Linda Tatreau, MARCH 9, 2010

NOAA Teacher at Sea: Linda Tatreau
Onboard NOAA Ship Oscar Elton Sette

Mission: Fisheries Surveys
Geographical Area of Cruise: Equatorial Pacific
Date: March 9, 2010

TOAD

Sunset
Sunset

It would be easy to start every post with a beautiful sunrise or sunset photo. In this one, you can see Anatahan Island in the background. Just before the sunset, 3 large wahoo were caught. Poke and fried fish are the favorite items on recent menus (breakfast, lunch and dinner).

Steve, Frances and Mills show off their catch.
This photo/diagram shows how sonar waves ping the seafloor and also shows the bathymetric map that is made from the data.

We used the multibeam sonar to map shallow banks north of Farallon de Mendinilla and east of Anatahan and Sarigan. The multibeam work continued day and night and produced huge amounts of data that needed to be processed. I can only sit at the computer for short periods, but the map team members work 10 hour shifts and most of that time is spent processing the data and making new maps. There are always 2 or 3 people processing the data.

The TOAD seen with cameras facing forward.

Monday night, we put out the TOAD (Towed Optical Assessment Device). This camera is towed behind the ship and sends video directly to the control room. We were able to see some of the seafloor we had been mapping. The first run of the camera went for 2.25 hours, covered a distance of 3 miles and went to a maximum depth of 400 feet. The second run went for 3.5 hours, over 4.5 miles to a maximum depth of 300 feet. Towing the camera sounds easy, but someone must be on the controls to keep the camera from crashing into the bottom. The camera needs to be close to the bottom for the best video, but without someone on the controls, it can crash. Driving requires constant attention. Most of the seafloor had a sand coverage with some algae. Occasionally, there would be oohs and aahs over something other than sand and sea weed: sea stars, large sea cucumbers, sponges, sea urchins or the infrequent fish. I really enjoy watching real time video of previously unseen seafloor, but I found myself falling asleep on my feet. I finally had to give up and head to the bunk.

Steve & Viv prepare the TOAD for launch.

Today, we are near Saipan planning to do BRUV work during the day and the TOAD tonight. A nap might be a good plan so I can watch the TOAD through the night, but I don’t want to miss the BRUV action either.

Linda Tatreau, FEBRUARY 13, 2010

NOAA Teacher at Sea: Linda Tatreau
Onboard NOAA Ship Oscar Elton Sette

Mission: Fisheries Surveys
Geographical Area of Cruise: Equatorial Pacific
Date: February 22, 2010

A HAPPY Valentine’s Day

Deploying the BotCam from a crane
Deploying the BotCam from a crane

The camera team got spectacular results with the BotCam and the BRUVs. I got to watch just a bit of the footage this morning. Everyone is talking about the great shot from the BotCam showing the stern of the ship and the propeller as the camera descends, then fading and picking up the sea floor. (You can see this video clip here.) The BotCam filmed lots of fish and a spotted eagle ray too.

Steve and Sparky preparing the BRUV for deployment.
Steve and Sparky preparing the BRUV for deployment.

The BRUV footage is beautifully clear. I watched only a short section and saw a white tip reef shark, grey reef shark, barracuda, red snapper (Lutjanus bojar), grouper and dogtooth tuna. Also seen were unicornfishes, groupers, Tanguisson wrasses and lots of tangs and butterflyfishes. The depth of the cameras was about 200feet.

Earlier today, the AUV (Autonomous Underwater Vehicle) was deployed. It travels the sea floor following a pre-programmed path for about 4 hours . It keeps itself about 8feet off the bottom. Unfortunately, it was not communicating with the ship, so it had to be retrieved for repairs. In 5 minutes they will deploy the TOAD. I’ll be back. Well, that was great fun and it worked perfectly. The TOAD (Towed Optical Assessment Device) lets us watch the video as the camera is towed above the sea floor. The ship was just drifting at a good speed for the camera. One of the scientists works the controls to keep the TOAD just a few feet off the bottom. This gives great video of the bottom cover, but the fish seem to shy from it. We did see some triggerfishes, jobfishes and a beautiful ray. We spent two hours watching the sea floor starting in an area about 90 feet deep with a lot of coral. We passed through a large sand flat and then dropped off the edge. It got deep so fast that the camera could not be lowered fast enough to keep sight of the bottom. The crew is bringing the TOAD back aboard and soon we will be working with the multibeam sonar to complete the map of Galvez Bank.