The introduction of the endemic fish species, Lamprichthys Tanganicanus (Poeciliidae), from Lake Tanganyika into Lake Kivu: Possible causes and effects

Abstract

In the present study we compared morphological characteristics of the endemic fish species Lamprichthys tanganicanus (Poeciliidae) from Lake Tanganyika to those of similar fish samples which have appeared in Lake Kivu since 2006 to assess: (1) the taxonomic status of fish samples from Lake Kivu fisheries; (2) the food habits and fecundity of this fish and (3) the way by which this fish may have been introduced into this lake. Fish samples from Lake Kivu were collected in the bay of Bukavu and in Lake Tanganyika at Uvira. Metrics and meristics of Lamprichthys tanganicanus samples collected from Tanganyika were similar to those of fish collected in Lake Kivu indicating that recent fish samples caught together with Limnothrissa miodon in this lake indeed belong to Lamprichthys tanganicanus, a non-cichlid fish well known to be endemic to Lake Tanganyika. Genetic studies carried out on samples of this fish from both lakes support those conclusions. Moreover, mixed schools of Lamprichthys tanganicanus and Limnothrissa miodon fry were collected in the littoral zone of Lake Tanganyika suggesting that fry of the former species may have been accidentally introduced in Lake Kivu together with that of Limnothrissa miodon fifty years ago. Late appearance of this Tanganyikan non-cichlid species thirty years after Limnothissa miodon is discussed in relation to the biological characteristics of these two species.