Diversity, distribution and abundance of fish species in Lake Langeno, Ethiopia

Abstract

This study of diversity, distribution and abundance of fishes in Lake Langeno (also written as Langano in the literature), Ethiopia, was conducted from March 2014 through February 2016. The basis for this study was that fish species were subject to uncontrolled fishing over many years and existing data on diversity has become unreliable for management and sustainability of the sector. In order to examine the existing diversity, habitat preference and seasonal distribution, spatial and temporal data were collected from six different sampling sites by using various mesh-sizes of gillnets and long lines. Data were analyzed by Canonical Correspondence Analysis (CCA), SPSS software and also by various descriptive statistics. The results indicate that all the physico-chemical parameters did not show significant spatial, but high temporal variations. A total of seven fish species dominated by cyprinid family were identified (H′ = 1.264). Carassius carassius and Cyprinus carpio, which were not reported in previous studies, now comprise 0.64% and 6.99% of the total collected specimens, respectively. All the fish species were collected from all the sampling sites, except at the middle site where C. carassius and Garra dembecha were absent. IRI was essentially similar for all the sampling sites, but differed in the relative importance of each species with the high importance of Oreochromis niloticus. Principal component analysis (PCA) did not produce distinct habitat-associated species patterns across the sampling sites. However, temperature and depth seemed to be the key environmental factors determining fish community structure in the lake. The results showed that the composition of the fishes has undergone some changes from what was reported in the literature. Therefore, appropriate management action is required in order to sustain the resources for conservation and continued fishing practices.

Keywords/phrases: Diversity, Ethiopia, Fish abundance, Fish distribution, Lake Langeno