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Sea temperature and habitat effects on juvenile reef fishes along a tropicalizing coastline


McCosker, E and Stuart-Smith, RD and Edgar, GJ and Steinberg, PD and Verges, A, Sea temperature and habitat effects on juvenile reef fishes along a tropicalizing coastline, Diversity and Distributions, 28, (6) pp. 1154-1170. ISSN 1366-9516 (2022) [Refereed Article]

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Copyright Statement

Copyright (2022) The Authors. This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License, ( which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

DOI: doi:10.1111/ddi.13484



Temperate marine systems globally are warming at accelerating rates, facilitating the poleward movement of warm-water species, which are tropicalizing higher-latitude reefs. While temperature plays a key role in structuring species distributions, less is known about how species’ early life stages are responding to warming-induced changes in preferred nursery habitat availability. We aim to identify key ecological and environmental drivers of juvenile reef fishes’ distributions in the context of ocean warming.


South-eastern Australian coastline from 30 to 37°S.


We used a decade of underwater visual census data to uncover latitudinal distribution patterns of juvenile reef fishes and habitats across 1000 km of coastline, from subtropical to temperate latitudes. We modelled how benthic habitat cover, depth, wave exposure and sea surface temperature influence distributions of warm-water and cool-water juvenile reef fishes on temperate rocky reefs.


We found sea surface temperature was typically the most important factor influencing densities of juvenile fishes, regardless of species’ thermal affinity or latitudinal range extent. Juveniles of tropical and subtropical range-expanding fishes responded more strongly to warmer temperatures and lower wave exposure, while juveniles of temperate species responded more strongly to benthic habitats. Species’ responses to greater availability of temperate reef habitat-formers such as kelp and other macroalgae contrasted, being positive for temperate and negative for tropical and subtropical juvenile fishes.

Main conclusions

The availability of both suitable habitat and sea temperatures for species’ early life stages is important considerations when predicting changes in reef fishes’ distributions in the context of ocean warming. Warming-induced isotherm shifts and feedback loops constraining the persistence of key temperate reef habitat-formers will favour range-expanding tropical reef fishes colonizing higher-latitude reefs, while disadvantaging some macroalgal-associated resident temperate species. Such varying responses to warming-induced environmental changes may strongly influence the structure of emerging tropicalized reef assemblages.

Item Details

Item Type:Refereed Article
Keywords:citizen science, climate change, recruitment, reef fish, species distributions, temperate reefs, tropicalization
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Global effects of climate change (excl. Australia, New Zealand, Antarctica and the South Pacific) (excl. social impacts)
UTAS Author:Stuart-Smith, RD (Dr Rick Stuart-Smith)
UTAS Author:Edgar, GJ (Professor Graham Edgar)
ID Code:150881
Year Published:2022
Web of Science® Times Cited:1
Deposited By:Ecology and Biodiversity
Deposited On:2022-07-04
Last Modified:2022-11-09
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