Research Document - 2007/005
Scallop Production Areas in the Bay of Fundy: Stock Status for 2006 and Forecast for 2007
By Smith, S.J., S. Rowe and M.J. Lundy
Abstract
This document reviews the status of scallop stocks in Scallop Production Areas (SPAs) 1, 2, 3, 4, 5, and 6 (Bay of Fundy and Approaches) for 2005–2006 with advice for 2006–2007. Landings in SPA 1A were 160 t against a TAC of 100 t for the 2005/2006 season. Commercial catch rates have been declining from a recent peak in 2002. Survey estimates for this area indicate that the larger than average 1998 year-class has been fished down with no strong upcoming yearclasses evident in the 2006 survey size frequencies. A fishing strategy of 75 t in SPA 1A for 2006/2007 and 2007/2008 has approximately a 0.30 probability of exceeding exploitation rate of 0.2 which could allow the population biomass to increase slightly. Landings in SPA 1B were 144 t against a TAC of 225 t for the Full Bay Fleet in the 2005/2006 season, and 185 t against a TAC of 225 t for the Mid and Upper Bay fleets in the 2006 season. Commercial catch rate has declined for all fleets during the last three years but it is still above the low that was observed in 1997. There were signs of two significant year-classes in the 2006 survey that will recruit to the fishery in 2007 and 2008. In the 2006 survey, there was no substantial change in abundance of commercial size scallops from 2005 but meat yield was the lowest of the last three years in the main areas of abundance. If meat yields persist at low levels during 2006/2007, fishing mortality will be higher than expected for any TAC established. Meat yield sampling will be required to evaluate this concern. If meat yields in 2006/2007 increase to levels observed during 1997–2005, then there would be no reason to change the advice provided in 2005/2006 (400 t). SPA 2 is considered to be marginal habitat for scallops and is not monitored regularly. A 2006 survey found minimal catch with a high percentage of clappers. There was little to no sign of recruitment suggesting that this area will not support a fishery in the near future. Landings in SPA 3 during 2005/2006 were 187 t against a TAC of 200 t. Commercial catch rate has declined in this area since the high of 2003 and the 2006 estimate of 13 kg/h falls below the long-term median (14.5 kg/h). The survey biomass index indicates an increase in population biomass in 2006 as the population is mainly made up of older scallops. There appears to be little sign of recruitment for 2007. Based upon a surplus production model, a catch of 200 t in 2006/2007 would likely result in little change in biomass. Landings in SPA 4 during 2005/2006 were 133 t against a TAC of 150 t. An interim TAC of 100 t was set for the 2006/2007 season which opened 1 October 2006. Commercial catch rates in 2005/2006 (11.4 kg/h) declined from the previous four years and were below the median for the time-series (21.3 kg/h). Average catch rates from October 2006 (9.9 kg/h) are 18 percent lower than the average for the same time in 2005 (12.2 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. A catch of between 100 and 125 t in each of 2006/2007 and 2007/2008 would result in exploitation rates with a 50 percent or lower probability of exceeding 0.2. Landings in SPA 5 during 2006 were 6.1 t against a TAC of 15 t. Commercial catch rate in 2006 (12.5 kg/h) was lower than the long term median (21 kg/h) and approximately half of the catch rate reported in 2005. Survey estimates indicate that the mean number per tow of commercial size scallops declined by 31 percent from 2005 to 2006. The commercial portion of the population is below the 1997–2005 median and little recruitment is expected for the next two years. The TAC for 2007 should not exceed the average over the low abundance periods (1997–1999) of 10 t. Landings in SPA 6 to 10 November 2006 were 91 t against a TAC of 100 t. The abundance of commercial size scallops in the survey appears to remain unchanged from 2005 in SPAs 6A and 6C and has possibly declined as much as 44–46 percent in SPA 6B. Above average recruitment was only detected in SPA 6A. There is no evidence to advise increasing the TAC for 2007 above the current catches of 82–91 t.
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