26 July 2013
Aboard the Henry Bigelow, Day 2
After a series of delays, we finally departed Newport, RI, the afternoon of July 25th and headed offshore for a very short survey focused on beaked whales! We only have a handful of days in which to work, so we hope to make the most of them. We transited out for about 20 hours, hitting our target area off Georges Bank early Saturday morning. Saturday was quite the day! In the wee hours of the morning, we started off with oceanographic sampling at one of the nearby EcoMon stations, where we did a CTD and bongo cast. As soon as we had daylight, our next order of business was to deploy a passive acoustic recorder (an AMAR, or autonomous multichannel acoustic recorder), that will be out for a year listening for everything from beaked whales to baleen whales. We had picked a site near Lydonia Canyon, so we did some scouting to find an area with our target depth, about 800m (or 2400 ft). At about 6:30am, the Bigelow crew delicately lowered the recorder, its floats, and its 400 lbs of weight over the side of the vessel and away it went! Now it’s sitting on the bottom and recording. Hopefully it will still be there in a year when we go back for it, and it will have a lot to tell us about seasonal occurrence of animals in that area.
That was just the start to our day! We surveyed for beaked whales all day long. We found scattered groups of dolphins and sperm whales, but didn’t have a lot of luck with beaked whales until about 5:00pm, when we hit a patch of glassy water near the shelf break and suddenly found ourselves in the midst of Sowerby’s and Cuvier’s beaked whales. That was exciting for everyone! We worked with them until dusk, collecting data on surfacing rates of groups and towing the hydrophone array, until we couldn’t see them anymore. Finally, around 7:30 pm, we broke off our effort and the day group took a well-deserved break. But the day still wasn’t over! At that point, we switched our effort over to oceanography, prey sampling, and passive acoustics. We spent the night in the same area where we had seen the beaked whales, deploying a small mid-water trawl to a depth of about 500m to target the deep-sea fishes that our beaked whales might be foraging on. It was the first time deploying this net off the Bigelow, and the first time towing through such a deep layer! The tow revealed an interesting composition of deep-sea fishes, including viper fish, hatchet fish, snipe eel, and Ilex squid.
Before long, dawn was upon us again, as we got ready for another 24 hours of surveying, listening, and sampling. We’ll send more updates tomorrow about the cetacean and bird activity out here!