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Assessing the variability of hydrographic processes influencing the life cycle of the Sicilian Channel anchovy, Engraulis encrasicolus , by satellite imagery
Author(s) -
LAFUENTE JESÚS GARCÍA,
VARGAS JUAN MIGUEL,
CRIADO FRANCISCO,
GARCÍA ALBERTO,
DELGADO JAVIER,
MAZZOLA SALVATORE
Publication year - 2005
Publication title -
fisheries oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 80
eISSN - 1365-2419
pISSN - 1054-6006
DOI - 10.1111/j.1365-2419.2004.00304.x
Subject(s) - engraulis , anchovy , sicilian , hydrography , empirical orthogonal functions , oceanography , channel (broadcasting) , mode (computer interface) , geology , environmental science , climatology , geography , fishery , biology , linguistics , philosophy , engineering , fish <actinopterygii> , computer science , electrical engineering , operating system
Three oceanographic surveys carried out in the Sicilian Channel during the spawning season (June to July) of anchovy ( Engraulis encrasicolus ) showed a close relationship between anchovy reproductive strategy and important hydrographic structures. A time series of satellite‐derived sea surface temperature images of the Sicilian Channel were analysed by means of empirical orthogonal functions and the dominant empirical modes were studied in detail. The first empirical mode captured much of the original variance and reproduced the trajectory of the Atlantic Ionian Stream (AIS), the principal hydrodynamic feature of the area. The time coefficients of modes 1 and 2 had seasonal signals which, when combined, accounted for the enhancement of the thermal front, clearly visible off Cape Passero (southernmost coast of Sicily) during summer. As the area constituted the principal nursery ground of the Sicilian Channel anchovy, the combination of the time coefficients of these modes was considered a potential indicator of the food particle concentration usually associated with oceanic fronts, which provided the energy requirements for larval growth. Mode 3 described the north/south displacements of the mean AIS trajectory, which modified the surface temperature regime of the anchovy spawning habitat. Therefore, the time coefficients of this mode were used as a potential indicator of anchovy spawning habitat variability. The capability of time coefficients of modes 2 and 3 to modify the main pattern depicted by mode 1 were tested successfully against in situ oceanographic observations.