Welcome to the Marine Mammal and wildlife Research and Community Development Expedition blog where you can keep up to date with all the happenings and information from Kenya

Monday, March 8, 2010

Increased sightings of reef sharks

During the last couple of weeks on the Marine Research Programme we have had a number of sightings of black and white tip reef sharks (Carcharhinus melanopterus and Triaenodon obesus). These tend to be found off shallow coral reefs in tropical regions, and the Kisite Mpunguti Marine Protected Area is a known habitat of theirs, but having not been seen frequently in the 9 months I have been part of the Marine programme here, there was growing concern that their numbers may have been dropping. However, these recent sightings have given us hope that this is not the case.

Just today, we saw one ominous black tip reef shark in the shallow warm water and a group of Big-fin Reef Squid (Sepioteuthis lessoniana) making a quick getaway, while snorkelling one of our turtle research transects within the Kisite Marine Park. Later we spotted one from the boat and watched it navigate effortlessly around the reef. These stunning creatures have not changed for millions of years, the species has had no need to evolve or adapt but has remained the top predator of the ocean. I feel privileged to have had such fantastic sightings of these awesome animals.

Blacktip reef shark near Kisite, low tide

The blacktip and the whitetip reef shark, Carcharhinus melanopterus and Triaenodon obesus, are among the most abundant sharks inhabiting the tropical coral reefs of the Indian and Pacific Oceans. These species prefers shallow, inshore waters. Most of these reef sharks are found over reef ledges and sandy flats and typically attains a length of 1.5 m.

Blacktip reef sharks have extremely small home ranges and exhibit strong site fidelity, remaining within same local area for up to several years at a time. They are active predators of small bony fishes, cephalopods, and crustaceans, and have also been known to feed on sea snakes and seabirds.

Blacktip and Whitetip reef shark distribution (Compagno, Leonard; Dando, Marc & Fowler, Sarah (2005). Sharks of the World. Collins Field Guides. ISBN 0-00-713610-2)

Blacktip reef shark (photo by David Burdick, http://www.photolib.noaa.gov/htmls/reef0925.htm)

Reef sharks are rarely aggressive towards humans, though they may investigate swimmers closely. The International Union for Conservation of Nature (IUCN) has assessed the whitetip and the blacktip reef sharks as Near Threatened, noting that its numbers are dwindling due to increasing levels of unregulated fishing activity across its range. The slow reproductive rate and limited habitat preferences of this species renders its populations vulnerable to over-exploitation.

This week we also watch the documentary SHARKWATER (winner of 26 international film festival awards), by filmmaker Rob Stewart who teamed up with Paul Watson, Sea Shepherd conservationist, about shark poachers and the shark fin trade industry. An amazing inside view about these animals and the threats they are currently facing worldwide. A must see film!

Marine team *