File(s) under permanent embargo
The world’s largest omnivore is a fish
journal contribution
posted on 2023-05-21, 09:44 authored by Meekan, MG, Patti VirtuePatti Virtue, Marcus, L, Clements, KD, Peter Nichols, Revill, ATThe evolution of very large body size requires a ubiquitous and abundant source of food. In marine environments the largest animals such as whale sharks are secondary consumers that filter feed on nekton, which is plentiful, although patchy. Consequently, feeding in coastal environments requires cost-efficient foraging that focuses on oceanographic features that aggregate both nektonic prey and marine debris such as floating macroalgae. Consumption of this algae could present an energetic challenge for these animals, unless some component can be digested. Here, we use a multi-technique approach involving amino acid compound-specific stable isotope analysis (CSIA) and fatty acid analysis to determine the trophic level of whale sharks and to identify likely items in the diet. CSIA analyses showed that the species has a trophic level consistent with omnivory. Fatty acid profiles of whale shark tissues, faeces and potential prey items suggest that the floating macroalgae, Sargassum, and its associated epibionts is a significant source of food. Although this overcomes the energetic challenge of consumption of floating algae, this mode of feeding and the need to focus on oceanographic features that aggregate prey also increases the threat to the species posed by pollutants such as plastic.
History
Publication title
EcologyVolume
103Issue
12Article number
e3818Number
e3818Pagination
1-7ISSN
0012-9658Department/School
Institute for Marine and Antarctic StudiesPublisher
Ecological Soc AmerPlace of publication
1707 H St Nw, Ste 400, Washington, USA, Dc, 20006-3915Rights statement
Copyright 2018 Ecological Society of AmericaRepository Status
- Restricted