Hake, Merluccius merluccius L., in the northeastern Mediterranean Sea: a case of disappearance

Hake was not an important commercial fish in the northeastern Levant until the 1990s when a sudden increase in landings was experienced. However, following a series of profitable years, landings declined sharply. The rapid development of the trawl fleet played a role in the decline; however such an episodic event cannot be explained within the fisheries context alone. In this study the results of sparse historical trawl surveys were evaluated together with oceanographic data, and the impact of hydrographical changes on the appearance/disappearance of hake in the Levant was considered. The formation and movement of different water masses in the area seem to have primary importance for the species. The winter occurrence of modified Atlantic water that temporarily intrudes in the region may favour hake. Parallel with the increase in hake, an increase in clupeid species not common in the area was also observed. The change in the hydrography of the region, which was probably linked to the cold period that prevailed at the same time, temporarily led to an additional late summer pulse in the production cycle. The consequent increase in clupeids along with the changes in the hydrology favoured the advent of clupeid-eating hake in the NE Levant. The growth pattern result of the modal shift in monthly length-frequency distributions also showed that the species underwent a rapid growth phase in winter, which was most likely associated with intense feeding.