Research Document - 2005/079
Scallop Production Areas in the Bay of Fundy: Stock Status for 2005 and Forecast for 2006
By Smith, S.J., M.J. Lundy, D. Roddick, and S. Rowe
Abstract
This document reviews the status of scallop stocks in Scallop Production Areas (SPA) 1, 3, 4, 5, and 6 (Bay of Fundy and Approaches) for 2004-2005 with advice for 2005-2006.
Commercial catch rate in SPA 1A has been declining from a peak observed in 2002. Survey estimates for this area indicate that the larger than average 1998 year-class has been fished down with no sign of strong recruitment for the upcoming years. A fishing strategy of 100 t in SPA 1A for 2005/2006 and 2006/2007 has a greater than 50 percent probability of resulting in median exploitation rates at or below 0.2 which could allow the population biomass to increase slightly. Lower removals would increase the probability of population biomass increase while higher removals would decrease this probability.
Commercial catch rate in SPA 1B has declined during the last two years but is still above the median level observed in 1982-2005. Survey estimates indicate there are two above average pre-recruit year-classes, however the pre-recruit year-class that appeared above average last year appears about average this year. The present quota of 400 t for SPA 1B should be maintained until the contribution of these year-classes is better defined.
Commercial catch rate in SPA 3 averaged 16.7 kg/h in 2005, compared to 22.1 kg/h in 2004 and was slightly above the median catch rate for 1996--2005 (14.5 kg/h). The 2005 survey index (1.4 kg/tow) indicated that the biomass of commercial size scallops declined after 2002, but remains just above the median (1.3 kg/tow) for the ten-year survey series. There appears to be little sign of recruitment for 2006. Based upon the survey trends in SPA 3, the population appears to be stable at the 150 to 200 t catch level with the possibility of an above average 2004 year-class that could recruit to the fishery within St. Mary's Bay in 2008.
Commercial catch rates in SPA 4 during 2004/2005 (21.8 kg/h) declined from 2003/2004 (38.6 kg/h) and were near the median for the time-series (21.3 kg/h). Mean catch rates in October 2005 (12.2 kg/h) were less than half the mean for October 2004 (27.0 kg/h). Survey numbers indicate that the stronger than average 1998 year-class has been fished down and there are no indications of any substantial recruitment for the next two to three years. An interim TAC of 200 t was set for the 2005/2006 season in SPA 4 which opened 1 October 2005. Our population model predicts that a TAC of 200 t will result in a median exploitation rate of 0.26 and a decline in population biomass. Meanwhile, a fishing strategy of 150 t in 2005/2006 and in 2006/2007 has a 0.50 probability of resulting in exploitation rates which could allow the population biomass in SPA 4 to increase slightly. Lower removals would increase the probability of population biomass increase while higher removals would decrease this probability.
Commercial catch rate in SPA 5 during 2005 (26.1 kg/h) was lower than in 2004 (32.1 kg/h) but still above the median for 1977-2005 (21.0 kg/h). Survey estimates indicate that the population abundance for commercial size scallops (126/tow) is just above the median for the time series (1997-2005; 123/tow) but little recruitment is expected for the next two years. The TAC for SPA 5 in 2006 should not exceed the average over the low abundance periods (1997-1999) of 10 t.
Landings in SPA 6 have been approximately 80-90 t per year for the last three years under a TAC of 195 t. Commercial catch rates in this area have been variable with low effort. Due to vessel problems, there was no DFO survey in SPA 6 in 2004. A survey with a commercial vessel in 2005 only covered part of SPA 6B due to time constraints. Most stock indicators show no sign of good recruitment, and a stock of fully recruited scallops that is being fished down. The TAC in SPA 6 should not exceed 80 t in 2006.
