Capello Manuela, Soria Marc, Potin G., Cotel Pascal, Dagorn Laurent. (2013). Effect of current and daylight variations on small-pelagic fish aggregations (Selar crumenophthalmus) around a coastal fish aggregating device studied by fine-scale acoustic tracking. Aquatic Living Resources, 26 (1), p. 63-68. ISSN 0090-7440.
Titre du document
Effect of current and daylight variations on small-pelagic fish aggregations (Selar crumenophthalmus) around a coastal fish aggregating device studied by fine-scale acoustic tracking
Capello Manuela, Soria Marc, Potin G., Cotel Pascal, Dagorn Laurent
Source
Aquatic Living Resources, 2013,
26 (1), p. 63-68 ISSN 0090-7440
Several pelagic fish species are known to associate with floating objects. However, quantitative information on the main factors that drive this associative behaviour is still lacking. Small pelagic fish offer a particularly interesting case study for this phenomenon, since the small spatial scales involved in their association with floating objects allow experimental data to be collected at a fine scale. Here, we monitored twelve acoustically-tagged bigeye scads, Selar crumenophthalmus (Carangidae), (mean fork length 16.4 cm, SD 2.1 cm) around a floating object moored in shallow water (15 m depth) playing the role of a coastal fish aggregating device (FAD). To quantify the role played by variations in current and daylight, we calculated the speed distribution, pair correlation function and group polarization for the tagged fish hourly, from midday to dusk (13:00-18:00), for varying current strengths and daylight conditions. We found that the current induced a shift in the position of the aggregation upstream of the FAD, at distances that increased with the current strength. We found evidence of an expansion and a higher coordination in the aggregation at dusk, with increasing speed, distance among conspecifics and alignment. We discuss possible scenarios in which group polarization increases at dusk and suggest complementary measurements for future experiments that could confirm our findings.
Plan de classement
Autoécologie [036MILMAR03]
;
Pêches par espèces [040PECHE02]
Descripteurs
POISSON MARIN ; ESPECE PELAGIQUE ; ETHOLOGIE ; PROSPECTION ACOUSTIQUE ; DISPOSITIF DE CONCENTRATION DES POISSONS ; VARIATION JOURNALIERE ; IMPACT DE L'ENVIRONNEMENT ; AGREGATION
