Tuesday, 27 September 2011 09:26

Hydrophones, Humpbacks, and Transients, what a day!

Written by Janie

September 24, 2011

By James Pilkington


Winter feels like it has arrived early this year;  the big Aleutian Low is getting pretty comfy out in the Gulf of Alaska.  For the past two weeks, storm force winds and pelting rain have become the norm, until today! Last night, conditions were calm enough and the tide high enough to get the boat off of the beach (where we safely stow it during storms), which meant today was going to be a day of working on the water!

 The first order of the day was to head to the Squally Channel hydrophone station to try to fix it after it ceased working during the last big storm.  On our way across Squally to the hydrophone site on Campania Island, Hermann and I were amazed at the large flocks of Pacific Loons on their southward migration.  And they are not the only ones looking for southern latitudes; flocks of scoters, Mallards and Sand Hill Cranes have also been passing by in the masses the past week, marking the peak of the fall waterfowl migrations!  The waterways around Gil Island and Caamano Sound are major migratory bird corridors for both the northward and southward migrations for thousands of waterfowl; the birds follow precisely the same routes around Gil Island as the proposed tanker traffic for the Northern Gateway Pipeline proposal.

 On our way back from a successful trip in Squally, we spotted a humpback whale on the west side of Ashdown Island and went over to try to get ID photos.  It wasn’t a surprise to spot a blow over there, the west side of Ashdown Island is notoriously productive.  Half a mile W of Ashdown Island, the bottom lies nearly 1000ft below the surface, but as you move closer to Ashdown the bottom rapidly ascends to within  less than 100ft of the surface.  This well-placed steep underwater cliff forces tidal currents to rise to the surface in an event known as ‘tidal upwelling,’ which brings cold water and rich nutrients to the surface where they create amazing amounts of productivity.  And just to make it even more interesting, the tidal currents from Whale Channel, Squally Channel and Campania Sound all collide at this particular location, potentially driving even more upwelling!  Well, if it wasn’t a surprise to see the humpback there, it also wasn’t a surprise to find hundreds of Bonaparte’s gulls and Black-legged Kittiwakes, dozens of Common Murres, Pacific Loons and Red-necked Grebes, several marbled murrelets, and the odd Rhinoceros Auklet gathered along the entire length of the shoreline.  The whale was moving erratically and making shallow dives, typical sub-surface feeding behaviour, but there was no indication at the surface of the type of the prey it was feeding on. Krill? Herring? Pilchard?  The birds were not any help in this respect either, as they seemed to be just ending a big feeding session soon before we arrived.

 This humpback eventually took us down to Sea lion Rocks at the South end of Ashdown, where at least 250 Steller Sea lions were hauled out growling, roaring, and gurgling in their special sea lion way.  We tried looking for one sea lion in particular, like trying to find a needle in a haystack.  Last week, a guide from a local ecotourism lodge called us to report seeing a subadult sea lion at the rocks with a plastic packing strap stuck around its neck, so tight that it was close to causing an open wound.   Plastic debris in the ocean is a major cause of pinniped (seals, sealions, furseals and walrus) deaths, and there is a large public awareness campaign underway to try to bite this bad littering habit of ours in the butt.  Even though most of us do not place trash directly into the oceans, it finds its way there in the wind, the drainage systems, by falling off boats, etc.  Which means we need to do one more thing to those packing straps and plastic can holders before throwing them out; break the loop!  All we have to do is look at something before throwing it out and ask ourselves if the article has a closed circle.  If it does, cut it or break it so that the circle no longer poses a risk to sea creatures in the event that the piece of trash does make it into our oceans (which happens much more than any of us realize, even if we live in places far from the ocean like Saskatchewan or Ontario).  We did not end up finding the sea lion, and were forced to ponder the thought of the painful few years it has left to live as we made our way back to whale point.

 Another item that was on the list for today was to go to the Skinner Island hydrophone and remove it before the storms removed it for us!  The Skinner Island hydrophone is a very special hydrophone because its purpose is to record the deep subsonic vocalizations made by fin whales.  Fin whales have been sighted very frequently in the past 4 years in the waters between Caamano Sound and Douglas Channel, and now have a near-constant spring and summer presence; one of the only nearshore coastal areas where fin whales are consistently seen close to shore (we do not yet know why, or whether they are also present in winter).  One of our major research questions right now is to try to understand how daily oil tanker traffic could affect fin whales in this unique area, but to answer this question we need to know a few things, like how many use the area, what they do while here, how frequently they are here, and whether they vocalize while in the area.  This last one is where the recorder on Skinner Island comes in.  Because fin whales vocalize in a frequency that is too low for us to hear, we do not know if they are making any sounds or communicating in these waters.  To get past this,  we have teamed up with the DFO Cetacean Research Program who generously supplied the equipment (recorder, hydrophone, cable, battery and solar panel).  After installing the hydrophone about 50-60ft below the surface, we set the recorder to record for 10 minutes every 20 minutes (or 10 minutes of every 30 minute period), all day every day.   We then download these recordings at the end of the season and analyze them using spectrograms (visual representations of sound) to look for the low frequency calls made by fin whales.  If we find that they are vocal then we can look at how frequently they vocalize, and what types of vocalizations they are making in order to get a sneak peak into their behaviour and better understand how the loud low-frequency sounds made by tankers could impact fin whales.



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