'Pingers' to scare dolphins away

KOCHI: Ring seine fishing boats which face dolphin `menace' could soon start using pingers or noise-attacks to deter the aquatic mammals away from boats. The dolphins attack boats returning after the catch thus damaging the nets and even getting entangled in them.
The Central Institute of Fisheries Technology (CIFT) with the help of fishers in Chellanam had earlier conducted sea trials with the imported acoustic deterrent devices.The pingers were attached to the nets to deter the animals.
“It was observed that dolphins on groups of around thirty congregate in the fishing area and surround the ring seine net. They take away fishes from the net and sometimes get entangled in them,“ said Leela Edwin, head, fisheries technology division, CIFT.
Some fishers use crackers to frighten away the dolphins or patrol the fishing boat using a small boat. They also use hard objects like anchors and tyres to scare away the dolp hins but this sometimes result in their death.
Of late besides traditional methods, fishermen started using Dolphin Wall Nets around ring seine nets to keep dolphins away , but these have not been very successful.
Pinger works by emitting a sound wave signal beyond 70 KHz that is known to be in the best hearing range of most dolphin species. This sound wave is not audible to human beings.
“As of now, the three-month study has shown that dolphins can be deterred from coming near the boats. The pingers help in conservation of the species which have to be protected,“ she added.