Length-weight relationships and condition factors of Sarotherodon melanotheron, Chrysichthys nigrodigitatus and Periophthalmus koelreuteri from tropical creek, southwestern Nigeria.

Abstract

The length-weight relationships and condition factor of Sarotherodon melanotheron, Chrysichthys nigrodigitatus and Periophthalmus koelreuteri inhabiting Abule-Eledu Creek, Lagos Lagoon were studied. Fish samples were collected using a gill nets which were set in the evening between the hours of 4pm to 6pm and retrieved the following morning between the hours of 6.00am to 9.00am. Fish collection was carried out from February to July, 2021. Length and weight data collected were analyzed with Microsoft excel to estimate relationship in body parameters. Results revealed that, mean b value for S. melanotheron was 2.7835. The value of 2.5894 was recorded for P. koelreuteri while 1.2681 was obtained in C. nigrodigitatus. This indicated that all the fish collected at the lagoon exhibited negative allometric growth, i.e. fish became slim as they increased in length. The results further revealed high correlation for S. melanotheron (R² = 0.9811 at p = 0.05) and P. koelreuteri (R² = 0.9174 at p = 0.05). This high correlation proved a strong relationship between the standard lengths and body weights of these fish species. However, a reverse performance was observed for C. nigrodigitatus (R² = 0.3894 at p = 0.05). Fish condition factor showed that S. melanotheron had values ranging from 0.001 to 0.094 with a mean of 0.04±0.02. Mean condition factor for P. koelreuteri was 1.97±1.28 while C. nigrodigitatus recorded 0.99±0.17. Based on these results, it could be concluded that both P. koelreuteri and C. nigrodigitatus (K ≥ 1.00) were in good condition of well-being. Thus, the present study revealed that these species were healthy despite that Lagos Lagoon receives wastewater from different anthropogenic sources. Thus, the study area is conducive for the development and sustenance of fisheries resources.