Published online by Cambridge University Press: 11 May 2009
Atlantic mackerel (Scomber scombrus L.) were sampled by pelagic trawl over the Porcupine Bank to the west of Ireland between 52°N and 54°N at peak spawning time, between 27 May and 10 June 1992. Distribution of juveniles (age classes 1 and 2) was inversely related to depth, comprising over 90% of hauls close to the coast of Ireland and 20% of the catch on the Porcupine Bank. Egg production increased westwards and was high along the continental shelf edge. Adult spawning fish were found throughout the shelf area and beyond, into waters over 3000 m deep. The results indicate that mackerel spawn over deep water some distance from the shelf edge and may exploit oceanic food resources from deep water.