Natural breeding process of carp fishes in the Halda River is being disrupted due to lack of rain this year as mother fishes have released only some sample eggs in the last three days to test the environment.
Natural breeding process of carp fishes in the River Halda is being disrupted because of a lack of rain this year as mother fishes have released only some sample eggs in the last three days to test the environment. According to people concerned, if this continues, the production of carp fishes will be greatly hampered.
They said rain is one of the driving forces for creating a suitable environment for carp mother fishes to release eggs in the Halda River. Carp fishes lay eggs in this river during the Bangla month of Chaitra (March-April) to Ashar (June-July) as heavy rains, thunderstorms, and mountain slopes make the waters of the Halda River muddy and turbulent.
The mother carps lay eggs during the period due to the presence of favourable physico-chemical factors at the bend of the river and a suitable temperature (25-28 °C). However, in recent years the effects of climate change have reduced rainfall, and increased temperatures. Salinity in the water of the Halda River is also increasing due to the rising sea level.
Dr Md Manzoorul Kibria, Halda researcher and professor of zoology at Chattogram University, told The Business Standard, “Mother carps have started to lay a few eggs from Saturday night due to the full-moon and high tides. A small amount of eggs are being caught on the nets of fishermen but all are sample eggs.”
“The temperature of the water is much higher than normal,” he said adding, “the required physico-chemical environment has not formed due to the lack of rain.” “If the mother fish lays eggs in an immature environment, it is less likely to get fish fries from those eggs. The fishermen and the country will be greatly affected if that happens. So, we are praying for rain to save us from that catastrophe,” added Manzoorul Kibria.
Veteran researcher and former professor of zoology at Chattogram University Dr Mohammad Ali Azadi said, “Mother fishes are fully ready to lay eggs. However, they are not laying eggs due to lack of a suitable environment.” Mohammad Dulal, a fisherman from Hathazari’s Garduara area, said, “I have been spending three nights on the banks of Halda. I found only 0.5 kg of eggs around 1:30 am on Sunday between Madunaghat area and Ramdash Hat area of the river.”
On the other hand, no eggs have been found in Nayakum, where the highest amount of eggs was found last year, he added. Recently, the physical and chemical parameters of 13 points of the river from Nazirhat to Madunaghat area were examined by the researchers.
Md Shafiqul Islam, Halda researcher and head of the Department of Biology, Chattogram Cantonment Public College, said, “The physical and chemical values of the water at 13 points of the river are within the standard limit. However, the water temperature is higher than normal. That is why there is a great need for thunder and rain along the mountain slopes. Only then will a suitable environment be created for the mother fish to lay eggs in the river.” Ashu Jaldash, a fisherman of Uttar Madarsha area, who has been examining eggs in Halda for 40 years, said, “All the eggs that are available now are samples. It goes without saying that there is no possibility of getting fries from these, so I have not sailed to the river yet.”