Can we save marine drive and the coast by saving oysters?
Do you think geo tubes are the last resort to stop the Bay of Bengal from devouring the coast? Marine scientists say that by saving oysters and building artificial oyster reefs, we can save the threatened marine drive and our entire coastline from erosion
Shakera Begum, a mid-aged woman from coastal Cox’s Bazar, collects seashells from the seashore for a living. A mother of four, Shakera said her entire family is involved in this business.
They collect molluscs like oysters, snails, clams and other seashells to make jewellery like necklaces, earrings, bangles, and various other ornamental showpieces. They sell the jewellery to local retailers and wholesalers in Cox’s Bazar.
On a regular day, Shakera could hardly manage time for a long conversation. Besides her family members, she employs five to seven labourers to assist her. She is busy. But these are no regular days.
“We idle away because we do not receive work orders. We have been suffering for more than a year since the lockdown was announced last year. The only means of our livelihood is gone,” Shakera told The Business Standard.
She is not alone. Thousands like her in the Cox’s Bazar coastal areas are in trouble as their seashell businesses dried up due to the persistent lockdowns.
At the backdrop of these people suffering, however, the oysters and snails they hunt perhaps now have a breathing space. Because they are also struggling to survive due to the indiscriminate collections.
“The number of snails and oysters on Cox’s Bazar sea beach has come down to less than 20% of that found three decades ago,” Dr M Kabir Ahmed, an oceanographer, researcher and former district fisheries officer at Cox’s Bazar told TBS in an earlier interview. It means as much as 80% of oyster and snail habitats — our ecosystem engineers — have been destroyed.
Other marine scientists we spoke to didn’t give us an exact figure, but they also agreed a large number of our bivalve species are gone. And the people including those are in seashell-jewellery businesses and the local Rakhine tribe who make a living on molluscs played a role in the existential crisis of these species.
However, marine scientists and oceanographers said that with proper planning and sincere actions, it is not only these endangered species that we can save. Instead, by saving oysters and building artificial oyster reefs, we can also save the threatened marine drive and our entire coasts from a devouring sea; and re-employ the people dependent on molluscs for livelihood in environmentally sustainable businesses.
The big idea: Saving marine drive and the coast with oysters?
If the idea of saving the coasts from big waves through artificial oyster reefs sounds new, let us tell you the story of the Billion Oyster Project (BOP) campaign in New York harbour. Just like the oysters in Cox’s Bazar are endangered, the New Yorkers wiped out their oyster population in the last 100 years.
So, the BOP, with a mission to restore the oyster reefs since 2014, have so far restored 47 million live oysters, restored oysters at 15 reefs across the five boroughs.
Beyond the water-filtering power of oysters, according to the BOP, their reefs provide habitat for hundreds of species. Oyster reefs can help protect New York City from storm damage — softening the blow of large waves, reducing flooding, and preventing erosion along the shorelines.
With nearly a 570 kilometre coastline, Bangladesh is one of the major vulnerable countries in regards to climate change. The Environmental Justice Foundation says that by 2050, with a projected 50 cm rise in sea level, Bangladesh may lose approximately 11% of its land.
Besides, there lies the risk of coastal erosion. Take the marine drive, for example. This lavish project for accelerating tourism in Cox’s Bazar is now endangered by erosion. Powerful waves charging directly from the Bay of Bengal has raised questions about its future.
We talked to the marine scientists in Bangladesh to learn if BOP-style artificial oyster reefs are possible in Bangladesh and if such a plan has ever crossed their minds.
And guess what? We met a marine scientist, Dr M. Shah Nawaz Chowdhury, Associate Professor at the Institute of Marine Sciences, University of Chittagong, who did his PhD research on this. Dr Chowdhury believes that if we can build such oyster reefs, they will emerge as a natural speedbump for the fearsome waves that rattle our coast.
He spent more than a decade researching oysters and now looking forward to an opportunity to implement a pilot project of artificial oyster reefs on the coastline.
Chowdhury had an opportunity to research with Dutch scientists, who pioneered natural coastal management, for his PhD for five years. Instead of basing his research in the Netherlands, this marine scientist established a field lab with experimental setup at Kutubdia Island, Cox’s Bazar, which is one of the most critical climate-vulnerable areas.
His research found that building artificial oyster reefs in our erosion-prone coastal areas could not only save the coast from erosion but it could also facilitate an environment that increases fisheries production in the region.
Dr Chowdhury’s eco-engineering techniques received scientific recognition. He has recently led another research titled “Ecological engineering with oysters enhances coastal resilience efforts” for high impact journal ‘Ecological Engineering’ in collaboration with renowned marine scientists from across the world.
Now, Chowdhury argues that the water resources ministry and their concerned water development board (BWDB) should come forward to implement the eco-engineering idea at the pilot scale to justify the feasibility of the technology.
The conventional engineering may provide immediate protection temporarily, but their inability to adapt to changing conditions, or to self-maintenance, limits their effectiveness to prevent coastal erosion over time. Moreover, wave attacks in monsoon season cause scouring that removes the soil surrounding the dike and eventually breaks it.
So, to dissipate the wave energy, it should be broken before it hits the primary dike, and “to break the wave you can build artificial oyster reefs in the water as natural wave breakers,” said Chowdhury.
The reef will make the dams safe and reduce maintenance costs because the wave can no longer remove soil to damage the embankments or dikes. “Besides, in our research, we found that 29 centimetres of land annually can be elevated through the sedimentation process by installing oyster reefs at intertidal zones.”
“It is actually an easy process,” Chowdhury said. “Oyster spats float in water for nearly a month, but they need to settle on a strong substance where they grow and stay forever. They settle on each other’s backs, and create strong walls.”
Although a large number of molluscs are already destroyed, Dr Chowdury said that there are still plenty of oyster larvae floating in the coastal water during non-monsoon months. These larvae can be utilised to create living shorelines for coastal protection.
He is not alone in such views. Some other marine scientists we spoke to also agreed that artificial oyster reefs can indeed reduce the wave impacts and save the coast, and they are not expensive.
However, marine conservationist Mohammad Arju is sceptical about artificial oyster reefs’s capability of saving the marine drive. “Enhancing and restoring oysters reefs might be suitable adaptation mechanisms in the tidal and estuarine floodplains of Chittagong and upper Cox’s Bazar. But not in the sea along the low-hills of Ramu, Ukhiya, or Teknaf where the authorities built the Marine Drive.”
Arju, instead, opposes the marine drive project itself because “from Himchori to Teknaf, in almost all the places, they built the Marine Drive road by destroying either old beach ridges or dunes. Like river encroachment, the Marine Drive road encroached the sea,” he said, adding that “If river encroachment is illegal, how come such a mega-infrastructure is allowed to encroach the Ecologically Critical Areas on the coast? So I think the marine drive road should not be there.”
In the light of conservationist Arju’s comment, marine scientist Dr Chowdhury said that he believes oyster reefs can indeed be made in foreshore areas to protect marine drive. To avoid coastal erosion in marine drive, waves need to be dampened. But the engineering process will be different. He calls it hybrid engineering that needs to be tested.
“Oysters combined with hard engineered structure can be effective. They can settle and make the hard dike self-sustaining by multiple recruitments of oyster spats. This approach can provide better sustainability of the dike and even can grow with sea-level rise (SLR). Because the oyster reefs can outpace the SLR. We can try this approach for the marine drive in combination with hard engineering techniques that have already been tested for the eroding coast in Kutubdia Island.”
Dr Chowdhury added that “Our authorities perhaps want to solve everything by hard engineering. But you cannot just put hard engineering solutions everywhere without considering ecosystems.”
Molluscs are endangered. What is happening?
We asked Tarikul Islam, a scientific officer and head of the chemical oceanographic department at Bangladesh Oceanographic Research Institute, for his observation of why the oysters and other bivalve species are endangered.
He mentioned two primary reasons for the bane — excess collections and indiscriminate development projects.
“First of all, even if the collectors (the likes of Shakera Begum) are allowed, they should collect molluscs in a sustainable way. There should be a limit. But the way they collect, we are on the verge of the destruction of food chains and the ecosystem.”
For the reader’s discretion, there is an Environment Conservation Act that prohibits the extraction and sale of snails and oysters, but the district administration of Cox’s Bazar has been reported to be permitting the collectors and the beach businessmen of this illegal trade.
“And take the dam Navy built in Teknaf’s Sabrang area. It used to be the largest natural bed of oyster in Bangladesh. Now the dam hinders the tidal waves, and consequently, the area becomes dry in winter. Hence, the oyster bed has been destroyed. No one is doing the protection rather destroying whatever they have already.”
Dr Asaduzzaman, an assistant professor of Marine Bioresource Science at Chattogram Veterinary and Animal Sciences University echoed Tarikul as he said, “There is exploitation but no conservation of the bivalve. Besides, this field doesn’t have the necessary focus of the government.”
Is there a way to save the molluscs?
Dr Asaduzzaman has been working on molluscs (oysters, snails, clams, etc) and seaweed artificial breeding projects for a long time. He looks after nearly a dozen molluscs’ cage cultures (pilot projects) in Cox’s Bazar.
“We can increase our effort in artificial breeding of molluscs. If our efforts are successful, this will not only save the molluscs, it will create a unique opportunity for the local people to do sustainable businesses with molluscs instead of ruining their natural habitat,” he hoped.
Secondly, Dr Asaduzzaman recommends a periodic ban on collecting molluscs from November to January — the breeding season of molluscs — just like the fishing ban period.
And thirdly, echoing Dr Chowdhury, he recommends building structures for oyster-spats where they can settle. When one oyster settles, a colony would emerge that eventually becomes a strong natural wave breaker.
Back to the beginning
Mohammad Rafik, a client of Shakera Begum, is one such retailer who sells molluscs-made jewellery at the beach. A father of two school-going children, Rafik was lazing in front of his closed shop on the beach when we met him.
“My savings dried up. I am surviving the days on debt. Now only if this lockdown is lifted, we have a hope to restart, otherwise, we are in big trouble,” Rafik told us in early June.
The local Oyster-Snail Jewelleries Shop Owner Association secretary Jakir Hossain told us that there are more than 300 shoppers like Rafik on Sugandha beach alone, and nearly 15,000 people’s livelihood in the Cox’s Bazar coastal area are dependent on molluscs-made jewellery business.
All of them are in trouble thanks to Coronavirus-led lockdowns.
A month since we talked to Rafik, Covid-19 condition is nothing but on the verge of getting worse than ever. The hope that Rafik was waiting for perhaps turned into a deep depression already.
This lockdown apparently has no end.
But life must go on. Both for humans, oysters and other molluscs. A policy step in the right direction perhaps can save all these species, and create an ecosystem where humans and molluscs build an intricate web of friendship to save our coast from the damaging impact of climate change.
