ICAR-CMFRI's Intervention Improves Short-Neck Clam Stock in Kerala’s Ashtamudi Lake
Success Story
ICAR-CMFRI's Intervention Improves Short-Neck Clam Stock in Kerala’s Ashtamudi Lake
A year after the ICAR–Central Marine Fisheries Research Institute (CMFRI) launched an ambitious stock enhancement programme in Kerala’s Ashtamudi Lake, early signs of recovery in the short-neck clam (Paphia malabarica) population have begun to emerge. Field monitoring data show clear evidence of spatfall and a marginal rise in standing stock.
Sea-ranching
The encouraging signs emerged after ICAR-CMFRI released three million hatchery-produced seeds of the clam from its Vizhinjam Regional Centre into the lake in December last year under the leadership of Dr M K Anil, Principal Scientist, CMFRI. Sock depletion of this clam had been reported in Ashtamudi following the 2018 deluge and associated environmental changes. This clam species has substantial export potential, as international demand for clams continues to rise, offering significant economic opportunities for local communities.
The ranching is a sustainable solution by replenishing the clam stocks and ensuring the continuity of this critical resource in the backwaters.
ICAR-CMFRI launched this initiative as part of its ecosystem-based fisheries management approach with an aim to rebuild depleted clam stocks and secure the long-term sustainability of the lake’s unique clam fishery, under the Pradhan Mantri Matsya Smpada Yojana (PMMSY) Blue Growth Project.
The sea-ranching was made possible after ICAR-CMFRI’s year-long research efforts led to the successful development of captive breeding technology for this clam species, enabling the production of seeds for the release.
The experiment conducted simultaneously with the sea-ranching initiative for monitoring showed remarkably high survival of 80%. The ranched clams also attained a marketable size of 34 mm in just seven months, demonstrating the viability of hatchery-based stock enhancement as a management tool for the lake.
Natural Spatfall
The Shellfish Fisheries Division of ICAR-CMFRI has been closely monitoring the clam beds throughout the year. The resource-mapping survey conducted under Dr Geetha Sasikumar, Principal Scientist, confirmed widespread spatfall in October showing successful natural recruitment. The smallest spat recorded last month measured 2.38 mm, and the multi-modal length distribution observed across clam beds indicates a healthy, multi-cohort population, according to the survey.
3-Month Fishery Closure
ICAR-CMFRI cautioned that the recovery remains fragile. The spawning season that began in October makes the following months critical for the survival of juvenile clams. Accordingly, ICAR-CMFRI recommended continuation of the December–February fishery closure, a measure already backed by fishers and implemented annually by the State Fisheries Department.
