Describing someone as having a "memory like a goldfish" would suggest they are forgetful, but rising ocean temperatures make memory loss a real problem for sea life.
A new study found that such an issue could be fatal for several tropical fish species.
What's happening?
Research from the Universidade Federal do Rio Grande do Norte in Natal, Brazil — summarized in Nature World News — examined the effects of warmer waters on the cognitive ability of fish.
Study author Ana Carolina Luchiari looked at damselfish in particular, which are known to scare away sea life much larger than they are. Memory is particularly important to their survival, as they act in such a way to protect supplies of their primary food source, algae.
To research the effects of increased temperatures on the fish, the scientists created a maze with a reward at the end of it. Fish were trained over five days to learn the location of the treat, then left for another five days before trying the maze again to determine how well they remembered the process.
Three groups were gradually exposed to different temperatures two weeks before the training began to see what kind of impact that would have when learning and returning to the maze.
The study found that the control group exposed to temperatures up to 83.3 degrees Fahrenheit did well when recalling the maze route. Those in the group with temperatures up to 86.9 degrees Fahrenheit, however, could not remember where the treat was, despite learning it five days earlier.
Meanwhile, the group exposed to waters of 89.6 degrees Fahrenheit never learned the maze at all.
Why are the study's findings concerning?
While Luchiari observed that there are studies on the effect of rising ocean temperatures on fish mortality, comparatively few have investigated how additional ocean heat impacts memory.
The findings suggest that warmer waters impair cognitive ability, making it more difficult for tropical fish to find food and shelter and to distinguish between friends and foes. This puts their chances of survival at serious risk.
"Cognitive ability in fishes is very important for their survival," Luchiari told the New York Times. "Decision-making in the natural environment is very important, it's something you have to do every day. If you decide wrongly, you are exposed to risk."
Can anything be done to stop ocean temperatures from rising?
Perhaps the top way to limit rising ocean temperatures is to reduce carbon pollution. By using renewable energy — such as solar or wind power — and lowering red meat consumption, among other activities, individuals can limit their personal footprints on the environment.
Using your buying power to inform corporations that sustainability practices matter is another great way to help the Earth.
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