Aspects of reproductive biology of curimba Prochilodus lacustris (Pisces, Prochilodontidae) in a tropical lake in Northeastern Brazil

Abstract

This study evaluated the annual cycle of biological reproductive aspects of Prochilodus lacustris, a neotropical fish species, in Baixada Maranhense Protection Area in northeastern Brazil. Fish were collected monthly between June of 2015 and June of 2016 using gill nets. In the laboratory, 600 individuals were weighed, measured, and eviscerated to obtain biometric data and data for the microscopic and macroscopic analyses of the maturation stages of the gonads. These analyses allowed the determination of the reproductive period using biological indicators such as the gonadosomatic index and hepatosomatic index, condition factor, stomach repletion index, and spawning season. Abiotic variables were measured in situ during the samplig: temperature, pH, dissolved oxygen, and electrical conductivity. In addition, local rainfall data was also obtained. The results showed that the total body length of individuals varied from 151 to 211 mm in males, and from 142 to 239 mm in females. The sex ratio showed a predominance of females over males, and the species showed negative allometric growth. The annual variation of reproductive indicators and the frequency of individuals in advanced stages of gonadal maturation suggest that the reproductive cycle of the species occurs between November and January, with a reproductive peak in January. This reproductive peak coincides with the beginning of the region's rainy season. Although we did not do the fertility analysis, our results suggest that the species presents partitioned spawning. In conclusion, this results demonstrates that the reproduction of the investigated specie is influenced by associations between environmental variables on a seasonal scale and can be contribute to improve the understanding of the dynamics of the physiological reproductive process in lentic environments.

Aspects of reproductive biology of the lesser spiny eel Macrognathus aculeatus (Bloch, 1786) from river Ganga, Uttar Pradesh, India

“…The high values of GSI and low condition factor were recorded in the month of June which indicated that there exists no relation between GSI and condition factor. The present finding is in corroboration with Cardoso et al (2019) who reported the reverse pattern for mean condition factor and GSI in Prochilodus lacustris. The condition factor relatively depended upon a number of factors such as environmental conditions and ecological parameters, seasons, food availability, gonadal development, fishing pressures and stress conditions (Zargar et al, 2012;Ahmad, 2013;Ali et al, 2014, Komsari et al, 2015.…”

“…reported by Abujam and Biswas (2011) and Kashyap et al (2016). However, it is worth mentioning here that several other workers (Qayyum and Qasim, 1964;Cardoso et al 2019) recorded the dominance of females over males. In the present study, male and female sex ratio was 1:0.93 which did not differ significantly from the hypothetical sex ratio of 1:1.…”

“…Reproductive biology studies in fish include the assessment of sex ratio, maturity stages, duration of reproductive season, gonadosomatic index (GSI) and quantification of reproductive capacity (Maurua et al, 2003;De Carvalho et al, 2009;Fontoura et al, 2009;Cardoso et al, 2019). Reproductive biology is one of the most important biological aspects which is a prerequisite for evaluation of the commercial potentialities of a fish stock and its preservation, conservation and management prospects (Jakobsen et al, 2009;Hliwa et al, 2017;Cardoso et al, 2019). GSI has been used as an indicator of reproductive activity of fish and for determination of the breeding season (Sley et al, 2015;Almukhtar et al, 2016).…”