Research 3: Spatial ecology and resource partitioning of marine predators

Competition can play a strong role in driving habitat selection in marine animals but few studies have investigated this for large predatory fishes.  We are using a combination of bio-loggers and acoustic telemetry to quantify space use and behaviour in sharks and large teleosts at Palmyra Atoll, in the central Pacific.  We are using empirical data to test predictions from theoretical models, so that we can determine which factors are driving habitat selection by predators over long and short time frames.  Palmyra is an uninhabited atoll run by The Nature Conservancy, US Fish and Wildlife, and the Palmyra Atoll Research Consortium (PARC). Due to its remote location and refuge status, Palmyra experiences very low levels of human influences.  We see large numbers of sharks at Palmyra, unlike many inhabited atolls where fishing has likely reduced shark numbers.  There appear to be obvious differences in macro-habitat selection by upper level predators at Palmyra.  Did these patterns arise via competition, or are other factors behind the observed distribution?

Collaborators: Dr Jenn Caselle (UC Santa Barbara), Dr Christopher Lowe (Cal. State Long Beach), Dr Yuuki Watanabe (Japanese Polar Research Institute), Darcy Bradley (UC Santa Barbara), Dr Alan Friedlander (University of Hawaii)

Publications:

Papastamatiou Y, Friedlander A., Caselle J., Lowe C. 2010. Long term movement patterns and trophic ecology of blacktip reef sharks (Carcharhinus melanopterus) at Palmyra Atoll. Journal of Experimental Marine Biology and Ecology. 386: 94-102

Papastamatiou Y, Caselle J., Friedlander A., Lowe C. 2009. Distribution, size frequency and sex ratios of blacktip reef sharks, Carcharhinus melanopterus, at Palmyra Atoll: a predator dominated ecosystem. Journal of Fish Biology 75: 647-654

Papastamatiou Y, Lowe C., Caselle J., Friedlander A. 2009. Scale dependent effects of habitat on movements and path structure of reef sharks at a predator dominated atoll. Ecology. 90(4):996-1008

A school of bigeye trevally. Photo: Y.Papastamatiou

Grey reef sharks on the Palmyra forereefs. Photo: Y.Papastamatiou