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Environmental factors controlling the spring immigration of two estuarine fishes Atherina boyeri and Pomatoschistus spp. into a Mediterranean lagoon
Author(s) -
Bardin O.,
Pont D.
Publication year - 2002
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2002.tb00896.x
Subject(s) - pomatoschistus , biology , mediterranean climate , pelagic zone , estuary , benthic zone , ecology , diel vertical migration , mediterranean sea , oceanography , fishery , geology , fish <actinopterygii> , goby
Atherina boyeri , a pelagic species, mainly entered a Mediterranean lagoon in the Rhone River Delta, during the day, whatever the flow direction. Flow velocity did not appear to be a significant factor and its swimming abilities seemed to be sufficient to cope with the observed velocity. The combined responses of Pomatoschistus spp., benthic species, to the different environmental factors clearly demonstrated a change in behavioural response during their ontogenic development, i.e. a shift from passive to active or active‐passive migration. Young Pomatoschistus spp. (<20 mm L T ) exhibited a behaviour that correspond to the classical selective tidal stream transport of young fishes towards estuarine areas (passive drifting). Large Pomatoschistus spp. were also able to enter the lagoon with the flow, but they remained negatively affected by the flow velocity. The diel cycle appeared to be the main factor controlling the immigration of A. boyeri into the lagoon whereas Pomatoschistus spp. seemed more sensitive to hydrographic conditions prevailing at the connection.