Sanctuary Integrated Monitoring Network
Monitoring Project

Pattern and Dynamics of Benthic Soft Sediment Faunal Communities

Principal Investigator(s)

  • Linda Kuhnz
    Monterey Bay Aquarium Research Institute
  • Patrick Whaling
    Monterey Bay Aquarium Research Institute
  • Jim Barry
    Monterey Bay Aquarium Research Institute
Start Date: June 06, 1994

The objectives of this project are to determine the patterns of abundance of marine megafaunal populations on the continental shelf and slope to 1000 m depth in Monterey Bay, and measure changes in abundance over time. Video transects recorded using the MBARI ROV Ventana are used to collected video records of benthic transects at depths of 200, 400, 600, 800, and 1000 m depth on "Smooth Ridge" in Monterey Bay.

Each transect is roughly 2 km in length. The ROV collects video of the bottom from each transect an average of 1 time per year. Paired lasers are used as a visual scale to determine the width of the video transect. All identifiable animals are recorded along each transect, from which measures of species' densities are calculated for each transect. Together, these data will provide a measure of the interannual variation in community structure in the region.

Summary to Date

We have collected video records from transects at 200, 400, 600, 800, and 1000 m. An interesting finding illustrated by the attached photograph, is the patchiness horizontally in the abundance of some species. Four shelf-dwelling rockfish species are much more abundant at one end of the 200 m transect than at the eastern end.

Findings are limited presently to the few transects that have been analyzed, though this will advance rapidly now that additional technician time is available for analyses We expect to be able to determine the stability of this pattern as we analyze additional years from this location.

Monitoring Trends

  • The structure of the slope community is variable from year to year, particularly in the shallower transect depths (200 m).

Study Parameters

  • Range/Biogeography
  • Habitat association
  • Abundance
  • Distribution
  • Density

Study Methods

The distribution and abundance of benthic megafauna on the continental shelf and slope in Monterey Bay are determined from the analysis of video transects of benthic seafloor habitats at five depths on Smooth Ridge, in Monterey Bay. Transects are located at 200, 400, 600, 800, and 1000 m depth. Each transect is ~2 km long. Video records are collected by flying the ROV as close to the bottom as possible, then zooming the camera system sufficiently that the width fo the vidao images is ~1 m. Width of the imageis determined by paired lasers dots projected onto the sea floor. Data are collected from the video transect recordings after the ROV has returned to Moss Landing.

Transects are optimally run each year at approximately the same time, but logistic concerns often disrupt this schedule.

Figures and Images

Location of long-term transects.

An example of data obtained for evaluating species distributions. Rockfish Sebastes saxicola, eelpout Lycodes cortezianus, and a Rathbunaster seastar from 200 m depth.

Benthic fish.

Large Humboldt squid sometimes hover just above the seafloor.