Today was a much calmer day on the water, which meant less sailing, but more chance to do science. We headed out from Snug Harbor into Haro Strait in the direction of Kelp Reef. The main experiment of the day was for Laura’s project. We lowered the hydrophone array vertically off the back of the Gato Verde and then tried to implode light bulbs about 100 meters from the array. If you get the light bulb to implode it makes a nice sound source at depth. Unfortunately we must have been too shallow as the light bulbs did not implode at depth. We’ll have to try that experiment again at a later date. Dominique also spent a fair amount of time learning how to use Noble Tech software (nautical chart software) that incorporates AIS (Automatic Identification System). Ships over about 65 feet give off a signal that lets others with an AIS receiver in the area receive the position and other information on that ship. Since Dominique is interested in the effects of ship noise of Southern Resident killer whale hearing, it will be important for her to know how far away the ship past us while she is recording their noise. After our day of experiments we headed in to Roche Harbor to pump out and then snuck around the corner into Garrison Bay to anchor. After dinner the students went ashore to English Camp (a National Historical Park) to stretch their legs. After returning to the boat we had our journal club meeting, during which we discussed a paper that modelled the acoustic impact of whale watching vessels on killer whales.
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Departing this morning around 9:30 am, we left Aleck Bay and headed up Haro Strait along the west side of San Juan Island. We took advantage of the slack tide to head up the strait and around noon used the changing tide push up as it flooded. It was a great sailing day! We reached 10 knots at one point and focused the day on perfecting our line and sail handling. Once anchored, we engaged in collecting recordings to calibrate our hydrophones. After a great dinner of Jason’s rosemary delight potatoes and Comrade Spengler’s (and assistance LH) delicious salad of mixed greens and cranberries, dressed oh so gently with a balsamic vinaigrette, we analyzed the data files from the newest version of the O’VAL software. We noticed that the Marantz files had large low-frequency excursions that made measuring the rms of the recorded call impossible. Let’s look into this the next time we put the Blue Box hydrophone into the water. The Sound Devices files (perhaps because the signal had been high pass filtered at 240 Hz) looked great!!! Good work == LED watchers!
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Today we got an early start at 7:30 am due to small craft advisory warnings and strong winds reaching 30-35 knots. We weighed anchor and cooked breakfast as well as did our chores while under way. We planned to reach False Bay at the south end of San Juan Island by noon, taking into account the wind and wave advisories; we experienced calm, flat waters instead, with some scattered rain fall. To take advantage of this weather, we passed over Salmon Bank, a shallow area with interesting bathymetric profiles, to record bathymetry with the echoloctor. Shortly after, the group deployed the CRT hydrophone as well as the hydrophone array in order to practice properly getting them into the water as well as play with the gain settings. We took recordings from all four channels for a background noise exercise which we threw ourselves into after dinner. We got experience plugging files into one of Val’s programs designed to read RMS and convert it into dB. We also calculated signal to noise ratios for multiple sound files.
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Today after our day at land we left Friday Harbor Labs to make our way to Port Angeles, with the hope of seeing the transients at Race Rocks and the Strait of Juan de Fuca. We did not deploy anything besides the Gato Verde hydrophone for opportunistic listening, and throughout the day analyzed and localized our data from 4-25-08. We did not find any whales today, but spotted harbor seals and Stellar sea lions at Race Rocks. We also spotted loons, perhaps a yearling bald eagle, and the mountains of the Olympic Peninsula.
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We made the short passage to FHL in the morning and spent the rest of the day cleaning, reprovisioning, and relaxing.
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After leaving Roche Harbor we went across Haro Straight into Canadian waters. We waited there for the currents in Spieden Channel to slacken. While there we did a localization exercise. Ryan and Jason had the speaker in the dinghy and we had the array deployed and did a drive by recording the calls they made. During the recordings we noted the distances and bearings of the dinghy in relation to the Gato Verde. We made a total of four recordings. This allowed us to practice using the hydrophone array as well as collect data which we can use to practice localizing calls. We anchored in Parks Bay to facilitate a quick return to FHL tomorrow morning.
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The Earth Day mooring kept us secure all night. Our science goals today are to keep working on methods, practice using and deploying the sound devices and hydrophones, and hopefully encounter actual whales for recording data.We practiced using the acoustic fish tags and saw how far we could detect them off Lime Kiln. The furthest distance was around a quarter of a nautical mile. We used the high frequency hydrophone to record the bleeps from the tags (pings). The raw data from these tests was loaded in a new folder titled with today’s date.
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We left Snug with a series of science goals for the day. We headed south on the ebb tide towards Lime Kiln. On the way there and back we deployed the Biosonics 200 kHz echosounder for the first time. This marks our first forays into using active acoustics. We got so excited that we even lowered a video camera under water to see if the objects we were interpreting as fish and eel grass really were fish and eel grass. We did see a few fish, but for sure the eel grass we saw on the echosounder was real eel grass. We also figured out how we would deploy the hydrophone array along with a high frequency hydrophone. Because some of the student projects involve high frequency clicks, we needed to add a hydrophone with a high frequency response. We figured out a new configuration that would allow us to do that with the regular linear array on the port stern and the single high frequency hydrophone on the starboard stern. After dinner we had our journal club discussion about an article on prey species of Northern and Southern Resident killer whales. All in all a productive science day.
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We awoke to white caps out in Boundary Pass and discussed navigation and weather forecasts. Emerging from Prevost Harbor we ran under jib alone around Turn Point lighthouse, enjoying our first views of Mt. Baker on the eastern horizon. The wind moderated in the lee of Stuart Island and we bore for Roche Harbor with a plan to pump out the sewage tank. Around noon we entered Roche, having noticed an unusual aluminum boat crossing Spieden Channel with us, pumped out and bought some lamp oil. Scott met the Al boat owners who had built it themselves and invited them to visit Gato Verde once we reached Snug. Around 1:15 we transited Mosquito Pass, anchored in Snug Harbor, and began our Earth Day project: creating and deploying an anchoring system that would do less damage to the bottom than spinning on our normal big anchor. About the time we were done, Bob and Helen Oliver (the owners of the Wharram Designs aluminum boat “Sanderling”) joined us for dinner on board and we all indulged in grilled cheese sandwiches and tomato soup.
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After an overview of passage planning (charts, currents, weather) from Todd, we practiced tacking and jibing in 10-12 kt winds, traveling NW between Spieden and Waldron Islands. The wind moderated in the early afternoon and we eventually motored into Prevost. At the dock the students each collected a series of mocked up data to test out their projects. We had everything from pseudo-pectoral slaps and fake socializing orcas. They also collected associated acoustic recordings that they could analyze at a later date. After dinner most of the students took advantage of the land and went for a walk.
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