MEPS 297:157-167 (2005)  -  doi:10.3354/meps297157

Bay-scale spatial growth variation of mussels Mytilus edulis in suspended culture, Prince Edward Island, Canada

Linda Waite1,3,*, Jon Grant2, Jeffrey Davidson1

1Atlantic Veterinary College, Department of Health Management, Charlottetown, Prince Edward Island C1A 4P3, Canada
2Dalhousie University, Department of Oceanography, Halifax, Nova Scotia B3H 4J1, Canada
3Present address: 202 Reade Street, Moncton, New Brunswick E1C 6S6, Canada

ABSTRACT: Spatial growth variation of experimentally cultured blue mussels Mytilus edulis in Tracadie Bay, Prince Edward Island, Canada, was consistent in both years of a 2 yr study. The spatial pattern displayed reduced tissue growth along a gradient of decreasing tidal exchange from the inlet mouth to the inner estuary. There was no indication of persistent spatial differences in seston concentration among stations. The data imply that the flux of food (expressed as the product of concentration and current speed) controls the spatial variation in growth, with decreasing flux from the outer to inner bay. Growth trajectories analysed by polynomial regression differed between years despite spatial similarities within each year. Results of multiple regression analyses explaining mussel growth suggested that temporal variability in seston characteristics was more important in explaining growth than annual mean seston levels. Chlorophyll a and meat weight showed similar patterns of increase during 1998. In 1999, higher summer temperatures were more important in determining upper limits of growth, with later growth stimulation apparently in response to an autumn phytoplankton bloom. The pattern of spatial variability in mussel growth, representing decreased growth rates in the inner relative to the outer bay, provided evidence that the density of mussels in Tracadie Bay was exceeding the food supply.

KEY WORDS: Mussels · Mussel growth · Food availability · Phytoplankton · Aquaculture · Carrying capacity

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