Reproductive Biology of Neotropical Fishes: A Guide to Identification to the Gonadal Morphology During the Reproductive Cycle of Catfish Rhamdia quelen (Siluriformes: Heptapteridae)

Abstract

In most Teleostei fish, the gametogenesis is a cyclical and seasonal event. The renewal of gametes, through their differentiation, development, maturation and release causes several changes in the morphological characteristics of the ovaries and testes throughout the annual reproductive cycles. These alterations are used to recognize different phases in the reproductive cycles. However, as the number of studies of fish reproduction increased, the number of types of gonadal classification and nomenclatures also diversified. This may make it difficult to communication between researchers and the aquaculture activity, since the recognition of these phases is one of the most important parameters applied in the management of fishery resources. In addition, the terminologies proposed in most of the current studies refer to reproductive stages applicable to marine fish, with marked and defined seasonality characteristics. In this way, this report presents a recent proposal for the recognition of reproductive phases originally developed for the Perciformes and here adapted for the Neotropical Siluriformes, using as a biological model a freshwater catfish Rhamdia quelen. In addition, we describe a brief characterization of the gametogenesis in this species. We hope that the material presented can be used as an easy and practical guide of identification for reproductive phases applicable to other neotropical freshwater fish, more especially Otophysi, such as Siluriformes.