Abstract
1. Many animals exhibit partial migration, which occurs when populations contain coexisting contingents of migratory and resident individuals. This individual-level variation in migration behaviour may drive differences in growth, age at maturity and survival. Therefore, partial migration is widely considered to play a key role in shaping population demography.
2. Otolith chemistry and microstructural analysis were used to identify the environmental- and individual-specific factors that influence migratory behaviour in the facultatively catadromous barramundi (Lates calcarifer) at two distinct life history stages: firstly, as juveniles migrating upstream into fresh water; and secondly, as adults or sub-adults returning to the estuarine/marine spawning habitat.
3. Monsoonal climate played an important role in determining the migration propensity of juveniles: individuals born in the driest year examined (weak monsoon) were more than twice as likely to undergo migration to freshwater than those born in the wettest (strong monsoon) year. In contrast, the ontogenetic timing of return migrations to the estuary by adults and sub-adults was highly variable and not strongly associated with the environmental parameters examined.
4. We propose that scarce resources within saline natal habitats during lower rainfall years may provide an ecological incentive for juveniles to migrate upstream, whereas more abundant resources in higher rainfall years may promote resident life histories within estuaries.
5. We conclude that inter-annual climatic variation, here evidenced by monsoonal strength, likely plays an important role in driving the persistence of diversified life histories within wild barramundi populations.
| Original language | English |
|---|---|
| Pages (from-to) | 83-94 |
| Number of pages | 12 |
| Journal | Journal of Animal Ecology |
| Volume | 93 |
| Issue number | 1 |
| Early online date | 2023 |
| DOIs | |
| Publication status | Published - Jan 2024 |
Bibliographical note
Funding Information:The research team acknowledge Traditional Owners across our study region, and recognise their continuing connection to land and water. John Woodhead from the University of Melbourne conducted the otolith microchemistry analysis. We are grateful to Mirjam Kaestli from Charles Darwin University for providing statistical expertise. Jane Thomas developed the conceptual illustration in Figure 5 . Patch Clapp provided photographs for the graphical abstract for online publication. We thank Northern Territory Fisheries, Murdoch University researchers, anonymous recreational and commercial fishers who provided fish frames that were used in this study. The research was supported through funding from the Australian Government's National Environmental Science Program (Northern Australia Environmental Resources Hub), Charles Darwin University, Murdoch University and an Australian Government Research Training Program Stipend Scholarship to B.H.R.
Funding Information:
The research team acknowledge Traditional Owners across our study region, and recognise their continuing connection to land and water. John Woodhead from the University of Melbourne conducted the otolith microchemistry analysis. We are grateful to Mirjam Kaestli from Charles Darwin University for providing statistical expertise. Jane Thomas developed the conceptual illustration in Figure 5. Patch Clapp provided photographs for the graphical abstract for online publication. We thank Northern Territory Fisheries, Murdoch University researchers, anonymous recreational and commercial fishers who provided fish frames that were used in this study. The research was supported through funding from the Australian Government's National Environmental Science Program (Northern Australia Environmental Resources Hub), Charles Darwin University, Murdoch University and an Australian Government Research Training Program Stipend Scholarship to B.H.R. Open access publishing facilitated by Charles Darwin University, as part of the Wiley - Charles Darwin University agreement via the Council of Australian University Librarians.
Publisher Copyright:
© 2023 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.
