PARENT SESSION
Contributed Oral Session 104: Predator - Prey Ecology: Communities; Defenses
Wednesday, August 10, 1:30 PM - 5:00 PM, Meeting Room 521 A, Level 5, Palais des congrès de Montréal
The influence of predator refuges on selective mortality in a coral reef fish.
Samhouri, Jameal*,1, Steele, Mark2, Forrester, Graham3, 1 University of California, Los Angeles, Los Angeles, CA2 University of California, Santa Barbara, Santa Barbara, CA3 University of Rhode Island, Kingston, RI
ABSTRACT- Many organisms, including amphibians, insects, and marine fishes and invertebrates have complex life cycles that consist of a larval phase and an adult phase occurring in two distinct habitats. Often, larval traits affect adult performance despite the fact that each life stage faces very different selective pressures. On coral reefs, predators cause intense mortality of juvenile fish during and after their transition from larval to adult habitat (i.e. settlement). We collected goldspot goby (Gnatholepis thompsoni) juveniles that had yet to experience this critical period, along with surviving older gobies from the same settlement cohort, from two sites in the Bahamas. We also directly manipulated goby shelter availability at each site to determine if the strength of predator-induced selective mortality was altered by the structural complexity of the reef habitat. By comparing the otolith-derived larval traits of the initial group to the larval traits of the survivors, we show that in this prey species intense juvenile mortality represents a selective bottleneck. In habitats with an experimentally-increased abundance of predator refuges, the smallest, slowest-growing goby larvae were most likely to survive reef-based predation as juveniles. In unmanipulated habitats, there was no evidence for this type of selection. This study represents one of the first experimental tests of the linkage between larval traits and selective mortality in coral reef fishes.
Key words: Caribbean, Lee Stocking Island, characteristics of survivors