A section of fishermen mix high powered insecticides like Ripcord, Thiodine and Sambush with boiled rice and 'chira' (flattened rice) and spray those in the canals.

Fishes after eating those float on water and also jump on banks. The unscrupulous fishermen then catch those in large quantities.

According to sources, forest guards in a recent drive recovered 30 kilograms shrimp and a bottle of Ripcord from a fishing boat at Dhabri area. Sensing presence of forest guards, other fishermen fled away leaving their boats.

This is destroying fishes and also affecting animals, fishery and livestock officials and local people said.

Some fishermen who oppose the criminal practice, said the unscrupulous fishermen are active in Chunar, Kabodak, Kholpatua, Roymongal, Mamundo, Jamuna, Arpangashia, Kachhikata, Jhatamukho, Ansarbaria, Chandimukho, Ulobaria, Dumuria, Dhabri, Takarkhal, Dhanchebaria, Alibandha and Shapla canals in the Sundarbans.

Due to use of pesticides, waters of the rivers and canals are being polluted, they said.

"Fish resources in the Sundarbans will be extinct due to use of poison for netting fish", District Fishery Officer Krishibid Rezaul Karim said.

"Fish production is gradually declining as a good number fish species has already vanished", he added.

On contact, District Livestock Officer Mrinal Kanti Mitra said Royal Bengal Tiger, deer and other animals may fall sick as they drink the water polluted with poison.

The Sundarbans is known as a natural storehouse of different varieties of fishes. But the criminal practice by a section of fishermen is destroying fishes including fries eggs in large quantities.

The canals will be devoid of fishes soon as there will be no natural breeding if the practice continues, they said.

This is also affecting the bio-diversity, they said.

Sundarbans, the largest mangrove forest in the world, is criss-crossed by about 450 rivers and canals, which comprise about 31 per cent of the total forest area. The rivers and canals, linked with the Bay of Bengal, are fish sanctuaries and breeding places as fish feed is available in abundance there.

About 210 species of fishes including shrimp, 13 species of crab and 42 species of snails are available in the rivers and canals.

Besides being a source of foreign exchange earning through export of fishes, several thousand fishermen living in areas near the Sundarbans earn their livelihood by catching fish in these canals.

When contacted, Range Officer of Sundarbans in Satkhira said catching fish by using poison is a crime.

He said unscrupulous fishermen may carry pesticides hiding those in their boats and may use those secretly.

"There should be patrol on all rivers and canals but our manpower is too inadequate to the need", he said.

He however said, strict measures will be taken against the culprits.