GPS for Sharks

Overview

Recent advances in satellite tagging and tracking are allowing scientists to “spy” into the secret lives of marine animals. We are currently using satellite tags to track the movements of shark species in the subtropical Atlantic. The goal of this work is to understand the migratory routes and residency patterns of these sharks to identify “hot spots” in place and time that are critical for mating, giving birth and feeding as well as locations where these animals are vulnerable to destructive fishing. By characterizing and identifying these hot spots, we can help supply policy makers with the data they need to implement effective management strategies that will improve conservation for these species. Some of the major questions we are currently investigating include:

  1. What is the distribution and scale of seasonal movement patterns of Hammerhead, Bull, and Tiger Sharks in the subtropical Atlantic?
  2. Do these species exhibit site fidelity and/or habitat specialization and if so, is there evidence of inter- and intra-specific differences?
  3. To what extent is shark habitat use divided among different marine protected and political-economic zones?
  4. Are long-term and large-scale shark movements influenced by ecotourism activities?
  5. What areas are sharks most vulnerable to capture by longline fishing?

Recent Study Highlights & Selected Examples

In a paper published in the journal Functional Ecology titled, “Don’t bite the hand that feeds: Assessing ecological impacts of provisioning ecotourism on an apex marine predator,” our team and collaborators conducted a satellite tagging study to examine the long term and long range movement patterns of tiger sharks in response to dive tourism. The tracking data suggested that over large spatial and time scales, the long-distance migration patterns of the sharks did not appear to be impacted by dive eco-tourism. Tiger sharks tagged in Bahamas and Florida exhibited previously unknown long-distance migrations of up to 3500 km into the Atlantic. These migrations appeared to follow the Gulf Stream through areas of high productivity that concentrate shark prey, suggesting the movements may be linked to feeding forays. The video below is a visual overview of a paper we published in the Journal of Functional Ecology based on our satellite tagging research.

Figure (Above): Kernel volume contours for 11 tiger sharks in Florida, displaying core use regions determined from the satellite tracking data. Figure modified from Hammerschlag et al. Functional Ecology 26(3): 567-576

See the Popular Science INFOGRAPHIC on our shark tracks

Image (Above): This is one of the satellite tags that SRC is currently using and testing in the field. These transmitters are capable of recording shark position as well as the water temperature and depth at which the animals are swimming.

VIEW OUR SATELLITE TAGGED SHARKS IN GOOGLE EARTH

Citizen Science

Our long-standing citizen science trips provide opportunities for students to join us in the field for a day of practical, hands-on research experiences. If you are interested in ways to get involved with SRC, please check out how to participate or donate.

Publications

Graham F, Rynne P, Estevanez M, Luo J, Ault JS, Hammerschlag N. (2016), Use of marine protected areas and exclusive economic zones in the subtropical western North Atlantic Ocean by large highly mobile sharks.Diversity and Distributions. doi:10.1111/ddi.12425

Queiroz N, Humphries N.E., Mucientes G., Hammerschlag N, Lima F.P, Scales K.L, Miller P.I., Sousa L.L., Seabra R., Sims D.W. (2016). Ocean-wide tracking of pelagic sharks reveals extent of overlap with longline fishing hotspots. Proceedings of the National Academy of Sciences; doi: 10.1073/pnas.1510090113

Hammerschlag N, Broderick AC, Coker JW, Coyne MS, Dodd M, Frick MG, Godfrey MH, Godley BJ, Griffin DB, Hartog K, Murphy SR, Murphy TM, Nelson ER, Williams KL, Witt MJ, Hawkes LA (2015). Evaluating the landscape of fear between apex predatory sharks and mobile sea turtles across a large dynamic seascape. Ecology, 96(8): 2117-2126.

Hammerschlag N, Cooke SJ, Gallagher AJ, Godley BJ. (2013). Considering the fate of electronic tags: user responsibility and interactions when encountering tagged marine animals; Methods in Ecology and Evolution. doi: 10.1111/2041-210X.12248

Hammerschlag N, Luo J, Irschick DJ, Ault JS (2012) A Comparison of Spatial and Movement Patterns between Sympatric Predators: Bull Sharks (Carcharhinus leucas) and Atlantic Tarpon (Megalops atlanticus). PLoS ONE 7(9): e45958. doi:10.1371/journal.pone.0045958

Hammerschlag N, Gallagher AJ, Wester J, Luo J, Ault JS. 2012 (Cover). Don’t bite the hand that feeds: assessing ecological impacts of provisioning ecotourism on an apex marine predator. Functional Ecology, 26(3): 567-576

Hammerschlag N, Gallagher AJ, Lazarre DM. (2011)A Review of Shark Satellite Tagging Studies. Journal of Experimental Marine Biology and Ecology; 398(1-2): 1–8.

Hammerschlag N, Gallagher AJ, Lazarre DM, Slonim C. 2011.Range extension of the endangered great hammerhead shark Sphyrna mokarran in the Northwest Atlantic: Preliminary data and significance for conservation; Endangered Species Research, 13: 111–116.