We have all seen images of schools of fish, or perhaps even seen a school of fish swimming together in an aquarium. There is safety in numbers; as a school, fish can confuse and evade predators.
More than 25 percent of fish prefer to live in a school. Thus, it is not surprising to see fish of the same species working together. But until now, we didn't know just how much tropical fish of different species communicated.
It turns out that fish are followers whether or not they live in a large group of their own species. If a fish sees another fish out eating in the open, they are more likely to go eat as well. The fish assumes that if the other fish is safe, they will be too.
Much like in a school, the fish gain safety in numbers. Researchers tested this by creating a shadow to make it look like a predator was coming into the area.
Normally, a lone fish would become frightened and swim away. However, when in a group of fish, an individual was less likely to act scared if other fish were closer to the predator's shadow.
If algae grow too much in an area, it can create too much shade, which can kill the coral reef. Many of the fish are herbivores and primarily eat algae. The safer the algae-eating fish feel eating, the less likely the algae are to grow out of control. All the fish have a better ecosystem when they work together.
The researchers filmed the reef and trained algorithms to recognize individual fish. Ray casting, a technique from Wolfenstein, showed where each fish was looking.
Ray casting is a visual representation that shows where characters can see in 3D virtual environments.
The seabed of the research area had a hidden waterproof iPad. When the researchers wanted to simulate an approaching predator, they used the iPad to simulate the shadow of the predator.
But the fish can not cope with rapid change. Over-fishing in an area can make a reef ecosystem more vulnerable to collapse by removing algae-eating fish and their collaborators.
h/t: Wired
