Morphometric Relationships among the Clariid Fishes of the Lake Victoria Basin, Tanzania

Chacha John Mwita

doi:10.4236/ojms.2015.51003

Abstract

Six hundred and fifty-eight specimens of the Clariidae were collected from seven localities in the Lake Victoria basin and the Malagarasi wetland, Tanzania. A total of three hundred unadjusted morphometric measurements and meristic counts were analysed with the aim of assessing the adequacy of morphometric technique to delineate the clariid species occurring in theLake Victoriabasin. Results showed that morphometrics augmented by multivariate analysis (PCA, DCA and cluster analysis) amalgamated the clariid fishes into three groups, the Clarias alluaudi/C. werneri, C. gariepinus/C. liocephalus andClariallabes petricola. Although other workers have used this technique, the present study concluded that, standing alone morphometrics is not a substitute for external morphology in the identification of clariid fish species, as it failed to separate the clariids into their respective taxonomic species. The technique, however, insinuates the regressional morphological relationships among the clariids occurring in the Lake Victoria basin.

Highlights

The external morphology of the family Clariidae is characterized by an elongated body with a long dorsal fin
The result revealed that the clariids body depth (BD), head depth (HD) and caudal peduncle depth (CPD) decreased from Heterobranchus longifilis, Clarias gariepinus, Clarias alluaudi, Clarias werneri, Clarias liocephalus and Clariallabes petricola in that order
The dorsal and ventral caudal peduncle lengths tended to diminish as the dorsal and anal fins get closer to the caudal fin

Summary

Introduction

The external morphology of the family Clariidae is characterized by an elongated body with a long dorsal fin. An adipose fin is present in Heterobranchus species [1]. The large species of Clarias attain lengths of up to 1.5 m. Mwita and have a large depressed head with a wide mouth [2] [3]. The anterior and posterior fontanels, remnants of foetal characteristics, are present in most clariid species and form an important taxonomic feature [2]. Clarias gariepinus has a grey mottled colouration; C. liocephalus is reddish, while C. werneri and C. alluaudi are more or less blackish in appearance The clariids have a wide global distribution; their greatest diversity occurs in continental Africa. They are found in Syria, Southern Turkey and Southeast Asia [3]

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Conclusion