Mayotte · France · Channel & pass · Drift
Passe en S
A drowned riverbed cutting the outer barrier, dived as a drift
Photo: Frédéric Ducarme · CC BY-SA 4.0
Passe en S is a long, winding natural channel that cuts the eastern arc of Mayotte's outer barrier reef, with a reported maximum depth of about 65 m. Tidal water moving between the lagoon and the open ocean keeps it open and makes it a drift dive, and the pass has been a no-take fishing reserve since 1990. Napoleon wrasse, large rays, turtles and, rarely, dugongs are what the pass is known for.
Also known as Longogori, Passe de Longogori, Passe Longogori.
Where it is and how deep
12.8666° S, 45.2689° EApproximate position — the dashed circle shows where the site lies; your operator's briefing has the mooring.
The dive
The pass is dived as a drift: the same tidal water that keeps the channel open, filling the lagoon on the flood and draining it on the ebb, is the water you go in with rather than against. Its reported maximum depth is about 65 m, so the level you intend to hold is a thing to agree before you drop in rather than something to settle on the way down.
The pass carries the giant sea fan Annella mollis, a species typical of the site, and the water is rich: small reef fish everywhere, turtles in numbers, and the rarer sightings the pass is named for in Napoleon wrasse, large rays and the occasional dugong. Anchoring is banned outside the marked sites and speed inside the reserve is capped at 10 knots, so the dive is run from a boat that stays with the group rather than from a fixed mooring.
Background
The pass began as a river. When sea level stood far lower, Mayotte extended out to the line of the present outer barrier, and the channel is the drowned bed of a watercourse from that time, kept open since by the tide moving in and out of the lagoon. Since 1990 the pass and 1,400 hectares around it have been classified a full fishing reserve: fishing is banned, boat speed is capped at 10 knots, and anchoring outside the buoys or damaging coral is prohibited.
Marine life and season
- Napoleon wrasse
- Sea turtles
- Dugongs & manatees
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Fair | Fair | Fair | Good | Prime | Prime | Prime | Prime | Prime | Good | Fair | Fair |
Season follows Mayotte: Dry season (May-Oct) brings calm seas and the clearest water, coinciding with the Jul-Sep humpback whale season; the wet season (Nov-Apr) raises cyclone risk.
Know before you go
- The channel is reported to reach about 65 m, deep enough that a drift along its axis can slide past recreational limits unnoticed — set a floor before you go in.
- The pass fills and empties the lagoon with the tide, so the state of the tide decides which way the drift runs and whether it carries you towards the lagoon or the open ocean.
Photos from Passe en S
Frédéric Ducarme · CC BY-SA 4.0
Frédéric Ducarme · CC BY-SA 4.0
Quality image This image has been assessed using the Quality image guidelines and is considered a Quality image. · CC BY-SA 4.0
Dive videos
Mayotte Passe en S · Youssef Barouti on YouTube
Passe en S-bouée 9-Mayotte · AHe974 on YouTube
Questions divers ask
How deep is Passe en S?+
The pass is reported to reach about 65 m at its deepest. That is a channel depth rather than a dive profile, so the maximum depth for the dive is something to agree with the operator before the drift starts.
How do you get to Passe en S?+
By boat, about 5 nautical miles (8 km) from Mamoudzou or Petite-Terre. Anchoring is banned outside the marked sites, so dives here are run as drifts with the boat staying with the group.
Sources
- Passe en S — Wikipédia
- La Passe en S de Mayotte — blogplongee.fr
- Passe en "S", Mayotte, France — OpenStreetMap
Photo credits
- Aerial view of the dark S-shaped channel cutting through Mayotte's pale barrier reef by Frédéric Ducarme, CC BY-SA 4.0, via Wikimedia Commons
- View of the Passe en S reef pass and lagoon from the hills above Mayotte by Frédéric Ducarme, CC BY-SA 4.0, via Wikimedia Commons
- White teatfish sea cucumber on the reef bed at Passe en S by Frédéric Ducarme, CC BY-SA 4.0, via Wikimedia Commons
- Spiny oyster with orange fringed mantle on the reef wall at Passe en S by Quality image This image has been assessed using the Quality image guidelines and is considered a Quality image., CC BY-SA 4.0, via Wikimedia Commons
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