After a decade, windowpane oysters back on Tiswadi shore

Panaji: Resurfacing of the extremely endangered windowpane oysters along southwest Tiswadi’s shoreline is cheering up local fishermen and others, as the unexpected revival has occurred after more than a decade.
Not far from the better known windowpane oyster (placuna placenta) habitat of Chicalim bay, this mussel delicacy is being found in the mudflats on Zuari’s northern bank.
In the hoary past, the shellfish was found abundantly in many rivers and spots near Goa’s coastline. But in recent decades, unsustainable exploitation has triggered its disappearance from many habitats.
“We are happy that window pane oysters are being found after 10 to 15 years. But they are still small in size,” Yogesh Mangueshkar, a resident of Nauxim, Bambolim said.
In nearby Cacra, St Cruz, local fishermen are unknowingly netting some quantities of this bioresource in their ‘kantayi’ (traditional nets). “Handpicking is difficult here due to deeper waters,” Sanjay Pereira, a fisherman from Cacra said.
The Nauxim bay has been identified as an important windowpane oyster habitat, G B Sreekanth, a fisheries scientist at ICAR said. “The current high harvests may be an indication of the spawning and recruitment success due to favourable environmental conditions, as the oyster fishery depends on these very factors,” he said.
The bivalve is an economically important bivalve, as pearls are also found in some of them. But due to its endangered status, it is included in Schedule IV of Wildlife Protection Act and its extraction is banned.
“They are harvested as live shells and also in dead forms. Generally two spawning peaks are recorded for this species — October-December and April-May, though the period may vary,” Sreekanth said.
In nearby Chicalim bay, the bivalve survives only as brood stock due to unregulated harvesting by extractors from far off places. Arriving on two-wheelers, they carry away sackloads and this delays its revival by a few seasons.
Traditional fishermen in Nauxim bay, as in Chicalim, are known to be more sensitive. They have been assisting in ICAR’s documentation and opposing illegal fishing in the Zuari river. The Old Goa institution has documented about 450 fish species in Zuari bay. “This area is a fish biodiversity hotspot and illegal and indiscriminate fishing activities disturb the habitat and fish breeding cycle,” Pereira said.
“The authorities, especially Goa state biodiversity board and forest department should work out a programme to protect these last few windowpane oyster sites,” Cyril Fernandes, an activist and convenor of Chicalim Biocrusaders said.