Recent occurrence and origin of juvenile Atlantic mackerel (Scomber scombrus L.) in Icelandic waters. HV 2019-03

The spawning‐ and feeding distributions of North‐East Atlantic mackerel have been expanding north‐ and westwards during the last decade. Juvenile mackerel have been observed sporadically in the annual ground fish surveys on the Icelandic shelf, since first recorded in 2004. Further, during the autumn survey of 2010, 0‐group mackerel was observed over a wide area south and west of Iceland. Estimation of 0‐group hatching date distributions by means of otolith microstructure analysis indicates that the juveniles may originate from spawning in the north‐westernmost part of the spawning area in the North‐ East Atlantic. The possible origin of juvenile mackerel in the area was investigated with the aid of a particle tracking software. It is concluded that juvenile mackerel are overwintering in Icelandic waters and it seems that its nursery areas are expanding.