The Mackerel egg survey is undertaken every 3 years by the Fisheries Ecosystems Advisory Services (FEAS) department of the Marine Institute of Ireland as part of a series of international egg surveys co-ordinated by the International Council for the Exploration of the Seas (ICES). The MEGS provides a unique opportunity for surveillance of the summer distribution of cetaceans in both shelf water and deep water habitats along Ireland’s Atlantic margins which can be difficult to reach by other means.

The Department of Arts, Heritage and the Gaeltacht (DAHG), through the Marine Institute, commissioned a cetacean survey from the MRV Corystes during the Mackerel Egg Survey (MEGS), running from 9th to 29th of June 2019.

A standard, single platform line transect survey methodology was employed by the cetacean observer with additional visual point sampling at oceanographic sampling stations. Survey transects were undertaken at speeds of 5-10 knots, with fishing activity being conducted at speeds of 3-4 knots. The cetacean observer’s survey effort was maximized and optimized during periods of sea state less than or equal to sea state 6 and with visibility of greater than 1km. A total of 127 hours and 57 minutes of survey effort was conducted over the course of the MEGS 2019 survey. In total, 126 hours and 18 minutes of survey effort were conducted using a line transect methodology, while 1 hours and 38 minutes of effort were conducted using the point sampling methodology.