Reef fish live and hunt as a team

When an individual chases its prey around a coral formation, others gather around to block escape routes. The unusual co-ordinated behaviour was observed by scientists in the Red Sea, off the coast of Egypt. The discovery, published in the journal Ethology, places the fish in an elite group of species known to hunt collaboratively. Yellow saddle goatfish (Parupeneus cyclostomus) are tropical fish found in the Indo-Pacific region, an area that is thought to be home some of the world's richest marine life. They have long whisker-like "barbels" protruding from their mouths, which they use to detect the movements of prey in coral reefs. Co-ordinated action Scientists from the University of Neuchatel, Switzerland, were studying the fish to find out more about their social structure. "The starting point of our study was [the] observation that [yellow saddle goatfish] co-ordinate their actions," explained Prof Redouan Bshary who led the study. The fish are known to live in groups that are based on their size rather than family relationships, with similarly sized fish forming groups. Scientists have suggested that this strategy might improve co-ordination for shoals of fish, making them more streamlined and better synchronised. The goatfish groups that Prof Bshary and his team studied spent the majority of their day chasing prey. During their frequent snorkelling trips to observe the species, the scientists noticed that each fish seemed to adopt a specific role during these hunts. When a single goatfish chased its prey, the rest of the group worked together as a team to ensure its success. "Blockers" spread out across the coral formation to prevent the prey from escaping while the "chaser" pursued its target. Similar behaviour has only been identified in a handful of species - primarily mammals including chimpanzees, orcas, lions and dolphins, but also birds. Very few fish have been seen to "work together". In some species each individual carries out the same role during each hunt, but, as Prof Bshary explained, the goatfish had a flexible approach. "Each individual may be a chaser or a blocker," he said. "The evidence is growing and growing that fish can show astonishing behaviours."