Sea cucumbers turn Rayong beach pink

Natural phenomenon poses no ecological threat, say marine experts

PUBLISHED : 6 Jun 2026 at 18:23

The appearance of thousands of pink sea cucumbers washed ashore on a beach in Rayong on Saturday is a rare natural phenomenon that poses no threat to the marine ecosystem, the Department of Marine and Coastal Resources (DMCR) said on Saturday.

The department said it believed the incident was caused by storm-driven waves and strong winds pushing the animals onto the shoreline, while warning tourists to avoid direct contact.

The incident occurred at Suan Son Beach in tambon Phe of Muang district of Rayong, where the creatures were strewn across several hundred metres of coastline, turning the sand a striking reddish-pink and drawing considerable attention from visitors.

Thanes Mannoi, director of the regional DMCR office, was among those at the scene, along with conservation officers and other officials.

Marine conservation officers and tourists observe pink sea cucumbers washed ashore on Suan Son Beach in Rayong on Saturday. (Photo: Suchart Chomklin Facebook page)

The marine animals were identified as sea cucumbers, specifically the pink sea cucumber, also known as the pink spiny sea cucumbers (Cercodemas anceps). The species is a marine invertebrate that lives on the seabed. It has a soft, cylindrical body resembling a cucumber or sausage, with skin covered in small bumps or spines. Their colours ranges from bright pink to reddish-orange, said the survey team.

The pink sea cucumber, also known as the pink spiny sea cucumber (Cercodemas anceps), is a marine invertebrate that lives on the seabed. It has a soft, cylindrical body resembling a cucumber or sausage, with skin covered in small bumps or spines. Their colours ranges from bright pink to reddish-orange, said the survey team.

Sea cucumbers play a crucial role in the marine ecosystem by breaking down organic matter and decomposing debris on the ocean floor. They are often described as the “cleaners of the sea”, helping maintain ecological balance and seabed health.

Researchers said the sea cucumbers found on the beach were still alive, and that the phenomenon was caused by strong wave action carrying them ashore in large numbers.

Officials stressed that the event does not negatively affect the ecosystem and is considered a rare natural occurrence. The animals are expected to return to the sea naturally when tides rise.

However, tourists and local residents are advised to refrain from approaching or touching the animals. Some sea cucumber species can release defensive substances that may cause skin irritation, particularly in people with sensitive skin.

Anyone encountering the animals is advised to contact the Forest and Marine Protection Hotline at 1362 or notify local authorities.

(Photo: Suchart Chomklin Facebook page)