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Woods Hole Oceanographic Institution

Kelton McMahon

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Projects
» Historical shifts in plankton communities

» Food web architecture in coral reefs

» Seascape connectivity of reef fish

» Ocean isoscapes

» Ocean-basin scale migrations of large pelagic fishes

» Bivalves as bioproxies for climate change

» Digestibility of Ice Algae and Phytoplankton

» Fundulus heteroclitus


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Despite being the second largest fish in the ocean, these peaceful giants have largely eluded close scientific study until now. (Creative Commons/Chris Gotschalk)


Tracking the ocean-basin scale migrations of large pelagic sharks

Collaborators:
Dr. Gregory B. Skomal (Mass Div. of Marine Fisheries), Dr. Simon R. Thorrold (WHOI), Dr. Michael Berumen (KAUST and WHOI)

Animal migrations are among nature’s most spectacular and biologically significant phenomena. Movement and migration behavior of individuals can reveal key ecological characteristics and population dynamics of a species. In an evolutionary context, the ability to move determines the genetic structure of geographically separated populations. Movement rates will determine colonization patterns of new habitats, the resiliency of populations to harvest, and the effectiveness of spatial management options designed to reverse declines in ocean biodiversity and marine-capture fisheries. The importance of an understanding of migration and connectivity is particularly timely as organisms are faced with adapting to global climate change  Yet, very little is known about the population connectivity and movement patterns of large pelagic fishes.  We have been using pop-up satellite archival tags (PSAT), acoustic tags, and microsatellite genetic techniques to examine migration behavior of whale sharks, white sharks, basking sharks, manta rays, and devil rays world wide.  We are currently working in the North Atlantic (Cape Cod, the Azores), Equatorial Pacific (Phoenix Islands), and the Red Sea. The information gathered will elucidate horizontal movements in addition to vertical and horizontal habitat utilization, diving behavior, and temperature and depth preferences of these fishes. This work  looks to understand basic population, growth, and maturity metrics that are currently poorly understood for these species. These data can also improve our understanding of what factors influence movement behavior and thus improve conservation and management strategies for these species.

Publications:
Skomal GB, Zeeman SI, Chisholm JH, Summers EL, Walsh HJ, McMahon KW, Thorrold SR. (2009) Mesopelagic trans-equatorial migrations by basking sharks in the western Atlantic Ocean. Current Biology 19:1019-1022


Popular Media: Cape Cod Times: http://www.capecodonline.com/apps/pbcs.dll/article?AID=/20090512/NEWS/90512006

CNN.com http://www.cnn.com/2009/TECH/science/05/07/eco.baskingsharks/index.html

Discovery.com http://dsc.discovery.com/news/2009/05/07/basking-shark-track.html

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