The rapid development of Mumbai's coastline has spotlighted the city's marine life. Marine Life of Mumbai has documented over 500 species. Here are some of them
Published on: Jul 10, 2023 6:00 PM IST
By Prayag Arora-Desai
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Rapid development along Mumbai's coast – primarily in the form of road infrastructure – has created an uncertain future not just for fisherfolk, but also the wildlife that inhabits the space between land and sea along the city's edge. The varyingly sandy, muddy, rocky and mangrove-covered shores of Mumbai boast a plethora of organisms which are invisible to most of the city's population and have only started gaining attention in some forums after the Marine Life of Mumbai (MLoM).
Mumbai's coast is not a land parcel or a tourist destination. It is an ecosystem (Shutterstock)
"There was some preliminary research happening here in the 60s and 70s, and then later for a short while in the 1990s, but a comprehensive repository began to take shape only around 2017, with MLoM," says Shaunak Modi, director of the Coastal Conservation Foundation. The citizen science initiative has since documented over 500 species from Mumbai's shores, some of which are new to science, and many of which are new to Mumbai.
Case in point: Goniobranchus bombayanus, a colourful sea slug that was first described from Mumbai's Back Bay region in 1946, with no public records thereafter. In 2018, Modi chanced upon the creature during a shore walk at Haji Ali organised by MLoM, confirming its presence in the city after 72 years. This particular patch of the coast has undergone a radical transformation in the last three years, and the slug's habitat has now been reclaimed under tonnes of terrestrial earth for the BMC's Coastal Road Project.
"From a policy lens, marine life is seen as valuable either when it is categorised as a protected species under the Wildlife Protection Act, like corals or dolphins, or as commercially valuable fish which are exploited. Creatures like sea slugs, crabs, anemones, and cnidarians which make up a thriving ecology are ignored from this perspective. If you browse through the environmental impact assessment (EIA) reports for any of these major projects along the coast, you will not find any mention of these creatures, but construction and reclamation work will no doubt impact their ability to survive. We have to acknowledge their presence. The coast is not a land parcel or a tourist destination. It is an ecosystem,” Modi said.
Sea sponge (porifera) (Shaunak Modi)
Sea sponge (porifera)
Sea sponges, in this case porifera, are a kind of invertebrate life form. They are a primitive species, which feeds through a network of pores and channels that filter their food – bacteria, phytoplankton and other organic matter – from seawater, much like oysters and other shellfish. They are a very common site in the intertidal rock pools across Mumbai. They are resilient creatures and can regenerate in surprisingly large numbers from very tiny pieces of sponge. They can be orange, yellow, pink, red, green or brown in colour. This sea sponge was photographed at Worli sea face.
This sea slug was described from Mumbai (then Bombay) in 1946 and was named after the city. There was no record of it thereafter until 2018, when Modi re-discovered it at Haji Ali after a gap of 72 years. The Haji Ali coastline has since undergone a massive transformation due to the Coastal Road project. This Bombay Dorid was photographed at Haji Ali.
Scaled worm snail (Thylacodes sp.) (Shaunak Modi)
Scaled worm snail (Thylacodes sp.)
Not what you’d imagine a snail to look like. These animals belong to a group of gastropods known as Vermetidae. Unlike other snails, they have given up their shells for tubes which are cemented to a hard surface, usually a rock where they lead a sessile life. They feed using strings of sticky mucus which grab small prey floating in the water, much like how fishers cast a net. They are found across the city’s rocky shores. This scaled worm snail was photographed at Haji Ali.
From a genus of slugs that feed on green algae, observing these minute sea slugs can be a bit of a challenge. These tiny creatures eat green algae without digesting chloroplast (a photosynthetic pigment; a chemical component, which is used by plants to produce their own food in the presence of sunlight). The slug utilises the 'ingested' chloroplast, working as a sort of solar-powered sea slug. This photo was taken at Airoli.
Spiny sea fans (Echinogorgia sp.) (Shaunak Modi)
Spiny sea fans (Echinogorgia sp.)
Sea fans are soft corals, that is, they are not corals made up of a calcium carbonate skeleton but are instead made up of a protein called gorgonin, much like the keratin of our hair and nails. Generally, sea fans are positioned perpendicular to the water current, exposing their maximum surface area to the current, through which the translucent whitish polyps capture drifting plankton and other food particles.
There are three species of soft corals we have found in Mumbai so far of which this is the most abundant. Large colonies of it can be found on some shores – Carter Road, Haji Ali, Marine Drive – of Western Mumbai but one can only see them on extremely low tides. These were photographed at Juhu.
Golden fern hydroid (Dynamena sp.) (Shaunak Modi)
Golden fern hydroid (Dynamena sp.)
These Dynamena hydroids were photographed at the rocky shore behind the Mahalaxmi temple. Unfortunately, this extremely biodiverse shore no longer exists. It was landfilled almost entirely for the construction of the Coastal Road. Though they look like plants, these hydroids are closely related to corals, jellyfish and sea anemones. Like corals, they live in colonies comprising tiny individual 'polyps'.
Octopus (Octopus sp.) (Shaunak Modi)
Octopus (Octopus sp.)
It’s not uncommon to see octopuses on all of our shores during the winters, likely because that is when more of them come to lay their eggs. This small octopus (possibly a juvenile) was seen on a rock. But it stayed there just long enough to get a few photos before vanishing through a small crevice under it. This octopus was photographed at the Worli rocky shore, which has now been entirely lost to landfilling for the Mumbai coastal road project. This octopus was photographed at Worli Sea face.
Indian spineless cuttlefish (Sepiella inermis) (Shaunak Modi)
Indian spineless cuttlefish (Sepiella inermis)
Our shores are not just excellent habitats but also very important nursery grounds for animals that live in coastal waters, such as the Indian spineless cuttlefish. This tiny cuttlefish, still in its dark brown cuttlefish egg, was photographed on a chilly winter evening at Juhu Beach. It was almost ready to hatch and make its way out into the open water. These eggs can be commonly seen on Mumbai’s sandy shores between November to January. This creature was photographed at Juhu Beach.
Red porcelain crab (Petrolisthes boscii) (Shaunak Modi)
Red porcelain crab (Petrolisthes boscii)
These ‘crabs’ are more closely related to the lobster family of crustaceans. They can be found living under boulders across all of Mumbai’s rocky shores. What distinguishes them from ‘true crabs’ is that they have six legs, while the latter has eight, along with the longer antennae that true crabs do. This crab was photographed at Juhu.
