Northwest Fisheries Science Center

Advanced Technologies Research Cruise to Cherry Bank

Cruise Updates

October 7

Report number one October 7, 2004 The scientific party and crew of the R/V Thompson made excellent time with fair weather and a following sea on the way to the study site, Cherry Bank. We arrived at about 1:00 am this morning. During the transit, Chris Goldfinger, OSU marine geologist, took the opportunity to map new areas along the continental shelf margin of the West Coast, using an EM 300 multibeam sonar system. The EM 300 collects detailed bathymetry and bottom hardness from acoustic backscatter, which together helps to better characterize the geology of the seafloor. This new information will add to our overall knowledge of both the geology and habitat types along the West Coast. Once we arrived at the study site, we began operations with measurements throughout the water column of conductivity, fluorescence, temperature and abundance of plankton using a CTD (a conductivity, temperature, depth, measuring instrument) and a Video Plankton Recorder (or VPR). The ROPOS ROV team used the temperature information in their calibration of a navigation system that will provide exact location of the remote robotic vehicle during subsequent dives. Calibration of the ROV's navigation system took most of the first night. Chris Goldfinger and his group then began the detailed seafloor mapping of areas around Cherry Bank in order to provide a more complete picture of this area's bathymetry. This high-resolution mapping of bathymetry produces a detailed picture of seafloor terrain, that when visualized with computer graphics, portrays the seafloor as if the overlying water has been stripped away. Starting at 9PM tonight, we began sampling at a predetermined series of stations in order to produce a picture of the temperature, conductivity, fluorescence and plankton distribution. Plans have been completed for the week's ROPOS operations on the bank. Tomorrow will be the first dive with the ROPOS and will begin our study of the distributions of bottom-dwelling fish and invertebrates. Unanticipated passengers on the ship today included a peregrine falcon and a northern pygmy owl, giving joy to the bird-watching members of the crew.

October 8-9

Report Number Two Oct 8-9, 2004 On, October 8th, we began our first ROPOS dive. We worked into the evening mapping the distribution of fish and invertebrates near the top of Cherry Bank. The video images we are getting indicate that the geology and biology in these habitats are very interesting. We are also collecting some biological samples using the mechanical arm on the ROPOS. The geologists are also obtaining rock samples from the area to validate the geology. The weather started to pick up in the evening. The EK-60 transducer was deployed on a tow fish and one leg of a map of fish distributions in the water column was completed. We had hoped to continue all night with the acoustic mapping but the weather worsened and the tow fish had to be brought back on board. We then began a series of CTD and VPR deployments in a grid pattern over the bank. This will allow us to produce a map of the physics and plankton. The video plankton recorder is working very well and we are getting some great images of plankton. On October 9 the winds were over 25 knots and the ROPOS could not be deployed. We continued all day mapping with the CTD and VPR. We completed most of a grid of locations over the bank. Chris Goldfinger's lab (OSU) then began mapping an area just off the bank with the magnetometer.

October 10-11

Report Number Three Oct 10-11, 2004 Because of weather we were still not able to deploy the ROPOS. We began CTD and VPR mapping in an expanded grid. Our early results showed some interesting features in the physics and biology on the bank and we took the opportunity to further refine this information. By the evening the weather had cleared enough to allow us to deploy the EK 60 transducer again on the tow fish and Guy Fleischer and his group were able to map about half the bank in the next five hours. On Oct 11, the weather had finally calmed enough to deploy the ROPOS. We began mapping the deep edge of the bank at greater than 800 meters. This is some of the deepest mapping that has occurred in this area and will help quantify the distribution and habitat of the deeper slope fishes.