Nearly 80% Of Whale Sharks In This Marine Tourism Hotspot Have Human-Caused Scars todayheadline

Gentle giants are getting scarred. A 13-year study shows that nearly four out of five whale sharks in the Bird’s Head Seascape of Indonesian Papua bear injuries from human activities, mostly through contact with fishing platforms and tourist boats. Researchers say these wounds, though often superficial, highlight how fragile the balance is between local livelihoods, tourism, and conservation in one of the ocean’s richest biodiversity hotspots.

Whale Sharks Under Pressure

Whale sharks are the largest living fish, slow-moving filter feeders that can live for decades but take up to 30 years to reach sexual maturity. They are already classified as endangered, with populations halved globally over the past 75 years. In the Indo-Pacific, losses may reach 63 percent. Recovery is glacial. Which makes the new findings all the more urgent.

“We found that scars and injuries were mainly from anthropogenic causes, such as collisions with bagans and whale shark-watching tour boats,” said Dr Edy Setyawan of the Elasmobranch Institute Indonesia.

The research, published in Frontiers in Marine Science, analyzed 13 years of sightings from Cenderawasih Bay, Kaimana, Raja Ampat, and Fakfak. Each shark was identified by its unique constellation of white spots, a fingerprint-like pattern catalogued by researchers and citizen scientists. Of 268 individuals documented, 206 showed visible scars or injuries. A full 80.6 percent of those injuries were traced to human causes. Serious propeller cuts and amputations were less common, but still present.

Bagans And The Tourist Boom

Most sharks were seen circling “bagans,” traditional wooden fishing platforms with lift nets suspended beneath them. These structures attract baitfish at night with bright lights, and whale sharks often barge in to feed, scraping against wood and nets. They also linger near bagans where tourists gather, sometimes even being hand-fed to prolong the spectacle.

Tourism has become an economic engine in this corner of Papua. In Cenderawasih Bay and Triton Bay (Kaimana), sharks were repeatedly resighted, year after year, becoming reliable attractions. One male was spotted 34 times over three years. Another was tracked across a decade. “High rates of residency and resighting indicate that they should be viewed as valuable tourism assets for local communities and governments,” said Dr Mark Erdmann, Shark Conservation Director for Re:wild.

“Whale sharks in Cenderawasih Bay and Triton Bay had high rates of residency and resighting, indicating that they should be viewed as valuable tourism assets,” said Erdmann.

A Missing Demographic

Curiously, almost all sharks observed were juvenile males, around four to five meters long. Females and older adults were scarce. That pattern matches global trends: mature females often roam the open ocean, hunting krill and schooling fish in deep-water canyons and seamounts. The nearshore nurseries are left to the boys, a kind of adolescent hangout that tourism operators have come to depend on.

Simple Fixes, Big Impact

The scars are not inevitable. Researchers stress that small changes could prevent most injuries. Removing sharp edges from bagan net frames and boat outriggers, enforcing codes of conduct for tour operators, and limiting direct feeding are all on the table. These are tweaks, not overhauls. And they could mean the difference between a superficial scrape and a serious fin amputation.

The Bird’s Head Seascape is protected by a network of 26 marine protected areas. But protection on paper is not always protection in practice. Bagans and tourism boats continue to be points of contact. For now, at least, the sharks keep coming back. But they carry the record of those encounters on their bodies, scar by scar.

Journal: Frontiers in Marine Science
DOI: 10.3389/fmars.2025.1607027