Science Advisory Report  2016/024

Assessment of the West Coast of Newfoundland (Division 4R) herring stocks in 2015

Summary

• Based on preliminary data for 2015, herring catches from the west coast of Newfoundland (NAFO Division 4R) totaled 19,436 tons from a TAC of 20,000 tons. The quotas allocated to the large and small seiners were reached, whereas 82% of the quota for fixed gear was taken.
• Catches of the fall-spawning stock are currently dominated by fish aged 11+ years and in lesser proportion by fish aged 7 years.
• Too few spring-spawning herring were available among the commercial samples in 2015 to reliably determine catch-at-age for this stock. The few spring-spawning herring available in the samples were mostly 2- and 3-year-old fish.
• An acoustic survey was performed in October 2015. Due to logistical constraints, it was necessary to prioritize some strata and to reduce spatial coverage intensity. Despite these constraints, the confidence interval of the biomass estimate was among the best of the time series.
• In 2015, fishing took place mostly in November and December, and thus few samples were available for the period during which the acoustic survey was conducted. Consequently, both the biomass index yielded by the survey and the age structure are sensitive to the samples used in the estimation.
• The total biomass index for spring-spawning herring from the 2015 acoustic survey was estimated at 1,200 tons. For fall spawners, the total biomass index was 97,000 tons. The biomass index for fall-spawning herring from the acoustic survey series has remained between 85,000 tons and 122,000 tons since 2009.
• A sequential population analysis (SPA) using data from the commercial fishery was tuned with the acoustic biomass indices. The 2015 acoustic index and the SPA both confirm that the spring-spawning stock has collapsed and that its current spawning biomass is below the limit reference point (LRP = 37,000 t).
• The SPA for the fall-spawning stock shows some retrospective patterns, but concurs with the acoustic indices that the spawning biomass has experienced a strong increase from 2003 to 2010 followed by a continuous decrease until 2015.
• Because of the retrospective patterns in the SPA, the absolute biomass of the fall-spawning stock remains uncertain. However, all indices agree that the current spawning biomass is above the upper reference point (URP = 61,000 t).
• If the older fish that have supported the fishery continue to decline, and in the absence of significant recruitment, there is a risk that maintaining catches at their current level will bring the fall-spawning stock below the upper reference point in the next two years.
• Given that the spring-spawning stock is still decreasing, it is recommended that the management measures implemented in the late 1990s remain in place

This Science Advisory Report is from the March 8, 2016 Assessment of the 4R herring stocks in 2015. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

Complete document (PDF, 1,313 KB)

Accessibility Notice

This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.