Background
Many species move among habitats to feed, shelter, reproduce, and disperse, linking ecosystems across land and seascapes. In coastal seascapes, juvenile fish movements connect habitats to form interlinked nurseries. While the concepts of nursery habitats and ontogenetic habitat shifts are widely accepted, how habitat and seascape features influence habitat selection across multiple habitats during ontogenetic shifts remains unclear.
Aims
We tested for ontogenetic habitat shifts and examined how seascape features, habitat cover, and protection from fishing influence the abundance and distribution of juvenile fish targeted by fisheries across multiple nursery habitats.
Methods
We surveyed fish from six habitat types using stereo-remote underwater video stations. Surveys were conducted four times over two years at 180 sites along 200 km of the inshore Great Barrier Reef, Australia.
Results
Key fisheries species exhibited clear ontogenetic shifts, migrating from mangroves and/or back-reef habitats to coral reefs at larger body sizes. Variation in seascape properties, particularly the composition and configuration of nursery habitats was linked to changes in the distribution and abundance of key fisheries target species. These strong seascape effects were evident across all habitats and sizes and were more important for nursery function than variation in habitat cover or protection from fishing.
Conclusion
Our findings provide strong support for the seascape nursery concept, demonstrating that seascape attributes can influence nursery function and illustrate how diverse and inter-connected habitats can form vital seascape nurseries for species that undertake ontogenetic shifts. Effective management will require a deeper understanding of how variation in seascape composition and configuration supports nursery function.