Cordell Bank Like You've Never Seen It Before

By Liz Liang

February 2014

Bright pink anemones and barnacles
Strawberry anemones (Corynactis californica) and barnacles. (Photo: Matt Vieta)

Orange and pink corals, sponges, and anemones emerge through an enormous cloud of widow rockfish. Using strobes and powerful lights that chase the darkness from the deep, a group of expert divers has captured amazing views of the rarely seen Cordell Bank.

A school of small fishes swimming over coral
Hundreds of rockfish over Cordell Bank (Photo: Clinton Bauder)

In 2013, after over a year of planning, the Bay Area Underwater Explorers (BAUE), a non-profit organization dedicated to the conservation and exploration of underwater areas in Northern California, took their first look at remote and rocky Cordell Bank. Thanks to a unique combination of ocean conditions and undersea topography, Cordell Bank has a mythical reputation among diving enthusiasts as a rich and diverse habitat for marine animals.

"As we descended into clouds of fish, I actually think I was laughing through my regulator!" said Mike Vieta, BAUE Project Leader for Cordell Bank Expedition. "Even at around 200 feet, life was thriving for as far down as you could see."

 fishes swim over reed crest
Cordell Bank reef crest. (Photo: Clinton Bauder)

Located 42 miles north of San Francisco, the centerpiece of Cordell Bank National Marine Sanctuary (CBNMS) is a four-and-a-half mile by nine-and-a-half mile rocky undersea feature on the edge of the continental shelf, with pinnacles jutting from the sea floor that reach within 115 feet of the ocean surface.

 octopus hides in coral
Hydrocoral (Stylaster sp.) and octopus (Photo: Matt Vieta)

Since the first expeditions at Cordell Bank in the late 1970s, diving activity has been sparse due to the remote location, volatile weather and strong currents. Moreover, the dive is not recommended for your average recreational diver.

To explore Cordell Bank, the BAUE team used advanced diving techniques that allow divers to reach depths up to 300 feet using a combination of open-circuit scuba equipment and mixed gas. Where a recreational diver can wear a single tank for a dive to 60 feet, technical divers wear double tanks (which are also larger) to ensure they have enough breathing mixture to cover the time between descending down and returning to the surface.

 SCUBA diver swims along coral surrounded by fishes
SCUBA diver swims along Cordell Bank among hundreds of juvenile rockfish (Photo: Clinton Bauder)

Vieta said the most striking part of the dive was the density and diversity of invertebrate life.

"It was a spectacular location from a diving perspective. The conditions were amazing - bright blue, clear water - those conditions are certainly rare," Vieta said "The sheer amount of biomass in terms of fish is certainly more than I've ever experienced before."

rock fish hides in between invertebrate
Rosy Rockfish and lush invertebrate cover on Cordell Bank.(Phtot: Matt Vieta)

For the rest of us who will probably never have the opportunity to behold Cordell Bank with our own eyes, we'll need to love it from afar. Thanks to BAUE, it's now easier than ever to do just that.