Dwarf surfperch are pretty common along the mainland coast, but they seem to prefer depths of about 10 feet or less: too shallow for divers. And, they are very quick. These were about the size of Kennedy half-dollars, so I expect that they are juveniles. A few of them had the black checkmark at the base of the pectoral fin that is the mark of the reef and dwarf surfperches. I think that these are dwarf because of the tartan markings on their sides.
Gull Island lies off the South side of Santa Cruz Island, 1000 yards south of Punta Arenas, and gives its name to the surrounding marine reserve. Lots of reefs and kelp forests radiate from the rock: it's a great place to dive.