Gonadal development and fecundity of the smooth weakfish Cynoscion leiarchus (Teleostei: Perciformes: Sciaenidae) in a tropical Brazilian bay

Abstract

ABSTRACT. Cynoscion leiarchus (Cuvier, 1830) is a coastal fish species that is widely distributed along the Western Atlantic coast, from Belize to Southern Brazil. In Brazil, C. leiarchus It is an important resource for commercial and artisanal fisheries.Our objective was to describe the oogenesis and spermatogenesis stages of the species and to estimate batch size and relative fecundity of a population at a tropical bay in southeastern Brazil. The examined specimens were obtained from artisanal catches that took place from July 2013 to June 2014. A total of 18 individuals (11 females and 7 males) were examined for histological analysis and 20 spawning-capable females were used to estimate fecundity. Five stages of oocyte development (primary growth, pre-vitellogenic, vitellogenic, oocyte maturation and atresia) and four stages of spermatocytes (spermatogonia, spermatocytes, spermatids, spermatozoa) were described in different phases of gonad development (immature, developing, spawning capable and regenerating), suggesting that spawning happens in batches, oocyte development is asynchronic and fecundity is indeterminate. Batch fecundity ranged from 100 × 10 3 to 866 × 10 3 oocytes undergoing final oocyte maturation, and relative fecundity ranged from 232 to 1,225 oocytes, averaging 467 oocytes per gram of ovary-free body weight. Fecundity tended to increase linearly with gonadal weight, total weight, total length, and age, but the highest linear correlation obtained was between fecundity and gonadal weight. This study provides the first information on the gonadal development of C. leiarchus from the Brazilian coast and is a baseline to compare with other populations and/or congeneric species.

Reproductive characteristics of the hermaphroditic four-finger threadfin, Eleutheronema tetradactylum (Shaw, 1804), in tropical coastal waters

“…In sheries management, an estimation of the rst maturation of sh (Lm 50 ) is essential to assess a minimum permissible mesh size and avoid over exploitation of juveniles [49,51,55,66]. Environmental condition can lead to changes of growth and onset of gonadal maturation [33,36,41,44,49,59]. Stock density and food availability can in uence sexual maturity of marine sh species [53].…”

“…For histological examination, 95 gonad samples, accounted for 22% of total sh sample, were wiped with tissue paper and weighed to the nearest 0.01g. They were xed in 10% buffered formalin and stored in bottle jars [9,15,33]. Immature individuals for which sex could not be identi ed with naked eye, were excluded for histological analysis.…”

NOTAS SOBRE LA REPRODUCCIÓN, MORFOLOGÍA Y ECOLOGÍA DE Pareques acuminatus (TELEOSTEI: SCIAENIDAE), EN LA REGIÓN DE SANTA MARTA, CARIBE COLOMBIANO.

“…La descripción histológica de las fases (en desarrollo y capaz de desove) y las etapas de desarrollo (oocitos vitelogénicos, alvéolos corticales y crecimiento primario) coinciden con las características mencionadas por Silva et al (2016) para la especie Cynoscion leiarchus (Cuvier, 1830). Estos autores especifican cinco etapas de desarrollo de ovocitos y un desarrollo ovocitario de tipo asincrónico con fecundidad parcial.…”

“…Se confirma este tipo de reproducción para P. acuminatus, en la que se pueden encontrar en los ovarios diferentes etapas de desarrollo antes y después del desove (Holden y Raitt, 1974). Estas características se han observado en las especies de la familia Sciaenidae mencionadas anteriormente; para M. furnieri, S. venezuelae, C. leiarchus y M. ancylodon, Escobar (1994), Silva et al (2016) y Cardoso et al (2018) describen una reproducción parcial y un desarrollo completamente asincrónico. Winemiller y Layman (2005) indican que este patrón de comportamiento puede considerarse como una respuesta adaptativa a las condiciones ambientales.…”

“…Finalmente, el peso gonadal indicó una correlación importante con respecto a la fecundidad parcial (R 2 = 0,83). Silva et al (2016) encontraron en el esciénido Cynoscion leiarchus un R 2 de 0,67 para esta variable y mencionan que el peso de la gónada es el mejor predictor de la fecundidad, comparado con otras medidas como la LT, el peso del individuo o la edad. La relación entre el peso total y la LT mostró un mejor ajuste positivo para las hembras maduras.…”