IMIS - Marine Research Groups

The Southern Gulf of St. Lawrence snow crab bottom trawl survey has taken place yearly since 1988 with the exception of 1996 when partnerships with industry ceased and no funding was available. The survey is conducted after the local fisheries are closed from early to mid-July and ends in early to mid-September. For the survey, we used a Nephrops bottom trawl towed over the bottom during 5 minutes at a speed of approximately 2 knots. A scanmar (1989-1998) or netmind (1999-present) hydro-acoustic instrumentation system is used to monitor the status of the trawl, such as depth, trawl opening width and height. On board computer systems record the position, time and status of the trawl (Moriyasu et al., 1998). Throughout the years, the snow crab survey has covered an ever widening range of the Southern Gulf of St. Lawrence area. In 1989 for instance, there were 155 stations mostly within Area 12. Since then the survey has grown to cover all fishing grounds in the Southern Gulf of St. Lawrence (Area 12, E, F, and 19) with over 300 stations. Three successive boats have been used since the first survey: the side trawler 'Emy Serge' from 1988 to 1998, followed by two stern trawlers, the 'Den C Martin' from1999 to 2002, and the 'Marco Michel' from 2003 to present. No boat comparisons were completed during the transitions. Because the fishing efficiency of the gear used is not yet known for snow crab, abundance is considered as relative compared to the absolute abundance.