MEPS 309:255-262 (2006)  -  doi:10.3354/meps309255

Impacts of simulated overfishing on the territoriality of coral reef damselfish

Daniela M. Ceccarelli1,*, Terry P. Hughes1, Laurence J. McCook2,3

1Centre for Coral Reef Biodiversity, School of Marine Biology and Aquaculture, James Cook University, Townsville, Queensland 4811, Australia
2Australian Institute of Marine Science, PMB3, Townsville, MC, Queensland 4810, Australia
3Present address: Great Barrier Reef Marine Park Authority, PO Box 1379, Townsville, Queensland 4810, Australia

ABSTRACT: The loss of large fishes from coral reefs can alter the composition of benthic assemblages and increase the abundance of smaller fishes at lower trophic levels. An experimental exclusion of medium and large fishes, maintained over 30 mo, had a major impact on the dynamics of 2 abundant damselfishes (Pomacentrus adelus and P. wardi) and altered their relative abundance in favour of the larger species, P. wardi. The territory size of both species inside exclusion cages increased by 20 to 50% in the first year, but then declined to their original size after a further 6 mo. The exclusion of larger fishes also led to an increase in the quantity and quality of food algae within damselfish territories. These results suggest that larger predatory and herbivorous fish influence the composition of coral reef communities not only directly, but also indirectly, by controlling the abundance and territorial activities of damselfish.

KEY WORDS: Territorial damselfish · Herbivores · Cage experiment · Trophic cascade · Overfishing

Full text in pdf format