All contacts with them were lost amid reports of bad weather and rough sea conditions. (Representational)

A total of 31 fishermen on board two trawlers have gone missing in the Bay of Bengal Sunday after they had ventured into the deep seas without paying heed to the warning of authorities, a state minister said.

Thirteen other fishermen on another boat which had developed a snag and drifted into the Bangladesh waters because of inclement weather were rescued by the coast guards of India and the neighbouring country in a coordinated operation, a Defence official said in Kolkata.

The missing 31 fishermen had started from Namkhana on two trawlers - FB Nayan and FB Dashabhuja - Thursday, Sundarban Development Minister Manturam Pakhira said.

All contacts with them lost on Sunday amid reports of bad weather and rough sea conditions, he said.

After getting information about this by the West Bengal Fishermen Association, Pakhira said he asked the South 24 Parganas district authorities to arrange for a search and rescue operation.

All the 31 missing fishermen were from Kakdwip area. Fishermen were advised against venturing into the sea on that day.

Meanwhile, the Indian Coast Guard (ICG) and its Bangladesh counterpart rescued 13 crew members on board an Indian fishing boat amidst very rough sea conditions and inclement weather, the Defence official said Sunday.

The 13 crew members of fishing boat 'FB Tara Shankar', which had ventured to the Bay of Bengal from Kakdwip were rescued on Saturday amidst very rough sea conditions and inclement weather, the official said.

The boat had developed a technical problem and, on receiving the information, the ICG regional headquarters contacted the Bangladesh Coast Guard (BCG) West Zone headquarter at Mongla.

On ICG's request, one Bangladesh Naval ship on patrol was diverted and one Bangladesh Coast Guard ship sailed from Mongla harbour for search and rescue.

The Bangladesh Navy ship located the Indian boat with 13 crew on board near the Mongla Fairway Buoy in the evening of July 6 and rescued all the crew members on the boat.

Despite very high sea conditions, with swell of five to six metres, Bangladesh Naval ship took the Indian disabled boat under tow and brought it to Pussur River mouth, which is approximately 60 nautical miles eastward of the Indo-Bangladesh maritime border, where 100 more Indian fishing boats were sighted.

"These fishing boats had taken shelter due to rough seas and inclement weather," the official said adding, that the Indian disabled boat was handed over to one of the operational Indian boats for towing back to India.

As the sea was rough, all around 100 Indian fishing boats, including the disabled one under tow, were guided by the Bangladesh Naval ship for taking passage through the riverine/coastal route westward up to the Haribhanga river, the official said.

The ICG and its Bangladesh counterpart have a memorandum of understanding (MoU) followed by a 'Standard Operating Procedure' for helping each other during such incidents and making waters of north Bay of Bengal safe, he added.