Microplastic Bioaccumulation Threatens Marine Life Goa

Recent studies along the Goan coast reveal alarming microplastic contamination in marine fish. Scientists from the CSIR-National Institute of Oceanography and the Academy of Scientific and Innovative Research analysed 251 fishes across nine species. Their findings show the extent of plastic pollution in commercial fish and its impact on ecosystems and human health.

Microplastic Bioaccumulation Explained

Microplastics enter marine food chains when tiny organisms ingest them. Larger animals then consume these organisms. This leads to bioaccumulation, where plastic particles concentrate in predators higher up the food chain. In Goa, microplastics were found in species like mackerel, anchovy, oyster, clam, catfish, sardine, and bamboo sharks.

Study Methodology and Findings

Scientists collected fish from various ocean depths in the Mandovi estuarine system. They identified 4,871 pollutants in fish, including 3,369 plastic particles of 19 polymer types. Sediments on the sea floor showed more contamination than open water. Most plastics originated from degraded fishing gear and human wastewater.

Impact on Fish Health

Microplastics disrupt gene expression and cause oxidative stress in fish. They damage reproduction and stunt growth. Filter feeders like anchovies ingest more microplastics due to their feeding habits. Benthic species such as catfish showed the highest microplastic concentration. Digestive tracts contained more plastics than gills, indicating ingestion through prey or water.

Human Health Risks

Consuming contaminated fish may lead to immune system dysfunction, increased cancer risk, and brain toxicity in humans. The study marks the risk posed by microplastics moving up the food chain from small fish to apex predators like bamboo sharks, which humans also consume.

Microplastic Types and Sources

Four main shapes of microplastics were found – fibres (53%), fragments (30%), films (13%), and beads (4%). Their colours ranged from blue and black to red and transparent. These particles stem from fishing gear, tyre residue, e-waste, packaging, and textiles, indicating diverse pollution sources.

Ecosystem and Economic Concerns

The benthic ecosystem faces higher risks than pelagic zones. Many shellfish showed poor nutritional status due to plastic contamination. This threatens fish fitness and reduces market demand, endangering coastal livelihoods dependent on fisheries. The study calls for urgent action to reduce plastic pollution and develop eco-friendly alternatives.

Questions for UPSC:

1. Discuss the phenomenon of microplastic bioaccumulation and its impact on marine ecosystems and human health with examples.
2. Critically examine the role of estuarine ecosystems in sustaining fisheries and the threats posed by pollution and habitat degradation.
3. Explain the sources and types of marine pollution and their effects on biodiversity and coastal economies in India.
4. With suitable examples, discuss the challenges and strategies for plastic waste management and sustainable fisheries in coastal regions.

Answer Hints:

1. Discuss the phenomenon of microplastic bioaccumulation and its impact on marine ecosystems and human health with examples.

1. Microplastic bioaccumulation occurs when small organisms ingest microplastics, which then concentrate in predators higher up the food chain.
2. Examples from Goa show microplastics in species like anchovies, sardines, catfish, and apex predators such as bamboo sharks.
3. Microplastics cause oxidative stress, gene disruption, reproductive damage, and stunted growth in marine animals.
4. Microplastics move through trophic transfer, affecting pelagic and benthic species differently, with benthic species showing higher contamination.
5. Human consumption of contaminated fish may lead to immune dysfunction, cancer risk, and neurotoxicity.
6. Sources include degraded fishing gear, wastewater, tire residue, packaging, and textiles, denoting diverse pollution inputs.

2. Critically examine the role of estuarine ecosystems in sustaining fisheries and the threats posed by pollution and habitat degradation.

1. Estuaries serve as critical nurseries and feeding grounds for juvenile and adult fish, supporting biodiversity and fishery productivity.
2. Species like anchovies, sardines, and mackerel rely on estuaries for plankton feeding and form a base for larger predatory fish.
3. Pollution, especially microplastics from human settlements and fishing debris, contaminates estuarine waters and sediments.
4. Habitat degradation through sediment contamination reduces fish fitness, reproductive success, and nutritional quality.
5. Decline in fish health and populations threatens livelihoods of coastal communities dependent on estuarine fisheries.
6. Conservation of estuarine habitats is vital for sustainable fisheries and maintaining ecosystem services.

3. Explain the sources and types of marine pollution and their effects on biodiversity and coastal economies in India.

1. Marine pollution sources include degraded fishing gear, wastewater discharge, tire residues, e-waste, packaging materials, and textile fibers.
2. Microplastics are found in various shapes—fibres, fragments, films, and beads—and multiple colors indicating diverse origins.
3. Pollution leads to bioaccumulation in marine species, causing physiological stress, reduced reproduction, and poor nutritional status.
4. Biodiversity loss occurs due to habitat degradation and toxic effects on aquatic fauna and flora.
5. Declining fish populations reduce market demand, threatening coastal economies and fisherfolk livelihoods.
6. India’s coastal zones require integrated pollution control and habitat protection to safeguard marine biodiversity and economy.

4. With suitable examples, discuss the challenges and strategies for plastic waste management and sustainable fisheries in coastal regions.

1. Challenges include widespread microplastic pollution from fishing gear, urban wastewater, and lack of effective waste disposal systems.
2. Microplastics accumulate in commercial fish species like mackerel, sardine, and bamboo sharks, impacting fish health and human consumers.
3. Strategies involve improving waste management infrastructure, promoting biodegradable alternatives, and reducing single-use plastics.
4. Community awareness and stakeholder engagement are essential for reducing plastic inputs into marine environments.
5. Regulating fishing practices and protecting estuarine habitats support sustainable fisheries and reduce contamination.
6. Scientific research and monitoring help identify pollution hotspots and inform policy interventions for coastal sustainability.