Bangkok: A survey of the upper Gulf of Thailand has identified over 40 Irrawaddy dolphins near the mouth of the Bang Pakong River, prompting authorities to expedite the implementation of an intensive conservation plan.
According to Thai News Agency, the plan includes testing the "Pinger," a sound transmitter aimed at reducing dolphin entanglement in fishing gear, and monitoring water quality and microplastic contamination across six river mouth areas in six provinces. This initiative aims to establish a protective environment for these rare marine creatures.
Dr. Pinsak Suraswadi, Director-General of the Department of Marine and Coastal Resources, stated that the survey was conducted in alignment with the policy of Dr. Raveewan Phuridej, Permanent Secretary of the Ministry of Natural Resources and Environment. The department carried out a survey of rare and endangered marine animals from January 12-16, 2026, using direct counting methods and monitored the dolphins' response to the Pinger transducer, which operates in the 50-120 kHz frequency range. This survey covered areas in Chachoengsao and Chonburi provinces.
The survey reported 35-40 Irrawaddy dolphins (Orcaella brevirostris) displaying group foraging and reproductive behaviors involving 5-18 individuals within a 3-5 kilometer radius of the Bang Pakong River estuary. Continuous observation of dolphin behavior was facilitated by drones. The Pinger device is considered a crucial innovation for reducing entanglement in fishing gear, which poses a significant threat to these dolphins.
In addition, environmental assessments were carried out by collecting seawater and sediment samples to test for microplastic contamination and water quality in areas susceptible to marine pollution accumulation. These assessments covered six locations: the mouth of the Bang Pakong River in Chachoengsao Province, Khlong Tamru in Samut Prakan Province, the Bang Khun Thian coastline in Bangkok, the mouth of the Tha Chin River in Samut Sakhon Province, the mouth of the Mae Klong River in Samut Songkhram Province, and the coastline of Laem Luang in Phetchaburi Province. Sediment samples from Laem Luang were specifically collected for microplastic testing, and temperature loggers were installed at the mouths of the Bang Pakong, Tha Chin, and Mae Klong rivers to evaluate environmental quality trends.
Initial findings suggest that overall seawater quality meets the standards for Category 3 (aquaculture) and Category 4 (recreation) as per the Pollution Control Department's 2021 criteria, except at the mouth of the Tha Chin River, where dissolved oxygen levels were below standard. The Department plans to closely monitor this situation.
This survey is viewed as a positive indicator of the health of coastal ecosystems in the upper Gulf of Thailand and will contribute valuable data for the sustainable conservation of rare marine animals through long-term policy management.