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

Tuesday, August 16, 2011

Amazing rays!

When out on the boat, or snorkeling a transect one of the most amazing megafauna we see are rays. There are over 30 species of rays from 10 different families. They have skeletons that are composed of cartilage rather than bone, so like sharks, they are known as a cartilaginous fish. The 3 most commonly spotted rays along the Kenyan coast are the spotted eagle ray, the blue-spotted ribbon tail ray and the manta ray.
The spotted eagle ray has a body length of up to 3.5 metres, with a white underside with a black dorsal surface with distinctive white spots. They have a long tail with serrated barbs at the base. They are found mainly on inshore shallow water around reefs all year round.  Most recently we have seen this species on our snorkel transect in the Marine reserve – an individual over 2m in width moving gracefully over the reef.
Blue Spotted Ribbon Tail Ray spotted on Transect 7

The blue-spotted ribbon tail ray has an oval shaped body, up to 90cm in diameter with a yellow brown colouration with numerous blue spots. Their tail has a fleshy ridge, blue stripes and a single sting. They are generally solitary and common on rocky shores and coral reefs. They are seen in the marine park throughout the year, and have been seen on numerous snorkel transects around Kisite island, though they can be hard to spot due their ability to camouflage themselves in the sand. Just last week we spotted two a managed to get this great photograph on Snorkel Transect 7.
Manta rays are the largest ray at a width of up to 6.7 metres and a possible weight of over 2000kg. They have a wide head with a pair of paddle like flaps at the front and possess 5 pairs of gill openings that are well equipped for filtering plankton. They have a black dorsal surface and a white ventral surface. Being very powerful swimmers they can jump clear of the surface of the water (which is thought to dislodge parasites).  They are seasonal visitors to the marine park, being found mainly between January and the end of March. Found mainly in deeper water but occasionally spotted close to the reefs. In 2002 up to 500 manta rays were seen between Kisite and Sii Island, and just yesterday our boat captain spotted one leaping clear of the water in the marine reserve.