Behavioral Ecology of Coral Reef Fishes at Spawning Aggregation Sites
Abstract
This thesis is an extensive investigation of the behavioral and ecological relationships between spawning reef fishes, their predators, and various environmental parameters at spawning aggregation sites. Underwater observations of spawning activities by eleven reef fish species and the hunting behaviors of both piscivorous and planktivorous predators were made at Johnston Atoll (Central Pacific). The spawning of reef fishes was typically correlated with local changes in current direction and predatory risks in daytime-spawning species, showing responses designed to reduce the mortality of propagules and adults. Dusk-spawning species generally did not respond to changes in flow direction or predator abundance. Piscivores were most active at spawning sites during the daytime hours, when spawning prey fish were most abundant, but showed low activity at dusk, the period of highest prey diversity. Alternate hunting behaviors (midwater or ambush attacks) were used by piscivores when feeding on spawning fishes, and resulted in different capture success rates. The difference in heights of spawning ascents by two trunkfish species was interpreted to be the result of intraspecific competition among males, and could not be explained by interspecific differences in susceptibility to predation, estimated as a function' of the specific toxicity of both species.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1998
- Accession Number
- ADA363347
Entities
People
- Gorka Sancho
Organizations
- Massachusetts Institute of Technology