Anacapa Island — Arch Rock

The arch itself is the landmark rather than the dive: a 12 m natural bridge standing above the water at the extreme east point of East Anacapa. Underwater, the dive sites along this stretch of the reserve run from about 15 m down to 37 m, so the profile is picked on the day — shallower rock and kelp bass close in, deeper reef further out — and the deep end eats bottom time quickly in water this cold.

Visibility averages 9 to 24 m, and what it shows is a Southern California line-up: California sheephead and garibaldi working the rock, kelp bass holding in midwater, moray eels and horn sharks tucked into ledges, leopard sharks and bat rays over the sand, and nudibranchs on almost any surface you slow down for. Giant sea bass are recorded here too. Everything inside the reserve is protected — the boundary runs along Anacapa's north coast from Arch Rock west to Tidepools, on the east part of West Anacapa — so nothing is taken and nothing is moved.