The incident happened yesterday evening when Arindam Bose, general manager of Floatel, somehow fell down from the launch at Podra Ghat at Nazirgunj where a picnic was organised, a senior official of Kolkata Police said.
Search operations were conducted by the force's disaster management group till late night but they could not spot the person, he added.
"We discontinued the search because of the almost zero visibility during last night. We have began the search this morning again," the officer said.