title: Habitat selection response of small pelagic fish in different environments. Two examples from the oligotrophic Mediterranean Sea.
abstract: A number of scientific papers in the last few years singled out the influence of environmental conditions on the spatial distribution of fish species, highlighting the need for the fisheries scientific community to investigate, besides biomass estimates, also the habitat selection of commercially important fish species. The Mediterranean Sea, although generally oligotrophic, is characterized by high habitat variability and represents an ideal study area to investigate the adaptive behavior of small pelagics under different environmental conditions. In this study the habitat selection of European anchovy Engraulis encrasicolus and European sardine Sardina pilchardus is analyzed in two areas of the Mediterranean Sea that largely differentiate in terms of environmental regimes: the Strait of Sicily and the North Aegean Sea. A number of environmental parameters were used to investigate factors influencing anchovy and sardine habitat selection. Acoustic surveys data, collected during the summer period 2002-2010, were used for this purpose. The quotient analysis was used to identify the association between high density values and environmental variables; it was applied to the entire dataset in each area in order to identify similarities or differences in the "mean" spatial behavioral pattern for each species. Principal component analysis was applied to selected environmental variables in order to identify those environmental regimes which drive each of the two ecosystems. The analysis revealed the effect of food availability along with bottom depth selection on the spatial distribution of both species. Furthermore PCA results highlighted that observed selectivity for shallower waters is mainly associated to specific environmental processes that locally increase productivity. The common trends in habitat selection of the two species, as observed in the two regions although they present marked differences in hydrodynamics, seem to be driven by the oligotrophic character of the study areas, highlighting the role of areas where the local environmental regimes meet 'the ocean triad hypothesis'.
authors.affiliation: Consiglio Nazionale delle Ricerche, Institute for Coastal and Marine Environment (IAMC), Detached Units of Capo Granitola (TP), Mazara del Vallo (TP) and Naples, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Bonanno
authors.affiliation: Hellenic Centre for Marine Research, Institute of Marine Biological Resources, Iraklion, Greece.
authors.forename: Marianna
authors.initials: M
authors.lastname: Giannoulaki
authors.affiliation: Consiglio Nazionale delle Ricerche, Institute for Coastal and Marine Environment (IAMC), Detached Units of Capo Granitola (TP), Mazara del Vallo (TP) and Naples, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Barra
authors.affiliation: Consiglio Nazionale delle Ricerche, Institute for Coastal and Marine Environment (IAMC), Detached Units of Capo Granitola (TP), Mazara del Vallo (TP) and Naples, Italy.
authors.forename: Gualtiero
authors.initials: G
authors.lastname: Basilone
authors.affiliation: Hellenic Centre for Marine Research, Institute of Marine Biological Resources, Iraklion, Greece.
authors.forename: Athanassios
authors.initials: A
authors.lastname: Machias
authors.affiliation: Consiglio Nazionale delle Ricerche, Institute for Coastal and Marine Environment (IAMC), Detached Units of Capo Granitola (TP), Mazara del Vallo (TP) and Naples, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Genovese
authors.affiliation: Russian Federal Research Institute of Fisheries and Oceanography (VNIRO), Moscow, Russia.
authors.forename: Sergey
authors.initials: S
authors.lastname: Goncharov
authors.affiliation: Russian Federal Research Institute of Fisheries and Oceanography (VNIRO), Moscow, Russia.
authors.forename: Sergey
authors.initials: S
authors.lastname: Popov
authors.affiliation: Consiglio Nazionale delle Ricerche, Institute for Coastal and Marine Environment (IAMC), Detached Units of Capo Granitola (TP), Mazara del Vallo (TP) and Naples, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Rumolo
authors.affiliation: Consiglio Nazionale delle Ricerche (CNR), Roma, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Di Bitetto
authors.affiliation: Consiglio Nazionale delle Ricerche, Institute for Coastal and Marine Environment (IAMC), Detached Units of Capo Granitola (TP), Mazara del Vallo (TP) and Naples, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Aronica
authors.affiliation: Consiglio Nazionale delle Ricerche, Institute for Coastal and Marine Environment (IAMC), Detached Units of Capo Granitola (TP), Mazara del Vallo (TP) and Naples, Italy.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Patti
authors.affiliation: Consiglio Nazionale delle Ricerche, Institute for Coastal and Marine Environment (IAMC), Detached Units of Capo Granitola (TP), Mazara del Vallo (TP) and Naples, Italy.
authors.forename: Ignazio
authors.initials: I
authors.lastname: Fontana
authors.affiliation: Consiglio Nazionale delle Ricerche, Institute for Coastal and Marine Environment (IAMC), Detached Units of Capo Granitola (TP), Mazara del Vallo (TP) and Naples, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Giacalone
authors.affiliation: Consiglio Nazionale delle Ricerche, Institute for Coastal and Marine Environment (IAMC), Detached Units of Capo Granitola (TP), Mazara del Vallo (TP) and Naples, Italy.
authors.forename: Rosalia
authors.initials: R
authors.lastname: Ferreri
authors.affiliation: Consiglio Nazionale delle Ricerche, Institute for Coastal and Marine Environment (IAMC), Detached Units of Capo Granitola (TP), Mazara del Vallo (TP) and Naples, Italy.
authors.forename: Giuseppa
authors.initials: G
authors.lastname: Buscaino
authors.affiliation: Hellenic Centre for Marine Research, Institute of Marine Biological Resources, Iraklion, Greece.
authors.forename: Stylianos
authors.initials: S
authors.lastname: Somarakis
authors.affiliation: Hellenic Centre for Marine Research, Institute of Marine Biological Resources, Iraklion, Greece.
authors.forename: Maria-Myrto
authors.initials: MM
authors.lastname: Pyrounaki
authors.affiliation: Hellenic Centre for Marine Research, Institute of Marine Biological Resources, Iraklion, Greece.
authors.forename: Stavroula
authors.initials: S
authors.lastname: Tsoukali
authors.affiliation: Consiglio Nazionale delle Ricerche, Institute for Coastal and Marine Environment (IAMC), Detached Units of Capo Granitola (TP), Mazara del Vallo (TP) and Naples, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Mazzola
mesh_terms: D000818:Animals; D018533:Biomass; D017753:Ecosystem; D004777:Environment; D005399:Fishes / Q000502:physiology*; D008522:Mediterranean Sea; D025341:Principal Component Analysis; D012621:Seasons