Science Response 2015/033

Updated assessment to 2014 of the fall spawning component of Atlantic Herring (Clupea harengus) in the southern Gulf of St. Lawrence (NAFO Div. 4T) and advice for the 2015 fishery

Context

The peer review meeting of the assessment of Atlantic herring (Clupea harengus) in the southern Gulf of St. Lawrence conducted in March 2014 identified issues with the indices of abundance from the gillnet fisheries and the assessment models for the fall spawning component (DFO 2014). Two assessment models were examined, differing in the assumptions about catchabilities in the gillnets for ages 4 and 5, presumably associated with observed declines in weight at age. The estimated absolute biomass values differed substantially between models although the trends in estimated abundance were largely the same. Neither model was considered appropriate as both were characterized by an important lack of fit to indices and retrospective patterns. As a result, catch advice for the fall spawner component of Atlantic herring was only provided for the 2014 fishery (DFO 2014). A framework review of the assessment approach for the fall spawning component was recommended to address the identified shortcomings and to review alternative model formulations. Updated catch advice for the fall spawner component of the 2015 fishery would be developed based on the recommendations from the framework review. Advice for the spring spawning component of Atlantic herring for the 2015 fishery was provided in DFO (2014) and remains valid.

This report results from the Science Response Process meeting held April 16, 2015 on the Atlantic Herring fall spawner stock assessment update for 2015. The timelines for the framework review and the need to provide updated advice for 2015 were very short. The updated assessment used the recommended approach from the assessment framework of April 13-15, 2015. The proceedings from the peer review process that document the recommended approaches from the framework review are in preparation.

Complete document (PDF, 1,340  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.