BMC seeks wildlife clearance to translocate 18 coral colonies on coastal road project path

On September 3, the civic body had applied for the wildlife clearance and submitted a proposal to the Mangrove Cell of the Maharashtra Forest Department to translocate the 18 coral colonies. However, the clearance was stalled pending clarification and details on the site of translocation, details regarding the project justification, legal status of the project among others.

After the primary inspection, the Mangrove Cell on October 12 forwarded the application to the PCCF (Wildlife) for final clearance.

The National Institute of Oceanography (NIO), appointed to study the presence of marine biodiversity along the project area, has identified six coral species at Worli and Haji Ali: two species of the Rhizangiidae family (Oulangia and one unidentified species) with 18 colonies documented across 0.251 square metres in Worli and another species (Dendrophylliidae family) along with Rhizangiidae across 1.1 feet area at Haji Ali. The species documented are hard corals and are visible during the low tide.

Corals found across rocky patches along the Mumbai coastline are mostly fast-growing and non-reef building corals.

Translocation of corals is at a nascent stage along the Indian coastline. Many pilot projects at Lakshadweep islands, Kutch, and Tamil Nadu have been undertaken to study their survival rate, method and site of translocation, creation of high heat-resistant coral colonies among others.

In a three-year-long Sindhudurg project, corals were cultivated — fragments of corals were taken and attached to concrete frames with the help of nylon threads — and then left on ocean beds at a depth suitable for its growth.

In a project in Andaman island, since 2017, ReefWatch Marine Conservation have transplanted coral fragments onto nine artificial structures, totaling a 20 square meter area.

Roshni Yathiraj, a marine biologist for 10 years and currently a Project Manager with ReefWatch Marine Conservation said, “A coral colony is made up of many genetically identical animals called polyps. One polyp buds and replicates over and over again to create a coral colony. All you need is,a small fragment as large as finger nail with three or more healthy polyps to regrow a coral at a new location that has similar conditions as the original location of the coral. We haven’t tried the method of cultivating corals in a nursery. However, our methods include picking up naturally broken fragments found on a reef that would have otherwise died via suffocation in the sand and instantly transplanting them onto an artificial metal structure, giving them a better chance to survive. We have so far only relocated corals within a radius of 200m.”

Some experts are of the view that for a high survival rate the same environmental factors will be key. Marine biologists say coral fragments taken from one place must be transplanted in another with the same environmental factors like depth range, current flow, amount of light, and pressure.

However, a proposal was submitted to the Ministry of Environment, Forests and Climate Change to translocate corals from reefs considered as relatively more temperature-tolerant in Gujarat’s Kutch region to the ones in Lakshadweep.

A 14-year-long study titled ‘Impact of sea surface temperature anomalies on giant clam population dynamics in Lakshadweep reefs’, by researchers at the Bombay Natural History Society and Wildlife Institute of India found that there are strong indicators that corals in Lakshadweep have undergone bleaching in the last few decades.

Bleaching is a process during which corals, under stress from warm weather, expel the algae that give corals its colours and live in their tissues and produce their food. Experts have documented bleaching of the corals found along Mumbai’s coastline. “These are the same algae that give colour to corals.

Harshal Karve, a marine biologist with Mangrove Foundation who identified 11 species of corals along the Mumbai coast, said, “During our study, we had noticed bleaching of these corals during the monsoon. However, post-monsoon these species rejuvenated. We had suggested to NIO and BMC to undertake translocation post-monsoon, as at that time the colonies will be healthy.”