Spatiotemporal distribution of European hake Merluccius merluccius related to environmental conditions on the continental shelf of the Sea of Marmara


Yıldız T.

Cahiers De Biologie Marine, cilt.61, ss.195-205, 2020 (SCI Expanded İndekslerine Giren Dergi)

  • Cilt numarası: 61 Konu: 2
  • Basım Tarihi: 2020
  • Doi Numarası: 10.2144/cbm.a.2d189cc3
  • Dergi Adı: Cahiers De Biologie Marine
  • Sayfa Sayıları: ss.195-205

Özet

Currently, knowledge of the spatial distribution of European hake Merluccius merluccius in the Sea of

Marmara is scarce, particularly regarding the dependency of this fish on biotic or abiotic conditions. A

generalized additive model (GAM) was used to model hake abundances in relation to depth, temperature,

dissolved oxygen, pH, and spatial location variabilities in the eastern Sea of Marmara (ESM). Furthermore, the

size distribution of European hake was analyzed by depth and season. Data were collected during a 4-year

sampling period (2014-2017) in the ESM using scientific demersal trawl surveys. The GAM results indicated that

although all given variables influenced the spatial distribution patterns of hake, the variables with the greatest

contributions in the ESM were longitude and depth. Hake abundance showed a strongly nonlinear dependence

on the explanatory covariates. The results concluded that areas with the highest hake abundances were located

at approximately 90 m. The results also indicated that a bottom temperature between 15 and 15.5°C,

representing relatively warm bottom waters in the ESM, had the highest hake abundances. Low oxygen values

did not adversely affect the abundance of hake. Hake preferences for areas with specific bathymetric and ocean

environmental conditions are considered to be linked to the oceanography of the ESM ecosystem. This study

also demonstrated that the size distribution of European hake differs by depth and season, and individuals larger

than 30 cm can mostly be found in waters deeper than 80 m.