Charru mussel: An invasive species in Kerala

Charru mussel: An invasive species in Kerala

Part of: GS-Prelims and GS-III – Environment

In News:

• An invasive mussel native to the South and Central American coasts is spreading quickly in the backwaters of Kerala.

Key takeaways 

• It is affecting the growth of other mussel and clam species and 
• It is also threatening the livelihoods of fishermen engaged in molluscan fisheries.
• It is speculated that the mussel may have reached the Indian shores attached to ship hulls or as larval forms in ballast water discharges.
• Then, the rapid spread of the Charru mussel (Mytella strigata) may have been triggered by Cyclone Ockhi which struck the region in 2017. 
• Ashtamudi Lake, a Ramsar site in Kollam district, Kerala, remains the worst-hit.
• With a high population, it has replaced the Asian green mussel (Perna viridis) and the edible oyster Magallana bilineata (known locally as muringa).
• Externally, the Charru mussel resembles the green and brown mussels (kallummekka in Malayalam), but is much smaller in size. 
• Its colour varies from black to brown, purple or dark green.

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