Comparative Gametogenesis and Biochemical Differentiation of Goatfish (Parupeneus heptacanthus and Parupeneus cyclostomus) from Red Sea

Abstract

Red Sea’s goatfish (Mullidae), locally referred as ‘Sultan Ibrahim’, are a popular recreational fish that also supports neighboring commercial markets. The present study compares spermatogenesis, oogenesis and gonad structure, in two species of goatfish from Jeddah coast. The reproductive parameters including changes in gonado-somatic index (GSI),and spawning seasons were analyzed for Parupeneus heptacanthus (cinnabar goatfish) and Parupeneus cyclostomus (goldsaddle goatfish). P. heptacanthus spawn from February to June and P. cyclostomus spawning season begins from August to September. Remarkable difference in the egg size has been observed P. heptacanthus had the egg diameter (325.9 μm), while the smallest one is P. cyclostomus (209.6 μm) when compared to other species of Mullidae. P. heptacanthus was observed with largest flagellum length (8.7 ± 0.2 μm). The ultrastructure revealed some common features in both species like oval ova; further the ovarian follicular epithelium consists of two layers, an inner granulosa layer with zona radiata under them and an outer theca layer. Centrioles of both species consist of the typically arranged nine triplets (9 + 0) of microtubules. The external lay of zona radiata is thinner than internal one. Disparity in protein patterns of muscle and gonads were observed in the present study. There was also variation in the number of specific bands for each species in both protein soluble muscle and gonads. The histology results reported gonads to be typically gonochoristic and exhibited asynchronous development of oocytes in the ovary. The outcome of this study has yielded essential information of some of the imperative reproductive biology of P. heptacanthus and P. cyclostomus.