Archive for April 30th, 2008

Snug Harbor to Garrison Bay

Today was a much calmer day on the water, which meant less sailing, but more chance to do science. We headed out from Snug Harbor into Haro Strait in the direction of Kelp Reef. The main experiment of the day was for Laura’s project. We lowered the hydrophone array vertically off the back of the Gato Verde and then tried to implode light bulbs about 100 meters from the array. If you get the light bulb to implode it makes a nice sound source at depth. Unfortunately we must have been too shallow as the light bulbs did not implode at depth. We’ll have to try that experiment again at a later date. Dominique also spent a fair amount of time learning how to use Noble Tech software (nautical chart software) that incorporates AIS (Automatic Identification System). Ships over about 65 feet give off a signal that lets others with an AIS receiver in the area receive the position and other information on that ship. Since Dominique is interested in the effects of ship noise of Southern Resident killer whale hearing, it will be important for her to know how far away the ship past us while she is recording their noise. After our day of experiments we headed in to Roche Harbor to pump out and then snuck around the corner into Garrison Bay to anchor. After dinner the students went ashore to English Camp (a National Historical Park) to stretch their legs. After returning to the boat we had our journal club meeting, during which we discussed a paper that modelled the acoustic impact of whale watching vessels on killer whales.

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