Long-term empirical evidence of ocean warming leading to tropicalization of fish communities, increased herbivory, and loss of kelp

Research Highlight

Tropical herbivores are kelp invaders

© Santiago Urquijo/Moment/Getty

© Santiago Urquijo/Moment/Getty

Tropical fish with a voracious appetite for kelp are staking claims in the warming waters of eastern Australia’s temperate coral reefs and stripping ecologically-important kelp forests.

A team, led by researchers from the University of New South Wales, studied video recordings taken at several kelp sites over a ten-year period, during which the water warmed by 0.6 degrees Celsius.

They saw increasing numbers of herbivorous species normally found in tropical and sub-tropical waters, such as rabbitfish, surgeonfish and drummer fish, with a corresponding erosion of the kelp forests. The researchers knew the influx of the tropical species was linked to the loss of kelp because they could see tell-tale bite marks on the fronds.

With kelp forests the “biological engine” that supports many marine ecosystems, the authors warned that climate-induced increases in herbivorous fish pose a significant new threat.

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  1. PNAS 113, 13791–13796 (2016). doi: 10.1073/pnas.1610725113
Institutions Share
University of New South Wales (UNSW Sydney), Australia 0.43
James Cook University (JCU), Australia 0.13
NSW Department of Primary Industries (DPI), Australia 0.08
Centre for Advanced Studies of Blanes (CEAB), CSIC, Spain 0.08
The University of Sydney (USYD), Australia 0.08
Sydney Institute of Marine Science (SIMS), Australia 0.08
The University of Queensland (UQ), Australia 0.06
Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 0.04
CSIRO Oceans and Atmosphere, Australia 0.02