4): 77-88 .

[Résumé disponible seulement en anglais]
The aim of this study was to identify appropriate indicators to determine the influence of mussel aquaculture on the benthic environment. Both sediment [particle size, sediment profile imaging (SPI), % OM] and benthic community (abundance, biomass, number of species, Margalef’s species richness, Shannon-Weiner diversity, Pielou’s eveness, individual body mass, trophic group, a biotic index — AMBI, and community structure) characteristics were evaluated at two mussel farms in Great-Entry (GE) and Havre-aux-Maisons (HAM) lagoons in the Magdalen Islands (Quebec, Canada). Sampling stations were positioned directly beneath the outer-most mussel lines (0 m) and at distances of 3, 6, 9, 15, 30 m and at a control site (at either 300 or 500 m) along a transect leading from each farm. Contrasting patterns were observed. At GE, sediment characteristics and benthic communities did not vary among stations and were characterized by low diversity, abundance and biomass. At HAM, % OM decreased and macrofaunal diversity and abundance increased with increasing distance from the farm. Biomass was low under the mussel line, increased between 3 and 30 m and was low again at 300 m. This was explained by the abundance of the polychaete Pectinaria granulata, which seems to have benefited from a moderate organic loading associated with the mussel farm. The mean individual biomass of the second-order opportunistic deposit feeders P. granulata and Heteromastus filiformis decreased with distance from the farm, whereas that of the pollution-sensitive suspension feeder Ensis directus and deposit feeder Tellina agilis increased with increasing distance from the farm. At HAM, the effects of mussel farming were restricted to the vicinity of the farm, while at GE the pattern was less clear. The GE mussel farm had either little effect on the local environment or else larger-scale but diffuse effects. The study showed that the a priori choice of the sampling stations and indicators may influence the interpretation of the results. Community structure and SPI were the most efficient indices for detecting both small- and broader-scale influences at both studied mussel farms.©2008 Elsevier B.V.