|
Shark Science
2000-2007
Research
with Marine CSI
Research Co-op
with CICIMAR
and U.C. Davis
GICF science in action video
Predator Is Prey: Sharks Killed for Fins
|
The Marine Conservation
Science Institute Research Projects
Michael Domeier has been researching great white sharks at Isla
Guadalupe since 2000. This includes an extensive satellite tagging
program and a photo-identification tracking program. Both of these
critical ongoing projects are uncovering exciting details about the
behavior patterns of these sharks.
Since January 2000, MCSI has deployed 72 pop-up satellite tags at this
site on sharks ranging in size from 8 to 18 feet long. Tags are inserted
into the backs of the sharks (as close to the dorsal fin as possible) as
they are lured close to the boat with large tuna carcasses. The tags
have remained on the sharks for anywhere from 2 weeks to 9 months and
have given invaluable information on the behavior and movement of white
sharks including swimming depths, temperatures encountered, daily
patterns, and migratory movements.
MCSI has found that the tagged sharks remain at Guadalupe Island for a
portion of the tagging period, but they leave the island for as much as
half the year and travel out towards the middle of the Pacific Ocean as
far as Hawaii. They seem to be traveling towards offshore seamounts,
which suggests that even away from shore, animals may be drawn to
topographical relief features in the ocean. Such features are frequently
gathering places for a wide variety of marine inhabitants.
MCSI has also been studying the sharks at Guadalupe Island through a
rapidly expanding photo-identification project. Individuals have been
identified using photos and video taken by MCSI's research team as well
as by photographers and divers on cage-diving expeditions at the island.
Using physical features such as: pigmentation patterns, the sex of the
animal, and any scars and mutilations, 78 individual white sharks have
been identified and tracked at Guadalupe Island. Many of these sharks
have been tracked around the island since 2001 and 63 of the 77
identified sharks have been photographed at the island over multiple
years, including 5 that have been sighted at Guadalupe Island 6 years in
a row. This study was recently published in Marine Biology, M.L. Domeier,
N. Nasby-Lucas. Annual re-sightings of photographically identified white
sharks (Carcharodon carcharias) at an eastern Pacific aggregation site
(Guadalupe Island, Mexico).
Mar Biol 150:970-984, 2007.
Download the report in .pdf format
It is clear that great white sharks are drawn to the area around
Guadalupe Island. The challenge remains to determine why they have
selected this spot. Perhaps they are taking advantage of the local seal
colonies on the steep rocky shores. Guadalupe is also known for as a
prime fishing spot for recreational anglers. The large tuna and
yellowtail that are found here may also attract one of the oceans
largest predators. Through additional research, MCSI hopes to learn more
about why the sharks are attracted to Guadalupe.
Visit the MarineCSI website at
www.marinecsi.org.
|
Donate to ongoing
White Shark Research
Donations will help fund valuable white shark research efforts at Isla
Guadalupe.
Since 2000, privately funded efforts have supported the collection of
critical white shark data.
 |
