Yes. We'll get to that in a second.
Mr. Chairman, committee, thank you for the invitation to present here. By introduction, I'm a physics professor at Memorial University, and my research areas are physical oceanography and sonar systems. My goal is to provide a bit of background to inform the deliberations of this committee.
To describe seismic systems a bit, they use sound to probe beneath the ocean floor. The sound sources are impulsive and loud. They're louder than normal physical sources of sound in the ocean, save perhaps lightning strikes and earthquakes. They're certainly louder than any biological sources—louder than shipping noise.
It's hard to describe what these sounds are like. There are discussions of so many decibels and things like that, so I thought it would be useful to play a recording. This is my little sound bite. This is from the south coast of Newfoundland.
[Audio presentation]
That's a seismic shot. It's from a ship that is about 15 kilometres away from the recording. Seismic surveys like that would go on for weeks at a time, and those shots are fired, nominally every 10 seconds; it depends on the exact details.
I should recognize Dr. Jack Lawson, from DFO, for providing me with that recording.
With regard to the impacts, there are acute impacts on animals from these sound sources. Animals within a hundred metres can suffer physical damage, hearing loss. That effect is restricted to within about a hundred metres or so. So that restricts the overall impact of that kind of effect.
Much more of a concern is the chronic exposure, because that sound will propagate for easily a hundred kilometres in the ocean, both because it's so loud and because sound propagates so well. Whales certainly react to seismic survey vessels. It's recently been demonstrated that they have stress response to chronic noise.
There's also an economic twist to this, because fish catch rates have been noted to decrease in response to seismic surveys. There's anecdotal evidence that crab and shrimp catch rates off Newfoundland have been decreased due to seismic surveys, so that implies an economic consideration here. In Newfoundland, the crab and shrimp market was worth somewhat less than $500 million last year; that's an industry that carries on year after year.
There are mitigations that the industry applies to these systems. Most of them target the acute exposure. They rely on visual observers to spot endangered species within about 500 metres of the survey vessel. Because they rely on that visual observation, they don't work at night. They don't work well in fog or rainy conditions, which are known to occur on the Grand Banks.
Surveys can also be timed to avoid critical times for biological processes, critical migrations, things of that sort, but that happens to occur in the summer in Newfoundland, and that also happens to be the time that's most suitable for seismic surveys.