Mother fishes of different species released eggs in Halda river, the only natural fish spawning centre in South Asia, reports news agency UNB.
Fishermen have initiated collecting the eggs from Friday dawn.
Generally, mother fishes release their eggs during heavy rain in the Bengali month of Chaitra and Baishakh. But the area witnessed low rainfall this year.
The indigenous fish species including Ruhi, Mrigel, Katol and Kalbaush started releasing eggs as heavy rain with thunderbolts started on Friday evening.
The authorities concerned said that egg collection rate may exceed all previous records as they have taken various supportive initiatives.