Population modelling results for the assessment of Atlantic herring (Clupea harengus) stocks in the southern Gulf of St. Lawrence (NAFO Division 4T) to 2015 / D.P. Swain.: Fs70-5/2016-061E-PDF

"For assessment purposes, Atlantic herring in the southern Gulf of St. Lawrence are treated as two independent components, spring and fall spawners. Spring spawning herring were assessed using a virtual population analysis (VPA) which allowed for time-varying catchability (q) to the gillnet fishery. Model estimated spring spawner spawning stock biomass (SSB) has been in the critical zone of the Precautionary Approach (PA) framework since 2004. The median estimate of SSB at the start of 2016 (9,660 t) was less than 45% of the limit reference point (LRP = 22,000 t). The estimated instantaneous rate of fishing mortality (F) on aged 6 to 8 year old spring spawner herring declined below the reference level (F = 0.35) in 2010 and averaged 0.18 in 2013 to 2015. Based on projections with catch in 2016 and 2017 varying between 0 t and 2,500 t annually, the probability that SSB will be less than the LRP in 2018 varies between 90 and 95%, the probability that average F for ages 6 to 8 will exceed the reference level (0.35) in 2017 varies from 0 to 70%, and the probability of a 5% decline in SSB between 2016 and 2018 varies from 23 to 65%" - Abstract - p.x.

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