Recruitment failure in the Australian lungfish, Neoceratodus forsteri (Osteichthyes : Dipnoi), in south-east Queensland

Abstract

Changes to the environment of the Australian lungfish, Neoceratodus forsteri, are associated with loss of recruitment of young lungfish to the adult population. Eggs laid by poorly fed adults lack volatile fatty acids and fail to develop normally. Problems in young fish first appeared in some specimens collected at Fernvale on the Brisbane River during a drought, when food supplies in the river began to fail. In 2016, after poor recruitment for several years, hatchlings from Lake Samsonvale were able to feed, and reached advanced stages in the laboratory, after a moderate amount of food for parent lungfish appeared in the lake during the summer before the 2016 spawning season. However, all died after 14 months. Lungs, intestines and nervous systems in the juveniles were anomalous, and would have precluded continued development in the wild. Survival of several young to juvenile stages in the laboratory does not mean that survival and recruitment to the adult population in the wild will follow.