The Caribbean reef shark: A valuable species

Enjoying a superb dive up at East End, in pristine conditions, I was lining up my camera on a tiger grouper being cleaned by peppermint shrimp. Patience, patience, patience…then I heard my daughter Jessica blow a couple of loud hoots in her regulator. I took the shot and looked up just in time to see a beautiful Caribbean reef shark pass not twenty feet away.

She just slid by on outstretched pectoral fins, smooth as a jet plane, sleek and graceful, sunlight dappling her grey/brown back. A couple of quick shots and she was gone, merging into the blue distance. Any dive in which you have a shark encounter is a great dive.

Commercial fishing for this and other large shark species around the world has all but annihilated shark populations to satisfy a growing demand for dried shark fins in the Orient. This is now having profound consequences on the habitats and ecosystems from which they have been removed.

How can we help save sharks? First of all we need to learn more about their biology and ecology. Acting on this information, policies can then be legislated to conserve these animals.

The Caribbean reef shark is the most abundant large carcharhinid shark associated with coral reefs in the Caribbean. The other main coral reef associated shark is the nurse shark. The Caribbean reef shark plays an important role as a predator in maintaining structure and overall health of coral reef communities.

The Caribbean reef shark is still fished throughout its range in the central western Atlantic, with the exception of the USA and Bahamas where it is now protected by law.

Until recent studies by the Guy Harvey Research Institute, surprisingly little was known about the ecology of this species. This research effort is very timely given the growing importance of these sharks in dive tourism in the Caribbean and in the Bahamas.

Extensive and long term field research has been undertaken on this species in Belize at Glover’s Reef atoll, in the Bahamas and in Brazil (Fernando de Noronha archipelago) by the institute’s scientists and collaborators at the University of Miami and the Universidad Federal do Rio Grande Norte of Brazil.
The sharks are tracked by scientists using a combination of satellite tags and acoustic tracking to study movement patterns and habitat utilization. Using this information helps in the design of Marine Protected Areas, fisheries management and conservation measures.

In Brazil, research revealed that the Fernando de Noronha archipelago is an important nursery area, with females giving birth there between February and April.

Acoustic tracking revealed that newborn and juvenile sharks show a very high degree of site attachment to the nursery area, inhabiting the same area year round mainly to avoid their predators, the larger shark species such as tigers and bulls. They start to move farther away after they get bigger, at two years old.

Commercial exploitation in this archipelago reduced the adult shark population to 10 per cent of its former level in just three years. Not only was the fishery unsustainable, but the species became threatened in a very short time. This is because sharks typically are long lived animals. They take many years to reach maturity, give birth to a few young, and so they are incapable of withstanding the levels of intensive commercial fishing to which they have been subjected.

In the diabolical practice of shark finning, it is estimated that tens of millions of sharks are killed every year worldwide. As populations decrease, so the value of the shark by-products increase, propagating an endless cycle of strip mining the oceans.

The institute has developed DNA forensic tests to identify detached reef shark fins in the world fin trade. There is now much concern about over-fishing of reef sharks and other species for fins in general because of their important role in maintaining the entire coral reef community structure. The institute is currently using its DNA tests to help in enforcement of fishery regulations of protected species in US waters.

In the Bahamas the institute has accessed Caribbean reef sharks that are part of numerous shark interactive experiences. These have become an important option in destination diving, and if properly managed and regulated provide an exciting encounter, in complete safety, for thousands of tourists per year. Shark encounters in the Bahamas generates 80 million dollars per year and in 2011 the Bahamas protected all shark species from commercial exploitation.

Similarly these interactive programmes provide jobs for many locals who would otherwise be extracting the very resource they now vigorously protect for tourism. All of these interactive programmes provide a very important educational component to their clients. For many it is their first open water shark encounter and the photographic opportunities are the big draw.

There now many destinations in the Caribbean, Eastern Pacific and Western Pacific that promote shark ecotourism through these interactive programmes. The value of a living Caribbean reef shark in the Bahamas and some Caribbean islands is now hundreds of thousands of dollars per year, in the same way the stingrays in Grand Cayman are now priceless.

If you want to see a Caribbean reef shark in the Cayman Islands, the best place to dive is at East End or in Little Cayman.

It is our collective responsibility to conserve the marine environment and maintain the biodiversity of the planet.  Please visit the Guy Harvey Research Institute website to see how you can get involved and make a difference: nova.edu/ocean/ghri.

Fish responsibly, dive safely.
 

 

ccreefshark