Ask any experienced Southern California diver what they consider the most spectacular dive in all the Channel Islands and it’s likely you’ll hear Farnsworth Bank mentioned. A lot.

Shearwater TERN
Farnsworth is series of tall underwater mountains and sharp pinnacles approximately 1.6 miles off the backside of Catalina Island. Surrounding waters are deep and the area is constantly bathed in clear oceanic currents. It is the main mountain at a depth of about 55 feet that is the most often dived. There are several other nearby pinnacles but most push the limits of safe recreational diving depths. Technical divers often visit this site for deeper exploration but proper training, experience, and equipment are a must.
Among the main attractions here are huge expanses of California purple hydrocoral (Stylaster californicus). In places on the deeper, less frequently dived pinnacles, it seemingly covers nearly every square inch of the reef. While the shallowest portion has less coral it is still very prevalent. Purple coral is actually not a true reef building coral as you would find on tropical reefs but rather a hydroid in the Phylum Cnidaria, which also includes anemones and jellies. Although it is not a hazard to humans, it is closely related to painful fire coral found in tropical waters.
On the few walls, valleys, and crevices where the coral is lacking, often there are vertical tapestries of pink, purple, and red corynactis anemones (Corynactis californica). In other locations bright yellow-orange zoanthid anemones (Epinzoanthus giveni) also carpet walls. In short, marine life here is insanely abundant.
This is a very fishy dive. Scorpionfish, both rainbow (Scorpaenodes xyris) and California (Scorpaenodes guttata), are found in nearly every pocket and perched on many of the reef tops and coral stands. They can be easily approached but stay clear of their venomous dorsal spines. Their interesting textured and colored faces make for great photos against the purple coral backgrounds or blue water. Often scorpionfish will take on skin tones to match their surroundings. Such was the case with most of these fish‚– mottled lavender. I’ve noticed that painted greenlings (Oxyleius pictus) here may also adapt hues of their reef home. They sometimes take on muted colors in stripe form on their bodies. Lingcod can also be seen balanced on the ledges or just cruising a foot or so over the reef. Keep your head on a swivel. Large aggressive electric torpedo rays are seen on nearly every dive. Often they will even rise far from the reef to circle you while at your safety stop.
Another common reef fish seen here is the blue-banded goby (Lythrypnus dalli) and its usually rare cousin the zebra goby (Lythrypnus zebra). These tiny but colorful fish are a challenge to approach but make for rewarding photos.
Shrimp, small crabs, big moray eels and nudibranchs round out the cast for macro photographers. But shutterbugs will find it hard to choose between macro and wide angle, as opportunities abound for both formats. With the way the fish perch on the sharp rocks and purple coral you may want to try your hand at close-focus wide-angle. Remember, get low and shoot up. It is not unusual to be able to clearly see the boat from the top of the pinnacle.
Conditions for this dive site are exciting but are also challenging. Clear water with 60-to 80-foot visibility is the norm. So are strong currents. Because the area is unprotected this is a site that should only be attempted when seas are calm. The best way to dive Farnsworth is with a professional dive charter operation that knows just where to put the hook.
Farnsworth Bank is a part of the Farnsworth Offshore State Marine Conservation Area and taking of purple hyrdocoral and other geologic features is forbidden. Reef fish are enjoying their protected status and their numbers are abundant. The only recreational take of marine life allowed is of pelagic finfish, including Pacific bonito, by hook-and-line or by spearfishing, white sea bass by spearfishing, and market squid by hand-held dip net.
To put it simply, in spite of its challenges, Farnsworth is a “must-do” dive for any serious experienced West Coast diver.
Location: Open-ocean approximately 1.6 miles off Ben Weston Point on the backside of Catalina Island. GPS for the main pinnacle is: N33°20.620′, W118°30.992′.  (GPS Coordinates are for reference purposes only.)
Access: Boat only. Experienced skippers only as anchorage can be difficult. Professional dive charter boat recommended.
Depths: 55 to 130+ feet.
Visibility: Excellent with 40 to 60 average, sometimes 100+.
Skill: Advanced
Photography: Excellent for both macro and especially wide-angle.
Hunting: Take of lobster and scallops prohibited. Only take of pelagic finfish, including Pacific bonito, white sea bass, and market squid by hand-held dip net is allowed.
Hazards: Deep depths and strong currents.
California Diving News