[ad_1]
- New research suggests that higher ocean temperatures and coral bleaching also cause rapid behavioral changes in reef fish.
- For two years, an international team of researchers spent more than 600 hours underwater observing the butterfly fish, a species considered a key indicator of coral reef health, before and after a global bleaching event. corals in 2016.
- The researchers found that the aggressive behavior of butterfly fish had decreased by an average of two-thirds, with the most important behavioral changes observed on the reefs where bleaching had killed the most corals.
New research suggests that coral bleaching triggers rapid behavioral changes in reef fish.
The increase in ocean temperature caused by global warming is the main cause of the massive bleaching events that have hit many coral reefs systems of the Earth in recent years. Research has shown that some reefs are no longer able to rebound from repeated disturbances and it is now proven that the reefs themselves are not the only part of the reef ecosystems that are experiencing longer-term effects because of the reefs. bleaching of corals.
In the past two years, an international team of researchers led by Dr. Sally Keith of Lancaster University in the UK spent more than 600 hours underwater observing the butterfly fish, a species considered a key indicator of coral reef health. In a study published last week in the journal Nature Climate Change, detailing their findings, Keith and his team write that even though it is well known that mass coral bleaching causes a decline in the reef fish population , their impacts on behavior are less well understood.
The research team applied the principles of behavioral theory and community ecology to its observations of 5,259 encounters between individuals from 38 Chaetodon (butterflyfish) on 17 reefs in the Central Indo-Pacific region, including Indonesia, Japan, the Philippines and Christmas Island. These observations were recorded before and after the global coral bleaching that hit the reefs in the region in 2016. Researchers claim that bleach-induced coral mass mortality can lead to significant changes in the behavior of fish feeding on coral reefs. corals.
"We found that the aggressive behavior of butterfly fish had decreased by an average of two-thirds, with the largest declines on the reefs where bleaching had killed the most corals," Dr. Keith said in a statement. "We think this is because the most nutritious coral was also the most susceptible to bleaching so the fish went from a balanced diet to the equivalent of eating only lettuce leaves." it was enough to survive rather than prosper. "
The researchers found that encounters between pairs of butterfly fish were more likely to be aggressive when both fish were specialists in coral feeding on reefs with high coral cover. They also discovered that after a bleaching episode, the amount of Acropora Coral consumption in the diet of butterfly fish has decreased significantly, with fish capturing up to 85% less nutrient rich coral bites and not offsetting this loss by higher overall bite rates.
"The decrease in observed aggression due to a nutritional deficit when resources are low, corresponds to the predictions of the economic theory of aggressive behavior," write Keith and his co-authors. "Our results reveal synchronous behavioral changes in response to coral mortality. Such changes could potentially disrupt the territories, leading to the reorganization of ecological communities. "
The researchers added that these behavioral changes could result in other, more obvious changes, including the decrease in the number of individuals and fish species on coral reefs. And the team suggested that their findings could help explain the mechanisms that cause population decline in such disturbed ecosystems around the world.
Nathan Sanders, co-author of the study, ecologist at the University of Vermont in the United States, said the findings of the team could also affect how we monitor the health of coral reef ecosystems: "That counts because butterfly fish are often thought of as & # 39; "reef canaries" because of their strong reliance on coral, they are often the first to suffer after a disturbance ".
Monitoring the behavior of butterflyfish could therefore provide scientists with an early warning system, helping to predict larger impacts, according to study co-author Dr. Erika Woolsey of the US. Stanford University in the United States.
"Our work emphasizes that animals can adapt to short-term disasters through flexible behavior, but that these changes may not be sustainable in the long term," said co-author Andrew Baird of the Center for Disease Control. ARC excellence for coral reef studies. James Cook University in Australia.
QUOTE
Keith, S.A., Baird, A.H., Hobbs, JA, Woolsey, E.S., Hoey, A.S., Fadli, N. and Sanders, N.J. (2018). Synchronous behavioral changes in reef fish associated with massive coral bleaching. Nature Climate change. doi: 10.1038 / s41558-018-0314-7
• Ortiz, J.C., N.W. Wolff, K.R. Anthony, M. Devlin, S. Lewis, and P.Mumby (2018). Bad recovery of the Great Barrier Reef under cumulative stress. Science Advances, 4 (7), eaar6127. doi: 10.1126 / sciadv.aar6127
[ad_2]
Source link
