TEAM HERALD
PANJIM: Amidst rising apprehensions about large scale death of clams in the catchment area of river Sal along Velim, Betul and Cutbona coast, the National Institute of Oceanography is being roped in to investigate the mysterious cause of this phenomena Forest and Environment Minister Alina Saldanha said.
Alina requested the Goa State Biodiversity board (GSBB) and other departments such as fisheries to visit the location and ascertain the cause of death of clams, locally known as ‘tisreos’ over the last two months. The phenomena is affecting on this shell fish and only along this coastal stretch. It is being assessed that this could be due to either a shell pathogen, shell fin toxin accumulated through filter feeding, stress induced mortality caused by hypoxia/anoxia or a very high biological oxygen demand in the lower water strata close to the sediments or salinity.
According to a press release issued here, Alina said that following a news report in a local daily on a mysterious phenomenon affecting shellfish in a certain area she “took suo moto cognizance of this report and requested the GSBB to carry out an urgent field visit for verification, as the livelihood of local fishermen was badly affected.”
Dr Nitin Sawant, Member Secretary of GSBB, Trupti Jadhav Scientific Officer and Dr Manoj Borkar, member of SEAC visited several sites along the River Sal as well as the Velim Panchayat met with its Sarpanch to understand the scenario. The team visited Musher fishing jetty and a clam bed site in Velim and interacted with the local fishermen who told them that since the last two months most of the clams from the clam beds were found dead and decomposed. Empty gaping shells have reappeared in the bed after a gap of nearly five years.
The team observed that this phenomenon was localized and has not been recorded from any other part of the taluka/State. The team examined the littoral zone as also the surface waters but could not find any evidence of land based discharge of contaminants/pollutants. Also it was clear through interaction and field observation that only the clams Paphia malabarica (locally known as tisreo) were being eliminated. The littoral zone had presence of diversity of gastropods, bivalves and crustaceans, further, confirming the possibilities only of a clam specific mortality inducing factor.
