Presentation is loading. Please wait.

Presentation is loading. Please wait.

Volume 26, Issue 15, Pages (August 2016)

Similar presentations


Presentation on theme: "Volume 26, Issue 15, Pages (August 2016)"— Presentation transcript:

1 Volume 26, Issue 15, Pages 2011-2016 (August 2016)
Extreme Inverted Trophic Pyramid of Reef Sharks Supported by Spawning Groupers  Johann Mourier, Jeffrey Maynard, Valeriano Parravicini, Laurent Ballesta, Eric Clua, Michael L. Domeier, Serge Planes  Current Biology  Volume 26, Issue 15, Pages (August 2016) DOI: /j.cub Copyright © 2016 Elsevier Ltd Terms and Conditions

2 Current Biology 2016 26, 2011-2016DOI: (10.1016/j.cub.2016.05.058)
Copyright © 2016 Elsevier Ltd Terms and Conditions

3 Figure 1 Gray Reef Shark Aggregation within the Fakarava Pass, in the Tuamotu Archipelago of French Polynesia These sharks (A) form large schools of up to 700 individuals that use the strong current of this narrow channel (B) (about 100 m wide × 30 m deep) to rest. Photo © G. Funfrock. See also Figure S1 and Tables S1 and S2. Current Biology  , DOI: ( /j.cub ) Copyright © 2016 Elsevier Ltd Terms and Conditions

4 Figure 2 Trophic Structure and Predator-Prey Dynamics in the Fakarava Pass (A) Biomass spectrum of the trophic structure typically observed in the pass is characterized by a positive slope (0.51), indicating an inverted biomass pyramid. (B) Total shark biomass is similar to the biomass of their potential prey (fish >12.5 cm). (C) During grouper spawning aggregation, numerous large-bodied fish enter the system, increasing the slope of the biomass spectrum (0.55). (D) The grouper aggregation decreases the predator-prey ratio by doubling the amount of prey available for sharks. Gray bands indicate 95% confidence intervals in (A) and (C), and SEMs are given with slope values in (A) and (C). See also Tables S1 and S2. Current Biology  , DOI: ( /j.cub ) Copyright © 2016 Elsevier Ltd Terms and Conditions

5 Figure 3 Temporal Dynamics of Prey Biomass as a Function of Shark Daily Food Requirements (A) Daily food requirement of sharks (kg ⋅ day−1; orange) varies within the year based on shark abundance and is higher than predicted prey production from the fish community of the pass (blue). In June and July, the grouper spawning aggregation supplies an additional 775 kg fish ⋅ day−1 (green), which exceeds shark needs. (B) Prey biomass then rapidly collapses with a rate that depends on the proportion of grouper consumed (d). If the diet does not include groupers (blue; d = 0), then no prey are available after 77 days. This collapse is delayed to 114 days if shark diet is made of 100% of grouper during the month of the spawning aggregation (green; d = 1). Note that d = 0 for all scenarios at time tS (end of the spawning aggregation). See also Figures S2 and S4 and Tables S3 and S4. Current Biology  , DOI: ( /j.cub ) Copyright © 2016 Elsevier Ltd Terms and Conditions

6 Figure 4 Photo Examples of Foraging on Fish in the Pass at Night
(A) Spawning aggregation of Epinephelus polyphekadion occurring between full moon of June and July each year. (B and C) Gray reef sharks foraging at night on E. polyphekadion. (D) Gray reef sharks foraging at night on Naso annulatus. These photos represent natural predation. Lights from cameras are unlikely to have modified the hunting behavior, as the sharks were observed hunting out of light range. Photo © L. Ballesta. See also Figure S3 and Table S3. Current Biology  , DOI: ( /j.cub ) Copyright © 2016 Elsevier Ltd Terms and Conditions


Download ppt "Volume 26, Issue 15, Pages (August 2016)"

Similar presentations


Ads by Google