Sexual Dichromatism and Feeding Habits of the Scale-eater Plecodus straeleni (Cichlidae, Teleostei) in Lake Tanganyika

By Yanagisawa, Yasunobu & M. Nshombo, M. Nishida, Y. Niimura

Journal of Ethology, v. 1990(n. 8), pp. 25-28 (1990)


" Plecodus straeleni is one of the 7 fish species known to exploit scales of living fishes in Lake Tanganyika (Poll 1956, Liem & Stewart 1976, Nshombo et al. 1985). Like many other cichlid fishes of this lake, this species has geographical colour variations (Brichard 1978). Two basic colour patterns have been recognized within a population (Brichard 1978, Konings 1988). Brichard (1978) inferred from his field observation that each individual of P. straeleni can alter its colour pattern at will from one to the other in correspondence to the depth of water where it stays. In contrast, Konings (1988) regarded that two colour types as belonging to closely related but different species. In our observations at Bemba and Makobora on the north-west coast of the lake in 1987 and 1988, we found no support for either hypothesis; individuals never changed colours between the 2 basic patterns even if they made a long vertical migration, and reproduction was carried out between the different colour types. To understand this species' colour variation, we captured 52 specimens with a gill net at a depth of 3-28 m and examined their external morphology and gonads in the laboratory. Stomach contents were also examined to know the relationship between colour and food habits "

Classification: Behavior, Lake Tanganyika.

Language: English

Yanagisawa, Yasunobu & M. Nshombo, M. Nishida, Y. Niimura. 1990. "Sexual Dichromatism and Feeding Habits of the Scale-eater Plecodus straeleni (Cichlidae, Teleostei) in Lake Tanganyika". Journal of Ethology. v. 1990(n. 8), pp. 25-28 (crc04479) (abstract)