Physical and spatial differences between the three color morphologies of the Atlantic trumpetfish, Aulostomus maculates

Mimetism allows organisms to blend into the environment and avoid detection by both predators and prey. The Atlantic trumpetfish, Aulostomus maculatus, uses three color morphologies blue, brown, and yellow to achieve this goal. The various colorations allow A. maculatus to stalk prey individuals and blend into tall gorgonians and sponges on the seafloor. Chromatophore and energy expenditure analysis showed these three morphs as steady and evenly dispersed. The present study focuses on behavioral and spatial differences between individuals of varying morphologies on a fringing reef in Bonaire, Dutch Caribbean. Length of trumpet fish, depth, and substratum association were noted on twelve 30-minute timed swims at varying depths and locations near Yellow Sub dive site. Results show no significant difference between the three morphology abundances, or between depth and color morphology. Only comparisons between brown and blue color morphologies were found to be significantly different with larger brown individuals and smaller blue individuals. Associations were found to be highest with sea-rods. Higher percentages of yellow color morphs associated with corals while more blue individuals tended to shadow fish. Brown morphs were found to have higher association rates overall which may account for their larger size. Trumpetfish that were not associated with one benthic substrate due to movement or hunting were considered to be active individuals. A difference in activity levels of the three color morphologies was not found to be statistically significant. Further research may include more investigation into the trumpetfish life history, and trumpetfish may serve as a model for color morphology studies in the marine environment.

This student research was retrieved from Physis: Journal of Marine Science XII (Fall 2012)19: 39-44 from CIEE Bonaire.