30 fish species vanish as pollution grips Sandwip Channel
Once teeming with more than 60 fish species, the Sandwip Channel, a marine passage nestled between Chattogram's Sitakunda upazila and Sandwip Island in the Bay of Bengal, has turned into an almost lifeless aquatic expanse for fish.
Researchers attribute the dwindling fish population in the channel to the combined effects of climate change and severe pollution from the world's largest ship-breaking industry and 400 other industries in Sitakunda upazila.
During the peak season, fishermen in the Sitakunda stretch of the channel, where at least 70 active ship-breaking yards are located, face a considerable drop in fish catches.
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Adding to the ecological concerns, surviving fish in the channel exhibit signs of contamination with heavy metals from the nearby ship-breaking yards.
Researchers report that the overall catch has dwindled to 20 fish species, with 30 species already disappearing from the channel.
The research also found that about 30 species of fish became irregular or are threatened with extinction more than they were 40 years ago. The disappearing fish spices include Osteogenous staenocephalus (Katamach) Scolopsis vosmeri (Nemipscol ), Eleotris fusca (Dora bailla), Uranoscopus guttatus (Faton), Dendrophysa russelli (Kala poa), Bahaba chaptis (Chapti), Pomadasys opercularis (Grunti), Polynemus sextarius (Kala tailla), Gobuis sadanandio (Nandi bailla), Gobuis melanosome (Kalthu bailla), Sphyraena fosteri (Khika), Sphyraena obtusata (Khika), Carangoides melampygus (Bungda muri), Saurida elongata(Tiktiki mach), Pricanthus macracavthus (Prica machh), Pricanthus tayenus (Prica machh), Cynoglossus macrolepidotus (Lamba kukurjib), Epinephelus lanceolatus (Bole coral), Otolithoides brunneus (Lombu fish), Cybium guttatuam (Maitta), Coilia ramkorati (Olua), Sphyraena forsteri (Dharkuta), Escualosa thoracata (Hichiri), Scomberooides commersonianus (Chapa Kori), Priacanthus tayenus (Pari Machh), Polynemus paradiseus (Hriska mach), Carangoides malabaricus (Lahmuri mach) Anodontostoma chacunda (Koiputi mach), Arius thalassinus (Kata mach), and Apocryptes serperaster (Dora chau mach).
Regarding the industries near the channel, Ferdaus Anwar, deputy director of the Department of Environment Chattogram office, said not all the industries in Sitakunda discharge liquid waste. "Those who do have an Effluent Treatment Plants (ETP)."
He, however, declined to provide additional comments, stating, "Without checking or testing, I cannot offer further insights on the issue."
Plight of fishermen
During a visit to the Sitakunda coast and various fishermen villages, The Business Standard observed that contaminated water of different hues, discharged by industries, flows into the channel through at least seven canals in Bhatiary, Shonaichhari, and Kumira union of the upazila.
Fishermen in the area lamented the lack of oversight on channel pollution, resulting in the depletion of the fish population.
Horilal Jaladas, a 50-year-old fisherman from Jahanbad in Sitakunda upazila, has spent 35 years netting fish in the Sandwip Channel. In the early years, he would return with a boat overflowing with a diverse catch.
However, the rise of the ship-breaking industry in the late 1980s altered the landscape. Nowadays, the fish he catches barely cover the fuel costs required for deep-sea fishing.
"We used to harvest 20 to 30 fish species year-round, with the Hilsa season being a lucrative festival during the monsoon. Those earnings helped us clear loans from the off-season," Horilal reminisced.
However, today Horilal and other fishermen face substantial losses during the fishing season, struggling to repay their debts.
Kamal Uddin, fisheries officer of Sitakunda Fisheries Office, highlighted the industrial challenges in Sitakunda, an area housing over 400 heavy and medium industries and 60 ship-breaking yards.
He noted that these industries discharge untreated waste into canals, heavily contaminating the channel's water.
Kamal Uddin said, "Over the past 30 years, industrial pollution has severely impacted the channel's biodiversity, compelling fish migration to adjacent channels and the Bay of Bengal. Fisheries data from the last decade indicate a decline in catches."
Approximately 6,000 fishermen, along with 12,000 family members in 26 fishing villages, face hardship due to meagre catches, he added.
"The fisheries office is not only offering government aid but also striving to secure alternative employment opportunities for these struggling fishermen to help them survive," the official said.
Impacts of climate and industrialisation
The research paper, "Changing Pattern of Heavy Metals Accumulation in Ship-breaking Area Over 40 Years and Its Impact on Fish Diversity in Adjacent Areas of Bangladesh," identified the ship-breaking industry as the source of channel pollution through heavy metal dumping.
High concentrations of metals such as iron, lead, chromium, manganese, zinc, nickel, copper, cadmium, and mercury were discovered in sediment collected from the ship-breaking area. The analysis showed a two to eightfold increase in selected heavy metals from 1980 to 2019.
In another study, titled "Present Status of Coastal Fisheries in Sitakunda Coast with Special Reference to Climate Change and Fish Catch," a connection was established between diminishing fisheries resources and both changing climate and industrial pollution.
The research noted that the average temperature in Sitakunda rose, and annual rainfall decreased over the 30-year span from 1980 to 2010 due to climate change.
Additionally, the study revealed a decline in fish catch per Set Bag Net (SBN) and the disappearance of approximately 30 fish species and fins from the channel over the past 40 years.
Dr M Muslem Uddin, associate professor of oceanography at the University of Chittagong, told TBS that rising temperature, reduced rainfall, industrial pollution, and increased acidity have collectively elevated the acidity and decreased oxygen levels in the channel water.
These factors have significantly disrupted the channel's biodiversity, compelling fish migration to the adjacent Bay of Bengal, he said.
Furthermore, the escalating sea level is eroding the mangrove forest at the Sitakunda coast, destroying the fishes' habitat.
The water flowing from hilly streams through 16 canals in the upazila, once abundant with phytoplankton and zooplankton—the favoured food for fishes—now suffers contamination from industries, rendering it inhospitable for these essential organisms. This ecological disruption has nearly annihilated the channel's ecosystem.
Dr Muslem Uddin also highlighted oil spillage from the ship-breaking industry and vessels navigating the channel as additional factors contributing to the channel's deteriorating biodiversity.
How to reverse course?
Researchers have highlighted the limited potential for reversing the situation, emphasising the need to address industrial pollution rather than the impact of climate change.
Dr Muslem Uddin stressed the importance of economic development without compromising the environment. He suggested transforming ship-breaking yards into "Green Yards," adhering strictly to international conventions to prevent pollution.
Additionally, he called for stringent monitoring of other industries to ensure they do not discharge untreated waste into canals leading to the channel.
