Zeeland · Netherlands · Muck & macro
Bergse Diepsluis
Spring cuttlefish in water with almost no current
Photo: Andra Waagmeester · CC0
The Bergse Diepsluis, known to local divers as the Oesterdam or the Thoolse Gat, sits in a tributary of the Oosterschelde where the tidal current barely reaches. That makes it the gentle option in an area that mostly is not: shallow, sheltered, and thick with anemones, crustaceans and other invertebrates the whole year round.
Also known as Oesterdam, Thoolse Gat.
Where it is and how deep
51.5172° N, 4.1737° EPublished position for this site.
The dive
The appeal is how little the site asks of you. Its position on a tributary of the Oosterschelde leaves little to no tidal current, so there is no slack window to hit and no reason to hurry, and the bottom stops at 19 metres. Average visibility is around 4 metres, with the monthly logs running from 2 to 5, which makes this a close-range dive worked slowly along the structure.
Anemones, crustaceans and other invertebrates are here in numbers the whole year round, and they are what most dives come back with. Sea bass hold under the platform and seahorses turn up as well. Spring adds the cuttlefish: divers here wait for the water to reach 12°C before expecting them, the same window that fills the Zeelandbrug in May and June. The water itself runs from 5°C in winter to 21°C in July.
Marine life and season
- Octopus & cuttlefish
- Macro critters
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Good | Good | Good | Prime | Prime | Prime | Good | Good | Good | Good | Good | Good |
Season follows Zeeland: Cuttlefish season runs Apr–Jun and is the year's highlight; winter is coldest at 4°C but gives the clearest water.
Know before you go
- Visibility drops to about 2 metres in May, the middle of cuttlefish season, so plan on close buddy contact rather than seeing across the site.
Photos from Bergse Diepsluis
Andra Waagmeester · CC0
Dive videos
Duiken Zeeland Oosterschelde Bergse Diepsluis Oesterdam · Dirk Van den Bergh on YouTube
Diving Bergse Diepsluis in Oesterdam with seahorses · Erik vd Berg on YouTube
Questions divers ask
How deep is the Bergse Diepsluis?+
The maximum depth is 19 metres and average visibility is about 4 metres. With little to no tidal current, it is one of the easier sites in Zeeland to plan a dive on.
When can you see cuttlefish at the Bergse Diepsluis?+
Spring is the season, and the local rule of thumb is to wait until the water reaches 12°C. Before that the site is still worth diving for the anemones, crustaceans and other invertebrates, which are there all year.
Sources
- Bergse Diepsluis dive site — PADI
- Bergse Diepsluis — Scubago
Photo credits
- Common hermit crab crawling over algae-covered rock in green water by Andra Waagmeester, CC0, via Wikimedia Commons
- Hermit crab in a shell tucked among dark seaweed by Andra Waagmeester, CC0, via Wikimedia Commons
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