The rivers to the sea: experiences with two endangered aquatic fish species

There are currently 20 species, populations or communities of fish, aquatic invertebrates and marine vegetation listed on the threatened species schedules of the NSW Fisheries Management Act 1994. Two of these species are the eastern freshwater cod Maccullochella ikei, and the grey nurse shark Carcharias taurus. In the 1970s, well over a decade prior to their listing as threatened, there were concerns over the population status of both fish, and various actions were initiated to help preserve and maintain stocks. For example, both species were totally protected from fishing in 1984, captive breeding techniques for eastern cod were investigated and underwater surveys of grey nurse shark populations commenced. Following listing, however, there has been a significant increase in emphasis on actions to help the recovery of both species, protect their habitat and increase knowledge of their biology and distribution. In the case of eastern cod, these actions have included surveys to document the distribution of remnant and stocked populations, tagging studies, genetic and ecological research, habitat restoration works and significant input into water sharing rules for relevant catchments. For grey nurse sharks, critical habitat areas have been declared at key aggregation sites, controls placed on fishing in and around these areas, additional diver surveys completed, tagging and tracking studies commenced to provide detailed information on movements and improved population estimates, and samples collected for genetic research. The changes in management strategies resulting from the listing of these threatened species in NSW may also have flow-on benefits for other aquatic species.