title: Does prey size matter? Novel observations of feeding in the leatherback turtle (Dermochelys coriacea) allow a test of predator-prey size relationships.
abstract: Optimal foraging models predict that large predators should concentrate on large prey in order to maximize their net gain of energy intake. Here, we show that the largest species of sea turtle, Dermochelys coriacea, does not strictly adhere to this general pattern. Field observations combined with a theoretical model suggest that a 300 kg leatherback turtle would meet its energetic requirements by feeding for 3-4 h a day on 4 g jellyfish, but only if prey were aggregated in high-density patches. Therefore, prey abundance rather than prey size may, in some cases, be the overriding parameter for foraging leatherbacks. This is a classic example where the presence of small prey in the diet of a large marine predator may reflect profitable foraging decisions if the relatively low energy intake per small individual prey is offset by high encounter rates and minimal capture and handling costs. This study provides, to our knowledge, the first quantitative estimates of intake rate for this species.
authors.affiliation: Department of Biosciences, College of Science, Swansea University, Swansea, UK. sabrina.fossette@googlemail.com
authors.forename: Sabrina
authors.initials: S
authors.lastname: Fossette
authors.forename: Adrian C
authors.initials: AC
authors.lastname: Gleiss
authors.forename: James P
authors.initials: JP
authors.lastname: Casey
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Lewis
authors.forename: Graeme C
authors.initials: GC
authors.lastname: Hays
mesh_terms: D000818:Animals; D049628:Body Size; D020387:Food Chain; D008297:Male; D008542:Melanesia; D011156:Population Density; D011235:Predatory Behavior; D012098:Reproduction; D037401:Scyphozoa / Q000502:physiology*; D014329:Tropical Climate; D014426:Turtles / Q000502:physiology*
references.citation: Physiol Biochem Zool. 2007 Mar-Apr;80(2):209-19
references.pmid: 17252517
references.citation: Ecology. 2009 Jul;90(7):2014-9
references.pmid: 19694148
references.citation: Comp Biochem Physiol A Mol Integr Physiol. 2007 Jun;147(2):323-31
references.pmid: 17188537
references.citation: Nature. 1999 Nov 18;402(6759):286-8
references.pmid: 10580498
references.citation: J Exp Biol. 2011 Jan 1;214(Pt 1):131-46
references.pmid: 21147977
references.citation: J Exp Biol. 2010 Dec 1;213(Pt 23):3961-71
references.pmid: 21075937