Sea turtles along Karnataka’s coastline are losing their nesting habitats due to increasing coastal erosion, seawall construction, and climate-induced extreme weather events, according to a new study by the ICAR–Central Marine Fisheries Research Institute (CMFRI).
The study, published in Regional Studies in Marine Science highlights how human interventions and changing ocean conditions are shrinking crucial nesting grounds. More than 52% of local fishermen surveyed attributed the decline in turtle nesting to sea erosion and the construction of seawalls along the coast.
Led by Dr. Bindu Sulochanan from CMFRI Mangaluru Regional Centre, the decade-long research combined field observations, marine productivity data, coastal water quality assessments, vessel traffic mapping, and traditional ecological knowledge to assess the degradation of turtle habitats.
Between 2013 and 2023, key nesting beaches at Panambur, Yermal, Kirimanjeshwara, and Bhatkal witnessed a marked narrowing of sandy stretches despite protective seawalls. The study found that these seawalls, while built to safeguard the coastline, have worsened erosion in several areas. Researchers suggested adopting “soft engineering” alternatives like living shorelines that use native vegetation and natural materials to stabilise coasts in an ecologically sustainable way.
The team also called for curbing artificial lighting near nesting beaches, which disorients hatchlings, and improving coastal waste management to stop litter carried by rivers and drains from reaching turtle habitats.
“Turtle strandings—mostly olive ridleys—were recorded along the coast between 2021 and 2024, with some rescued and released by fishermen,” said Dr. Sulochanan. She noted that vessel traffic data showed over half of fishing boats moved at low speeds, opening up the potential for fishermen to become conservation partners through awareness and incentive programmes.
The study further linked rising sea surface temperatures and recurring El Niño events to changes in coastal productivity, altering the turtles’ foraging zones. Karnataka’s nearshore waters, though rich in marine life, are becoming increasingly vulnerable to sediment loss and storm surges, with 88 storms affecting India between 2012 and 2023.
“The interplay of erosion, seawalls, and climate change poses a compounded threat to both sea turtles and coastal communities,” Dr. Sulochanan said. She added that conservation efforts must integrate habitat restoration, local community participation, and adaptive coastal engineering.
The researchers urged authorities to designate protected nesting zones, promote community-led initiatives like solar fish drying and net-mending to maintain clean beaches, and preserve coastal wetlands that act as natural shields against erosion and pollution.
The findings underscore the urgent need for a balanced approach that protects both the coast and its marine life from human and climate pressures.