KOLLAM, 29 November 2025: A year after the ICAR–Central Marine Fisheries Research Institute (CMFRI) launched an ambitious stock enhancement programme in 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. Considering the spawning and early growth phase of the resource, CMFRI has recommended imposing a three-month fishery closure from December 1 to protect the clam during this critical period.
Sea-ranching
The encouraging signs emerged after CMFRI released three million hatchery-produced seeds of the clam from its Vizhinjam Regional Centre into the lake 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. 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.
The programme is part of CMFRI’s 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.
Natural Spatfall
The Shellfish Fisheries Division of 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
However, 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, CMFRI has recommended continuation of the December–February fishery closure, a measure already backed by fishers and implemented annually by the State Fisheries Department.
The institute also flagged environmental concerns—especially unscientific sediment extraction and broken-shell collection in spatfall zones—which can destroy seed clams before they grow. The bar mouth region near the Neendakara Bridge, identified as a closed area, has been recommended as a NO-TAKE ZONE, similar to earlier management measures. CMFRI emphasised that sustaining this resource is vital for the livelihood security of hundreds of fishers who depend on Ashtamudi Lake.
