Bottomfish Observing

SE‐11‐02 March 8, 2011 progress report

The Oscar Elton Sette conducted nighttime targeted fishing operations over acoustic targets last night, resumed acoustic surveys of the grid, and then deployed a 6‐hour BotCam unit with daytime acoustic surveys conducted over it.

Charter fishing operations were resumed today with all 3 vessels on the survey grid, completing 20 daytime stations and 12 nighttime stations tonight. The Sette’s acousticallytargeted fishing operations were mostly unsuccessful last night due to the fast drift and difficulty at finding promising acoustic targets. The 6‐hour BotCam unit was successfully deployed at a similar spot as both of the 2 days prior, but further on the summit in shallower water.

Initial indications from the TDR, visuals from the BotCam, and acoustic signals indicate that the BotCam may have landed exactly as targeted on the shallower, flatter summit, thanks again to excellent ship driving and coordination between bridge, acoustics, and back deck. This station had a large number of opakapaka (Pristipomoides filamentosus), which quickly converged upon the BotCam unit several minutes after reaching bottom.

The photos on this page show the bait plume immediately upon reaching bottom, fish converging upon the bait, a large individual which was adept at suctioning the bait from the canister, the extent of the school, and a flight reaction shortly before the appearance of some large kahala.

After retrieving the BotCam unit, the Sette did its last scientific operation with 2 hours of targeted fishing on acoustic signals. This was more successful than prior 2 attempts, yielding an opakapaka and an ehu from acoustic signals.

Leg 1 of SE‐11‐02 officially concluded with the ship now proceeding into the North Pacific for oceanographic research. Scientists and ship’s staff enjoyed some homemade shave ice on the transit back to Oahu, expertly prepared by survey tech Stephanie Floyd (photo courtesy Ben Richards). Updates of survey effort are seen on subsequent pages and on the following webpage.

Some video clips from BotCam drops 4 and 5 are also available here (please note that these are “cherrypicked” clips from targeted drops onto acoustic targets):