I could easily see China treating the Arctic as something similar to Antarctica or the South China Sea. Poaching and ignoring Canadian shipping directions etc. Conducting military operations in the area.
If you are worried about Russian subs then a network of microphones, a 12 conventional subs and 24 x P8's would make life extremely difficult. Those P8's when armed with LRASM would make quite effective long range antishipping platforms.
This is Canada we are talking about. 24 x P-8A? 12 SSK? Only if the government were on the electric puha (mary jane) and then some. @John Fedup
will be ROTFPHSL when he reads your post.
To put it into perspective you have a better chance of the current NZ PM ringing up ScoMo tomorrow and ordering 4 Hunter Class frigates without any modifications. Oh yes she'll put a 20% down payment on them to and the cheque is being delivered to the Aussie High Commission in Wellington as they speak.
The trouble with Canadian defence is that it has political problems not to dissimilar to NZ where the government talks the talk but goes out of its way to avoid walking the walk. The second problem is that like Australia, Canada wants to indiginize as much as possible. Unlike Australia the Canadians are fundamentalists about it. Offsets and Canadianization are their religion which they enthusiastically worship. However this comes at great fiscal cost and one would have to wonder whether the revenue clawed back through direct and indirect taxation and government charges, levies etc., make it worthwhile.
Secondly their procurement system is both overly bureaucratic and inefficient creating increased costs both financially and temporally because the procurement process involves two government bureaucracies before it even gets to the political approval stages. The other FVEY nations have a single Defence Ministry / Department to undertake procurement projects before submitting them to the political process. Even in NZ where the MOD & NZDF are separate organisations, they still report to the same Minister. MOD are responsible for procurement projects valued over NZ$15 million, and during a procurement project, NZDF SME are seconded to the MOD procurement project team.
So it's very easy to suggest something like 24 x P-8A and 12 x SSK but given Canadian politics, history and procurement, it's unrealistic.
Finally one point WRT to SOSUS line in the Arctic. The ice is very noisy and thats why subs love hiding in it because the ambient noise masks their presence. It would be very difficult to detect a sub in that environment using a SOSUS setup. However where the water is clear of ice then it's another story. Mind you modern subs are very quiet and it may well be quite difficult for a SOSUS type of capability to locate and hold them, unlike during the Cold War.