On International Coastal Cleanup Day last weekend, communities across Sri Lanka participated in efforts to clear plastic waste, fishing debris, and other marine litter from popular beaches. While such activities highlight growing public concern over visible pollution, marine experts and locals have noted a more subtle yet significant change: a marked decline in the presence and variety of seashells along the coastline.
Many older Sri Lankans recall childhood memories of gathering abundant and diverse shells such as cowries, cone shells, murex, and chanks on beaches. Today, those experiences are diminishing. Manel Ramvayala, a 59-year-old resident of Wattala who regularly cleans a nearby beach, says the variety and quantity of shells have noticeably decreased over the years. “We used to find many different large shells, but now they are mostly missing,” he said.
Seashells represent the outer remains of marine mollusks—animals that play crucial ecological roles in coastal environments. Sri Lanka's waters host hundreds of mollusk species, including gastropods like sea snails and bivalves such as clams and oysters. These animals inhabit diverse habitats from coral reefs and rocky shores to seagrass beds and mangroves. Their shells, primarily composed of calcium carbonate, often wash ashore, reflecting the health of the marine ecosystems from which they originate.
Dr. Malik Fernando, an expert on Sri Lankan marine mollusks, explains that shell distribution on beaches is influenced by factors including local marine habitats and ocean currents. Most shells found on beaches belong to bivalves, which live in shallow coastal zones and leave behind durable shells upon death that waves and tides transport ashore. In contrast, larger shells like cowries tend not to wash onto beaches naturally and are often collected directly by divers.
The recent reduction in visible shells, experts say, may stem from multiple causes. Overharvesting driven by demand for decorative shells, habitat destruction, pollution, by-catch in fisheries, and changes from climate impacts have all contributed. Former National Aquatic Resources Research and Development Agency scientist Arian Rajasuriya noted that prized shells such as tiger cowries, once common, have become rare due to collection and environmental pressures.
Fisheries by-catch is a significant concern as bottom-set nets often capture non-target marine mollusks that are discarded dead. Samantha Gunasekara, chairman of the Marine Environment Protection Authority and former head of Sri Lanka Customs’ Biodiversity Protection Unit, emphasized that while some species like chank require export licenses, illegal and undersized shell shipments continue to be seized. He also highlighted how modern fishing techniques, including mechanized beach seine nets, have increased by-catch volumes in regions such as Mannar, Kalpitiya, and the Eastern Province, further depleting mollusk populations.
The degradation of coral reefs, critical habitats for many larger mollusk species, coupled with ocean warming linked to climate change, threatens larval development and survival rates. Rajasuriya cautioned that these combined stressors put further strain on already vulnerable populations.
Experts stress that effective conservation will require strengthened enforcement of existing protections, sustainable fishing practices, habitat management, and public education. Gunasekara underscored the broader implication of these trends: overexploitation and habitat damage reflect a failure to value natural resources adequately, reinforcing the need for a green transition in Sri Lanka’s marine governance.
Given that millions of Sri Lankans depend on healthy oceans for food, employment, and coastal protection, maintaining marine biodiversity and ecosystem services is essential. Sustainable use of marine resources involves limiting unnecessary extraction, minimizing waste, safeguarding habitats, and allowing ecosystems to recover.
“The sea is not an endless resource,” Gunasekara remarked. “Its health must be central to Sri Lanka’s Green Transition if we are to secure a sustainable future.”