Do Sharks Associate with Fish Spawning Aggregations?

This new study (see paper here) investigated whether three species of shark utilize deep Caribbean reefs. Shark species studied were Tiger, Lemon and Caribbean Reef sharks. The researchers found that out of the three species, Lemon sharks were consistently found at deep reefs during spawning aggregations. Though this study was done in the U.S Virgin Islands, it would be interesting to see if the same was found here in The Bahamas. See below for a summary of this group’s research and a popular news article here.

Understanding of species interactions within mesophotic coral ecosystems (MCEs; ~ 30–150 m) lags well behind that for shallow coral reefs. MCEs are often sites of fish spawning aggregations (FSAs) for a variety of species, including many groupers. Such reproductive fish aggregations represent temporal concentrations of potential prey that may be drivers of habitat use by predatory species, including sharks. We investigated movements of three species of sharks within a MCE and in relation to FSAs located on the shelf edge south of St. Thomas, United States Virgin Islands. Movements of 17 tiger (Galeocerdo cuvier), seven lemon (Negaprion brevirostris), and six Caribbean reef (Carcharhinus perezi) sharks tagged with acoustic transmitters were monitored within the MCE using an array of acoustic receivers spanning an area of 1,060 km2 over a five year period. Receivers were concentrated around prominent grouper FSAs to monitor movements of sharks in relation to these temporally transient aggregations. Over 130,000 detections of telemetered sharks were recorded, with four sharks tracked in excess of 3 years. All three shark species were present within the MCE over long periods of time and detected frequently at FSAs, but patterns of MCE use and orientation towards FSAs varied both spatially and temporally among species. Lemon sharks moved over a large expanse of the MCE, but concentrated their activities around FSAs during grouper spawning and were present within the MCE significantly more during grouper spawning season. Caribbean reef sharks were present within a restricted portion of the MCE for prolonged periods of time, but were also absent for long periods. Tiger sharks were detected throughout the extent of the acoustic array, with the MCE representing only portion of their habitat use, although a high degree of individual variation was observed. Our findings indicate that although patterns of use varied, all three species of sharks repeatedly utilized the MCE and as upper trophic level predators they are likely involved in a range of interactions with other members of MCEs.

Alexandria E. Pickard, Jeremy J. Vaudo, Bradley M. Wetherbee, Richard S. Nemeth, Jeremiah B. Blondeau, Elizabeth A. Kadison, Mahmood S. Shivji. Comparative Use of a Caribbean Mesophotic Coral Ecosystem and Association with Fish Spawning Aggregations by Three Species of Shark. PLOS ONE, 2016; 11 (5): e0151221 DOI:10.1371/journal.pone.0151221

About the Author:

Ryann Rossi
My general research interests lie in the ecology of marine coastal ecosystems. I am most interested in the role plant diseases have in shaping the ecology of coastal and estuarine environments. I am currently studying the role of a plant pathogen in a die-off of Red Mangroves in The Bahamas. Follow Ryann Rossi

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