Popular topic. The heritage brook trout is in fact the native strain that has evolved here during the past 10,000 years. This native strain was thought to be wiped out due to overfishing and stream habitat destruction beginning in the 1840s.
Stocking of East Coast strains of brookies began early in the 1900’s an brookies eventually rebounded. Scientists feared stocking East Coast trout also contributed to the demise of the native “heritage” brook trout. Not so.
U of MN researchers performed genetic fingerprinting showing these native brookies thrived while many stream with the East Coast strain went belly up.
Conclusion: Sixteen out of nineteen brook trout streams tested in southeast MN contain native heritage brook trout.
Cold Spring Brook was specifically mentionied. IMHO, it is one of the best brook trout streams. It also has the occasional “pig” brown trout if you put in your time and are not afraid of the dark. Also keep in mind trophy browns are meat eaters. In this instance they get fat eating all the heritage brook trout their heart desires at night and sleep all day in an undercut bank.
Source: DNA reveals secrets of brook trout. Brule River Sportsman article, spring 2006.