Estrutura de cardumes da sardinha-verdadeira, Sardinella brasiliensis (Steindachner, 1879), no estado do Rio de Janeiro (Brasil)

Abstract

ABSTRACT. Schooling structure of Brazilian-sardine, Sardinella brasiliensis (S teindachner), in the State of Rio de Janeiro (Brazil). This paper deals with the schooling strueture of Brazilian-sardine, Sardinella brasiliensis (Steindaehner, 1879), in eoastal waters of Rio de Janeiro State (Brazil ). Samples were obtai ned from sehools eaught by eommereial fishery in the area of Angra dos Reis (23°-24°S, 44°_45°W), from autumnll999 to summerl2000, eomprising 2,278 fishes. In average, males had total lengths and weights lower than those of females, with major differenees in weights. Seasonal fluetuations of average total weights are assoeiated with the annual reproduetion eycle and eondition faetor, mainly in females. Sex-ratio was around I: I, exeept in winter, when females were in majority. Mature males and females were found ali along the year, with a peak in the spring-s ummer, show ing a long reproduction period of sueeessive spawning of reprodueers in a same sehoo l, si nee individual spawn in g is complete. Total lengths when 50% of fishes are mature di ffer between males (18.2 em) and females (19.2 em). The sehools can be eonsidered as spawning sehool s, as they were found in a spawning gro und , and eonsisted almost exclusively of adults, with a long annual reproduetion period. KEY WORDS. Brazi li an-sardine, Sardinella brasiliensis, sehooling strueture , Rio de Janeiro, Southeast Brazil