Gull Lake is a large, shallow lake that mixes completely during most of the summer, and temperature remains uniform from the surface to the bottom.  Marie Lake is not of uniform temperature top to bottom (Marie Lake is strongly thermally stratified).  Will the stratification be lost? Will the stratification cause ducting of the sound without diminishing the intensity?

Travers reservoir is oligotrophic (I did not know what that meant so I looked it up ( refers to any environment which offers little to sustain life)), Marie lake is not. So this is not a valid comparison. 

Lake Newell I could not even find on the Atlas of Alberta Lakes. But it is the largest Man Made Reservoir in Alberta.  So it is not a naturally occurring water body, so it will be hard to compare it to a water body with limited in and outflow, such as Marie Lake.   Also the slopes into the water and bottom sedimentary conditions will be different. 

Here is what Lindy Weilgart (associate at Dalhousie University) had to say:

“Probably even worse than in the ocean because fish would be more restricted and can’t get away. Seismic is known to harm fish, either by changing their behavior, causing them to leave the area, probably temporarily, but for weeks, or even deafen them if close and loud enough. There is a fairly extensive literature showing how catch rates plummet around seismic surveys. Depending on what the lake bottom looks like (whether hard rock, mud, or sand), the damage could be worse/better (rock would be the worst, mud best, probably). I don’t expect seismic to be less harmful in freshwater.”

So the future of Marie Lake if siesmic is carried out does not look good.

Yes the government needs to revise how they grant mineral rights and where, and consult with local land owners, before leasing them.