CMLRE Study Confirms Major Ecological Impact of ELSA 3 Shipwreck in Arabian Sea

The sinking of the ELSA 3 cargo vessel in the south-eastern Arabian Sea has triggered serious ecological concerns, according to a comprehensive scientific investigation carried out by the Centre for Marine Living Resources and Ecology (CMLRE) under the Ministry of Earth Sciences (MoES). The study, conducted between 2nd and 12th June 2025 onboard the research vessel FORV Sagar Sampada, assessed the immediate and ongoing impacts of the shipwreck on the region’s marine environment and biodiversity.

The Shipwreck and Oil Cargo

ELSA 3 went down at coordinates 09°18.76’N and 76°08.22’E, at a depth of 54 meters. Official records confirmed that the vessel was carrying 367 tonnes of furnace oil and 84 tonnes of low-sulphur diesel at the time of sinking. Such a large quantity of petroleum products raised fears of widespread contamination, particularly given the region’s role as a spawning ground for many commercially important fish species.

Oil Slick and Water Contamination

Initial surveys revealed a visible oil slick stretching nearly two square miles around the wreck. Chemical analyses confirmed the presence of petroleum hydrocarbons at elevated concentrations. Interestingly, the pollutants did not remain static; during calm sea conditions they concentrated at mid-depths, whereas subsequent surveys showed higher concentrations at the surface due to oceanic mixing and turbulence.

The analysis of Polyaromatic Hydrocarbons (PAHs)—toxic compounds found in oil—identified harmful fractions such as naphthalene, fluorene, anthracene, phenanthrene, fluoranthene, and pyrene. Elevated naphthalene levels, often considered a clear marker of human-induced oil contamination, pointed to ongoing leakage from the ship’s fuel compartments.

Heavy Metals and Sediment Pollution

Beyond hydrocarbons, trace metals commonly linked to petroleum—nickel, copper, lead, and vanadium—were detected in water and sediments near the wreck site. This indicates that the contamination is not only affecting the water column but also the seabed environment, with potential long-term implications for benthic ecosystems and fisheries.

Biological Impacts: From Plankton to Fish Larvae

The ecological effects of the spill were visible across the marine food chain:

• Zooplankton samples contained elevated levels of petroleum pollutants, confirming widespread bioaccumulation.

• Fish eggs and larvae collected from the area showed signs of decay and mortality, coinciding with the southwest monsoon season, a critical period for spawning and recruitment of species such as sardines, mackerel, and anchovies.

• The loss of these early life stages poses a serious threat to fisheries resources in the Arabian Sea.

Seafloor and Benthic Stress

On the seabed, benthic organisms—the key indicators of sediment health—showed dramatic changes. Sensitive species disappeared within days of the incident, replaced by only pollution-tolerant worms and bivalves, a clear sign of acute ecological stress and habitat degradation.

Microbial Community Response

Metagenomic analyses revealed a surge in hydrocarbon-degrading bacteria such as Neptunomonas acidivorans, Halomonas tabrizica, and Acinetobacter baumannii. While their presence points to the ocean’s natural ability to break down hydrocarbons, it also underscores the scale of contamination near the wreck site.

Oceanographic Factors and Persistence of Oil

Despite strong south-westerly winds and southward-flowing surface currents during the survey period, oil residues remained concentrated near the wreck even after eight days, suggesting continued leakage. This persistence highlights the need for immediate intervention to seal the wreck’s fuel compartments.

Impacts on Higher Marine Life

The effects were not limited to microorganisms and fish. A Brown Noddy seabird (Anous stolidus) was observed on the wreck, showing repeated preening behavior—a typical response to oil-contaminated feathers. Such incidents indicate the spill’s broader impact on marine birds and higher trophic organisms.

Conclusions and Recommendations

The findings confirm that the ELSA 3 shipwreck has caused significant ecological disruption, affecting:

• Water quality and chemical balance

• Plankton populations and the marine food chain

• Fish eggs, larvae, and fisheries potential

• Seafloor and benthic ecosystems

• Marine birds and higher fauna

Given the persistence of oil and heavy metals, the study strongly recommends:

1. Immediate sealing of the wreck’s fuel compartments to prevent continued leakage.

2. Long-term monitoring of the affected area to track ecological recovery.

3. Fisheries management interventions to safeguard livelihoods dependent on the Arabian Sea.

4. Strengthened disaster preparedness protocols for future shipping incidents in ecologically sensitive waters.

The incident serves as a stark reminder of the fragility of marine ecosystems and the urgent need for proactive measures to protect ocean health, particularly in regions critical for India’s fisheries and coastal communities.