Modelling of European hake nurseries in the Mediterranean Sea: An ecological niche approach
Résumé
An ecological niche modelling (ENM) approach was developed to model the suitable habitat 36 for the 0-group European hake, Merluccius merluccius L., 1758, in the Mediterranean Sea. 37 The ENM was built combining knowledge on biological traits of hake recruits (e.g. growth, 38 settlement, mobility and feeding strategy) with patterns of selected ecological variables 39 (chlorophyll-a fronts and concentration, bottom depth, sea bottom current and temperature) 40 to highlight favourable nursery habitats. The results show that hake nurseries require stable 41 bottom temperature (11.8-15.0oC), low bottom currents (< 0.034 m.s-1) and a frequent 42 occurrence of productive fronts in low chlorophyll-a areas (0.1-0.9 mg.m-3) to support a 43 successful recruitment. These conditions mostly occur recurrently in outer shelf and shelf 44 break areas. The prediction explains the relative balance between biotic and abiotic drivers 45 of hake recruitment in the Mediterranean Sea and the primary role of unfavourable 46 environmental conditions on low recruitment in specific years (i.e. 2011). The ENM outputs 47 particularly agree spatially with biomass data of recruits, although processes such as fishing 48 and natural mortality are not accounted for. The seasonal mapping of suitable habitats 49 provides information on potential nurseries and recruitment carrying capacity which are 50 relevant for spatial fisheries management of hake in the Mediterranean Sea.
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