Research Document - 2012/143
Some results from spring acoustic surveys for capelin (Mallotus villosus) in NAFO Division 3L between 1982 and 2010
By F.K. Mowbray
Abstract
The spring NAFO Division 3L acoustic survey for capelin provides an index of abundance of 2J3KL capelin, as well as information on its distribution, biology and behavior. Spring capelin acoustic surveys have been conducted annually in 1982-1992, 1996, 1999-2005, and 2006-2010. The abundance of capelin has changed dramatically within this time series. Abundance peaked at nearly 7 million tonnes in the late 1980s, dropped an order of magnitude once in the early 1990s and again in 2010, with the 2010 biomass less than 1% of the historic levels (23,000 tonnes). Coincident with these changes have been shifts in distribution (to the north and toward the shelf break), as well as changes in the vertical distribution, depths of water occupied, and diel vertical migration patterns. Age composition and size structure have also changed over time with the current index comprised of mainly ages 2 and 3 fish, while ages up to 5 were present historically. The age at maturation has also decreased with approximately 10 times more age 2 fish maturing.
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