{"id":2356,"date":"2021-08-23T15:01:06","date_gmt":"2021-08-23T15:01:06","guid":{"rendered":"https:\/\/meridian.cs.dal.ca\/?p=2356"},"modified":"2021-08-24T16:32:56","modified_gmt":"2021-08-24T16:32:56","slug":"listening-under-the-waves-at-tlches","status":"publish","type":"post","link":"https:\/\/meridian.cs.dal.ca\/fr\/2021\/08\/23\/listening-under-the-waves-at-tlches\/","title":{"rendered":"Listening under the waves at Tl\u2019ches"},"content":{"rendered":"

Author: Amalis Riera – Acoustic Data Analyst<\/p>\n\n\n\n

On Monday August 9, 2021, MERIDIAN team member Amalis Riera was invited to participate in Indigenous land-based learning and community engagement on the Tl\u2019ches Islands as part of the Living Lab Project<\/a>.   <\/p>\n\n\n\n

Tl\u2019ches (Lekwungen name), also known as Chatham and Discovery Islands, are Songhees reserve lands located 2 kilometres from Oak Bay on Southern Vancouver Island, BC.<\/p>\n\n\n\n

Tl\u2019ches is one of the last locations in Songhees homelands that remains almost as it was 200 years ago, presenting a unique ecosystem that reflects the Songhees relationship to the land and water. It was inhabitated for thousands of years by Songhees-Coast Salish people until colonization in the late 1800\u2019s. <\/p>\n\n\n\n

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Group gathering by the Tl\u2019ches shore, reading organisms names in Lekwungen language on the field guides.<\/figcaption><\/figure><\/div>\n\n\n\n

As part of this summer\u2019s Living Lab Indigenous Youth Eco-Stewardship Program, 15 Lekwungen youth aged 16-30 arrived to Tl\u2019ches to gather with knowledge keepers, community members and UVic folks. This included scientists who shared their knowledge and created interactive activities for the youth to learn about tides and currents (Luci Marshall, ONC), clams (John Taylor, UVic), intertidal invertebrates (Louise Page, UVic), and underwater sound (Amalis Riera, MERIDIAN).<\/p>\n\n\n\n

Amalis brought a portable hydrophone-and-recorder system to eavesdrop on the island\u2019s underwater shore, as the tide was rising. Young curious souls gasped in wonder as they heard the rustle of a hermit crab scurrying near the hydrophone in a tidepool that was full of tiny sculpins (who were unfortunately too shy to say hello to the audience). The tidepool sounds were more quiet and less variable than those heard under the waves, in a rocky bottom. The rush of the tide could be heard, sounding \u201clike a washing machine\u201d as some would say. A distant speedboat made a convenient appearance, to demonstrate how far their sound can travel, how quickly the volume increases, to decrease as soon as the boat moved away. <\/p>\n\n\n\n

Recording of boat noise as it starts, approaches, and fades away. The \u201crasping\u201d noise that can be heard 6 seconds from the beginning of the clip is the sound of an outboard engine being cranked and started.<\/figcaption><\/figure>\n\n\n\n

The constant popping and crackling sound that is so characteristic of these waters was likened to \u201cfireworks\u201d, which was a refreshing new take on the \u201cfrying pan\u201d metaphor.<\/p>\n\n\n\n

Compilation of popping sounds that are very common in our waters (including varying degrees of background boat noise).<\/figcaption><\/figure>\n\n\n\n

The Hydrophone Lowering Down and Pulling Back Out events were particularly popular moments for listeners, as they were notoriously loud compared to the sound captured by a static hydrophone.<\/p>\n\n\n\n

Sound of the hydrophone as it is being dragged along the ocean floor, yanked up (it got stuck), and pulled out of the water (warning: lower the volume, it may be loud).<\/figcaption><\/figure>\n\n\n\n

But the unanimously favourite acoustic experiment was to listen underwater for the sound of a rock thrown by a helpful assistant.<\/p>\n\n\n\n