Ecomorphological patterns of the sagitta in fish associated with bottom marine shelf in the Mar Argentino.

VOLPEDO, A.V; ECHEVERRÍA, D.D

FISHERIES RESEARCH

Elsevier Science,

Lugar: Netherlands; Año: 2003 vol. 60 p. 551 - 560

0165-7836

Morphology and morphometry of the sagittae otolith were studied in fish associated with different substrates. The shape, margins and rostrum of three groups of otoliths from several species were analyzed: group 1 (fish associated with soft substrates, N= 10 species), group 2 (fish associated with hard substrates, N= 10 species) and group 3 (pelagic fish, not associated with the bottom, N= 6 species). E and R indexes were calculated for each species. The value of E = maximum width of the sagitta (WO)/maximum length of the sagitta (LO) %, expresses the relative tendency in the shape otolith (from circular to elongate). The value of R = length of the rostrum (LR)/LO%, expresses the percentage in the total length of the otolith that corresponds to the rostrum. The sagittae of group 1 were circular or polygonal with rounded borders. The rostrum can be absent or poorly developed. The sagittae shape of group 2 was elongated, with ornamented borders and a rostrum. The sagittae of group 3 possessed a prominent rostrum, a deep V-shaped cisure and ornamented borders. Statistical analysis showed no significant differences in the E index of groups 1 and 2, while R-values of the three groups were significantly different. These results were compared with 80 other species, belonging to 12 families, from the publisher literature. E and R-values could be used to characterize the sagittae of the marine fish and could be considered a useful tool for fish ecology studies.