A group of cichlid fish (Neolamprologus caudopunctatus) in Lake Tanganyika, 7 metres deep (Photo: Stefanie Schwamberger)
Fish in East Africa’s Lake Tanganyika engage in adoption as a risk mitigation strategy for keeping some of their offspring from being eaten, finds a new study published in the journal Behavioral Ecology.
The research involves a group of fish known as cichlids, which practice advanced forms of parental care relative to other fish species. Franziska Schaedelin and colleagues at the Konrad Lorenz Institute of the University of Veterinary Medicine in Vienna, Austria found that parent fish of Neolamprologus caudopunctatus exchange their young with other parents to reduce the risk that their entire brood will be eaten.
A press release from the Konrad Lorenz Institute explains:
Most nests were found to contain fry that were unrelated to both “parents”, with some nests containing fry produced by several pairs of parents. Because the locations of the nests were known, the scientists were able to show that fry had been born in nests that were separated by less than one meter to over 40 meters from their adoptive nests. Although very small fry may be able to swim several meters to a new cave without being eaten, it is highly unlikely that they could travel much longer distances. Instead it is probable that they were carried to new nests in the mouths of their parents, a mode of transport that is known to occur in cichlids. Transporting the fry to fairly distant nests would ensure that some young are protected even if all the nests in the immediate neighborhood are predated or destroyed
The results suggest that parent Neolamprologus caudopunctatus strive to avoid putting all their eggs in one basket.