Distribución, abundancia y reproducción de Opisthonema oglinum (Pisces: Clupeidae) en la plataforma continental del sur del Golfo de México

Abstract

At present the ecological understanding and evaluation of tropical demersal fish communities have their bases on studies about the biology and ecology of dominant species. The Campeche Sound, in the southern Gulf of Mexico, has more than 300 species in the demersal fish community and 30 are dominants Among these species, Opisthonema oglinum is dominant by its frequency, distribution and abundance. This work determined the pattern of abundance and distribution of O. oglinum, and its reproduction, maturity and recruitment. Fish were collected with a shrimp trawl net during six oceanographic cruises in the Campeche Sound. The cruises correspond with the three characteristic seasons in the area: rainy, "nortes", and dry season. A total of 813 individuals with sizes between 56 and 205 mm of total length were collected; they weighted 30 211.5 g. O. oglinum is a typical pelagic-neritic species, and is estuarine dependent. This species occurs in the inner shelf waters of the Campeche Sound, less than 36 m deep and mainly in areas influenced by coastal discharges. It also occurs in the Terminos Lagoon (southern Campeche Sound) and occasionally in the riverine systems that drain into the lagoon. The highest biomass and density are on depths lesser than 20 m, in June and August-October. The high density of juveniles mainly determines the higher biomass. Maturity can start at a total length of 126 mm, but the size of first maturity is 135 mm of total length. Reproduction occurs from May to October with two evident peaks during May and August in depths greater than 18m. The juveniles are found in the shelf and inside of the Terminos Lagoon. Recruitment is from June to October (rainy season). The visceral and gonadic indices showed that the greatest alimentary activity is from June to August and in November. The condition factor is lowest in June, where the recruitment is highest, and highest in November, after spawning.