Social Structure, Nest Guarding and Interspecific Relationships of the Cichild Fish (Julidochromis marlieri) in Lake Tanganyika

Abstract

Social structure, nest guarding and interspecific relationships of the Tanganyikan cichild Julidochromis marlieri were investigated at Gitaza, Republic of Burundi. Six social groups were found and classified into 3 types by the composition of the members: branching group with the largest adult (first adult [FA]), 2 smaller adults (second adult [SA] and third adult [TA]), and juveniles; linear group-A with one member each of FA, SA, and TA and juveniles and linear group-B with one FA, one SA and juveniles. The time the TA, SA, and FA each stayed at the nest declined with size. When potential preditors on juveniles (Lepidiolamprologus elongatus and L.profundicola) approached, J. marlieri vigorously intercepted. J.marlieri nests were located near the home ranges of Neolamprologus savoryi, which also attacked such predators. N. savoryi also attacked J.marlieri, but the nest proximity may be beneficial for the latter, because N.savoryi excluded the approaching predators near the nest of J.marlieri.