Research Document - 2014/067

Summary of 2011 and 2012 Herring Acoustic Surveys in Northwest Atlantic Fisheries Organization (NAFO) Divisions 4VWX

By R. Singh, G.D. Melvin, A. Clay and M.J. Power

Abstract

Automated acoustic recording systems deployed on commercial fishing vessels have been used since 1997 to document the distribution and relative abundance of Atlantic herring from industry vessel surveys and fishing excursions in the Bay of Fundy and coastal Nova Scotia area within Northwest Atlantic Fisheries Organization divisions 4VWX. In 2011 and 2012, regularly scheduled surveys at approximately 14 day intervals were again conducted on the main spawning components, and the spawning stock biomass for each component estimated by summing these results. In 2011 and 2012, five structured surveys were conducted each year in Scots Bay and three each year on Trinity Ledge. One structured survey was done in 2011 on Spectacle Buoy. In 2011, there were five surveys on German Bank and six in 2012. In most cases, these surveys provided good coverage of the spawning areas consistent with established protocols.

In 2011, the biomass estimate increased by almost 43% above the 2010 estimate for the combined survey areas of Scots Bay, Trinity Ledge and German Bank. The 2012 estimate for the same overall areas increased a further 6% over the 2011 estimate. As a result, the overall estimate is now closer to the long term average. These estimates indicate positive growth in the 4X stock, but most this growth has occurred in the Scots Bay survey area and not on German Bank, which has historically been the major spawning area.

Biomass estimates from surveys of the coastal Nova Scotia spawning components for the Little Hope/Port Mouton, Halifax/Eastern Shore and Glace Bay areas were also examined. Six (2011) and two (2012) surveys were completed for Little Hope, three (2011) and two (2012) surveys for Halifax/Eastern Shore and one (2011) for the Glace Bay area. There were continued decreases in spawning stock biomass recorded for Little Hope and Halifax/Eastern Shore areas, while Glace Bay again showed virtually no fish in the one survey completed in 2011.

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