Reproductive biology of the freshwater drum Aplodinotus grunniens in Tabasco, Mexico

Abstract

ABSTRACT. Aplodinotus grunniens supports a sustained artisanal shery in the Usumacinta River; however, there are few studies to understand the population dynamics of the species. Relevant aspects of the reproductive biology were documented over an annual cycle, using 593 specimens captured with seine nets. The results indicate that females had a median TL of 32.05 cm, while males had 29.71 cm. The estimated sex ratio was 1.2:1 (males: females). The length-weight relationship showed signicant dierence between sexes, observing an allometric-type growth represented by TW=0.0013(TL)with 89.17 % of the data variability explained by the model. Gonadosomatic index (GSI) in females was higher in September (4.29), with males displaying a higher GSI in October (1.02). The highest HSI increase in females was observed in October (1.0). The estimated relative fecundity was 138.74 (± 74.30) oocytes/g of female weight. The macroscopic analysis of gonads indicates that the highest frequency of mature females occurs in June (75 %), while in males it takes place in March and June (35 %). The estimated L 50 for females was 31.89 cm (TL) and 28.78 cm (TL) for males. Though A. grunniens reproduces throughout the year, reproductive peaks coincide with the period when the river level decreases, and shing increases considerably. Hence, preventive measures must be applied in regards to the size of the species at capture and the exploitation volumes of this resource.Key words: Fishery biology, reproduction, Usumacinta river RESUMEN. Aplodinotus grunniens soporta una pesquería artesanal sostenida en el río Usumacinta; sin embargo, existen pocos estudios que permitan entender su dinámica poblacional. Se documentaron aspectos relevantes de la biología reproductiva a lo largo de un ciclo anual, empleandose 593 especímenes capturados con redes de cerco. Los resultados indican que las hembras presentaron una mediana de 32.05 cm de LT y los machos de 29.71 cm. La proporción sexual estimada fue de 1.2:1 (machos: hembras). La relación longitud-peso presentó diferencias signicativas entre sexos, observándose un crecimiento de tipo alométrico representado por TW=0.0013(TL) 3.5985 , con un 89.17 % de la variabilidad de los datos explicada por el modelo. El índice gonadosomático (IGS) en hembras fue mayor en septiembre (4.29) y en machos en octubre (1.02), mientras que el mayor incremento de IHP en hembras se observó en octubre (1.0). La fecundidad relativa estimada fue de 138.74 (±74.30) ovocitos/g de peso de la hembra. El análisis macroscópico de gónadas indica que la mayor frecuencia de organismos maduros en hembras se presenta en junio (75 %) y en machos en los meses de marzo y junio (35 %). La L 50 estimada para hembras fue de 31.89 cm (LT) y para los machos de 28.78 cm (LT). A. grunniens se reproduce la mayor parte del año, con picos reproductivos que coinciden con la disminución en los niveles del río y un considerable aumento de la pesca. Por lo tanto, se deben establecer medidas preventivas sobre su talla de captura y los volúmenes de exp...

Age and growth of Aplodinotus grunniens (Perciform: Sciaenidae) in the mid-Usumacinta River

“…In this study, slight patterns are associated with higher temperatures and the end of the reproductive season, but, due to the lack of a strong sample size during some months, more information is needed to elucidate the growth patterns of A. grunniens in the Usumacinta River. The cause of ring formation has been biologically related to temperature because changes in this environmental factor accelerate or delay the speed of biochemical reactions (Tarifeño 2004, Hernández-Gómez et al 2017. Consequently, the net effect of ambient temperature change on the physiology of A. grunniens may depend on the temperature divergence and the range and speed at which the change occurs, as Tarifeño (2004) mentioned.…”

“…This species is commercially important in Mexico in several regions (SAGARPA 2004, 2014, Rivera et al 2015, particularly in the Usumacinta river, supporting an essential artisanal fishery. However, studies on its biology and ecology are scarce, and the few existing focus on parasites, embryonic and larval development (Hernández-Gómez et al 2013), and reproductive biology (Hernández-Gómez et al 2017, Hernandez-Gómez et al 2019. Age studies are used to establish a fish species' growth rate and the age compositions of a given population.…”