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Extreme Inverted Trophic Pyramid of Reef Sharks Supported by Spawning Groupers
- Source :
- Current Biology-CB, Current Biology-CB, Elsevier, 2016, 26 (15), ⟨10.1016/j.cub.2016.05.058⟩
- Publication Year :
- 2016
- Publisher :
- HAL CCSD, 2016.
-
Abstract
- International audience; The extent of the global human footprint [ 1 ] limits our understanding of what is natural in the marine environment. Remote, near-pristine areas provide some baseline expectations for biomass [ 2, 3 ] and suggest that predators dominate, producing an inverted biomass pyramid. The southern pass of Fakarava atoll—a biosphere reserve in French Polynesia—hosts an average of 600 reef sharks, two to three times the biomass per hectare documented for any other reef shark aggregations [ 4 ]. This huge biomass of predators makes the trophic pyramid inverted. Bioenergetics models indicate that the sharks require ∼90 tons of fish per year, whereas the total fish production in the pass is ∼17 tons per year. Energetic theory shows that such trophic structure is maintained through subsidies [ 5–9 ], and empirical evidence suggests that sharks must engage in wide-ranging foraging excursions to meet energy needs [ 9, 10 ]. We used underwater surveys and acoustic telemetry to assess shark residency in the pass and feeding behavior and used bioenergetics models to understand energy flow. Contrary to previous findings, our results highlight that sharks may overcome low local energy availability by feeding on fish spawning aggregations, which concentrate energy from other local trophic pyramids. Fish spawning aggregations are known to be targeted by sharks, but they were previously believed to play a minor role representing occasional opportunistic supplements. This research demonstrates that fish spawning aggregations can play a significant role in the maintenance of local inverted pyramids in pristine marine areas. Conservation of fish spawning aggregations can help conserve shark populations, especially if combined with shark fishing bans.
- Subjects :
- 0106 biological sciences
Food Chain
Coral reef fish
Ecological pyramid
Reef shark
Fishing
010603 evolutionary biology
01 natural sciences
Models, Biological
General Biochemistry, Genetics and Molecular Biology
Polynesia
Predation
Animals
14. Life underwater
Trophic level
Biomass (ecology)
biology
Ecology
Coral Reefs
010604 marine biology & hydrobiology
Carcharhinus amblyrhynchos
Feeding Behavior
biology.organism_classification
Fishery
Sharks
Bass
[SDE.BE]Environmental Sciences/Biodiversity and Ecology
General Agricultural and Biological Sciences
Energy Metabolism
Animal Distribution
Subjects
Details
- Language :
- English
- ISSN :
- 09609822 and 18790445
- Database :
- OpenAIRE
- Journal :
- Current Biology-CB, Current Biology-CB, Elsevier, 2016, 26 (15), ⟨10.1016/j.cub.2016.05.058⟩
- Accession number :
- edsair.doi.dedup.....7d02dfb733205f15bb63445e7c03b4e8