Even though the short-neck clam is the major resource and export coming from Ashtamudi Lake in Kerala, India – the first fishery to be awarded with a a Marine Stewardship Council certification for sustainability in the country, a recent study found out that the mollusc had been subject to mistaken identity.
Further, this is not the first time when the species and genus name of this clam has been changed. At first, the species was identified as Paphia malabarica, which is also the name one could read in all hitherto published reports, including the Marine Stewardship Council’s register. Later on, as the name was proved to not be compliant with the current nomenclature, the Ashtamudi short-neck clam began to be referred to as Protapes gallus.
However, the latest in-depth taxonomic study points to the clam having been misidentified from the very beginning. According to the finding of the team of A. Arathi, R. Ravinesh and A. Biju Kumar of the Department of Aquatic Biology and Fisheries, University of Kerala, and Graham Oliver of National Museum Wales, United Kingdom, the Ashtamudi short-neck clam belongs to a totally different genus, while its rightful scientific name actually is Marcia recens. Their paper was published in the open access journal ZooKeys.
During their research, the scientists identified another edible species from Ashtamudi Lake that belongs to the Marcia genus: Marcia opima. While it could easily be mistaken for its commercially important relative thanks to a multitude of colour variations, it does not appear to contribute significantly to the export. Meanwhile, the actual species identified as Paphia malabarica (Protapes gallus) can be found in shallow coastal waters in the south of the country, but not in the studied brackishwater lake.
“No deleterious effects on the viability of the fishery have resulted from this error in identification, but from a legislative perspective applying the incorrect name to the exploited species could undermine its certification and protection,” comment the researchers.
“On the basis of this study, the species involved in the Marine Stewardship Council certification would be better considered at the generic level of Marcia or at the species level for Marcia recens, the most dominant species in the Ashtamudi Lake clam fishery zone.”
In conclusion, the authors of the study say that, “misidentification can undermine comparative biological studies and conservation, while more molecular studies are required to resolve the taxonomy of all clams involved in fishery.”
Arathi AR, Oliver PG, Ravinesh R, Kumar AB (2018) The Ashtamudi Lake short-neck clam: re-assigned to the genus Marcia H. Adams & A. Adams, 1857 (Bivalvia, Veneridae). ZooKeys 799: 1-20. https://doi.org/10.3897/zookeys.799.25829
Photos by Dr Biju Kumar.