Farnsworth Bank is a relatively small, semi-isolated feature composed of sharp pinnacles and located on the seaward side of Santa Catalina Island, southern California. Despite its heavy colonization by the rare purple hydrocoral Stylaster californicus (verrill, 1866), and its popularity as a fishing and diving site, no complete fish survey of this site had been conducted. Using the occupied submersible Delta, we made four dives (comprising 15 transects and 342 habitat patches) in waters between 30 and 90 m deep, totaling 12,605 m2 (6325 linear m) of sea floor. During the survey, fishes, purple hydrocoral colonies, and marine debris were assessed. We observed a total of 10,404 fishes, representing at least 43 species and 13 families. Rockfishes (genus Sebastes), comprising 25 species and 7070 individuals, dominated the assemblage. The most abundant fish species were squarespot rockfish, blacksmith, and dwarf-red rockfish, all schooling and aggregating epibenthic or midwater taxa. Commonly observed solitary species included blackeye goby and rosy rockfish. Most economically important fish species were uncommon and were represented by small individuals. Purple hydrocoral colonies were observed at depths between 31 and 66 m, primarily between about 30 and 40 m, and only on rocky substrate. Although we observed hydrocoral colonies with diameters as large as 120 cm, most were 40 cm or less and the largest colonies tended to be in the shallowest waters. Relatively large amounts of debris, mostly recreational and commercial fishery related lines and nets, were observed.

Depth range
30- 90 m

Mesophotic “mentions”
0 x (total of 3775 words)

Classification
* Presents original data
* Focused on 'mesophotic' depth range

Fields
Biodiversity
Community structure
Ecology
Fisheries
Disturbances

Focusgroups
Fishes
Hydrozoa

Locations
USA - Continental Pacific Ocean

Platforms
Manned Submersible