Nearly 100 Dead Sharks Wash Up on Belgian Beaches

Since Thursday, May 28, 2026, nearly 100 dead spotted smoothhound sharks have washed ashore on the beaches of Koksijde, a coastal municipality in West Flanders, Belgium. The mass stranding has prompted a scientific investigation led by researchers from the Institute for Agriculture, Fisheries and Food Research (ILVO) and the Royal Belgian Institute of Natural Sciences (KBIN), with initial findings pointing to bycatch from coastal fisheries as the primary cause.

Background: What Happened in Koksijde?

The first dead sharks were spotted by evening walkers on May 28. By Friday, May 29, the municipality’s environmental service had collected 24 specimens. The number escalated rapidly over the weekend, reaching 80 by Sunday, May 31, and approaching 100 by Monday, June 1, according to Het Laatste Nieuws. A few additional sharks were also found in the neighboring municipality of De Panne.

All of the deceased sharks are spotted smoothhounds (Mustelus asterias), a species commonly found in the North Sea. The vast majority are pregnant adult females carrying young, according to Joanna Desmidt, a researcher at ILVO who has examined 57 of the specimens.

The Leading Hypothesis: Bycatch from Fisheries

Researchers have converged on a leading explanation: the sharks were caught as bycatch in fishing nets and then discarded back into the sea, often already dead. “I’ve seen several photos and the animals look completely intact,” Desmidt told VRT NWS. “We see no clear injuries indicating bite marks. Presumably the sharks were thrown back as bycatch from fisheries.”

Kelle Moreau, a marine biologist at KBIN, echoed this assessment: “We also assume it’s bycatch, that the animals were caught and thrown back and didn’t survive that process. But you never know if something else is going on, maybe the warm weather has something to do with it.”

Why Pregnant Females Are Particularly Vulnerable

The timing of the stranding coincides with the species’ seasonal migration pattern. Desmidt explained to HLN that the pregnant females were likely migrating to warmer coastal waters to give birth, possibly heading to the Scheldt Delta in the Netherlands — a known nursery area — or to a potential new nursery near De Panne and Koksijde. This seasonal migration brings them closer to shore and directly into fishing grounds, making them especially vulnerable to nets.

The Legal and Economic Context

Under EU regulations, fishermen are required to land all caught quota species. However, sharks and rays are exempt from this landing obligation and may be thrown back alive. If they die in the nets, they must be kept on board unless there is no quota for that species. Spotted smoothhounds have no commercial quota, meaning fishermen may legally discard them even when dead.

Desmidt noted that shark consumption is not part of local culinary culture. “If sharks were in the store, they probably wouldn’t be ordered often,” she told HLN. “That’s why this species is not popular with fishermen.” This lack of economic value means there is little incentive for fishermen to handle the species with care.

A Parallel Event in Wales

A similar mass stranding of smoothhound sharks recently occurred in Wales, United Kingdom, where hundreds washed ashore. The coincidence has raised questions about whether broader environmental factors — such as warming sea temperatures or shifting prey distributions — may be contributing to the phenomenon.

What Species Live in the North Sea?

Contrary to popular belief, several shark species inhabit the North Sea. According to HLN science expert Martijn Peters, the three most common species regularly encountered in Belgian waters are the small-spotted catshark (the most common, found year-round), the spotted smoothhound (the species involved in this stranding, found mainly from early summer to autumn), and the common smoothhound. Other species occasionally sighted include the tope shark, velvet belly lanternshark, nursehound, porbeagle, and even the massive basking shark — the second-largest fish in the world.

Public Safety: No Cause for Alarm

All experts agree that these sharks pose no danger to swimmers. The spotted smoothhound is a small, shy species that feeds on crustaceans and small fish. None of the three common North Sea shark species are aggressive toward humans.

What Happens Next?

ILVO and KBIN are continuing their investigation, examining the specimens for internal injuries, toxins, and parasites. The ELASMON project, which studies sharks and rays in the Belgian North Sea, is now investigating whether a new nursery area exists near the Belgian coast. If confirmed, this area could be mapped and potentially protected to help conserve the species.

Desmidt does not rule out more sharks washing ashore in the coming days. “Such a mass is exceptional in any case,” she told De Morgen. “As a researcher, this is a challenging assignment.”

The event highlights the ongoing challenges facing shark populations in the North Sea, where overfishing and bycatch have significantly reduced populations of many species. Sharks’ slow growth rates, late maturity, and low reproductive output make population recovery particularly difficult.