ENHANCED GROWTH RATES AND CONDITION INDEX OF BLUE MUSSELS (MYTILUS EDULIS) HELD AT INTEGRATED MULTITROPHIC AQUACULTURE SITES IN THE BAY OF FUNDY

Atlantic salmon (Salmo salar) farms in the Southwest Bay of Fundy area of New Brunswick were investigated for possible advantages of nutritional enrichment for the blue mussel (Mytilus edulis) when grown in integrated multitrophic aquaculture (IMTA) systems. Mussels grown in IMTA systems may be exposed to higher concentrations of organic matter at the salmon farms that can enhance growth rates and decrease time to market for the grower. In this experiment, mussels were sock-cultured at 2 distances from 2 separate salmon farms (0 m and 200 m), with 3 growth parameters (shell length, wet meat weight, and condition index) measured monthly and compared with the same growth parameters in mussels grown at a reference site outside the aquaculture influence. After a12-mo period, mussels grown directly on the cages grew faster than mussels 200 m away on all parameters except shell length at 1 location. Mussels grown at 0 m and 200 m performed significantly better (P<0.05) in all growth parameters compared with mussels grown at a reference site outside the aquaculture influence. Differences in growth and condition index were most pronounced in the fall and winter, when ambient seston concentrations were low. Results of a second study in which growth rates for individually tagged mussels was monitored for a 6-mo period confirmed that there is a significant growth benefit for mussels in integrated aquaculture with salmon compared with mussels grown 500 m away at a reference site.