Strategy Spotlight: Nearshore Survey of Semi-Pelagic Rockfish

Oregon’s nearshore semi-pelagic Black, Blue and Deacon Rockfish all lack statewide fisheries independent surveys. These fish all live in subtidal rocky habitat and are important to both the ecosystem and Oregon fisheries. Rocky reef habitat has proven to be a difficult place to sample, especially over larger areas in a short period of time. Semi-pelagic means that these schooling rockfish species are usually found up above the rocky reefs and they are often found in big schools with the species sometimes mixed together. After being selected for funding by the competitive federal Saltonstall-Kennedy grant program administered NOAA Fisheries, ODFW researchers demonstrated that combined data collected with a scientific fish finder and a suspended underwater camera was an effective survey tool to accomplish this goal. Even better, these combined technologies were able to do so without killing any of the fish or destroying their habitat. ODFW’s marine fisheries research team also worked with ODFW’s underwater Remotely Operated Vehicle team to determine that using these methods didn’t miss fish right on or near the bottom. Thus, this great project suggested that the scientific fish finder and underwater camera combination was effective at counting Oregon’s nearshore semi-pelagic rockfish. To learn more details see the report available here.

ODFW staff then set out to conduct the first ever statewide survey to estimate the populations of these three fish species in Oregon’s nearshore waters. With funding from ODFW’s Restoration and Enhancement fund, the survey began on August 1, 2021. The video below provides a walk through of how the boat was set up for this work just before they started the survey.

While conducting the survey ODFW staff encountered low oxygen (hypoxia) conditions from the Washington border to approximately Heceta Head. Therefore, in order to assess how low oxygen conditions influence fish abundance, staff redid the survey from Three Arch Rocks to Waldport. A summary of the survey work can be seen in the video below.

During this survey the team also captured some fish with hook and line to provide additional data on ages and weights that is needed for stock assessments. These data, together with the fish finder and video data will be available for stock assessment scientists to use after the results are finished and should help provide better estimates of the population sizes of these economically and ecologically important species.