It’s no secret how much we love fishing mouse patterns for big Alaskan rainbow trout. We do a lot of it and, as odd as it may sound, it is our most productive method for catching trout on the surface. With a conveyor belt of salmon flesh and eggs throughout an already short growing season, these trout are looking for a meal, and that size 16 mayfly is just not going to do it.
However, we are often asked if ‘trout really feed on mice?’ Or if our mouse fly is just acting as an ‘attractor to an extremely opportunistic fish?’ Due to the fact that we release every trout we see, it has been difficult for us to prove that these trout do indeed consume mammals in the wild, until now.
Just this past summer, researchers from the U.S. Fish and Wildlife Service conducted some research on rainbow trout from our river in the Togiak National Wildlife Refuge. While collecting their sample, one fish was deemed a mortality capture, and as standard protocol, the fish was opened up to examine the stomach contents. What did they find? Not 1, not 2, but 19 (with some counts at 20) partially digested shrews in its stomach! Shrews are a smaller mammal on average to a typical mouse, and while there are some feeding differences, they are very similar in appearance to a mouse. Certainly similar enough to justify our mouse patterns! The best part? The trout only measured out to 19 inches in length! Certainly a good trout, but not quite trophy caliber in Alaska standards!
There’s your reason to fish a mouse fly in Alaska, all 19 of them.
German Telge says
I had also found several times, partially digested mice on the stomach of rainbow trouts. in southern Chilean Patagonia.
Since then, I always carry a pair of mouse flies in my fly box.
Kyle Shea says
Awesome! That’s a great point, never can be too prepared!
Thanks for the input German!
I know big bad urban tail water Brown’s loveeeeee mouse patterns right at dusk!!
Mark C says
Here in NZ that’s a very good option especially after what we call a Mast year which is when the beech forests flower very heavily.
That was last summer so here’s hoping there will be some big fish about this season and as we know a 5lb fish can be pumped to 7-8lb in a short period when on the mice.
Think massive protein boost!