Science Advisory Report 2011/069
Assessment of the Ocean Quahog (Arctica islandica) Stock in Southwest New Brunswick
Summary
- This assessment is based on information gathered during two surveys conducted in 2006 (Mace’s Bay) and 2007 (Grand Manan) in order to provide stock advice for the developing fishery in Southwest New Brunswick.
- Ocean Quahogs are long lived and slow growing. However, the quahogs in Southwest New Brunswick do not appear to reach the sizes found in the offshore populations.
- Based on the 2006 survey, the biomass estimate of Ocean Quahogs in Mace’s Bay is 38,800 t. Based on the 2007 survey, the biomass estimate of Ocean Quahogs in areas surveyed around Grand Manan is 3,920 t.
- A Maritimes Region Expert Opinion recommended a constant harvest strategy based on F0.33M. Based on the current biomass and natural mortality estimates, the resulting harvest levels would be 1,537 t for Mace’s Bay and 155 t for Grand Manan.
- Size at 50% maturity (38 mm) is close to the current retention size for the commercial gear.
- Survey dredge efficiency is unknown; the assumption of 100% efficiency is a conservative approach.
- By-catch in the survey (using commercial dredges) was low. The majority of the by-catch was other bivalves; no Species at Risk were observed.
- Quahog dredges have an immediate impact on the substrate and benthic organisms, and there continues to be uncertainty about the impact of dredges on overall benthic productivity, especially dry dredges used in areas with mud and clay substrates.
This SAR was developed during a Maritimes Region Science Advisory Process on 21 October 2011. Additional publications from this meeting will be made available on the CSAS website .
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