Ecologist George Wuerthner sent me this article about Gray Wolves in northern Minnesota preying on fish(likely Northern Pike and White Suckers)...........This is the first documentation of Wolves dining on freshwater fish outside of northwest Coastal Alaska and the British Columbia Islands of Canada................Researchers reported that two Wolves in Vogageurs National Park spent 1/2 of their hunting day mid April-mid May 2017 hunting fish rather than Elk, Deer, Beaver, their historical dietary staples in this part of the world

https://www.sciencedirect.com/science/article/pii/S161650471730349X

MAMMALIAN BIOLOGY

Do wolves hunt freshwater fish in spring as a food source?

Author links open overlay panelThomas D.GableSteve K.WindelsAustin T.Homkes

11/2/2017

ABSTRACT

In April-May 2017 we documented GPS-collared wolves (V034 and V046) from the same pack in northern Minnesota responding to a spring fish (northern pike and presumably white suckers) run, which to our knowledge is the first description of wolves outside of coastal British Columbia and Alaska using fish as a seasonal food source.

During this period, we opportunistically observed V046 hunting and consuming fish along a single creek, and documented a substantial number of wolf-killed fish in this area. We estimated V034 and V046 spent 43–63% of their daily time budget from mid-April to mid-May hunting and consuming fish at the same creek.

Based on visual observation and the concentration of GPS locations, it appears the wolves targeted shallow, narrow areas along the creek to capture fish. Although short-term responses to alternate foods, such as fish, can be infrequent and challenging to document, they provide valuable insight to the flexibility of wolf hunting and foraging behavior.

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http://blogs.nature.com/news/2008/09/let_them_eat_fish.html

Let them eat fish

02 Sep 2008 | 21:06 BST | Posted by Amber Dance

Wolves, powerful pack hunters who take down elk, moose, and deer,
would rather feast on salmon if given the option.

Scientists knew wolves enjoyed the occasional fillet 

(Wildlife News 2004), but assumed they turned to salmon only 

when their usual prey — big, hoofed mammals — were scarce.

 But a study in Monday’s BMCEcology suggests that when the

 salmon are running, wolves prefer finned food.

http://www.dailymail.co.uk/news/article-1332918/Wolf-catches-salmon-using-fishing-technique-copied-bear.html