Research Document - 2012/127

Results of the Atlantic mackerel (Scomber scombrus L.) egg survey conducted on the Scotian Shelf and Newfoundland’s South Coast in 2009

By F. Grégoire, J.-L. Beaulieu, M.-H. Gendron, and D. LeBlanc

Abstract

Using funds from the Larocque Scientific Program, a survey of Atlantic mackerel (Scomber scombrus L.) eggs was conducted on the Scotian Shelf and Newfoundland’s South Coast in 2009. The objectives of the survey were to describe the spatial egg distribution and to calculate the daily and total egg productions and the corresponding spawning biomass. The survey was also intended to test the hypothesis that a significant portion of the Canadian contingent of Atlantic mackerel could spawn in this region for some years. During the survey, Atlantic mackerel eggs were found in only 28 (30%) of the 93 stations sampled. The mean daily egg production per station was estimated at 0.162 eggs/m², which is much lower than the productions measured in the southern Gulf of St. Lawrence. Daily egg production and total egg production for the entire sampled area were estimated respectively at 3.322 x 10¹⁰ and 1.884 x 10¹² eggs for a spawning biomass of only 2,576 t (2,141-3,010 t). Water temperatures varied between 4.8 and 11.7°C, with a mean of 8.8°C. Compared to similar temperatures, higher egg densities have been already measured in the southern Gulf of St. Lawrence. The survey results rule out the possibility that a significant portion of the Canadian contingent spawns on the Scotian Shelf and Newfoundland’s South Coast. The results also suggest that the low egg densities measured in the southern Gulf of St. Lawrence since 2005 reflect a real decline in stock abundance.

Complete document (PDF, 3092 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.