From the Galapagos National Park Service
During a recent 12-day trip to Darwin and Wolf Islands in the
north of the archipelago (only visited by dedicated scuba diving
cruises - no land visits are possible here), technicians of the
Galapagos National Park Service, with support from scientists of
the Charles Darwin Foundation and the University of California
Davis, managed to capture and mark eleven sharks of different
species, as part of a shark monitoring program. The idea is
to understand the movement patterns of sharks within and outside
the protected area.
To tag the shark, one must first capture it, put it on a stretcher
where it is secured and taken onto the research vessel. Once
there, it is measured and satellite tags are fixed to the dorsal
fin. During this process, seawater is supplied to the shark through
a hose that runs it over their gills.
Tags have so far been placed in 5 silky sharks, 2 hammerhead
sharks, 2 Galapagos sharks, and 2 black tip sharks. The
tags include a small antenna - so when the shark's dorsal fin pokes
out of the water (as it does when they are swimming at the
surface), the device sends a satellite signal which is then relayed
back to the Park's monitoring. Earlier such studies have
demonstrated that some sharks move between Cocos Island (Costa
Rica) and Galapagos.
CNH Tours notes that this kind of information helps develop
effective shark conservation policies. For example, if the
scientists discover that the sharks migrate regularly to other
places, it will be clear that their long term conservation will
require cooperation with the fisheries management authorities in
these places as well.
The large schools of hammerhead sharks are one of diving wonders
of Galapagos - divers come from around the world to witness this
phenomenon. But sharks have been aggressively fished
over the past several years, mostly to feed the growing Chinese
market for "shark fin soup". Even in the
Galapagos marine reserves, sharks are often illegally fished for
their fins and all efforts must be made to stop this practice, both
by controlling illegal fishing, and by encouraging the main
consumers of shark fins that the practice is not sustainable.