For the first time, an international team of researchers has used satellites to track the movements of manta rays, providing valuable new information about the massive rays, which are considered "vulnerable" to extinction by the International Union for Conservation of Nature. The preliminary findings for the Atlantic mantas showed that they traveled as far as 680 miles over a one- to two-month period searching for food, sticking close to the coastline. They also spent considerable time in shipping lanes, which rendered them vulnerable to being hit by freighters.
The manta ray, Manta birostris, is the largest of the rays, reaching as big as 25 feet across. Although they are closely related to sharks and are often called "devilfish" because of their frightening appearance, they are actually harmless to humans. The animals are filter feeders, straining large volumes of water through their mouths to extract zooplankton and fish eggs. They are considered vulnerable because fisherman often capture them to use as bait for sharks. Their gill rakers (fingerlike structures that filter out prey) are also used in traditional Chinese medicine.
A team headed by Rachel T. Graham of the Wildlife Conservation Society in Punta Gorda, Belize, attached transmitters to six individuals -- four females, one male and one juvenile -- off the coast of Mexico's Yucatan peninsula. They reported in the journal PLoS One that they monitored the rays for periods ranging from 27 to 64 days, until the transmitters fell off.