Maturation and gill-net selectivity of two small sea breams (genus Diplodus) from the Algarve coast (south Portugal)

• Published in: Fisheries research Vol. 36; no. 2; pp. 185 - 194
• Main Authors: Santos, Miguel Neves, Monteiro, Carlos Costa, Erzini, Karim, Gerard Lasserre
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.1998; Elsevier
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Biology; CATCH COMPOSITION; COMPOSICION DE LA CAPTURA; COMPOSITION DE LA CAPTURE; D. annularis; D. bellottii; DIPLODUS; Diplodus annularis; Exploitation and management of natural biological resources (hunting, fishing and exploited populations survey, etc.); Fundamental and applied biological sciences. Psychology; Gill-net selectivity; GILLNETS; LARGURA; LENGTH; LONGUEUR; MANET; Marine; Maturation; PESO; POIDS; PORTUGAL; REPRODUCCION; REPRODUCTION; TRASMALLO; WEIGHT; East Atlantic; Portugal; Europe; ANE, Portugal; D. bellottii; Gill-net selectivity; Biology; D. annularis; Maturation; Marine environment; Vertebrata; Sexual maturity; Pisces; Body size; Length weight relation; Selectivity; Net; Fishing
• ISSN: 0165-7836; 1872-6763
• DOI: 10.1016/S0165-7836(98)00100-3

Diplodus annularis and Diplodus bellottii, two species of small sea breams from the Algarve coast (south Portugal), were studied to obtain information on the spawning period, first maturity, weight–length relationship and gill-net selectivity curves. These species are important in local gill-net catches, and there is no information on their biology and selectivity in the Algarve waters. Spawning lasts for 6 months. Total length (TL) at first maturity for females was 13.4 cm in case of D. annularis and 11.4 cm in case of D. bellottii. The relationships between weight and length were W=0.0132 TL 3.096 for D. annularis and W=0.0093 TL 3.193 for D. bellottii. The Sechin method was used to estimate gill-net selectivity curves. The estimated selectivity curves correspond closely to the catch curves of the legal mesh size (60 mm), but were narrower for the other meshes. D. annularis and D. bellottii will be caught using the legal mesh size in the following length ranges: 13–19 cm and 11–19 cm.