Science Advisory Report  2016/004

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, and changes have been documented and reviewed.
• Scallop Production Area (SPA) 2 is considered to be marginal habitat for scallops and is not monitored regularly. SPA 2 was last assessed in 2006.
• SPA 6 was modelled for the first time using the Bay of Fundy stock assessment model.
• Harvest scenario tables that assess the consequences of different harvest levels in SPAs 1A, 1B, and 3 to 6 for 2015/2016 are presented.

SPA 1A

• The Full Bay Fleet caught a total of 361.55 tonnes (t) against a Total Allowable Catch (TAC) of 350 t during the 2014/2015 fishing year in SPA 1A.
• Commercial catch rate in this area has been increasing since 2011/2012; the catch rate in 2014/2015 was the highest in over a decade.
• The number and weight per tow of commercial scallop in the survey increased in both the 2 to 8 and 8 to 16 mile subareas. In Middle Bay South there was a decrease in the number and weight per tow of commercial scallop in 2015. The number and weight per tow of recruit size scallops in 2015 were less than in 2014 for all subareas of SPA 1A. Prerecruit scallop abundance decreased from 2014.
• Condition increased in all subareas of SPA 1A.
• Population biomass estimated by the model was 3,790 t (meats) in 2015, an increase of 54% from the estimate of 2,462 t in 2014.
• Commercial biomass in SPA 1A is currently in the healthy zone.

SPA 1B

• In 2014/2015 fishing year, the TAC in SPA 1B was 550.024 t. The Full Bay Fleet caught a total of 303.96 t against a quota of 301.8 t, the Mid Bay Fleet caught 164.02 t against a quota of 175.6 t, and the Upper Bay Fleet caught 78.2 t against a quota of 72.7 t.
• In Scallop Fishing Area (SFA) 28B, catch rates for the Full Bay Fleet have been similar over the last three years, while Mid Bay Fleet catch rates declined in 2015. In SFA 28C, Mid Bay catch rate in 2015 was among a high in the time series for this subarea. The catch rate for the Upper Bay Fleet in SFA 28C decreased in 2015 relative to 2014.
• The number and weight of commercial scallops per tow in 2015 increased overall in SPA 1B, although the trend differed among subareas. With the exception of Middle Bay North, number and weight per tow of recruit scallops decreased from, or was similar to, 2014 in all subareas of SPA 1B. Prerecruit scallops were less abundant in 2015.
• Condition increased in all subareas of SPA 1B.
• Population biomass estimated by the model was 4,350 t (meats) in 2015, an increase of 27% from the estimate of 3,197 t in 2014.
• Commercial biomass in SPA 1B is currently in the healthy zone.

SPA 3

• The Full Bay Fleet caught a total of 234.96 t against a TAC of 250 t in the 2014/2015 fishing year.
• Catch rates in St. Mary’s Bay have been relatively similar over the last 3 years. Catch rates in the Brier/Lurcher area, both in the summer and fall, have been similar for the last three years.
• Number per tow of commercial scallops in the survey decreased in 2015 relative to 2014 in all subareas of SPA 3. Weight per tow of commercial scallops decreased in 2015 relative to 2014 in St. Mary’s Bay and the Outside Vessel Monitoring System (VMS) Stratum, and increased slightly in the Inside VMS Stratum. Number and weight per tow of recruit scallops decreased in St. Mary’s Bay, and increased in both VMS strata. Prerecruits were less abundant in 2015 than in 2014.
• Condition increased in all subareas of SPA 3.
• Population biomass estimated by the model was 2,620 t (meats) in 2015, a decrease of 7% from the estimate of 2,814 t for 2014.
• Commercial biomass in SPA 3 is currently in the healthy zone.

SPAs 4 and 5

• Before the start of the 2013/2014 fishing year, SPAs 4 and 5 were joined under one TAC. In 2014/2015, the Full Bay Fleet caught a total of 124.09 t in SPA 4 and 8.26 t in SPA 5 against a combined TAC of 135 t.
• The 2015 catch rate in SPA 4 was virtually unchanged from the catch rate in 2014. The catch rate in SPA 5 declined in 2015 relative to 2014.
• The number per tow of commercial scallop in SPA 4 increased greatly in 2015. Weight per tow of commercial scallop also increased in 2015. Number and weight per tow of recruit scallops decreased in 2015 relative to 2014. Prerecruit scallops were less abundant in 2015 than in 2014.
• The survey results for SPA 5 are presented with reference to the medians of the survey series from 1996 to 2008. The annual survey in SPA 5 started in 1990 and was discontinued in 2009. Starting in 2014, survey tows resumed in this area. The number and weight per tow of commercial scallop were above the medians in 2014 and 2015, while recruit number and weight per tow were near the medians in 2014, and increased in 2015.
• Condition in 2015 increased in SPA 4.
• Population biomass estimated by the model was 2,213 t (meats) in 2015, an increase of 70% from the estimate of 1,300 t for 2014.
• Commercial biomass in SPA 4 is currently in the healthy zone.

SPA 6

• A total of 231 t was landed against a combined TAC of 240 t in SPA 6 in 2014/2015.
• Catch rates for Mid Bay decreased in 2015 relative to 2014 across all subareas but are still at the second highest level observed over the Mid Bay time series. For Full Bay, catch rates increased in 2015 relative to 2014 in subareas 6A, 6B, and 6C.
• Until 2014, SPA 6 was assessed based on management areas. In 2014, the survey index was improved by restratifying the survey according to VMS “fishing” intensity from 2002 to 2014 and defining two VMS strata. In 2015, the survey index was further improved by refining the Inside VMS Stratum and redefining the Outside VMS Stratum.
• Commercial and recruit numbers and weight per tow increased in the Inside and Outside VMS strata in 2015. With the exception of commercial biomass in the Outside VMS Stratum, biomass and abundances of both commercial and recruit scallops observed in 2015 are at time series (since 1997) highs. In 2015, prerecruit abundances of between 10 to 100 per tow were found throughout the survey area.
• Condition remained relatively similar from 2014 to 2015.
• This is the first time the Bay of Fundy stock assessment model has been used in SPA 6, and the model fits the survey mean estimates well and gave reasonable parameter estimates.
• Population biomass estimated by the model was 1,361 t (meats) in 2015, an increase over the average of 368 t from 2006 to 2012.
• Reference points in SPA 6 are defined in terms of commercial catch rate. The catch rate index is currently in the healthy zone.

This Science Advisory Report is from the November 17-18, 2015, Assessment of Bay of Fundy Scallop in Scallop Production Areas (SPAs) 1A, 1B, and 3-6. 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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