Background: This manuscript is one contribution from a multi-disciplinary program that has goals 1) to develop new methods to characterize essential fish habitats in deepwater shelf and canyon areas of the central California coast; 2) to assess the importance of small-scale natural refugia to economically important fishes in submarine canyons; and 3) to evaluate the effectiveness of marine protected areas as a fishery management tool. This particular study was partially funded by NOAA's West Coast NURC, and included biologists and geologists from NMFS-SWFSC PFEL, Moss Landing Marine Laboratories, California Fish and Game, and Santa Barbara.
Purpose of Activity/Goal of Project: This study had four specific objectives: 1) to characterize the geomorphology, classify the substrata and locate rock outcrops on a large scale (i.e., 100's of meters to kilometers) using bathymetric mapping and side scan sonar imaging; 2) to map and quantify the amount of exposed hard substrata at depths suitable to rockfishes; 3) to verify and enhance our interpretations of the remotely-sensed images of habitat using a manned submersible, and to determine frequency of occurrence, distribution and type of habitat on a smaller scale (i.e., 1 meter to 10's of meters); and 4) to estimate and compare species composition, abundance, size, and diversity of fishes among habitat types, depth zones, and locations of varying amounts of fishing activity within the canyon.
Description of Accomplishment and Significant Results: In situ submersible surveys and geophysical remote sensing of the seafloor are a unique combination of techniques that are essential in appraising and managing our deepwater coastal resources. The resulting species
habitat associations are valuable in predicting community structure and evaluating changes to that structure, as well as in applying small scale species-habitat relationships to broader scale fishery resource surveys. Additionally, establishing these groups is critical when incorporating the concept of essential groundfish habitats, and negative impacts to them, into the management of fisheries in relatively deep water, as required by the Sustainable Fisheries Act of 1996.
Significance of Accomplishment (e.g., to the Center, to Management, and to NMFS Strategic Plan Goals): We have developed new uses, interpretation, and evaluation of geologic data of the seafloor, in terms of identifying and describing benthic fish habitats. Results will be useful when incorporating the concept of Essential Fish Habitat into Fishery Management Plans for groundfish. In addition, we are now applying these techniques to an evaluation of harvest reserves as alternate management tools for marine fisheries. Our techniques also are being successfully used to improve stock assessments of commercially important fishes on a habitat-specific basis in southeastern Alaska.
Problems: This manuscript is still in the review stages of publication. Because of its interdisciplinary nature, it has been reviewed by several biologists and geologists. It already has been revised twice, with incorporation of comments from four of the six co-authors. It is now being reviewed by PFEL and California Fish and Game biologists. These reviews and revisions have contributed to a delay in submission of the manuscript to Fishery Bulletin for publication. It will be submitted during the fourth quarter of FY 1997.
Key Contact: Mary Yoklavich (831-648-9036)