Habitat transitions by a large coastal sciaenid across life history stages, resolved using otolith chemistry. (April 2022) - Russell, Angela
Abstract: Many coastal species move between estuarine and coastal environments throughout their life. Migration patterns develop as a result of ecology and evolution and must be understood to effectively manage harvested stocks. This study examined movements across estuarine and coastal marine habitats in adult Mulloway ( Argyrosomus japonicus ); a commercially, indigenous and recreationally harvested sciaenid of south-eastern Australia. Chemical profiles across the otolith (ear bone) were used to examine transitions between estuary and marine habitats over life history. Patterns in otolith Ba:Ca concentrations indicated that the majority of fish migrated between estuary and marine habitats, but a small proportion of fish appeared to remain in either the estuary or the marine habitat. Such movements may potentially be driven by a range of biological and environmental factors. This approach allows questions about the life history and habitat use of Mulloway to be addressed, which will aid management and provide a platform for future research on Mulloway, other sciaenid's and coastal migratory species. Highlights: Otolith Ba:Ca identified potential migrations between marine and estuarine habitats. Multiple migration strategies were evident in Mulloway ( Argyrosomous japonicus ). Most fish were considered migratory with small numbers residing entirely in estuaries or marine habitats. Most fish ingressed to nursery estuaries within 40 days post hatching. Fish spent around 9 months in nursery habitats.