Identification of threats faced by otters in Goa

Before this study there was no data available on threats faced by otters in Goa. Our project work addressed this data deficiency and has provided clarity on their conservation needs.

Six probable threats faced by otters documented through extensive field surveys and digitally mapped using Garmin GPS and QGis.

River bank construction projects

Construction along riverbanks causes habitat loss for otters. Concrete retaining walls construction along the river banks in Goa have significantly impacted Smooth-coated otters.

During our study we also recorded that traditional way of retaining wall construction using mud and stones is essential for healthy riverbank ecosystem.

High density of check dams

Check dams makes it difficult for otters to travel upstream and downstream. High density of check dams along river stretches causes otter habitat fragmentation and loss.

Check dams showed negative correlation of – 0.513 to otter presence.

Check dams impacted both Smooth-coated and Asian Small-clawed otters.

We documented 172 check dams in Goa.

Iron ore mining

Iron ore mining impacted Smooth-coated and Asian Small-clawed otters causing habitat deterioration and loss.

Iron ore mining impacted on two accounts

1. Leakage of ore waste into rivers at mining sites located near rivers

2. Increase in river traffic. Barges traveling through rivers increase challenges faced by otters.

Sand mining

Sand mining activity in forest streams destroys Asian Small-clawed otter habitat.

Sand mining in major rivers causes habitat deterioration impacting Smooth-coated otters.

Asian Small-clawed otter habitats were found to be more vulnerable to sand mining compared to Smooth-coated otters.

Fishing and retaliatory killing

One instance of retaliatory killing documented, information about two others came to light from informal discussions with fishermen. One otter died after being caught in the fishing net. These events were found to be rare.

Fishing areas showed a positive correlation of 0.445 with otter presence indicating that these areas may be a food-rich zone for otters.

Waste dumped in rivers

Waste dumped in rivers affect water quality and could consequently affect prey availability for otters.

Smooth-coated otters were impacted more by the waste as majority of their habitat lies close to human settlements.

Otters were found more tolerant to plastic waste as compared to untreated sewage or chemical waste.