Animal Oh how beautiful are the Bahamas - hammerhead sharks become couch potatoes
Who can blame them? Some hammerhead sharks love the Bahamas so much that they forgo their usual seasonal trips and stay for years.
21.03.2025, 06:30
22.03.2025, 08:02
SDA
A research team reports in the journal "Frontiers in Marine Science" that it is possible that everything that great hammerheads need is simply available there. Plenty of prey and access to deep waters, which remain cool during the summer rainy season, could be what attracts them to stay. Sharks are also protected in the region.
The head of hammerhead sharks is strongly widened at the sides - probably for better sensory perception - and the eyes and nostrils are located at the ends of these hammer-shaped extensions. Great hammerhead sharks (Sphyrna mokarran) are found in the tropical and warm climate zones of all the world's oceans and undertake long-distance migrations of up to 3000 kilometers, according to the study. The animals, which can be up to six meters long, like to spend the winter in warmer places and then move around again in the summer.
Great hammerhead sharks classified as "threatened with extinction"
Hammerhead sharks are particularly vulnerable to overfishing due to their slow growth, late sexual maturity, long gestation period and low number of offspring. Great hammerhead sharks are classified as "critically endangered" by the International Union for Conservation of Nature (IUCN). The population is estimated to have shrunk by more than 80 per cent in the last three generations and genetic analyses show little genetic variation, explained Tristan Guttridge from the non-profit organization Saving the Blue.
"Understanding the movement patterns of hammerhead sharks is important in order to improve conservation measures," said Guttridge. His team caught and measured 22 great hammerhead sharks off the island of Andros, and tissue samples were also taken. The analysis revealed that barracudas and stingrays made up around two thirds of the diet of the solitary animals, with smaller sharks making up the rest.
Trackers were attached to seven of the captured animals to locate them. The data from these hammerhead sharks was combined with records of accidental sightings. The large fish prefer to stay in a relatively small area off northern and central Andros. Andros is the largest island in the Bahamas. According to Guttridge's team, this is probably the most untouched shallow habitat in the entire Caribbean.
Why don't all the animals stay in the Bahamas?
Sharks that left the Bahamas migrated to the east coast of the USA - but some animals stayed all year round, for several years. Why don't all animals stay if there is so much food and good habitat off Andros? "We found evidence of individual differences in their diet, so the decision whether to stay or go could depend on what they feed on," explained Guttridge.
The Bahamas are an island nation in the Atlantic Ocean southeast of the USA, and only 30 of the more than 700 islands are inhabited. The main industry in the Bahamas is tourism. Parts of the land and sea are protected as national parks. The Central Andros National Park includes mangroves and wetlands as well as parts of the Andros Barrier Reef, which is one of the largest reefs in the world.
The national parks are an important refuge for a number of animal and plant species, as the current study also shows. "Our research shows how important the waters of the Bahamas and their protection are," says Guttridge.
