A worrying incident has occurred on St. Martin's Island in Cox's Bazar

An alarming environmental change has recently been observed in the marine ecosystem surrounding St. Martin’s Island in Cox’s Bazar. Fishermen who once relied on these waters for their daily catch are now returning empty-handed, as the number of regular fish has sharply declined. Instead, fishing nets are being filled with jellyfish and jellyfish-like organisms known as gelatinous zooplankton, locally referred to as “Nuinya,” which have appeared in huge numbers.

According to fisheries experts, gelatinous zooplankton have soft, jelly-like bodies that resemble jellyfish. They are weak swimmers and cannot move effectively against ocean currents, causing them to drift and form massive swarms. Contact with human skin can cause itching, but the more serious concern lies beneath the surface. These organisms consume or destroy fish eggs, larvae, and essential food sources, disrupting the marine food chain and leading to a significant reduction in fish populations. Their rapid spread is also affecting the movement and availability of commercially important species, including hilsa.

Local fishermen are already experiencing the harsh consequences. Abu Taleb, former president of the St. Martin’s Boat Owners’ Association, said that small fish were still being caught during the first week of December. However, for the past seven to eight days, fish have virtually disappeared from the sea. Fishermen strongly believe that the excessive presence of Nuinya is the main reason behind the sudden decline in fish.

To assess the situation, a research team led by Professor Dr. Mohammad Shah Nawaz Chowdhury from the Institute of Marine Sciences at the University of Chittagong conducted a detailed survey. The team explored the island’s southwest coast and a vast marine area extending up to 12 nautical miles, covering approximately 250 square kilometers. Their observations confirmed the presence of massive swarms of gelatinous zooplankton stretching several kilometers, highlighting the severity of the ecological imbalance.

Researchers suggest that global climate change, rising sea surface temperatures, and the declining population of sea turtles—natural predators of jellyfish—may be key factors contributing to the surge in gelatinous zooplankton. This phenomenon is causing serious disruption to the marine food web and is widely viewed as a warning sign of growing instability in ocean ecosystems.

The impact is already being felt beyond the sea. Local fishermen are struggling to earn a living, fish eggs and larvae are being destroyed, and both the local economy and food security are under threat. Marine scientists warn that if the spread of gelatinous zooplankton continues unchecked, it could pose long-term risks to fishery resources and marine biodiversity around St. Martin’s Island.

Experts emphasize the urgent need for further research, continuous monitoring, and effective management strategies to identify the root causes and mitigate the damage. Without timely intervention, the rich marine environment of St. Martin’s Island—and the livelihoods of countless coastal families—could face lasting and potentially irreversible harm.