Page 314 - Hawaii: Diving, Surfing, Pearl Harbor, Volcanoes and More

Eagle Rays, Manta Rays and Stingrays

agle Rays - Eagle rays feed on mollusks and crustaceans, sharks traveling together.
E crushing their shells with their flattened teeth, while devil
and manta rays filter plankton from the water. They are excellent anta Rays - The larger species, M. birostris, reaches 7 m (23
swimmers and are able to breach the water up to several metres M ft) in width while the smaller, M. alfredi, reaches 5.5 m (18
above the surface. Compared with other rays, they have long tails, ft). Both have triangular pectoral fins, horn-shaped cephalic fins
and well-defined rhomboidal bodies. They are ovoviviparous, giv- and large, forward-facing mouths. The largest mantas can reach
ing birth to up to six young at a time. They range from 48 centi- 1,350 kg (3,000 lb). Manta rays are known for their large size,
metres (19 in) to 9.1 metres (30 ft) in length. The spotted eagle broad heads, triangular pectoral fins, and the horn-shaped cephal-
ray, Aetobatus narinari, also known as the bonnet ray or maylan, ic fins located on either side of their mouths. The name “manta”
belongs to this genus. The ray bears numerous white spots on its is Spanish for cloak or blanket, a type of blanket-shaped trap
inky blue body. It has a span width of 2.5 m (8 ft) and a maximum traditionally used to catch rays. They are protected in international
reported weight of 230 kg (about 507 lbs). Including the tail, it can waters by the Convention on Migratory Species of Wild Animals,
reach up to 5 m (16 ft) in length. The spotted eagle ray is found but are more vulnerable closer to shore. Areas where mantas con-
in the tropical areas of all oceans, including the Caribbean Sea gregate are popular with tourists. Only a few aquariums are large
and the Gulf of Mexico. The genus also includes the much smaller enough to house them. In general, these large fish are seldom
longheaded eagle ray, Aetobatus flagellum, which is a widespread seen and difficult to study. Manta rays are Chondrichthyes, fish
but uncommon species of Indian Ocean and western Pacific coasts. with tough cartilage rather than bone in their skeletons. As filter
This is considered an endangered species due to huge pressure feeders, manta rays consume large quantities of zooplankton in
from fisheries throughout its range. Eagle rays live close to the the form of shrimp, krill and planktonic crabs. An individual manta
coast in depths of 1 to 30 m and in exceptional cases they are eats about 13% of its body weight each week. The greatest threat
found as deep as 300 m. The eagle ray is most commonly seen to manta rays is overfishing. In 2011, mantas became strictly
cruising along sandy beaches in very shallow waters, its two wings protected in international waters thanks to their inclusion in the
sometimes breaking the surface and giving the impression of two Convention on Migratory Species of Wild Animals.