Chemical alarm signals in juvenile green sunfish (Lepomis cyanellus, centrarchidae)

We investigated the presence of chemical alarm signals in juvenile Green Su nfish (Lepomis cyanellus) under laboratory conditions. We exposed individua l sunfish to skin extracts of conspecifics and swordtails (Xiphophorus hell eri), a species not known to possess alarm pheromones and that is phylogene tically distant and allopatric from green sunfish. Sunfish significantly in creased time spent freezing and time with dorsal fin rays erect (known anti predator postures) in response to conspecific skin extract but not to sword tail skin extract. No significant difference was noted in change in area us e for sunfish exposed to conspecific versus swordtail skin extract. These r esults suggest that juvenile green sunfish possess chemical alarm signals. This is the first such demonstration in a centrarchid species.