Climate change threatens trout

Climate change threatens trout

JAMES COOK UNIVERSITY

"Valuable fishery species such as coral trout could be under long-term threat." Image:Tammy616/iStockphoto Scientists are concerned that the impact of climate change on reef fishes is greater than first thought. Behavioural changes found in small fishes such as damselfish has highlighted concern that valuable fishery species such as coral trout could be under long-term threat. James Cook University’s Professor Philip Munday recently discovered that ocean acidification, specifically declines in pH caused by the addition of carbon dioxide (CO2), led to significant behavioural changes in damselfish and anemone fish, which left them open to predation. Researchers from the Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies and JCU had already found that many coral reef fishes would be vulnerable to environmental and habitat changes due to climate change. “Coral reefs are extremely vulnerable to sustained and ongoing climate change, mainly because of the temperature sensitivities of reef-building corals,” the project’s chief investigator, JCU’s Dr Morgan Pratchett said. “But climate change not only threatens the corals that build reefs, but the animals that live on coral reefs, including many different fishes.” Professor Munday said increased ocean acidification interfered with the ability of small prey fishes to distinguish potential predators through smell. “The effects of ocean acidification on the behaviour of reef fishes are much more striking than any of us had thought possible,” he said. Dr Pratchett said the evidence showed it was high time for greater understanding of how climate change impacted on fisheries species, such as coral trout. “This is an important step in demonstrating the potential economic ramifications of climate change,” he said. The commercial value of coral trout alone was $40 million in Queensland, notwithstanding the social and recreational value for the community. JCU is working with Queensland Department of Employment, Economic Development and Innovation (DEEDI) to assess if climate change’s impact on the Great Barrier Reef would improve or cause a decline in wild stocks of coral trout. Dr Pratchett and DEEDI fisheries biologist Adam Reynolds will be working closely with colleagues during the two-year project. The project, funded by the Fisheries Research and Development Corporation (FRCD) through the National Climate Change Adaptation Research Plan, is directly testing environmental sensitivities of coral trout during reproduction, fertilization and early development. “This project will be fundamental in understanding the threat of climate change on coral trout, but will also be important for assessing the aquaculture potential of this species,” Dr Pratchett said.