Research Document - 2008/046

Preliminary results from the groundfish and shrimp multidisciplinary survey from August 2007 in the northern Gulf of St. Lawrence

By H. Bourdages, D. Archambault, B. Bernier, A. Fréchet, J. Gauthier, F. Grégoire, J. Lambert and L. Savard

Abstract

In 2007, the annual summer survey for the assessment of abundance and distribution of groundfish and shrimp in the Quebec region was conducted from August 3^rd to September 1^st in the estuary and northern Gulf of St. Lawrence on board the CCGS Teleost. One of its primary objectives was to estimate abundance indices for the main groundfish species, including the three species targeted by the survey (cod, Greenland halibut, redfish) and Northern shrimp (also targeted by the survey), identify spatial distribution and their biological characteristics. Among the other objectives, the survey aimed at providing a concurrent portrait of environmental conditions in the Gulf for 7 of the Gulf’s 8 geographic regions considered in the assessment of the Gulf’s physical conditions.

This report describes for 14 species the preliminary results for catch rate and distribution, as well as their size frequency distribution. These results were compared with the results from the historical survey series introduced in 1990, taking into account the equivalency factors used to convert the data from the tandem CCGS Alfred Needler-URI with the tandem CCGS Teleost-Campelen. None of the species showed much variation compared with the two previous years, except for Atlantic halibut with a still increasing abundance index in 2007. The geographic distribution of catches recorded for the different species in 2007 can be compared to the five previous years.

In 2007, the temperatures recorded for surface waters and for the cold intermediate layer (CIL) were generally colder for the entire covered area compared with the temperatures recorded in 2006. The layers <1°C and <0°C of the CIL were much thicker in 2007 than in 2006. However, the temperatures recorded for deep water (300+m) were similar during these two years. Concentrations of dissolved oxygen in the Estuary waters were still considered hypoxic in 2007.

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