Long-term archaeological and historical archives for mulloway, Argyrosomus japonicus, populations in eastern South Australia

Abstract

Native fish populations have been strongly impacted by fishing, habitat alteration and the introduction of invasive species. Understanding the dynamics of native fish populations prior to commercial fishing can be problematic, but provides critical baseline data for fish conservation, rehabilitation and management. We combined fish size, age and growth data, as well as month of catch data, from archaeological fish otoliths (1670–1308 cal BP to 409–1 cal BP), historical anecdotes (CE 1871–1999), and contemporary data sources (CE 1984–2014) to examine changes to mulloway, Argyrosomus japonicus, populations in the waters of eastern South Australia. We found that the data from the three different sources – archaeological, historical and contemporary – corroborate each other in many aspects. The time of catch for all three datasets was seasonal, with increases evident during the summer months. No significant changes in fish length over time were evident over the time span of the three data sources. Given the impact that fishing in the region is regarded to have had, this may imply that while the maximum recorded sizes of the species have remained stable, the abundance of these large specimens may have declined.