Predator size-prey size relationships of marine fish predators: interspecific variation and effects of ontogeny and body size on trophic-niche breadth

Abstract

We utilized a long-term data base collected over a broad geographic range to examine predator size -prey size relationships for 18 species of marine fish predators from continental shelf waters off the northeast US coast. Regression analysis was used to illustrate interspecific variation in ontogenetic patterns of prey size use, gape allometries, and ratio-based trophic niche breadths. Sizebased feeding strategies were assessed through comparison of frequency distributions of relative prey sizes eaten and were related to general predator feeding tactics and gape morphology. The results demonstrated that the range of prey sizes eaten expanded with increasing predator body size for each of the marine predators examined, leading to asymmetric predator size -prey size distributions. Absolute maximum prey size and slopes of maximum prey size versus predator size varied widely among predator taxa. Distinct size-based feeding strategies were evident, as diets of some predators were dominated by prey that were 10 to 20% of predator size, whereas other predators frequently consumed prey > 50% of predator size. Gape sizes and allometric relationships with body size were also diverse among predators and often were closely associated with maximum prey sizes. Ratio-based trophic-niche breadths generally did not expand with predator ontogeny and tended to narrow for the largest predators, which may be common for animal taxa.

Trophic restructuring of coral reef fish communities in a large marine reserve

“…However, for marine fishes, consumption of food types is limited by gape and body size (Wainwright & Richard 1995, Scharf et al 2000. Body size correlates well with trophic relationships when viewed on the community level (Jennings et al 2001), although this trend may deteriorate among smaller species due to the diverse size and morphology seen in the larger species base at this level (Layman et al 2005).…”

“…First, we determined whether the estimated response ratios varied systematically with species size. We assumed that species size served as a suitable proxy for trophic level due to the correlation of consumption of food types with gape and body size (Wainwright & Richard 1995, Scharf et al 2000, and its consequent determination of trophic relationships and ecological role on the level of fish communities (Jennings et al 2001, but see Layman et al 2005. Body size was summarized as the mean TL of individuals within a species observed in the study.…”

The signature of phylogenetic constraints on food-web structure

“…For the analysis of body masses, we use the large data set of Brose et al (2005), which encompasses 16,863 records of trophic interactions from 10 food-web studies (Warren, 1989;Dawah et al, 1995;Yodzis, 1998;Memmott et al, 2000;Cattin Blandenier, 2004;Woodward et al, 2005;Jonsson et al, 2005;Harper-Smith et al, 2005; Ledger, Edwards, and Woodward, unpublished data; Jacob, Brey, and Mintenbeck, unpublished data), supplemented by data for some specific groups (Andrassy, 1956;Hansen et al, 1994;Ulrich, 1999Ulrich, , 2001Scharf et al, 2000;Pinnegar et al, 2003;Cohen et al, 2005;Dell, unpublished data;Rayner, unpublished data;Ruess, unpublished data;Warren, unpublished data). For the purpose of comparison and to avoid pseudoreplication, we retain the 5103 records of Brose et al (2006b).…”

Diet composition and feeding habits of the eyespot skate, Atlantoraja cyclophora (Elasmobranchii: Arhynchobatidae), off Uruguay and northern Argentina

“…The predator-prey size pattern found in A. cyclophora and R. agassizii (i.e. consuming both small and large prey) is the most common among elasmobranchs, specially in piscivorous predators (Scharf et al, 2000;Lucifora et al, 2006).…”