This summer marked a new beginning for the Great Bear Sea Hydrophone Network. We deployed five Autonomous Multichannel Acoustic Recorders (AMAR G2s) around the Central Coast in Heiltsuk territory. Autonomous recorders are basically very sensitive, waterproof, battery-powered audio recorders with a hydrophone (underwater microphone) plugged in. The AMARs were donated to Great Bear Education and Research, Pacific Wild’s sister organization, by JASCO Applied Sciences in Victoria, a company that has been collecting and analyzing underwater acoustic data since 1981.
To record the soundscape with an autonomous recorder, you drop in the water with an anchor system, pick it up once the memory cards are full (ours are set to record for three months), download the data and change the batteries, and then put it back down again. JASCO will use their automated detection software to sort through the audio and automatically pick out cetacean calls, echolocation clicks, and songs, saving us countless hours of manually scanning through recorded audio files.
With our new AMARs, we can gather data more reliably than we could with Great Bear LIVE’s live streaming systems. The hydrophones can be calibrated annually when they are out of the water, unlike our old hydrophones, which were at the end of a long cable anchored to the seafloor. This means that the ambient noise data we collect can be accurately compared with noise levels in other places. [Ambient noise is the background sound in the ocean. It is created by ship noise and other human activity, and natural phenomena like waves and rain]. With our live streaming systems, hydrophone placement was limited by the need for line-of-sight connections between wireless radios. The new systems can be located in areas that we couldn’t reach before.
Research: As in the past, we will collect data on humpback whales, killer whales (both Northern Resident and Bigg’s), and Pacific white-sided dolphins that we pick up on the hydrophones, to increase our understanding of where these animals are at different times of the year. This knowledge can be used to protect whales with better resource management decision-making, for example, limiting noisy underwater activity to periods when whales are generally less active in an area [click here to listen to our archived recordings] There are currently no critical habitat designations for cetaceans listed as threatened under SARA on the Central Coast. Ambient ocean noise levels will be measured and compared between seasons and locales, so that management action can be considered if human noise emissions reach levels known to be damaging for underwater life. Ambient noise is one of the key measures of habitat quality for BC’s threatened and endangered killer whale populations because they need a quiet ocean to be able to find food, communicate, and navigate.
JASCO’s ambient noise processing can also pick out particularly noisy vessels, which can be singled out with Automatic Identification System (AIS) ship tracking. Other research possibilities include pairing a camera with a hydrophone to identify noisy vessels that aren’t picked up on AIS – mainly the smaller recreational boats.
After consulting with the Heiltsuk Integrated Resource Management Department, we placed some of the recorders near the junctions of East-West running channels with the North-South trending Inside Passage, a.k.a. the Alaska Marine Highway, a shipping lane that runs right through the Great Bear Rainforest. Humpback whales use the Central Coast section of the Inside Passage heavily in summer and fall, where sinuous schools of pilchard and other tasty forage fish travel along the shorelines. Unfortunately, humpbacks in this area have often been entangled in fishing nets, which are strung out perpendicular to the shore where they feed. Northern Resident Killer Whales also voyage along this highway in pursuit of Spring salmon on their way up the long, mountainous channels that lead to their natal river systems. Another of the recorders is on the outer coast near Gosling Rock, a sea lion haul-out where Bigg’s Killer Whales hunt, also near the Hecate Strait shipping channel.
We are excited to hear the first results when we pull up the AMARs in November and December. By January we hope to have the AMARS back in the water again, with one of them located in an important herring spawning area in Heiltsuk territory. Did we mention the hydrophones can pick up fish sounds, and that fish are affected by human-caused noise in the ocean? By spring, we hope to be working with a graduate student to work with the data and make it accessible to resource managers, planners, and other researchers. Our network is just part of the bigger picture – here in BC non-profit societies like Orcalab, the North Coast Cetacean Society have been monitoring cetaceans for many, many years using passive acoustic monitoring and visual surveys, as well as have government and university-run programs.
Many members of B.C.’s amazing community of bio-acousticians and whale researchers have generously helped us with their time and advice along the way. Without them, we would be lost. These include HIRMD, JASCO Applied Sciences, Tom Dakin (Ocean Networks Canada), Lance Barrett-Lennard (Marine Mammal Research Program), Kathy Heise (Ocean Wise). Xavier Mouy (JASCO), Ben Hendricks (WWF), Matt Pine and other researchers in the Juanes Lab at the University of Victoria, James Pilkington (Pacific Biological Station), Harald Yurk, Hermann Meuter (Cetacealab), Janie Wray (North Coast Cetacean Society), Paul Spong and Helena Symonds (Orcalab), and Jackie Hildering (Marine Education and Research Society).