The pollution level in the Thane creek is indeed a factor that contributes to greater availability of food materials for flamingos, says N Vasudevan.What will be the consequences of infrastructure projects like MTHL and now the Mumbai-Ahmedabad Bullet train on the wetlands/creeks ecosystem?
Given the ever-growing population of Mumbai and the changing lifestyles of its citizens, it is inevitable that the city’s infrastructure undergoes upgradation from time to time. Creation of state-of-the-art infrastructure is essential even for maintaining a cleaner environment, as it will reduce our carbon footprint by avoiding traffic congestion and economising on fuel use. Every large infrastructure has to necessarily obtain a series of statutory environmental clearances. This is to ensure environmental safeguards and mitigation measures are put in place to minimise the predicted impact of the infrastructure project on the environment. For example, in particularly sensitive areas like the Thane creek, the high-speed train is designed to pass through a long and deep tunnel to make sure that the impact on the surface would be minimal. MTHL could have some impact on the flamingo population of Sewri during the construction phase, but the avian population is likely to bounce back once the work is completed. A number of mitigation measures have been identified and being put in place for both these projects.
This January saw an increase in the number of flamingos — over one lakh visited the Thane creek. There is a surge in flamingos flying to Thane creek. Is pollution and sewage flow into the creek a possible reason for this?
The pollution level in the Thane creek is indeed a factor that contributes to greater availability of food materials for flamingos, but there is no evidence that the pollution levels have shot up in recent years, resulting in a sudden surge in the flamingo population. In my opinion, the increase is attributable more to the shrinking wetlands elsewhere, which makes Mumbai one of the last and largest safe havens for the flamingos.
What have been the consequences of poor sewage management in the city? And to what extent it is affecting the ecosystem of mangroves, wetlands?
Discharge of untreated sewage into our water bodies and wetlands continues to pose a great challenge to these ecosystems, a major concern being the declining fish population. Mangroves are quite resilient to this, but only a few species like Avicennia marina can survive in this stressful environment. The result is, a drastic reduction in species diversity of mangroves. High level of pollution is also known to affect the breeding behaviour of birds, which throng these wetlands in large numbers.
According to data from the Coastal and Marine Biodiversity Centre, fishermen from the Thane creek have reported a 75 per cent dip in fish yields as compared to the eighties. What is the reason and what are we doing to improve the fishing conditions?
When the Biochemical Oxygen Demand (BOD) levels in waters are very high, it does not augur well for the health and survival of fish. Excessive nutrients in the water can lead to algal blooms, oxygen depletion and mass mortality of fish. The tolerance level of fish with respect to pollution also varies widely. In the end, only a few species with a wide range of tolerance remains. The government is contemplating a few measures to improve the water quality of the Thane creek and the coastal waters surrounding Mumbai, but it might take a few years before we see any tangible results.
Why are mangroves important for a coastal city like Mumbai?
Among all the metropolitan cities of the world, Mumbai can stake its claim to be the one with the largest mangrove cover. Mangroves are extremely important to the city as a bio-shield against extreme weather events, as a regulator of land-based pollution and as a very effective mechanism to contain floodwaters. They are very efficient in removing carbon dioxide from the atmosphere, which make them one of our best tools in fighting climate change impacts. Mangroves also act as a nursery ground for many species of fish in their juvenile stages and act as a habitat for many birds, reptiles, mammals and invertebrates. In a city starved of open spaces, mangroves provide succour with their aesthetic and recreational value. I have always felt Mumbaikars have an emotional connect with mangroves, as they look up to them as the green oases at the edge of the concrete jungle.
Tell us about the mangrove conservation efforts? Also, explain the mangrove park plan and its status?
Maharashtra is the only state in the country with a dedicated unit called ‘Mangrove Cell’ to address the issues of mangroves and marine biodiversity conservation. A task force called ‘Mumbai Mangrove Conservation Unit’ (MMCU) is created especially for Mumbai and Navi Mumbai. MMCU is doing commendable work in protecting the mangroves and in removing illegal encroachments on mangrove land. Here I must add that contrary to popular perception, not even 1 per cent of the mangroves notified as reserved forests are under any kind of encroachment. More than 15,000 hectares of mangroves on government land in the state are now notified as reserved forests. Mangrove Cell also promotes large-scale mangrove plantations and organises a number of programmes to spread awareness about mangroves and coastal marine biodiversity in the state. The Maharashtra government has also created a ‘Mangrove and Marine Biodiversity Conservation Foundation’, which is the first of its kind in the country. The foundation promotes mangrove-based livelihoods, research and capacity building and gives financial support for marine biodiversity conservation, mangrove protection, plantations and allied activities. As a result of these measures, the mangrove cover in Maharashtra has registered a whopping 63 per cent increase since the formation of Mangrove Cell.
How is the community and villagers occupying the mangrove belt involved in the conservation effort? Can you also throw some light on the hatchery at the Coastal and Marine Biodiversity Centre?
To secure people’s participation in mangrove conservation efforts, the Maharashtra government has launched a new scheme, which combines mangrove conservation with sustainable livelihood activities. Through this scheme, we are implementing livelihood activities like crab farming, mussel and oyster farming, cage culture of brackish water fish, ornamental fishery, agriculture and eco-tourism. At least 10,000 families are soon expected to become beneficiaries of the livelihood programme as well as partners in mangrove conservation.
The hatchery in the Coastal and Marine Biodiversity Centre is a central breeding facility for ornamental species like clown fish, which is in great demand in the aquarium trade. When the fish are one-month old, they will be dispatched from the hatchery to dozens of rearing units managed by self-help groups in coastal villages. After rearing them for the next two months, these SHGs can sell the fish and earn a decent income. With the combination of mangrove conservation and aquaculture, we are endeavouring to usher in a ‘blue-green revolution’ in the coastal belt of Maharashtra.
