Offspring mortality during mouthbrooding in two open-water spawning cichlids from Lake Tanganyika

Mouthbrooding in cichlids is a behaviour that protects vulnerable offspring. However, the efficacy of this behaviour has not been properly estimated in mouthbrooders that spawn on the bottom or in open water. The present study examined changes in brood size during mouthbrooding in two open-water spawning cichlids from Lake Tanganyika, Cyprichromis coloratus and Cyprichromis leptosoma, using a large number of samples and accounting for the mouth size of mouthbrooding females. Analyses of 279 and 263 mouthbrooding females showed that the average egg number decreased by 22.8% and 11.2% from spawning to hatching and average larval number decreased by 11.6% and 16.2% from hatching to independence in C. coloratus and C. leptosoma, respectively. Future studies should compare these egg and larval mortality rates with those of bottom-spawning mouthbrooders to assess the relative efficacy of this behaviour amongst mouthbrooding species in different aquatic environments.

Automated summary

This study examined changes in brood size during mouthbrooding in two open-water spawning cichlids from Lake Tanganyika, and found that the average egg and larval numbers decreased during the mouthbrooding process. Future studies should compare these species with bottom-spawning mouthbrooders to assess the efficacy of mouthbrooding behavior in different aquatic environments.