Per the 2014 'Lake Nipissing Fisheries Management Plan'...the first evidence of double crested cormorants breeding on Nipissing was noted in the early 1980's....they are not native to the lake (which is the same for many other inland lakes throughout Quebec, Ontario and Manitoba).
In 1993 there was approximately 100 breeding nests on lake Nipissing...by 2013 the number of breeding nets was estimated by the OMNRF at 3000.
One adult cormorant eats about a pound of fish per day and dietary studies indicate they will eat 7 perch for each walleye (perch being one of the preferred fish species, of many, they consume).
The double crested cormorant is not a game bird, so there is no hunting or trapping season for the species. Originally, they were protected under the 1997 Fish and Wildlife Conservation Act (FWCA) as a species 'wild by nature' (meaning no one could destroy, take or possess their nests or eggs).
In 2016, through the Ontario legislature (under private members Bill 205), an amendment was introduced to the 1997 FWCA....to permit hunting and trapping of double crested cormorants.
Here's everything you pretty much need to know (courtesy of the OFAH) about double crested cormorants...and their current status/situation in Ontario.
https://www.ofah.org/wp-content/uploads/201...ntrol-in-ON.pdf