Swarna Prava Mohapatra
Climate change is having disastrous impacts on our ecosystem. Various remedial actions are undertaken across the world, like widespread planting of mangroves, which act as bio-guards along the coastal region. The need to protect the marine ecosystem is also important, and this is done through restoration of the coral reef. Amid these, one of the main frontiers lies in the coastal platform known as seagrass — a marine flowering plant that is often considered as ‘meadows’ of the coastal area.
The seagrass ecosytem provides supporting, regulating, provisioning and cultural services. It plays a pivotal role in combating climate change through carbon storage and sequestration. Comprising a small fraction of the world’s ocean area, seagrass meadows are responsible for three to 20 per cent of the global carbon sequestration. The carbon accumulation in the sediment increases to a range of 4.2 – 8.4 pg C.
The rich organic productivity beneath the seagrass meadows harbours the marine biotope. It supports the inshore fisheries by making available the rich abundance and assemblage of fish and crustacean communities and fish’s life cycle stages. The leaves of seagrass favour the retention of suspended particles in the water column, they behaving like a filter for the coastal waters, giving some level of transparency to the water. The extensive rhizome system, roots and leafy canopy stabilizes the sediment over which seagrass grows, minimizing the resuspension of the sediment by wave and current actions.
Dugongs (Dugong dugon), the legendary seacows, also known as ‘farmers of seagrass’, are the only herbivorous marine mammal on earth which feeds exclusively on seagrass. They can eat up to 40kg of seagrass every day. The constant trimming thus results in regenerating a healthier seagrass ecosystem which can further boost other ecosystem activities. Dugongs help maintain seagrass habitats that are also important for other species such as turtles and offer immense support towards reviving the culture of many coastal communities.
The dugong is currently listed as vulnerable by the International Union for the Conservation of Nature (IUCN). The number of dugongs has hit a sorry figure, dwindling to nearly 200 individuals, according to a report by Wildlife Institute of India (WWI).
The current difficult scenario of dugongs can be attributed to several human-related disturbances. Human actions provide a series of environmental, biological and climatological stressors, delivering locally specific impacts. On the one hand, eutrophication, thermal pollution, coastal infrastructure developments and overfishing pose serious threats to seagrass meadows. On the other, the fish trawling activities sweep out the sea. Boat traffic, ghost nets and plastic pollution have caused the declining trend in the figures of the dugongs.
With the dugongs acting as the farmers of seagrass habitats, their role in seagrass maintenance is indispensable. The key to the restoration of healthier seagrass lies in the day-to-day grazing. The latter phenomenon leaves the required gaps in between the seagrass that facilitate further growth and makes the seagrass habitats conducive for breeding of fishes. These species do not confer benefit directly, but provide ample opportunities for livelihood of fishermen. The estimated value of a dugong and its habitat is put at Rs 2 crore per year in India. The conservation purpose of the crucial species is further necessitated by the fact of its slow reproductive cycle, it producing a single calf in a year. The curtailed number in case of dugongs has resulted in failure of experimentation, their breeding in captivity and translocation to other viable locations. So, the best option lies in spreading awareness regarding the conservation purpose in the existing habitat. Initiatives like prohibition of trawler fishing within the territorial waters up to 12 nautical miles, fishing other fish and shellfish other than dugong may be encouraged. It is very necessary to imprint the need of sea cows for the future in the minds of the fishermen so that a harmony can be established between nature and man. This year, let’s make a pledge for dugong, “Save dugong, save livelihood.”