Crab migration halts access to La Herradura beach in Peru

The massive presence of crabs has led to the temporary closure of La Herradura, in the Chorillos district. The work of removing stones from the coast has transformed the ecosystem

Thousands of crabs have taken over Peru’s La Herradura Beach in the Chorrillos district, residents and tourists alike left speechless. The surprise phenomenon, which began early in February, led local authorities to make a drastic move: closing the beach to the public starting February 5th.

Temporary closure is to protect both the crustaceans, whose habit was disrupted by the recent shifts along the coastal areas, and visitors, who are not supposed to come in contact with the animals to prevent accidents and distortions of the natural migration trail.

Restoration work disrupts a sensitive environment

The peculiar crab migration indicates the ecological footprint of coastal restoration efforts undertaken by the Chorrillos Municipality in November 2024. The wetland site under the uprooted rocks had for a long time been inhabited by Ocypode gaudichaudii, a ghost crab species that specializes in camouflaging itself as part of the sand because of their coloration and size.

Over 21,000 cubic feet of rocks were removed, and new sand was filled in to increase beach accessibility to tourists. This drastic alteration, however, forced the crabs to relocate in search of a new rocky, humid habitat.

A dramatic natural phenomenon warrants closure

Since early morning of Feb. 5th, a file of crabs have been marching in single file along the beach. While attracting attention of observers, the phenomenon has also led to swift action on part of authorities to ensure that nature’s own course in the migration is preserved.

“Mayor Fernando Velasco requested that this natural phenomenon be respected. We observed many individuals with the crabs, which we attempt to stay away from when we visited the beach. We appreciate the Peruvian National Police for the assistance in asking individuals on the beach to leave. Our local business operators have complied with the measure and are removing their equipment,” stated Andrés Cruz Maza, image director for the Chorrillos Municipality, stating again that the crustaceans need to be protected.

Authorities impose bans to protect the crabs

With the help of municipal workers and the Peruvian National Police, the evacuation of tourists was carried out rapidly. The beach will remain closed until environmental and disaster risk management authorities determine that the migration process has ceased.

In addition, the state has already begun negotiating with the Callao Port Authority and the Ministry of the Environment (Minam) in order to see if the migration of the crabs could also be due to a reproductive cycle of the species.

The experts attribute the migration to habitat disruption

Early estimates indicate that the migration is a result of the removal of the rocky substrate where the crabs inhabited. This was also the view of Juan Carlos Prieto, scientific director at Oceana Peru, who emphasized the ecological disturbance caused by the coastal alteration.

It seems that (this phenomenon) is related to material extraction from the sea, specifically stones. These are where these animals live. They have lived there for a long time now, and when suddenly they no longer had that rock, they seek another rocky area to hide behind,” Prieto said in an interview.

Experts also theorized that the crab mating season could overlap with the beach restoration works, making the migration stronger. The transformation of marine currents because of the new coastline, which is now sandier, could also have hastened the movement of crabs in quest of an appropriate habitat.

Municipality stands up for environmental safeguards

In response to accusations, Chorrillos Municipality’s Andrés Cruz averred that environmental impact studies had been conducted before the restoration was undertaken. “I know we have a technical study from our expert departments. We already have the analyses and assessments. Here, the problem with the sand was not change but just sieving. Unlike other projects that pour sand on stones, we just sifted the sand that is already here,” he stated.

But eco-activist organizations argue that the early studies may have underplayed the impact on indigenous species. Despite the backlash, the municipality justifies its effort to restore one of Lima’s hallmark beaches. Popular with surfers and high-income families in the past, La Herradura had become less inviting as boulders accumulated and narrowed the path.

Balancing tourism and ecology

The rebuilding provided an estimated 21,000 cubic feet of sand, transforming the coastline from rough land to a wider, travel-accessible beach. But the change had also unsettled the regional ecosystem, generating a natural wonder that is interesting and environmentally sensitive.

The beach will be closed temporarily to create an “ecological corridor” for the crabs to migrate safely without interference from tourists. The beach will be reopened after environmental studies confirm that the migration has ceased and the ecosystem has stabilized — hopefully before the summer season is over.

For visitors, this rare spectacle is a unique reminder of the delicate balance between revitalizing natural beauty and preserving local ecosystems. Once the migration is finished and experts confirm that environmental risks are reduced, La Herradura Beach will once more be accessible to visitors.