Fréon Pierre, Soria Marc, Gerlotto François. (1990). Short-term variability of Sardinella aurita aggregation and consequencies on acoustic survey results. In :
Collected reprints of the main contributed papers of EICHOANT program (Evaluation of Behaviour Influence on Fishery Biology and Acoustic Observations in Tropical Open Sea) presented during congresses from 1/1/87 to 4/30/90 = Compilation des principales communications du programme EICHOANT (Evaluation de l'Impact du Comportement en Halieutique et sur les Observations Acoustiques en Milieu Naturel Tropical) présentées à des congrès entre le 1/1/87 et le 30/4/90. Fort de France (MTQ) ; Le Robert : ORSTOM ; IFREMER, 16 p. multigr. (Document Scientifique - Pôle de Recherche Océanologique et Halieutique Caraïbe ; 26). Réunion du Conseil International pour l'Exploitation de la Mer, 77., La Haye (NLD), 1989/10.
Titre du document
Short-term variability of Sardinella aurita aggregation and consequencies on acoustic survey results
Année de publication
1990
Type de document
Colloque
Auteurs
Fréon Pierre, Soria Marc, Gerlotto François
In
Collected reprints of the main contributed papers of EICHOANT program (Evaluation of Behaviour Influence on Fishery Biology and Acoustic Observations in Tropical Open Sea) presented during congresses from 1/1/87 to 4/30/90 = Compilation des principales communications du programme EICHOANT (Evaluation de l'Impact du Comportement en Halieutique et sur les Observations Acoustiques en Milieu Naturel Tropical) présentées à des congrès entre le 1/1/87 et le 30/4/90
Source
Fort de France (MTQ) ; Le Robert : ORSTOM ; IFREMER, 1990,
16 p. multigr. (Document Scientifique - Pôle de Recherche Océanologique et Halieutique Caraïbe ; 26).
Colloque
Réunion du Conseil International pour l'Exploitation de la Mer, 77., La Haye (NLD), 1989/10
A single fish assemblage of Sardinella aurita was tracked over 24 hours by a research vessel equipped with acoustic devices in order to study the short-term variability of its distribution pattern in the Gulf of Cariaco (Venezuela). Obviously the studied assemblage did not follow the usually observed aggregation pattern, considered to depend mainly on the light intensity. Nor did the mean depth of the biomass correspond exactly to the usual diurnal cycle pattern. Dense schools were observed during the first night in absence of moonlight; they dove from 15 to 35 m depth in the morning, but came back close to the surface (19 m) early in the afternoon and remained dense during the following night. Futhermore the fish assemblage apparently presented a contagious structure most of the time, with an increasing density from the periphery (dispersed fish and/or small schools) to the center (large schools or aggregation). Practical conclusions are drawn from these observations, specifically on the survey design (oversampling strategy on densest area) and on the data analysis (inaccuracy of the night/day data split in some cases). (Résumé d'auteur)
