Missing finger found inside trout two months later

Missing finger found inside trout two months later

Quite a catch! Har har har.

Earlier this month, an angler named Nolan Calvin was fishing for trout in Priest Lake in Idaho. While he was cleaning one of the trout he had caught, he discovered a human finger inside the trout's stomach. 

Calvin did the sensible thing: he put the finger on ice and called the Bonner County sheriff's department. Officers collected the finger, took fingerprints from the severed digit, and located the owner: a wake boarder named Haans Galassi, who had lost four fingers in the lake last June. Galassi suffered an accident when his fingers were caught in a tow rope. The fingers obviously were never recovered.
 
When the Bonner County sheriff's department asked Galassi if he wanted his finger back, Galassi politely declined. 

My question is, how exactly did this happen? Clearly the finger was preserved well enough to have fingerprints taken from it. There are two possibilities that I can see: either the trout snapped at the finger as it floated down from the accident, or the trout ate the finger recently when it stumbled across it on the lake bed.
 
Both of these theories raise more questions than they answer. The first scenario seems more plausible, given what I know of trout - that they are more likely to strike at something floating in the water column than lying on the lake bed. 
 
But wouldn't you think that the trout's stomach would have dissolved the finger by this point? I could see it taking a very long time in winter, when cold temperatures slow down the digestive process in cold blooded creatures like fish. But at the height of summer, surely the trout would have been able to break down the finger.
 
The second scenario requires that the finger lay on the bottom of the lake for two months, essentially undisturbed and undamaged. Again, this is something that would seem more plausible in winter, as you would think it would require cold water (like refrigerator cold). And in summer you would think that the more active colonies of scavengers would have destroyed the finger within two months.
 
There is a long and active body of literature regarding things found inside fish. And this isn't the first record caught in Priest Lake, either: the largest Lake trout caught in the United States was pulled from Priest Lake. Although the average Lake trout weighs less than 10 pounds, the record fish clocked in at a whopping 57.5 pounds.