MANTA

How many kinds of manta are there?

Manta rays belong to the taxonomic family Mobulidae. This family contains eleven species of plankton eating rays. Within this family there are two genera, Mobula and Manta and more specifically within the genus manta there are two species, Manta birostris (the giant oceanic manta) and Manta alfredi (the resident reef manta). These two species have much in common, but a few important differences in life history exist between the two. These are important to note as they have very different implications for the management and conservation of these species. Whilst the main focus of the work of the Manta Trust is the two known manta species we are also trying to improve knowledge and understanding of the nine species of mobula.

How large do they grow?

Oceanic mantas (M.birostris) are the bigger of the two manta species; reaching a wing span of up to 7 meters! A large oceanic manta might weigh in at up to 2 tons, making them a real ocean giant! Although smaller than the oceanic mantas, the reef mantas (M.alfredi) are still pretty big fishes, growing to an average wing span of 3-3.5 meters and a possible maximum of 4.5 meters, reaching weights of up to 1.4 tons. In both species the wing span is roughly 2.2 times the length of the body.

How long do they live?

Research would indicate that mantas probably live to at least 50 and possibly up to 100 years.

Where are they found?

The giant oceanic manta ray has a widespread distribution in tropical and temperate waters worldwide. In the Northern Hemisphere, it has been recorded as far north as southern California and New Jersey in the United States, Aomori Prefecture in Japan, the Sinai Peninsula in Egypt, and the Azores in the northern Atlantic. In the Southern Hemisphere, it occurs as far south as Peru, Uruguay, South Africa, and New Zealand. It is an ocean-going species and spends most of its life far from land, travelling with the currents and migrating to areas where upwellings of nutrient-rich water increase the availability of zooplankton. The oceanic manta ray is often in association with offshore oceanic islands.

What do they eat?

Despite their status as an ocean giant, manta rays feed on some of the smallest organisms in the sea! They are planktivores, feeding especially on zooplankton; tiny animals such copepods, mysid shrimps and arrow worms. Mantas are known to make seasonal migrations in order to take advantage of particularly abundant areas of food.

How do they reproduce?

It is believed that mantas are sexually mature at around 15-20 years of age. Courtship in mantas can last days or even weeks and is an intricate process led by the female. The males compete to mate with the female, following her around the reef in what is known as a mating train; Watching a mating train of mantas is an enthralling experience, with the female leading the males as she races, twists, turns and dives around the reef with each male following her every move. In doing this the female tests the fitness and persistence of the males as they try to keep up with her and gain the first place in the train. At the end of this process the female selects a single male and the two mates as a pair, belly to belly in the mid water, the male biting down on the female’s left wing to secure them together. Currently it is not known how often females give birth, but the latest research suggest birth rates average around one pup for each mature female every 2-5 years. This extremely slow rate of reproduction, coupled with the long gestation period, late maturity age and small litter size, makes manta rays very vulnerable to exploitation.