Giant African snails invade Goa, ecology under threat | Goa News - The Times of India

Panaji: Giant African land snails (GALS), one of the world's most invasive species, are being randomly spotted in the state, as experts said this could be an indication of a local population entrenching itself in Goa's landscape.The species (Achatina fulica) likely entered Goa through transport routes. In severely infested states, such as Kerala and Karnataka, the gastropods have devastated crops and troubled farmers and residents.With a few invasive species -- like African catfish, certain plants, and ants -- already affecting native species and local ecology, the snails loom as another threat.Scientist Nandkumar Kamat reported the first specimen of this agricultural pest near Goa University's (GU) main office (TOI report, July 9, 2015) and two more 4.3-inch-long specimens nearby (TOI report, Sep 18, 2016).Stray cases of their occurrence were being reported over the years. But in recent weeks, the snails have popped up in odd places, sending the finders - piqued by their size and colour to social media for details.Andrea Costa, a lab technician at a Margao hospital, spotted a single specimen recently. "As I saw it climbing the compound wall near a drain, I thought it was a water snail," Costa said.More photos of them surfaced on social media from Bogmalo, Varca and Chicalim. A few were spotted near the chapel at Maquinez Palace, Panaji."I saw them for the first time and I wasn't aware that they were pests," said Eddie Viegas, a Bogmalo-based ship and marine consultant.It was Viegas' grandson, Romero Viegas, a kindergarten student, who first saw them and clicked photos. "I saw many snails on our compound wall after the first rains. Though less now, I still see them on our glass window, " Romero said.The increasing presence of GALS is raising a grave environmental concern. "This snail is a hermaphrodite, having both male and female reproductive organs in the same body. Their recruitment dynamics are unbelievable, as they breed fast," said Goa state biodiversity board (GSBB) member Manoj Borkar.Borkar said he had seen numerous GALS during a survey in Mysuru over a decade ago. "There were so many snails that they were getting crushed under the wheels on the roads," he said.Goa's native field snails (Pila globosa), whose population has depleted over the years, are barely thumb-sized. But the exotic species grows up to 8.6 inches, though the Bogmalo specimens were about five inches long. These giant snails are voracious and can destroy crops within a few days.Experts suggest using salt to destroy snails present in small numbers. "For a large population, tobacco decoction copper sulphate (TDCS) solution is better," said a researcher from the forest entomology department, Kerala Forest Research Institute."In Mysuru, an indigenous herbal paste is used. Chemicals are definitely a 'no-no' as they can enter the food chain," Borkar said.To preempt a catastrophic infestation of these snails, an urgent state-wide surveillance is required. Citizens can provide inputs about their presence across Goa."The effort will require close coordination between GSBB and the agriculture department, with active involvement of citizens," he said.A GSBB official said the gradual spread of the snails has been noted and will be included as a concern in Goa's state biodiversity strategy and action plan.