Effects of body size, age and maturity stage on diet in a large shark: ecological and applied implications

By L. Lucifora, Verónica B. García, R. Menni, A. Escalante, Natalia M. Hozbor. Ecological research, 2008

136 citations recorded by the source corpus.

Ontogenetic diet shifts are a widespread phenomenon among vertebrates, although their relationships with life history traits are poorly known. We analyzed the relative importance of body size, age and maturity stage as determinants of the diet of a marine top predator, the copper shark, Carcharhinus brachyurus, by examining stomach contents using a multiple-hypothesis modeling approach. Copper sharks shifted their diet as size and age increased and as they became sexually mature, incorporated larger prey as they grew, and had a discrete shift in diet with body size, with only individuals larger than ≈200 cm total length able to prey on chondrichthyans. Body size was the most important trait explaining the consumption of chondrichthyans, while age determined the consumption of pelagic teleosts. Pelagic teleosts were consumed mostly by medium-aged sharks, a result, probably, of a risk-reducing feeding strategy at young ages coupled with either a senescence-related decline in performance or a change in sensory capabilities as sharks age. Copper sharks of all sizes were able to cut prey in pieces, implying that gape limitation (i.e., the impossibility of eating prey larger than a predator’s mouth) did not play a role in producing the diet shift. Our results suggest that, contrary to the current practice of setting minimum but not maximum size limits in catches, any plan to conserve or restore the ecological function of sharks, through their predatory control of large prey, should aim to maintain the largest individuals.

Subfields: Ecology, Nature and Landscape Conservation

View Paper: https://www.semanticscholar.org/paper/435fc6a49cc5bb3301415c22e798e5d56e369431

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Citations in the corpus

Apparent Resource Partitioning and Trophic Structure of Large-Bodied Marine Predators in a Relatively Pristine Seagrass Ecosystem (2013, background): “…understanding the trophic interactions and positions of largebodied predators is an important step in elucidating the dynamics of marine communities (e.g. Williams et al. 2004, Lucifora et al. 2009) and the potential for top predators to couple various trophic pathways (e.g. Rooney et al. 2006).”
Stable isotope analysis as a tool for elasmobranch conservation research: a primer for non-specialists (2012, background): “Some authors have suggested that under an ecosystem-based management model, different age-classes of the same species should be managed as separate species because their diets are so distinct (Lucifora et al. 2009; Grubbs 2010).”
Ecological importance of sharks and rays in a structural foodweb analysis in southern Brazil (2014, background): “species) have on trophic network compartments (Lucifora et al., 2009; Heithaus et al., 2013).”