Enhancing survey coverage with no net increase in survey effort

No abstracts are to be cited without prior reference to the author.

The mackerel egg survey (MEGS) delivers the only fishery independent data for the assessment of Northeast Atlantic mackerel. Changes in the temporal and geographical distribution of mackerel spawning coupled with renewed discussion surrounding the spawning biology in mackerel necessitated an examination of the traditional MEGS design. During the 2007 MEGS a large expansion of the mackerel spawning area to the Northwest was observed for the first time. This raised concerns whether it would be possible to cover the entire spawning area during future surveys with the limited available ship time. As an alternative survey strategy sampling on every other standard transect was proposed in order to gain ship time to survey a much larger area in the Northwest. However, reliability of the survey results shouldn’t be affected by such modification of the survey strategy.