Fish recruitment in the Saguenay Fjord
In the Saguenay Fjord, the fish community is composed of more than 60 marine, diadromous and freshwater species, including many species exploited by the winter sport fishery such as the rainbow smelt (Osmerus mordax), redfish (Sebastes spp.), Atlantic cod (Gadus morhua), Greenland cod (Gadus ogac), and Greenland halibut (Reinhardtius hippoglossoides). We do not know if the recruitment of the fish species exploited by the winter sport fishery depends on the local production of recruits in the Saguenay Fjord or on exchanges with the St. Lawrence Estuary populations. Hence, we measured the spatio-temporal distribution of ichthyoplankton in the Fjord to identify zones of larval production, retention or advection, in order to investigate the recruitment mechanisms of these stocks. We sampled ichthyoplankton at 21 stations on six occasions, from May to October 2004, and on five occasions, from June to September 2005. Results indicated that the recruitment of capelin (Mallotus villosus) and of the anadromous rainbow smelt (Osmerus mordax) relied on the local production and retention of larvae within the Fjord. However, the recruitment of redfish (Sebastes spp.) and cods (Gadus spp.) depended on the immigration of juveniles from the St. Lawrence Estuary. Our results are corroborated by a review of previous studies of these fish populations. Studying the recruitment mechanisms of fish populations in the Saguenay Fjord supports a sustainable exploitation of these locally important fisheries resources, in accordance with the mission of Fisheries and Oceans Canada and consistent with the conservation program of the Saguenay St. Lawrence Marine Park.