EFFECTS OF LOSS OF MALE PARENT ON BROOD SURVIVAL IN A BIPARENTAL CICHLID FISH

When brood-guarding males of the biparental convict cichlid, Cichlasoma nigrofasciatum, held in experimental ponds, deserted their mate and brood, or were removed from the pond, survival of the young depended on their age when the father left. If they were embryos, few broods survived, but if they were up to seven days into the free-swimming juvenile period, most broods survived. The cause of brood mortality is not certain, but predation by conspecifics is most likely (no other fish species were in the ponds). The willingness of a deserted, brood-guarding female to continue defending her young probably depends, in part, on their age. If they are very young, the benefit/cost ratio of guarding them to independence may be so low that she should give up that breeding attempt and begin another. If they are older, the benefit/cost ratios is higher and she should continue to guard them alone.