Natures wonders: fish warn danger with released chemical (Introduction)

by David Turell , Thursday, April 18, 2019, 23:44 (2044 days ago) @ David Turell

Especially if among fish in their species:

https://www.sciencedaily.com/releases/2019/04/190418141739.htm

"The USask researchers discovered that wild fish release chemicals called 'disturbance cues' to signal to other fish about nearby dangers, such as predators.

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"Fish signaled most when in the presence of familiar fish, but signaled far less or not at all when in the presence of strangers, or when on their own.
The signals provoked a 'fright response' in fish they knew, including freezing, dashing about and then shoaling tightly together. Fish use this behavior to defend themselves against predators.

"'When minnows were present alongside familiar minnows, they were much more likely to produce signals that initiated close grouping of nearby fish, a strategy used to avoid being eaten by predators," said Bairos-Novak, who is now at James Cook University, Australia.
Disturbance cues are voluntarily released by prey after being chased, startled or stressed by predators.

"One of the main constituents of the signal is urea, found in fish urine.

"Fathead minnows, caught at a lake, were placed in groups with familiar fish, unfamiliar fish or as isolated individuals. The research team then simulated a predator chase. The fish responded by shoaling, freezing and dashing when they received a signal from a group they knew. But they did not take significant defensive action when receiving cues from unfamiliar fish or isolated minnows.

"Disturbance cues are voluntarily released by prey after being chased, startled or stressed by predators."

Comment: Plants warn of danger by releasing gases. It is not surprising that evolution has provided a similar mechanism in fish, certainly an example of convergence.