Highly Invasive Snail Species Reported in Kerala

In News

• A tiny snail with a striking, pellucid golden-yellow shell found in the Edappally canal in Kochi has been flagged as an invasive species that could play havoc with native ecosystems. 

About

• Kerala: This is the first time that this snail has been reported in Kerala.
• Features of the newly discovered species: What makes its discovery worrying is that it plays host to worms that can cause food-borne diseases and skin itches in humans.
  • Moreover, its rapid growth rate, air-breathing capability, and tolerance to pollution make the Physella acuta a potential competitor to native fauna.
• Using a scoop net: The team recovered 23 live specimens from the Eroor part of the Edappally canal during the biodiversity impact assessment carried out for the Integrated Urban Regeneration and Water Transport System (IURWTS) in Kochi.
  • The specimens were found clinging to Ceratophyllum demersum, an invasive freshwater plant, and other gastropod species such as Indoplanorbis exustus and Racesina luteola.
  • Ceratophyllum demersum is used as a decorative plant in aquariums.

Physella acuta

• Native to North America: First described by J.P.R. Draparnaud in 1805, Physella acuta is considered native to North America but is now found in all continents except Antarctica.
• The snail was first reported in India in the early 1990s.
  • It is believed to have reached Kerala through the aquarium trade, a major vector for invasive species.
• Edappally canal: the snail had made its home in a highly polluted reach plagued by high sedimentation, untreated sewage, commercial effluents, construction wastes and a thick growth of invasive aquatic weeds.
• Characteristics: Small in size, the snail can grow to 16 mm in height and 9 mm in width. The dead, vacant shell is brownish-yellow while that of the live individuals are translucent golden-yellow with a mottled appearance. 

Issues

• Threat to global biodiversity: The study also draws attention to the threat posed by invasive species to global biodiversity; how their ability to quickly dominate new environments endangers native species, even causing serious economic loss.
• Dominating a region: They disrupt by dominating a region and disrupting the natural equilibrium.
• An alteration in the genetic pool:  is a major threat by the invasive species. 

Common features of invasive exotics include

• The ability to reproduce both asexually and sexually
• Fast growth
• Rapid reproduction
• High dispersal ability
• Tolerance of a wide range of environmental conditions
• Ability to live off of a wide range of food types

Source: TH