SIMoN
  Sanctuary Integrated Monitoring Network
Monitoring Project

Deepwater Demersal Fishes and Habitats

Principal Investigator(s)

  • Mary Yoklavich
    NOAA Fisheries
  • Bob Lea
    California Department of Fish and Wildlife

Funding

  • NOAA
Start Date: August 15, 1992

This is an assessment of benthic groundfishes (primarily of rockfishes in the genus Sebastes) and associated habitats in deep water conducted in Soquel Submarine Canyon, Monterey Bay, California.

Rock habitats at depths to 300 m have been identified using multibeam and side scan sonar imaging, verified with visual observations from a manned submersible, mapped and quantified. Species composition, abundance, size, and habitat specificity of fishes is determined using a video camera and parallel laser system along transects made by Delta occupied submersible.

Summary to Date

At least 52 species have been identified from 83 10-min strip transects in 1992-93, and from 26 10-min transects in 2002-03. Distinct habitat guilds of fishes have been identified.

Monitoring Trends

  • Small species are associated with mud and cobble substrata of low relief, while larger species of rockfishes are on high relief structures such as vertical rock walls, ridges and boulder fields.
  • High numbers of large rockfishes, specifically from those species that are classified as overfished, are locally associated with rock ledges, caves, and overhangs at sites having little or no evidence of fishing activity. This trend has persisted over a 10-year period.
  • Abundance and size of several species were lower at fished than unfished sites.
  • It appears that small rock outcrops of high relief interspersed with mud in deep water on the steep walls of this submarine canyon are less accessible to fishing activities and thereby can provide persistent natural refuge for economically important fishes, as exemplified in parts of Soquel Canyon.

Study Parameters

  • Habitat association
  • Habitat
  • Diversity
  • Density
  • Size structure
  • Substrate characterization

Study Methods

10-min strip transects

Rock habitats at depths to 300 m have been identified using multibeam and side scan sonar imaging, verified with visual observations from a manned submersible, mapped and quantified.

Species composition, abundance, size, and habitat specificity of fishes is determined using a video camera and parallel laser system along transects made by Delta occupied submersible.

Figures and Images

Cowcod and greenspotted rockfish.


Rockfish abundance rock habitat guild in Soquel Canyon.


Documents