Science Advisory Report  2014/018

Assessment of Scallops (Placopecten magellanicus) in Scallop Production Areas 1 to 6 in the Bay of Fundy

Summary

General

• Models used in this assessment have been reviewed previously; however, one change was made in 2013 to include sample variances from the survey time series in the observation models.
• The standard harvest scenario tables used to provide Total Allowable Catch (TAC) advice now include probabilities associated with being above the Lower Reference Point (LRP) and Upper stock reference (USR) point. The USRs presented here were used for illustrative purposes and were based on methods developed for an industry/DFO working group. Formal adoption of USRs will be finalized through discussions with the Inshore Scallop Advisory Committee in the coming year.

SPA 1A

• The Full Bay Fleet caught a total of 206 t against a TAC of 200 t during the 2012/2013 fishery in Scallop Production Area (SPA) 1A.
• Commercial catch rates in 2012/2013 increased from the 2011/2012 fishing season to 20.5 kg/h, above the long-term median (1995/1996 to 2011/2012) of 15.3 kg/h.
• Recruit (65-79 mm) abundance and biomass decreased slightly in 2 to 8 mile area, but increased in the other areas of SPA 1A. The abundance of commercial scallop (≥ 80 mm) in the survey has been stable in all areas of SPA 1A since 2005. Pre-recruits (<65 mm) scallops were present in all areas of SPA 1A, with the greatest abundance in the 8 to 16 mile area.
• Condition factor (g/dm3) has increased in SPA 1A over the last two years, and all areas are above their respective long-term means (1997 to 2012).
• Population biomass estimated by the model was 1,607 t (meats) in 2013, up from the estimate of 1,231 t for 2012 which was approximately equal to the median biomass of 1,206 t (1997 to 2012).
• Catches up to 287 t for 2013/2014 are projected to be at or below a reference exploitation rate of 0.15. The current population biomass is above the LRP of 480 t and the proposed USR (1000 t).

SPA 1B

• The total 2012/13 landings for all fleets in SPA 1B was 422.9 t against a combined TAC of 375 t.
• In Scallop Fishing Areas (SFAs) 28B and 28D, catch rates almost doubled for the Full Bay Fleet. The Mid Bay Fleet had increases of over 50% in both areas fished, and Upper Bay Fleet had an increase of 62% in 28D and 42% in 28C.
• Recruit biomass from the survey increased in all subareas with the highest increase in SFA 28B. Survey estimates of commercial biomass increased in SFAs 28B, 28C, and 28D. Pre-recruits were seen in all subareas, but the highest abundances were in the Cape Spencer area.
• Condition factor had increased in all subareas of SPA 1B since 2011. Most subareas are at a high in the survey time series.
• Population biomass estimated by the model was 2,635 t (meats) in 2013, a substantial increase from the estimate of 1,757 t for 2012 and well above the median biomass of 1,798 t (1997 to 2012).
• Catches up to 500 t for 2013/2014 are projected to be at or below the reference exploitation rate of 0.15 and are projected to result in an increase in biomass. The current population biomass is above the LRP of 880 t and the proposed USR (1800 t).

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 2012/2013 fishing season were 261 t against a TAC of 260 t.
• Commercial catch rates in 2013 for St. Mary’s Bay increased 26% from 2012, while June catch rates for the Brier/Lurcher area did not change.
• The abundance of recruit scallops decreased in 2013 in all parts of SPA 3. Survey indices indicate increases in commercial biomass in St. Mary’s Bay and the Inside area of Brier/Lurcher. Pre-recruits were seen in very large abundances in both the Inside and Outside areas of Brier/Lurcher.
• The best condition was observed in St. Mary’s Bay, which increased in 2013 after two years of decline, but condition increased in the other areas as well.
• Population biomass estimated by the model was 1,606 t (meats) in 2013, an increase from the estimate of 1195 t for 2012, and well above the long-term median (1996-2012) biomass of 1,008 t.
• Catches up to 300 t for 2013/2014 are projected to be at or below the reference exploitation rate of 0.15 and are projected to result in an increase in biomass. The current population biomass is above the LRP of 600 t and the proposed USR (1000 t).

SPA 4

• Total landings in 2012/2013 fishing season were 109.4 t against a TAC of 110 t.
• Commercial catch rates increased in 2013, from 15 to 20 kg/h, and are currently above the long-term median.
• The survey estimate for number of recruits did not change in 2013 and are still at low levels, and absent from a lot of the area. Numbers of commercial scallop have been relatively stable in this area since 2005. In 2013, the commercial biomass increased, mainly due to increases in condition. Pre-recruits were observed in SPA 4 at the highest levels since 2007.
• Condition in this area increased in 2013 and is well above the mean and among the highs in the time series.
• Population biomass estimated by the model was 1,041 t (meats) in 2013, an increase of 33% from the estimate of 782 t in 2012. Estimated recruitment in 2013 is 17 t, below the long-term median of 38 t. Recruitment has been below the long-term median since 2008.
• Catches up to 160 t for 2013/2014 are projected to be at or below the reference exploitation rate of 0.15 and are projected to result in a decrease in biomass. The underlying reason for this decline appears to be the low recruitment since 2008. The current population biomass is above the LRP of 530 t and the proposed USR (750 t).

SPA 5

• Total landings in 2013 were 5.7 t against a TAC of 10 t.
• Commercial catch rate (19.7 kg/h) increased from 2012, and is above the long-term median (18.6 kg/h).
• The annual survey was discontinued as of 2009 in this SPA.
• Since 2006/2007, the average annual catch has been 6.5 t and the average catch rate has been 16.1 kg/h
• Reference points and TAC advice have not been developed for SPA 5 because this area will be managed with SPA 4 starting with the 2013/2014 fishing season.

SPA 6

• Total landings for Full Bay and Mid Bay fleets in the 2013 fishing season were 125.6 t against a TAC of 140 t.
• Catch rates for the Mid Bay Fleet increased in all subareas of SPA 6 relative to the lower than average rates in 2012.
• Condition in SPA 6 increased in 2013 for 6A and 6B, and decreased in 6C. However, 6C still has the best condition relative to other subareas of SPA 6.
• Survey estimates of commercial numbers and biomass increased in both SPA 6A and 6B in 2013, but showed no change in 6C. Abundance of recruits increased in all subareas, and pre-recruits were observed in all subareas.
• Catch and effort trends for this area suggest that at the current exploitation level (i.e., mean effort levels), population numbers are close to equilibrium levels with biomass fluctuations subject more to changes in condition than to overall increases or decreases in numbers. It is not known if this equilibrium corresponds to a maximum catch situation.
• The TACs set in this area since 1997 have varied reflecting average catch trends in recent years and were not based on an assessment model or any other indicator of productivity. The current total TAC of 140 t has been in place since 2007.
• The commercial catch rate series starting in 1997 has been proposed as the stock status indicator for this area. The lowest catch rate in the series of 6.2 kg/hr (1997) has been proposed as the LRP for SPA 6.

This Science Advisory Report is from the November 6-7, 2013 Assessment of Bay of Fundy Scallop. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

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