Nearly 80% of whale sharks in this marine tourism hotspot have human-caused scars

Weld sharks, the largest species of living fish, are classified as threatened on the Red List of the IUCN of endangered species. Over the past 75 years, populations have decreased by more than 50% worldwide and up to 63% in the Indo-Pacific region. Because whale sharks take up to 30 years to become sexually ripe, populations can only slowly recover threats such as hunting for fins, meat and oil, loss of habitat and tangle in fishing nets.

Now, an international group of researchers has shown that in the sea landscape of the bird of Western Papua, 62% of whale sharks have scars and injuries of avoidable human causes. They argue that simple interventions could considerably reduce this burden on the local population of these sweet giants.

“We found that scars and injuries came mainly from anthropogenic causes, such as collisions with` `Bagans ” – traditional fishing platforms with lifting nets – and shark observation turned boats,” said Dr. Edy Setyawan, main scientist of the Conservation of the Elasmobran study correspondent.

“Relatively harmless minor abrasions were the most common. The serious injuries of natural causes such as predator attacks or boat propellers were much less common.”

The results appear in Borders in marine science.

Repotment of whale sharks

Between 2010 and 2023, Setyawan and his colleagues studied the presence of whale sharks in the bay of Cenderawasih, Kaimana, Raja Ampat and Fakfak in the seastand for the head of the bird, a region hosting a network of 26 marine zones and a hotspot for marine megafauna and tropical marine biodiversity.

Each whale shark sports its own unique scheme of white spots and scratches, which allowed scientists to use photos of researchers and scientific citizens to identify each individually. The team also recorded the date and time of each observation, its GPS contact details, sex and maturity status of the shark, size, behavior and visible injuries.

During this period, they observed a total of 268 unique whale sharks, 98% of which were seen in the bay of Cenderawasih and Kaimana. The observations of whale shark was almost exclusively seen near Bagans, where they generally fed on fish-appliaments like anchovies, herring and sprats-swimming horizontally or in a vertical position. They were also observed to suck fish directly from Bagans, who have often damaged the nets. Most of the light individuals were juveniles between four and five meters long, while 90% were men.

The team noted that 52.6% of whale sharks were resistant at least once, up to 11 years apart. The record holder was a young man who was recorded 34 times over three years.

Of the 206 sharks recorded with injuries or scars, 80.6% presented injuries attributed to causes of human manufacture, while 58.3% suffered injuries that probably come from natural causes (Note: Some people have undergone anthropogenic and natural injuries). Serious lacerations, amputations and evidence of blunt trauma of anthropogenic causes were relatively rare, observed in 17.7% of individuals. However, non -fatal abrasions were common and frequently due to whale sharks rubbing against Bagans or boats.

Other seafish

But where did women and older and sexually mature people drag? Researchers have a good idea.

“Previous Studies from surround the world have shown that adult whale sharks, especially female, prefer the deep ocean where they feed on prey like krill and schoooling fish, while the younger males stay closer to shore in shallow, plankton-rich waaters that help Them Grow Quickly, “Said Co-Author Mochamad Iqbal Herwata Putra, A Senior Manager at the Focal Species Conservation Program of the National Foundation Konservasi Indonesia.

“Our own satellite monitoring data also show that women and adults frequently use deep sea characteristics such as canyons and submarines.”

“Whale sharks in Cenderawasih Bay and Triton Bay (Kaimana) had high rates of residence and recovery, indicating that they should be considered as precious tourist assets for local communities and governments,” said Dr. Mark Erdmann, the last author and director of the study of the study of the study for Re: Wild.

Given that the majority of the observations of whale sharks took place in Bagans, at a time when the bench tourism developed, the researchers expect the risk of injury of bagans and boats increases in the future – unless simple measures are taken to protect the whale sharks more effectively.

“We are aiming to work with the protected marine areas management authorities to develop regulations to require slight modifications for bagans, including the abolition of the lively edges of boats and net frames. We think that these changes will considerably reduce the scars of whale sharks in the region,” said Erdmann.