Research Document 2022/014

Sentinel Surveys 1995-2020 – Catch rates and biological information on Atlantic Cod (Gadus morhua) in NAFO Subdivision 3Ps

By Mello, L.G.S. and Simpson, M.R.

Abstract

Catch rates and biological information for Atlantic Cod from the Sentinel survey Program in the Northwest Atlantic Fisheries Organization (NAFO) Subdivision 3Ps are updated for 2019, and preliminary results presented for 2020. Temporal trends in gillnet (small 3¼ inch mesh, large 5½ inch mesh) and linetrawl unstandardized catch rates were similar for all gears, with the highest values at the beginning of each time-series, sharp declines after 1997, and oscillations around or below the series’ mean catch rate thereafter. Age-disaggregated standardized catch rates for recent year-classes were generally weaker than those in the past. Age-aggregated catch rates were higher at the beginning of each time-series for both gears, declined over the mid-to-late 1990s, then remained at their lowest levels; decreasing below the series’ mean of 6.4 fish/net (large mesh gillnet) in 1999, and 86 fish/1,000 hooks in 2009 (linetrawl). Gillnet and linetrawl catch rates for 2019 were 3.4 fish/net and 92 fish/1000 hooks (control sites), and 2.5 fish/net and 114 fish/net (experimental sites), respectively.

Length frequencies of Atlantic Cod measured in Sentinel surveys indicated that the small mesh gillnet was the least selective gear (retaining small and large fish from multiple length-classes), whereas large mesh gillnet and linetrawl captured larger fish in specific size ranges and few overlapping length-classes. Fish lengths from small mesh gillnet showed several modes ranging between 37-43 cm and 53-60 cm throughout the time-series, while those of fish from large mesh gillnet and linetrawl ranged between 60-68 cm and 42-61 cm, respectively. Indices describing the physiological condition of Atlantic Cod varied at both seasonal and annual scales. Total annual removals of Atlantic Cod by Sentinel harvesters peaked at 38 t (2001), then declined to a minimum of 9.9 t (2016), prior to increasing to 14.3 t in 2019. At least 15 fish species have been recorded as Sentinel bycatch over 2005-19, with American Plaice and Redfish been the most common in gillnet and linetrawl, respectively.

Research Document 2022/014 (PDF, 1,804 KB)

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