Sea State, Sounds, Skiffs

There are many things I’d like to report on, but I decided to concentrate on our water based progress. After a short delay Noble Stead is now on the water and operating daily. We’ve had some fairly large tides in the past week- the 4th of July saw a 23 foot tidal shift- and our team has been deftly navigating Noble Stead around the island. Trial and error has taught us that two hands are better than one when it comes to handling our two hydrophones and the associated gear.

We have two C-55 Cetacean Research Technology dip hydrophones which we lower from the side of Noble Stead to 25 meters. They are weighted with ½ pound weights and outfitted with a sort of “shock absorber” to reduce the impact of wave and bounce related noise. Two interns man the hydrophones with a Zoom Acoustics recorder, a GPS, a thermometer, and a compass. We record in 30 minute intervals (time with tower observations) and mark each sound we hear.

And we are hearing things! Purrs and groans, tear drops and grunts, and a myriad of combinations have all made their way through our hydrophones and into the ears of our interns and myself.

A thick fog kept us off the water periodically (much to the chagrin of Ryan and Nicole who were poised on the glassy southeast Alaskan waters in Noble stead for a dawn survey at 3:15am). That morning we had to pull everyone in to the lighthouse by 5:30 and rather than work our way back to bed we settled in with headphones and data books to review our sound files.

Our initial acoustic analysis is done aurally (by ear). We listen for sounds while recording from Noble Stead, and then review our recordings in the controlled environment of the lighthouse. Each sound is verified, clipped, and then added to a general catalogue to be incorporated into our spreadsheet. Our spreadsheet then tells the story, including the vocalizations, of exactly what we saw on a given day.

Our catalog is growing. We’re becoming more familiar with the vocal range of the humpbacks, and our accuracy is improving. We’ve started the process of categorizing sounds, and each intern (including those of you coming this week!) will have the chance- and perhaps the responsibility- to listen to the sounds and place them into categories. At the end of the season we’ll have 13 groupings of sounds which we’ll check for consistency and overlap. This ‘blind’ categorizing is the first step in classifying sounds.

In addition to hearing our beloved humpbacks we’ve also started picking up vocalizations that are distinctly odontocete-esque. As if to confirm our suspicions this evening during our dusk survey a small pod of killer whales worked their way right next to our island, before startling a raft of sea lions and buzzing past Noble Stead on their way north. Despite what the weather keeps telling us (3 foot seas and rain) tonight and last night have been breathtakingly beautiful. It’s almost painful to see the photographs… which I’m hoping will be uploaded soon by our Session 1 interns.

I regret to say that Session 1 is coming to an end. Norma, Kate, Ryan, and Nicole will be sadly departing on Wednesday. While I intend to recruit them to post photographs for me, it’s not a happy departure. It’s been an adventure and a pleasure having them here… I’m sure they know I mean that.

Look for posts on our Session 2 interns- Laura, Crisitina, Meghan, and Venus- they arrive just as Session 1 departs… and so it continues.

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