It rained in Hathazari, and there was turbulence in the Halda. When the clock struck midnight, quite a few boats gently glided down the river.

Five of them belonged to Kamal Uddin Sawdagor. With a flicker of excitement in his eyes, Kamal swiftly commanded his boatmen to cast their nets into the depths below.

Standing at the corner of his vessel, he looked up at the sky, his heart beaming with joy, for he knew the heavens had granted him a favour this very night. Looking through the dark water, he sought a glimpse of what glistened beneath.

Kamal was not alone in his endeavour. Other boat owners, motivated by the same hopeful spirit, joined him in this timeless tradition. Their boatmen, with a graceful arc of their arms, released their nets into the embrace of the river.

Then, suddenly, a loud cheer erupted from all the boats, filling the air with elation. Their long wait and heartfelt prayers had been answered at last. The indigenous sweet water fish have started to release eggs in the river.

The combination of the full moon or the dark fortnight on Sunday, along with the prevailing favourable parameters, created the perfect conditions for this event.

— Dr Shafiqul Islam a Halda researcher and the head of the Department of Biology at Chattogram Cantonment Public College

Kamal, who has been collecting spawns from the river for around 50 years, said each of his  boats collected four buckets (approximately 40kg) of spawns from Napiter Ghona and Ramdas Munshirhat areas.

The carp fish released a huge amount of spawns this year,  compared to the past five years, he said.

END OF A LONG WAIT

With indigenous sweet water fish releasing eggs in the Halda, spawn collectors' long wait finally came to an end on midnight of June 18.

After three instances of broodfish releasing sample eggs since mid-May, the collectors had been eagerly anticipating the full-fledged spawning in the river.

The months from April to June mark a crucial period when native carp species, including rui, katla, mrigel, and kali baush, migrate from various rivers, such as the Karnaphuli and Sangu, to the Halda for releasing eggs. During this process, the mother fish rely on a delicate balance of natural conditions, including optimal temperature, water quality, strong currents, and thunderstorms, to create a favourable environment for successful egg release, as explained by experts.

This year, however, the eagerly anticipated spawning was notably delayed due to a variety of factors. Insufficient rainfall during the current season played a significant role in prolonging the wait from April to mid-June. Additionally, experts point to the impacts of climate change, overfishing of mother fish, and the degradation of the river system, all contributing to the delay.

However, the stage was set for the indigenous fish to release their spawns in the Halda when nature unleashed its might upon the river on Saturday night, as arelentless downpour and thunderbolts cascaded down the hills, accompanied by a formidable current.

According to Dr Shafiqul Islam, a Halda researcher and the head of the Department of Biology at Chattogram Cantonment Public College, the fish started releasing sample eggs on that night. As the river flowed with fervour and the elements aligned in perfect harmony, the mother fish chose Sunday midnight to release their eggs in full force.

"The dark fortnight on Sunday, along with the prevailing favourable parameters, created the perfect conditions for this event," he explained.

Hundreds of spawn collectors, patiently waiting since Sunday morning, witnessed their long-awaited moment of triumph as the carp fishes began releasing spawns at Napiter Ghona in the Halda. The spawning was observed in various other spots, including Khalifar Ghona, Gar Duara, Azimer Ghat, Baria Ghona, and Ramdas Munshir Hat areas.

Now, the once serene Halda is alive with the bustling activity of over 300 boats and more than 600 spawn collectors actively harvesting the eggs. With precision and skill, the collectors strategically position their nets at different points in the river during low tide, capturing the precious eggs of the carp mother fish.

Harun, an egg collector, expressed his excitement, saying, "I have been eagerly awaiting this moment for the past one and a half months. Finally, I can collect the eggs today [Monday]. There is a possibility of a higher egg count this time if the weather remains favourable."

Roni Das, another spawn collector, said, "Most of the 300 boats collected on average three to four buckets of spawns. Each of my boats collected four buckets of spawns."

HATCHERY CRISIS

However, the spawn collectors expressed apprehension about the challenges they may face in nurturing such a substantial amount of spawns, as there is a lack of sufficient hatcheries and traditional wells.

According to Halda researcher Dr Manzoorul Kibria, a professor at the Zoology Department of Chittagong University and the director of the Halda River Research Laboratory, an approximate total of 20,000kg spawns may have been collected this year. These spawns will now undergo a nurturing process at hatcheries for a duration of 96 hours to develop into fries.

Photo: Rajib Raihan

However, there is a pressing issue regarding the availability of sufficient hatcheries in Hathazari upazila. Currently, only five hatcheries are in operation, with four established by the government and one privately owned.

Prof Kibria emphasised that traditional wells can also serve as alternative nurturing grounds for the spawns.

In the past, Hathazari boasted a total of 168 traditional wells, but this number has significantly reduced to just 68, due to the construction of a dam in the upazila.

Hathazari UNO Shahidul Alam said, "We have encouraged them to create new wells since February, but they seemed uninterested as only 7,500kg spawns were collected last year."

"However, I would suggest the authorities concerned to establish more hatcheries in the upazila."

Each hatchery has the capacity to accommodate a maximum of 2,000kg of spawns, he added.

In 2020, a record-breaking 25,000kg eggs were collected from the Halda. However in 2021, only 8,500kg eggs were collected, and in 2022, it decreased further to 7,500kg.