Research Document 2019/068

Assessment of Capelin (Mallotus villosus) in SA2 + Div 3KL in 2017

By Mowbray, F.K., Bourne, C., Murphy, H., Adamack, A., Lewis, K., Varkey, D., and P. Regular

Abstract

Information from spring acoustic surveys, larval surveys, distribution patterns, biological characteristics and spawning behaviour were used to inform the status of Capelin in NAFO Divisions 2J3KL up to and including 2017. Following a period of increased abundance in 2013-2014, the acoustic index of Capelin abundance declined unexpectedly in 2015 and further in 2017 falling to levels typical of the period of low abundance seen in the 1990s and early 2000s. These declines were accompanied with poor spring condition of Capelin, delayed roe development and late spawning times. The 2017 age composition from the acoustic survey was strongly dominated by age 2 fish, although the proportion of Capelin first maturing at age 2 remained lower than during other periods of low abundance. More capelin were found on the shelf break during spring surveys, and reduced diel vertical migration observed. Fall distributions determined from bottom trawl survey catches were centered further south than in the four preceding years. Larval indices suggest that 2016 and 2017 cohorts will be below average. It is expected that the spawning stock biomass of capelin in 2018 will be low, although composed of a larger size fish due to the presence of virgin age 3 spawners.