Life History Strategies and Recent Changes in Population Structure in the Lizardfish Genus, Saurida, on the Australian Northwest Shelf

Abstract

Aspects of the life history of four sympatric species of the lizardfish genus, Saurida, were examined based on material obtained by demersal trawling on the Northwest Shelf of Australia. The four vary widely in age and size at sexual maturity and in maximum age and length: two species (Saurida undosquamis and Saurida sp. 1) reach large size and live for 6-7 yr, whereas two others (S. longimanus and Saurida sp. 2) reach sexual maturity within a few months of settling to the substratum and may rarely live more than a year. The minimum generation time for Saurida sp. 2 is shorter than that yet reported for any other species of tropical demersal fish species. These life history features are discussed in relation to recent changes in the lizardfish population on the Northwest Shelf and compared to those of other tropical demersal fishes. Limited data suggest that very short generation times may not be unusual for such demersal fishes, which may have important implications for both population dynamics and management of tropical fish species.