Environmental Influences on the Spatio-Temporal Distribution of European Hake (Merluccius merluccius) in Izmir Bay, Aegean Sea
2016
Yalcin, Esin | Gurbet, Rasit
In Izmir Bay, Aegean Sea, the influence of abiotic environmental factors besides depth and fishing pressure on the spatio-temporal distribution of European hake, Merluccius merluccius L. 1758, abundance were analysed using a Generalized Additive Model (GAM), with the Catch Per Unit Effort (CPUE) as the response-dependent variable and a Geographic Information System (GIS) software-based approach to display relationships. Data were collected on a monthly basis from 2007-2009 using a conventional bottom trawl net in Izmir Bay. European hake is mostly abundant in Izmir Bay during summer and early autumn temporally (particularly during September) and spatially, in the region to the north of Uzunada Island and between the east coast of the island and the centre of the bay. GAM models also demonstrated that higher European hake abundances were located in waters of >50 m in depth with Sea Bottom Temperature (SBT) values ranging from 14.5-19 °C and Sea Bottom Salinity (SBS) values >38.55. In addition to this, the effects of fishing pressure were clearly evident throughout the area where bottom trawling is permitted. A better knowledge of the changes in spatio-temporal distribution of the species will allow the improved management of this important resource.
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