King Island Hydrophone Installation

Two Fridays ago we set up the fourth hydrophone in the Central Coast Hydrophone Network. This new station will allow us to begin monitoring the acoustics of Fitz Hugh Sound, an area known for its abundance of humpback and killer whales.

Hydrophone installations are complicated and involve a lot of unknowns. Will there be good signal? What does the bottom of the ocean look like? Is there a protected spot for the equipment box? Approaching King Island in the boat, we were all wondering these things, how long we would be there, and how many times we would have to come back before everything was working smoothly. From the shoreline, our broadcasting hub on the mountain on Campbell Island was not in view. The radios need a line of sight in order to connect with one another, so this was a problem. After some quick scouting, we found a tall hemlock just up the hill from our new station that looked like our best chance for radio contact. The last time I climbed a tree, I wound up with a lot of scratches, branches in my hair, and no signal. As I looked up into the forest canopy, I was not feeling optimistic.

Tree climbing, for the most part, is fun. Focus is key. With two lanyards, you can leapfrog branches, with one always wrapped safely around the tree while you unclip the other. If you unclip the wrong lanyard, however, you’d better hope gravity is taking a nap. Focusing on climbing then, it wasn’t until I came to a clear spot near the top of the tree that I noticed a small blip rising above the treeline of Denny Island. It was our mountain!

Once you’re up in the canopy with the eagles and the ravens, it’s fun to look around just so long as you don’t look down. After some sparse limbing, this view appeared. A couple more minutes and the radio was up, plugged in, and communicating with the rest of the network.

The next step was to get the hydrophone in the water. We were pleasantly surprised on the morning of our installation with the arrival of friend and occasional co-worker Tavish Campbell. After having just spent most of his summer skippering charter trips between Vancouver Island and Alaska he was surprisingly keen to jump in the boat with us and do some diving. As I got down from the tree Tavish was getting suited up to get in the water.

Diving is serious business and we were lucky to have a commercial diver with us to set things up properly. After a lengthy discussion of signals and depths, Tavish got in the water. He swam out to 90 feet with a float attached to a line. When he got to a spot on the bottom that looked appropriate, he was to send us “the signal”. The signal was a plastic bottle he took down with him. When it popped up, we went to where it had surfaced and started lowering the hydrophone, anchor, and leadline. Once it hit bottom, Tavish gave the float a sharp tug and we knew to start heading back to shore. Abandoning his float, Tavish started swimming towards the shore, following a crevasse in the rock. We followed his bubbles until we were able to jump off and unload the rest of the cable to take it up to the box. As Tavish surfaced, he gave an enthusiastic, “That went amazing!” So far so good at King Island.

Now that most of the hard work was done, we decided it was a good time for a lunch break. Sitting on the rocks watching a passing ferry, we were briefly alarmed as the ferry stopped and started to turn around. Immediately we thought, man overboard, and rushed to the boat to turn on the radio to see if there was a mayday call. After hearing nothing and taking a closer look, we realized that what actually caused the ferry to turn around were two humpback whales breaching and feeding in a tideline. Even from the other side of Fitz Hugh Sound we could see the sun lighting up the splashes they were making. Feeling relieved, and then excited, we jumped in the boat to go have a look. A mother and calf who, of course, had stopped breaching by time we got there, were rolling about and feeding on the thousands of fish caught in the current.

Pleased that we’d selected a site that was already receiving whale traffic, we returned to finish the installation. The next step was to set up a solar panel to recharge our battery bank. With good southern exposure and a nice straight cedar tree, this was a simple feat. With our 450 amp hour battery bank, our stations can operate for almost a month without being recharged. Sunshine in the Great Bear can be hard to come by during the winter months, but this 120 watt panel will be enough to keep us going.

The final stages of this installation were the easiest, but not without suspense. Connecting the power to the radio, and the hydrophone to the digital encoder, there is always a moment where you wonder if you will hear the sound of the ocean coming clear through the headphones as you plug them in. Here’s Diana listening. Crystal clear!

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