A seasonal nudibranch phenomenon in Dahab
Every year around March, I watch the same quiet transformation happen on Dahab’s reefs. While many divers move on, our local sites suddenly come alive.
Shallow areas like Mashraba get covered in thick seasonal algae — messy, colourful, and very temporary. For a few short weeks, this algae turns the reef into a perfect feeding and breeding ground for nudibranchs, sea slugs, flatworms, shrimps, and other small invertebrates.
A simple shore night dive can be overwhelming. Just a few fin kicks from the entry point, I’ve seen dozens — sometimes hundreds — of critters on a single dive. Sea hares are everywhere, and among them appear rare seasonal species that never show up during the rest of the year.
And then, usually sometime in May, it ends. The algae disappears, most adult slugs vanish, and the reef looks ordinary again. What remains are thousands of eggs, waiting for the next cycle to begin.
This happens every year, almost unnoticed — and after watching it repeat again and again, we realised it was time to start paying proper attention. Join me for a citizen science event Dahab Sea Slag Census 2026!
Dahab Sea Slug Census FAQ
What is it?
This is more than just a nudibranch hunt. Sea Slug Census is a collaborative effort to document and map nudibranch diversity in Dahab and the surrounding area.
Together, we’re building a regional visual database — a real-time snapshot of which species 
live here, where, and when.
Participants take photos of sea slugs during dives and upload their findings to a public platform iNaturalist. Observations are identified and verified by the community — and occasionally lead to surprising discoveries.
Sharp-eyed spotters are the heart of this event — whether you’re behind a camera or just love finding tiny critters, your contribution matters.
Who is organizing this event?
Me, Andrey Ryanskiy – naturalist, citizen scientist, long-time friend of Scuba Seekers, an expert underwater photographer and publisher of field photo guides on marine life.
Irina Khlopunova – my wife, constant buddy partner, underwater photographer & videographer.
Who can join?
– Certified divers
– Underwater photographers (from action cams to macro pros)
– Experienced spotters — or those who want to become one
– Anyone passionate about marine life, even without a camera
Why April?
April brings ideal conditions: cooler water and seasonal algae blooms that often attract huge numbers of nudibranchs.
Location: Dahab, Egypt
Dates: 28 Mar 2026 – 4 Apr 2026
How to join?
The organizing team will dive with Scuba Seekers. You can book your trip via email info@scubaseekers.com — they’ll help with accommodation, transfers, and gear.
Participation fee?
There’s no additional cost — just your usual diving and lodging costs.
The goal is not profit, but knowledge-sharing and marine appreciation.
Let’s map the slugs of the Red Sea — one dive at a time
More information about Nudibranchs of the Red Sea in my book Red Sea Marine Life
