Marine Megafauna Foundation Galapagos Whale Shark Season Press Release

 

Puerto Ayora, Ecuador (October 7, 2015)  With the permission  of the Galapagos  National Park Directorate,  experts from around the globe sailed to Darwin Island in the far northern  region  of the Galapagos Marine Reserve in Ecuador. The objective was to document the movements and behaviors of the world’s largest fish, the whale shark (Rhincodon typus), in order to better understand its natural history and improve international conservation measures.

Although  whale sharks are found in tropical and temperate  waters around the globe, little is known about their ecology. Most studies have occurred at locations primarily visited briefly by juvenile males perhaps to feed (e.g., Western Australia, Mozambique,  the Gulf of Mexico, Republic of Philippines). Few adult whale sharks have been seen at these same locations.  The whereabouts, movements, and behaviors  of  adult  whale  sharks  has  long  remained  a  mystery,  and  scientists  have  rarely  had opportunities to get close to them until now in the Galapagos.

Jonathan Green, project leader and member of  Fundacion   Megafauna   Marina  Ecuador, has been observing  whale sharks at Darwin Island for over 20 years. “It became clear to me  that  we  are  dealing  here  with  a  very specific  portion  of the population.  Almost  all whale sharks we observe are large females, with distended abdomens, suggestive of pregnancy.”

The research team pose with the Explorer’s Club Flag. From left to right: Dr. Alex Hearn, Dr. Alistair Dove, Jonathan Green, Dr. Simon Pierce, Dr. Chris Rohner, Leandro Vaca, Dr. Brent Stewart, Clare Prebble. Photo: Brent Stewart.

The research team pose with the Explorer’s Club Flag. From left to right: Dr. Alex Hearn, Dr. Alistair Dove, Jonathan Green, Dr. Simon Pierce, Dr. Chris Rohner, Leandro Vaca, Dr. Brent Stewart, Clare Prebble. Photo: Brent Stewart.

In    2011,    together    with    the    Galapagos National Park Directorate and other partners, Green created the Galapagos Whale Shark Project.   The  project   began  an  ambitious study  to  attach  satellite  tags  to  sharks  at Darwin Island to track their movements. The initial results were surprising. The team found that rather than a resident group of whale sharks, there was a steady stream of whale sharks moving past Darwin throughout the season.

Although there may be only three or four whale sharks present at any given time, the turnover rate is around two days, so over a season several hundred sharks may use the site.”

Dr. Alex Hearn  of Turtle  Island  Restoration  Network  and Universidad  San Francisco  de Quito has worked on the project since its inception.

We found that the sharks were moving over a thousand kilometers offshore along the equatorial front, then back again past Darwin to the highly-productive  waters off the shelf break of southern Ecuador and northern Peru. Could these movements be related to pupping grounds?”

Only a handful of neonate (newborn) whale sharks have ever been reported, some from the bellies of oceanic mako and blue sharks, others from deep-water fisheries. Almost nothing is known about the early life stages of whale sharks.

Thanks to support from the Galapagos Conservation Trust and a private trust, this year we were able to bring together  whale  shark  experts  from all over the globe,  a unique  collaboration  for a unique location,” added Green.

Dr. Brent Stewart of the Hubbs-SeaWorld Research Institute was one of the pioneers of whale shark tracking and has been studying whale sharks in waters around Kenya, the Maldives, Western Australia, the Philippines, Indonesia,  and  the  Gulf  of California.  During the research cruise he attached long-term satellite  tags  to  four  female  whale  sharks. These tags will now provide information on movements for up to eight months.

We hope to document where these adult females travel and spend their time, how they interact with local and regional marine ecosystems,  and perhaps too where they give birth  and  mate,”  he  remarked.  The scientists also attached a further six short-term satellite tags and a custom camera tag.

The  scientists Dive team attaches towed satellite tag to adult whale shark at Darwin Island, Galapagos (Ecuador). Photo: Clare Prebble.

The  scientists Dive team attaches towed satellite tag to adult whale shark at Darwin Island, Galapagos (Ecuador). Photo: Clare Prebble.

Dr. Simon Pierce and Dr. Chris Rohner of the Marine Megafauna Foundation have been working with whale sharks internationally  and are part of a global effort to maintain a photo database of individual whale sharks.

Whale sharks can be identified by the pattern of spots behind their gills, the equivalent of a human fingerprint.  By submitting  photos  to  www.whaleshark.org,  an online  collaboration  system  for whale shark  researchers,  we  are  documenting  global  connectivity  between  feeding  sites  along  with  the residency of sharks at particular favored areas,” explained Dr. Pierce. “Citizen science plays a key role in this effort, and any divers that have visited Galapagos can also submit their encounters to the global database,” added Rohner.

By  taking  small  skin  samples  from  sharks,  Galapagos-born  biologist  Leandro  Vaca  of Galapagos Science  Center,  Universidad  San Francisco  de Quito  and Ph.D.  candidate  Clare  Prebble  from the Marine Megafauna Foundation hope to determine where the sharks are spending their time and what they eat.

The tissue samples can be analyzed for their stable isotope levels and fatty acid content, which can then  be  related  back  to plankton  samples  we  took  during  the  cruise  at Darwin,”  explained  Vaca. “Unlike at other places where whale sharks are regularly seen, the sharks at Darwin have never been observed  feeding.  Using  tiny  pieces  of skin,  we can  compare  the sharks’  tissue  composition  with samples from Peru and other locations to reconstruct their movements between feeding and possible breeding or pupping areas,” added Prebble.

Dr. Alistair Dove of Georgia  Aquarium  in Atlanta is leading  the effort to take blood from the whale sharks in order to analyze their hormonal levels and carry out basic health assessments.  “We have developed techniques to take blood under aquarium conditions, but applying them in the field presents huge challenges. After this trip however, I am confident that it can be done.” Dove was struck by the marine  life at Darwin.  “This  is such  a special  location,  not just because  of the whale  sharks.  We encountered walls of hundreds of scalloped hammerhead sharks just off the reef on every dive, along with yellowfin tuna, bottlenose dolphins, silky and Galapagos sharks and green turtles. The Galapagos National Park Service have a jewel here, and we feel honored to be able to contribute to their work conserving the rich biodiversity of these islands.”

The  Galapagos  National  Park  Directorate  is  currently  reviewing  the  zonation  of  the  marine  and terrestrial  areas.  The  information  gathered  on habitat  use  for whale  sharks  and  other  key  marine species  is  extremely  important  for  this  process,”  said  biologist  Harry  Reyes,  Head  of  Marine Ecosystem Use and Conservation at the Galapagos National Park Directorate. His colleague Eduardo Espinoza, Coordinator of Marine Ecosystem Monitoring, explained that the Galapagos National Park Directorate carries out conservation actions for protected species in accordance with the international agreements  and treaties  to which  Ecuador  is party.  Whale  sharks  are listed  on the Convention  of Migratory Species and are categorized as Vulnerable on the IUCN Red List.

OUR PARTNERS

Turtle Island Restoration  Network works to mobilize people and communities  around the world to protect marine wildlife, the oceans and the inland waterways that sustain them.  www.SeaTurtles.Org

HubbsSeaWorld Research Institute’s mission is “To return to the sea some measure of the benefits derived from it” by conducting research on marine fauna to support conservation and maintenance of vital populations on in healthy oceans.

Georgia Aquarium in Atlanta is a 501(c)(3) non-profit organization that contains more than 10 million gallons of water and has the largest collection of aquatic animals. Georgia Aquarium’s mission is to be a scientific  institution  that  entertains  and  educates,  features  exhibits  and  programs  of the  highest standards,  and  offers  engaging  and  exciting  guest  experiences  that  promote  the  conservation  of aquatic  biodiversity   throughout   the  world.  Georgia  Aquarium   is  an  accredited   member  of  the Association  of Zoos and Aquariums  and the Alliance of Marine Mammal Parks and Aquariums.  For additional information, visit  www.georgiaaquarium.org.

CONTACTS

Jonathan R. Green
Director of Whale Shark Investigation Fundación Megafauna Marina, Ecuador jonathangwsp@gmail.com

Dr. Alex Hearn
Marine Science Advisor, Turtle Island Restoration Network Professor/Researcher,  Universidad San Francisco de Quito

Ahearn@usfq.edu.ec,  alex@tirn.net

Brent S. Stewart, Ph.D., J.D.
Senior Research Scientist

Hubbs-SeaWorld Research Institute
bstewart@hswri.org

Sara Flores
Coordinadora de prensa

Universidad San Francisco de Quito
sflores@usfq.edu.ec

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