Microplastics pose macro challenge for sea mammals

AHMEDABAD: The pernicious plastic plague has hit our seas and now posing a serious threat to sea life. In a first, Wildlife Institute of India (WII) scientists have recovered microplastic shreds of 0.1 mm in length, and nylon threads of 5 cm length from fishing nets from the stomachs of a two dead dugongs--an endangered sea mammal--washed ashore off Bet Dwarka and Ajad coasts in Gulf of Kutch in Gujarat last year.

Microplastics are small plastic filaments, less than five millimetres in size, which shred from plastic products, loosely discarded by us in the open, which enter our drains, rivers and finally the seas. WII recovered 30 g of microplastics from the guts of one dugong and 5g from the other, which had also eaten parts of nylon thread from fishing nets. The scientists have reported their find in their study ‘Recovery of Dugong and Their Habitat in India’.

Prof K Sivakumar of the department of endangered species management at WII, who led this study says, “Our study is probably the first which has documented presence of microplastics in marine mammals in the country.” He adds, “Two dead Dugongs, a female and a male were found in February and May 2018 respectively. Plastic microfilaments were recovered along with leaves of Halophila Beccari and Halodule uninervis after the stomach content analysis.”


He further says that in the case the Dugong consumed plastics which was found on the surface of sea and was consumed by sea cow along with sea grass.

Sivakumar who is heading the study says “The presence of plastics in the stomach in the long term may lead to loss of appetite resulting in death.”

Moreover, in case of predators like whale or dolphins, microplastics are ingested accidentally after they prey on contaminated fish. “As far as our knowledge goes there are no research papers which have established presence of microplastics in sea mammals off Indian coast,” Prof Sivakumar says.

Senior Gujarat Pollution Control Board (GPCB) officials claim that most sewage treatment plants in Indian cities and in Gujarat have no provision to separate microplastics from the sewage it receives. “Plastic microbeads in our toothpastes, cosmetics and filaments from our clothes from washing machine.”