Microplastics pollution threatens Goa’s estuarine fisheries, human consumers

For Preliminary Examination:  Current events of national and international Significance like Plastic Pollution

For Mains Examination: GS III - Environment and Ecology

Context:

Researchers identified 4,871 polluting particles, of which 3,369 particles were plastic polymers of 19 types. Researchers found more contamination on the sea floor than in open water. Particles were mainly from fishing material and wastewater

Read about:

Single Plastic Use

Microplastic Pollution

Key takeaways:

• Microplastics present in aquatic environments can be consumed by microscopic organisms, which are then eaten by progressively larger species. This causes microplastics to build up in the bodies of animals higher in the food chain, increasing their overall exposure and toxic effects — a process known as bioaccumulation.
• To investigate how microplastics accumulate along the Goan coastline, researchers from the CSIR–National Institute of Oceanography (Goa) and the Academy of Scientific and Innovative Research (Ghaziabad) examined the feeding habits and habitats of 251 fish belonging to nine species of finfish and shellfish.
• Their samples included economically important species such as mackerel, anchovy, oyster, clam, catfish, and sardine, collected from varying ocean depths.
• Their findings, published in Environmental Research (August edition), identified 4,871 foreign particles within the sampled fish, out of which 3,369 were confirmed as plastic polymers representing 19 distinct types.
• The researchers observed higher concentrations of these particles on the sea floor and bottom sediments (benthic region) compared to the open-water (pelagic zone).
• Most of the detected plastics originated from discarded fishing gear and wastewater runoff from human settlements.
• According to the study, affected fish showed signs of genetic disruption, oxidative stress, reproductive impairment, and stunted growth. Humans consuming such fish could also face immune system disturbances, increased cancer risk, and neurological toxicity.
• Fishing activities around Goa are mainly concentrated in estuaries, which are ecologically vital zones supporting young fish and providing feeding areas for mature ones. These estuaries are rich in finfish and shellfish, species that are popular in Indian diets for being nutritious, affordable, and easily available.
• Small pelagic species such as anchovies, sardines, and mackerel are central to estuarine food chains. They feed on plankton and attract larger predators. As filter feeders, they trap particles from surrounding water, making them especially prone to microplastic ingestion.
• These smaller fish are preyed upon by larger species, including elasmobranchs like sharks, which dwell in coastal shelf waters. Through this trophic transfer, microplastics gradually travel up the food web, ultimately reaching apex predators and humans.
• The study focused on fish from the Mandovi estuarine system, part of the Mandovi–Zuari network