Estudo biológico-pesqueiro da manjuba Opisthonema oglinum (Lesueur, 1818) da região de Itapissuma,Pernambuco

Abstract

The Atlantic thread herring Opisthonema oglinum (Lesueur, 1818), inserted in the Clupeidae family, appears in pelagic, marine and coastal areas, until 5m deep. They form young compact schools in Santa Cruz canal, Pernambuco, Brazil, where feed on small fishes, crabs and shrimps (adults) and planktonic organisms (juveniles). They’re spread in the whole American Atlantic coast, since New England until Argentina. The shortest (shorter than 20 cm) are called “manjuba” and marketed salted. The tallest – called “sardinha-de-laje” – are sold fresh or frozen. In spite of be the most important specie in handmade fish in Itapissuma region, the researches about its biology are very superficial. So, the aim of this work is getting fish and biology data of this specie. Since 2000 until 2002, 930 types were collected and they were measured (morphological characters) and was seen the Sex and the maturity stat to determinate the first maturity length (Lpm) and the period of reproduction. The data collected were: standard length, 52,5 – 209,0 mm; head, 9,0 – 47,0 mm; size, 12,0 – 70,1 mm; mouth, 2,0 – 16,0 mm; interorbital space 2,0 – 12,0 mm; eye diameter, 2,5 – 12,8 mm; dorsal fin, 0+19–21 radius and anal fin 0+21–26 radius. The morfometrical data were shared in 16 types (10 mm), between 55 mm (50 – 60 mm) until 205 mm (200 – 210 mm). The averages wereplotted in graph, to specify the characters, being the classes from 85 mm and from 95 mm the most representative with 24,9 % and 24,2 %, in the total of kinds that were caught. O. oglinum lays every year and the first maturity length (Lpm) is 117 mm. 92,7 % of the species is low of this Lpm. In natural environment, however, this specie can be used like grazing specie in mariculture.