Mangrove clam (Geloina erosa)

Source: DD News

Subject: Environment

Context: The ICAR–Central Marine Fisheries Research Institute (CMFRI) has successfully achieved induced breeding of the mangrove clam under captive conditions, a rare global scientific feat.

About Mangrove clam (Geloina erosa):

What it is?

• An ecologically important bivalve (mud/mangrove clam) found in mangrove and estuarine ecosystems of South and Southeast Asia; locally called “Kandal Kakka” in northern Kerala.

Scientific name: Geloina erosa (also placed under the genus Polymesoda in some literature).

Habitat:

• Organic-rich muddy substrates of intertidal mangrove zones.

• Tolerates a wide salinity range (brackish to near-freshwater).

• Deep-burrowing, semi-infaunal species; adults often landward, juveniles more tide-independent.

Key characteristics:

• Large-sized mud clam: One of the world’s largest mangrove clams, reaching ~10 cm shell width, making it valuable both ecologically and as a food resource.

• Efficient filter feeder: Filters suspended particles and plankton from water, recycling nutrients and improving estuarine water quality.

• Distinct gonadal identification: Sexes are identified by gonad colour and structure, not external organs, aiding reproductive studies and broodstock selection.

• Ecosystem stabiliser: Burrowing behaviour stabilises sediments, enhances nutrient cycling and strengthens overall mangrove ecosystem resilience.

Method used to restore / conserve:

• Induced breeding in hatchery: CMFRI achieved controlled spawning under captive conditions, overcoming dependence on wild seed collection.

• Complete life-cycle closure: Successful rearing from embryo to larva to spat (from ~18th day) proves hatchery-scale feasibility.

• Hatchery seed production for multiple uses: Grow-out farming: Enables estuarine aquaculture with minimal external inputs. Mangrove ranching: Seeds can be released into degraded mangroves to restore natural populations. Stock enhancement: Reduces harvesting pressure on wild clam beds by replenishing natural stocks.

• Grow-out farming: Enables estuarine aquaculture with minimal external inputs.

• Mangrove ranching: Seeds can be released into degraded mangroves to restore natural populations.

• Stock enhancement: Reduces harvesting pressure on wild clam beds by replenishing natural stocks.

Significance:

• Requires minimal feed and infrastructure, making it environment-friendly and climate-resilient.

• Integrates aquaculture with ecosystem regeneration, reinforcing mangrove–benthic linkages.

• Provides an affordable high-protein seafood source for coastal and estuarine communities.