This citizen science initiative aims to explore and document tide pool ecosystems along Indian coast

A moment from a previous shorewalk in in the city

With nearly 16 km of accessible beaches, it's not hard to find a Mumbaikar who swears by the therapeutic effects of sitting by the city's shoreline; some regulars might even call it ‘home'. Marine life expert Shaunak Modi breaks our bubble - the real residents, he says, are not the hurried Mumbaikars finding respite in the beaches, but more than 600 species of sea slugs, snails and octopus that have quietly inhabited the intertidal zones (see box) on the shores since time immemorial. Yet, they remain largely under-researched. The India Intertidal BioBlitz 2025, a large-scale collaborative citizen initiative, is set to change that.

Spread across 10 days, to account for fluctuating tidal activity across the coast, the effort will be joined by naturalists from Rushikonda and Thotlakonda beaches in Andhra Pradesh, Karwar in Karnataka, Baga and Bambolim in Goa, Sitapur and Govind Nagar beaches in the Andamans, Nandgaon and Vengurla in Konkan, Minicoy and Kavaratti in Lakshadweep and other locations in addition to local efforts at the Juhu, Nepean Sea Road, Haji Ali and Carter Road shores in Mumbai. "The end goal is to get a snapshot of the existing species and the condition of the tide pools to help us plan our conservation efforts. It's the first step towards something larger in scale akin to the popular nationwide bird counts," says Modi.

Those interested in joining hands with the initiative can register through a form where they must faithfully declare their level of expertise in the field. The log of all sighted creatures will be available on the online worldwide wildlife repository, iNaturalist. Experts recommend not stepping out in intertidal zones without professional guidance to avoid unforeseen accidents and harm to fragile marine ecosystems.

The tide pool trail

Juhu Koliwada
This spot near Granth Book Store is the easiest location for first-timers and children joining expert-led marine walks. During low tide, you'd be lucky if you spot the Coral star (left), Orange striped hermit crab, Octopus and Pearly sea anemones.

Carter Road
The sightings at this muddy and rocky shore include Feather duster worm (right), Scribbled nudibranchs, and the False pillow coral.

Haji Ali
Haji Ali's rocky shore is where the rare Glossodoris Bombayana sea slug (below), was sighted in 2018, nearly 18 years after it was first identified in 1946 and suitably named after Mumbai.

PICS COURTESY/SACHIN RANE

Nepean Sea Road
The Priyadarshini Park shore is famous for colourful sea slugs. The vibrant Star-tentacled bornella (above) and Verril's encrusting cup coral stand out among other creatures like Violet zoanthids and Anemones.

Pearly sea anemone

What are intertidal zones and tide pools?
Intertidal zones are the areas between the high tide mark and the low tide mark on any shore. When the tide recedes from high to low, naturally formed crevices and burrows in the intertidal zones trap marine life like oysters, molluscs, sea stars and slugs, giving rise to tide pools. Most tide pools host a mixed bag of lesser-known marine creatures, many of them visible to the naked eye.

Tidy up, Mumbai
In addition to climate change and rising sea levels, Modi states coastal development projects and the subsequent release of pollutants into the sea as a major threat to the intertidal ecosystems.

Shaunak Modi

The habitat in Mumbai's intertidal zones isn't as rich as its southern counterparts in the Konkan belt, but there is still time to save them, he suggests. "Conservation can only speed up when there is documentation on what is there to save in the tidepools. This initiative is step one in that direction," Modi shares.

Inputs by Sachin Rane, naturalist