Science Advisory Report 2009/012

Assessment of scallops (Placepecten magellanicus) in scallop production areas 1 to 6 in the Bay of Fundy

Summary

General

• Some observer coverage was funded by DFO in 2008 for exploration of bycatch. No information from this program was available in time to be included in this assessment.
• The determination of stock status for scallops in all of the areas in the Bay of Fundy is highly dependent upon the estimates from the annual drag survey. The total number of survey stations covered in the Bay of Fundy and Approaches in 2008 was 754 (including 25 stations funded by the Petiticodiac Monitoring Program), less than the 855 stations in 2006 but still above the number of stations in recent previous years (520 to 702).

SPA 1A

• Landings were 225 t for the Full Bay Fleet during the 2007/2008 fishing year against a quota of 216 t. An interim TAC of 120 t was set for the 2008/2009 season based on the 2007 assessment advice. Recent commercial catch rates have been stable around the median.
• The research survey boundaries have been revised since 2007, which has resulted in the increase of survey area within 1A (with a corresponding reduction in 1B). As a result, biomass calculations are now higher for this area than seen in previous assessments (reduced for 1B).
• Since the above average 1998 year-class recruited to the fishery in this area, recruitment has been lower and the abundance of commercial size scallops has been fished down.
• The only sign of above average recruitment is in the 8 to 16 mile area. While the densities of scallops in the 50 to 70 mm size range appear higher than observed in recent years, they are much lower than observed for the 1998 year-class at the same size.
• Population biomass estimated to be 1426 t (meats) in 2008, has increased over the estimate for 2007 (1408 t) and is above the median biomass of 1246 t (1997 to 2007).
• Catches of 196 to 265 t for 2008/2009 should result in a small increase in biomass for 2009. However, the model has a tendency to overestimate the commercial size population when forecasting ahead and catches in the upper part of this range may actually result in a small decrease in biomass.

SPA 1B

• The Full Bay Fleet landed 210 t against a total quota of 206.25 t over all three subareas. Landings for the Mid Bay fleet were 120 t in total against a TAC of 148.28 t for SFA 28B and SFA 28C. The TAC for SFA 28C and 28D was 85.47 t for the Upper Bay fleet and they landed 87 t in total for 2008. An interim TAC for 2008/2009 was set at 100 t for the Full Bay fleet.
• Commercial catch rates have been increasing for all three fleets since 2006 mainly due to better than average recruitment in the Cape Spencer, Middle Bay North (Quaco Ledge) and SFA 28C area. The increase for the Upper Bay Fleet in 2008 was partly due to fishing in the small but very productive Advocate area of SFA 28D.
• The research survey boundaries have been revised since 2007, which has resulted in the decrease of survey area within 1B (with a corresponding increase in 1A). As a result, biomass calculations are now lower for this area than seen in previous assessments (increased for 1A).
• Survey estimates in the SFA 28B, 28C and Advocate Harbour areas (28D) indicate above average densities of scallops in the 40 to 64 mm size range in 2008.
• Population biomass estimated to be 1890 t (meats) in 2008 has increased slightly over the estimate for 2007 (1864 t) and is above the median biomass of 1638 t (1997 to 2007).
• Catches for 2008/2009 of 290 t or less should not result in a decline in biomass for 2009. Recruitment prospects look much better for 2009/2010 and the incoming year-class will be commercial size for the 2010/2011 fishery.

SPA 2

• This area is considered to be marginal habitat for scallops and is not monitored regularly. SPA 2 was last assessed in 2006 (DFO 2007).

SPA 3

• Total landings for the 2007/2008 fishing year were 80 t against a TAC of 70 t. An interim TAC of 50 t was set for October of the 2008/2009 fishing season.
• Commercial catch rate has been stable and close to the median over the time series since 2006.
• A voluntary closure to protect areas of high densities of scallops in the 10 to 40 mm size range observed in the 2007 survey was instituted at the request of the Full Bay fleet. While the 2008 survey found high densities of scallops in the 10 to 40 mm range, there was no evidence that the high densities from 2007 had resulted in similar higher than average densities in the next age class (40 to 70 mm) in 2008.
• Comparison of differences between survey estimates from the 2007 and 2008 surveys indicated significant decreases in mean numbers per tow of recruits and mean weights per tow of commercial size scallops and recruits.
• Population biomass estimated to be 463 t in 2008 has decreased over the estimate for 2007 (531 t) and is below the median biomass of 655 t (1996–2007).
• The commercial size biomass is predicted to decrease from 2008 to 2009 if the interim quota of 50 t was caught. Catches as low as 35 t in 2008/2009 will also result in a decline. Recruitment is expected to be low for at least the next two years.

SPA 4

• Total landings in 2007/2008 were 79 t against a TAC of 100 t. An interim TAC of 100 t was set for the 2008/2009 season was based on last year’s assessment.
• Commercial catch rates declined after the above average 1998 year class recruited to the fishery but have been either relatively stable or slightly increasing since 2005/2006.
• A voluntary closure to protect areas of high densities of scallops in the 10 to 40 mm size range observed in the 2007 survey was instituted at the request of the Full Bay fleet. There was no evidence of similar high densities in the next size class (50 to 80 mm) in the 2008 survey.
• Overall, the survey indices indicate that the population has been stable since 2006 with low levels of recruitment, pre-recruits and clappers. Given the trends in the pre-recruit estimates, low levels of recruitment will probably continue for the next two years.
• Population biomass estimated to be 779 t (meats) in 2008 has increased over the estimate for 2007 (760 t) and is just below the long-term median biomass of 792 t (1983 to 2007).
• A TAC of 100 t for 2008/2009 should result in little change in the population biomass of commercial size scallops for 2009.

SPA 5

• Landings in 2008 were 7 t against a TAC of 10 t.
• Commercial catch rates in 2008 increased over 2007 and were close to the long-term median levels (1977–2007).
• Survey shell height frequencies indicate that the 2007 year-class may be the strongest seen since the 1999 and 2000 year-classes. Currently, the mean catch per tow for commercial size scallops is below the long-term median and close to the lowest seen in this series.
• The TAC for 2009 should not exceed the average catch of 9 t over the period 1997 to 2008 excluding the high catch in 2004. Good recruitment prospects may improve the stock status in 2010.

SPA 6

• Landings in 2008 were 68 t against a TAC of 140 t.
• Both catch and catch rates for both fleets have been relatively stable over the last four years.
• Comparison of survey estimates from 2007 and 2008 suggests there has been little change in mean numbers per tow of commercial size scallops in 6A, 6B or 6C.
• Recent levels of catch do not appear to result in a decrease in the population abundance of scallops in the SPA 6 area as a whole.

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