In season Basket Star Aggregation — Pacific Northwest USA
The basket star (Gorgonocephalus eucnemis) aggregation on the rocky subtidal reefs of Puget Sound and the San Juan Islands — the extraordinary ophiuroid whose arms branch 5 times into thousands of fine filaments, the extended feeding posture (arms held upward in a branching tree of 80,000 filaments to capture plankton from the current) creating the most complex body form of any invertebrate visible in recreational diving — creates one of the Pacific Northwest's finest accessible marine invertebrate encounters. The basket star's nocturnal extension (the animal contracts to a fist-sized ball by day, invisible on the reef, expanding to 50 centimetres diameter at night to feed) requires night diving, and the Puget Sound's aggregations (multiple individuals on adjacent rock faces, the current-facing posture aligning all animals simultaneously) creates a visual encounter with no marine equivalent in form or function. The basket star's combination of its alien architecture and its completely peaceful ecological role (a passive filter feeder despite the intimidating form) creates one of diving's most visually extraordinary encounters.
About this spectacle
Descending into the cold, dark waters of Puget Sound or the San Juan Islands at night, divers encounter one of the ocean's most otherworldly spectacles: basket stars (Gorgonocephalus eucnemis) fully extended in feeding posture. By day, these creatures contract into fist-sized balls, virtually invisible against the reef. But as night falls and current picks up, each animal unfurls to 50 centimetres across, raising branching arms — splitting five times into thousands of fine filaments — upward into the water column to snare passing plankton. Where aggregations form, multiple individuals line adjacent rock faces, all oriented into the current simultaneously, creating a forest of living, fractal-like forms. The cold Pacific Northwest water carries superb visibility on calm nights, and divers' torchlight illuminates the animals' intricate architecture in extraordinary detail. Despite their intimidating, almost alien appearance, basket stars are entirely passive filter feeders. The combination of their extreme morphological complexity, nocturnal behaviour, and the eerie silence of a night dive makes this one of recreational diving's most visually arresting invertebrate encounters.
When to go
Jan — Dec, peak Oct — Mar
Getting there
Nearest airport: SEA. Nearest city: Seattle.
Booking options
Goyova doesn't process bookings directly. When you tap "Plan this trip" in the app, you'll see options from our partner providers — accommodation, tours, transport — with affiliate links where applicable. See our affiliate disclosure for details.
More like this.
Peak season Aardvark Night Foraging — Kalahari Botswana
Maun, Central District, BW
Peak season Aardvark Night Foraging — Kalahari South Africa
Upington, Northern Cape, South Africa
Returns Jan 2027 Adélie Penguin Highway — Ross Sea Antarctica
Cape Royds, Antarctica, AQ