Aspects of the Biology of Heterobranchus bidorsalis in Oguta Lake, Imo State, Nigeria

Abstract

The catfish H. bidorsalis is an important component of the local aquatic ecosystem in Oguta Lake. However, the ecological impact of this species remains poorly understood poorly understood, but is one of the common species that is highly valued as fish for food and for their commercial importance in freshwater artisanal fisheries in the country and other West African countries. This study aimed to investigate the length–weight relationship, condition factor, and feeding habits of H. birdorsalis in Oguta Lake, Imo State, Nigeria. A total of sixty fish specimens (ten per month) were collected bi-weekly for six months at three landing sites of fishers using gears such as gill net, cast net of various sizes (50mm to 100mm). The length-weight analysis, incorporating minimum and maximum values, revealed a negative allometric growth pattern, with a significant exponential b value of 2.4304 (log W = -1.0639 + 2.4304logL), indicating an accelerated increase in weight relative to length. The correlation coefficient (r = 0.9679) further underscored the robustness of this relationship. The species exhibited a diverse size range, with a minimum length of 15.5 cm and a maximum length of 33.6 cm. Corresponding weights ranged from 50.5g to 324g. The mean length and mean weight were 23.9 cm and 205.6g, respectively, with a mean condition factor of 1.64. The stomachs content was examined using the frequency of occurrence of each diet expressed as a percentage of the total number of specimens examined, which revealed a balanced trophic strategy, with insects (29.6%) and small fish parts (19.5%) dominating, followed by worms (13.8%) and aquatic plants (12.8%). These findings contribute valuable insights into the growth dynamics and ecological role of H. bidorsalis in Oguta Lake. The results have implications for fisheries management and highlight the need for conservation measures to sustain the ecological balance of this freshwater ecosystem. Protecting the natural habitats within Oguta Lake is essential to ensure the availability of diverse food resources and suitable environmental conditions for H. bidorsalis and other aquatic species. Regular monitoring of habitat quality and food availability to detect any changes and implement appropriate management strategies to mitigate potential threats is of great importance.