Development of longline mussel farming and the influence of sleeve spacing in Prince Edward Island, Canada

This paper describes the historical development of blue mussel (Mytilus edulis) farming in Tracadie Bay (Prince Edward Island, Canada) and relates the spacing of suspended sleeves (SS) on longlines to seston uptake. From 1990 to 2001, mussel biomass in Tracadie Bay increased by a factor of four (from 1137 to 4743 t). By 2001, seston uptake rates were approximately three-fold water renewal rates, and harvest yields (kg sleeve− 1) were significantly lower than in the early 1990s. A one-year field experiment was carried out to determine whether a change in SS could restore harvest yields. We found that SS (10, 20, 40, 60, 80 cm) had no significant effect on the condition index of mussels. However, high SS positively affected shell growth and abundance for small seeds that were densely packed within sleeves. A complete husbandry shift toward high SS and high seeding densities (within sleeves) may enhance farm productivity (production per unit of effort) and curtail seston uptake at the bay scale.