Beam Reach

Hydrophone calibration

Thursday, September 13, 2007

We woke up to a thick fog bank off Snug Harbor and scrambled eggs prepared by Ashley. We finished up our post-breakfast chores and sat down to voyage planning for the day. Our pager alerts informed us that no killer whales had been spotted, so we decided to calibrate all of the hydrophones. We lowered the hydrophones tied together like a bunch of bananas off the port side, and a speaker off the starboard. Alex, Tim, and Ashley recorded tones at various gains. Todd prepared homemade mayonnaise for an egg salad that Sam and Shannon whipped up for lunch. After lunch and coffees all around, the students began analyzing preliminary data. In the afternoon, Gato Verde headed out of Snug Harbor and Tim hoisted the main for a bit of sail training. We deployed the hydrophones again and recorded a passing steamer and ferry while collecting data on range, latitude, and longitude. After practicing jibes and chicken jibes, we headed north for Stewart Island and secured a mooring buoy in Redi Harbor. After a very refreshing sunset swim, we sat down to a Greek meal of briam cooked by Alex.

First-ever localization of mother/calf calls

First ever mother/calf recording!

An amazing scientific feat was accomplished during the first sea-week of the fall 2007 program. At the end of the first deployment of our hydrophone array, a mother and calf were recorded vocalizing on the west side of San Juan Island. While orca calves rarely leave their mother’s side, this calf seemed adventurous. It left its mother and another female foraging along a tidal front, approached the hydrophone array we were towing, made an underwater turn to parallel our heading, surfaced close off our port bow, and then diverged from our course to rejoin its mother.Luckily, the Beam Reach team was already effectively collecting data when this rare mother/calf separation occurred. Most of us were watching and listening carefully enough to remember the course of events. Todd was helping Sam take bearings on the orca calf with a hand-held compass and Shannon was taking photographs to help identify the whales. I was writing down the bearings and GPS-synchronized times, noting when good calls were heard (listening through the deck speakers). Val’s computer was recording the data from each of the four hydrophones in the array. Mike was doing a good job of being Whale Wise and maintaining a steady heading (to keep the array straight).

When the array data were analyzed with software that allows us to “localize” sounds recorded on all four hydrophones, the locations of the calls corresponded well with the visual bearings Sam took and the general sequence of events we all remember (and wrote down). This is remarkable because we have struggled for two years to get all of the technologies functioning together. Courtney (2005) and Peggy (2006) will certainly appreciate how lucky we were to have the ability to localize the calls that were made during this unusual mother/calf interaction.

The localization results tell us a lot. It is clear that the calf’s calls are interspersed with the calls of the two nearby adults (mother or brother). This is the first documented call/response interaction of southern resident killer whales! While we have long suspected that the residents call and respond to each other, it isn’t clear which animal makes which sound when listening through a single hydrophone. The array enables us to learn that different animals are making the calls. It also allows us to assign particular calls — and even voices — to specific individuals. So, now we know what one calf’s call sounds like, and we have an opportunity to compare its voice with its mothers voice. This is a fledgling, but critical, first step to voice-recognition in the southern residents. A final breakthrough is being able to visualize the trajectory of the calf underwater. By combining such “passive localization” techniques with acoustic fish tags and bleeding-edge 3-D active sonar technologies (at frequencies above killer whale hearing), we will soon be able to observe how the whales navigate within their complex ecosystem and interact with other animals, their prey, plankton, and the rest of the environment.

So, the fall 2007 program has already made a great technological leap. Congratulations all around! Let’s hope the Beam Reach class continues to have such great luck. Clearly, we are poised to learn a lot more about the southern residents this year with the array system.

VaTo week 2 at sea

Sunday – Tuesday, September 9-11, 2007

Sunday, Gato Verde docked at the FHL docks and the crew swap began. Lots of students headed toward showers and a bit of distance and 5 eager souls brought loads and loads of food on board. We motored a bit south and anchored in Griffin Bay. That night a ‘heavy breather’ seal entertained us. We listened through two hydrophones and Ash and Sam showed there acuity in accurately determining the bearing of the sounds of objects thrown in various directions. The night was calm and the sunrise elegant.

Where are the whales? We did not know so we talked about methods and then set up a whale pass-by. This was done by putting the underwater speaker in the dinghy and anchoring the dinghy in a little bay on the south side of Lopez. We deployed the array and the high frequency hydrophone and drove around observing the stationary “dinghy-orca”.  Then I drove the dinghy at high speed to generate some boat noise.  Todd calmly told me on the radio that I should pull up the dinghy’s anchor before taking off. This neat thought came to me as I was zipping along at ~20 kts, anchor flying behind me! It will be good to see just what it takes to ‘analyze’ these data.

Today, Sept. 11, began with long discussions of lots of important ‘stuff’ and mid-morning we set off. Since we didn’t know where the whales were, we let the current draw us toward the sea (Straits of Juan de Fuca). It turned out that Alex’s suggestion that we go toward Race Rocks was prescient. By afternoon, we got reports of J, K, and L pods incoming west of Victoria. Tim and Ann configured a 3-d array by attaching the ‘high-frequency’ hydrophone below the array and everyone worked to get everything in the water and connected to the various computers and recorders. Cameras and protractors and note papers and range-finder were limbered up and THEN, the orcas came. They were spread out and not vocalizing. Later, as we approached San Juan Island, just south of the Lighthouse, vocals began and lots and lots of files were recorded and observations. It will be a huge effort to make any sense of this.

Good luck, Beam Reachers!

Superpod

Thursday, September 6, 2007

Today, we got an early start and raised the anchor before 8 a.m. Motoring down the west coast of San Juan Island, we spotted Ruffles with two females. This was a rare opportunity as the Gato Verde was the only boat in the vicinity, so we got to enjoy the killer whales on our own. Unfortunately, once we deployed the hydrophone array, we realized that the three killer whales were silent and not vocalizing. The orcas headed southwest and we followed in the same direction, trailing the hydrophone. We met up with the rest of J pod, as well as members of K and L pod in between Vancouver island and San Juan Island. Kenna took ID photos, while Wessal, Elise, and Heather gathered data on calls, time, latitude, longitude, bearing, and behaviors. We observed spyhopping, tail slapping, and breaching. We headed back to Roche Harbor to enjoy stuffed mushrooms and corn for dinner.

Bowriding porpoises and killer whales spyhopping

Wednesday, September 5, 2007

After breakfast at Snug, the Gato Verde sailed south along San Juan Island. We heard rumors on the radio that J pod was offshore, so we headed towards Victoria. We found a tight formation of killer whales and deployed the hydrophone array. There was lots of spyhopping, as well as occasional breaches and tail slaps. We followed the group of orcas back towards shore and caught up with them again near Lime Kiln. Their formation had broken up slightly and the killer whales were more spread out. We continued south to False Bay, taking a number of different recording of killer whale vocalizations, before turning around to head back to Snug Harbor where we would meet up to head for a talk at the Whale Museum in Friday Harbor. On our way back up north along the coast, Elise spotted a small pod of Dall’s porpoises and we all watched from the bow as a number of individuals took advantage of the Gato Verde for some bowriding pleasure.

Localization experiment

Tuesday, September 4, 2007

The first thing we had to do today was head to Roche Harbor to pump out our holding tank, or black water, which was at full. On our way out of Roche, Liz, Wessal, Heather, and Scott calibrated our holding tank and sewage system by pouring a 5 gallon bucket into the heads onboard and noting the centimeters on the holding tank. We did a lot of sailing today—deploying the screecher and jib, and tacking back and forth. In the afternoon, Jason and Kenna boarded the dinghy (Gatito) and motored a distance away for a localization experiment. After being certain no marine mammals were within sight, they played a recording of a hammer and then killer whale calls with an underwater speaker, while the rest of the group listened the sounds and collected data with the hydrophone array. After making 3 passes to test the accuracy of our localization algorithms, Mike headed the Gato Verde back to Snug harbor in the cold fog where Wessal and Liz prepared a delicious veggie curry.

Killer whales and harbor popoises

Monday, September 3, 2007

We woke up in Snug Harbor for the second group’s first full day on the Gato Verde. We motored through thick fog, heading south along the coast. Elise and Heather took up watch on the bow and pointed out logs and kelp.Off Kanaka Bay, we deployed a hydrophone to make this group’s first recording of killer whale calls. We tested out a possible gunkhole anchorage at Kanaka Bay, but mostly dredged up mud and kelp. Shannon spotted a mother harbor seal with a pup swimming in the bay and a number of seals were just outside the bay as we headed back up the coast of San Juan Island. On our way to Roche Harbor, we deployed a high frequency hydrophone to attempt to record vocalizations of harbor porpoises.

Localizing mother/calf pair

Saturday 9/1/07
Snug Harbor to Snug Harbor

Got a call from Giles saying KW were between False Bay and Lime Kiln. Dave Ellifrit of the Center for Whale Research volunteered that they might be heading north, but not definitely. We needed to pump out and pick up Captain Mike, so we headed for Roche Harbor. Mike and Jason arrived just as we finished pumping out and Mike took the helm as we steamed through Mosquito Pass. By that time the J pod had headed south and diverged from the southern end of San Juan Island (Marla was with them by then). We took the hypotenuse and encountered the pod just N of Hein Bank. Straitwatch approached to see who we were and we met Hillary and Sally. Tim talked Hillary into doing a few drive bys and we recorded her at high and low speeds at ~400m range. Then we followed the fleet back towards False Bay and caught up to the pod leaders around 5 pm. Just as we deployed the array and heard a few calls while heading north, Ruffles and Granny made a sharp left turn and headed SW. We waited a bit, then made a similar turn. Slowly the off- and on-shore whales headed back south. We paralleled and intermittently heard great calls. The final half hour or so was the best with a lone juvenile approaching the boat, making some powerful calls, and then rejoining two adults (females). Some 20 minutes later, we heard a group of (3?) whales foraging and then tracked them (including magnetic bearings from Todd’s hand-bearing compass) as the passed us. Both encounters led to successful localizations!

Gato Verde source level

Friday 8/31/07
Fish Creek to Snug Harbor
Winds SW 5-15 knots, light rain in morning

Spent morning measuring source level of Gato Verde main generator. Around noon, started transit to Snug Harbor, looking for KW en route. Sighted some harbor porpoises in Haro Strait on run downwind under screecher.

Searching Haro and measuring receive levels

Thursday 8/30/07
Garrison Bay to Fish Creek
Winds S 5-20 kts, sunny

Pump out at Roche Harbor. Travel south into Haro Strait winds, practicing tacks and going with the ebb. Search for killer whales on E/W beam reaches just N of Middle Bank. In late afternoon, ride flood through Cattle Pass (at 12 knots over the ground) and anchor in Griffin Bay, just N of Fish Creek. Spend evening processing spreading experiment data from dock experiment, learning how to measure Vrms and compute calibrated receive level of both test signals and background noise.