Jewels Of The Mountains

Fall is spawning time for brook and brown trout

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On The Fly Freshwater

October 2026

By Paul DiPrima

Photos by Jimmy Jacobs.

Trout are seasonal fish. I am not referring to the old “trout season,” when many states regulated the days of the year when trout could be legally caught. I mean the effect that the hours of daylight and the angle of the sun has on the lives of wild trout and the plants and animals that live in or near trout habitat. In the fall, daylight hours become shorter, the days begin to cool and – just as the deciduous trees change from the many shades of green to vibrant yellow, orange and red – the trout also change.

In Georgia, from August thru November, and late as December, wild brook and brown trout that are mature enough to spawn change their behavior, and their bodies also change.

Male brooks and browns often develop a hooked lower jaw or kype that is used to fight off competing males. The colors of the male and female trout will become more vibrant, with the male having the richest colors. The belly of the male brown trout turns deep yellow, almost golden, and the reddish-orange spots often ringed with pale blue halos grow more visible. The belly of a male brook trout becomes deep orange, almost red. The pectoral, pelvic and anal fins also turn the same reddish-orange with a narrow leading edge of white followed by a stripe of black. The colors on the back and sides of the male brook also intensify and the spots are more prominent.

These fish with their brilliant spawning colors are often referred to as the “jewels of the mountains.”

What are the triggers for this transformation from a pretty fish into a spectacular one? What causes the biological changes? The sun is the culprit. Trout have evolved over hundreds of centuries to the point that, as the hour of daylight become less, their need to spawn triggers hormones to be released. As the seasons go from summer to fall, the hormones increase and the colors intensify. At the same time the fish begin to feed actively to supply energy needed to make the color transformation. It also starts the male to seek out possible spawning areas.

Georgia’s native brook trout are found in small headwaters streams.

In Georgia and many of the southeastern streams in high elevation mountains where natural reproduction occurs, the streams have low levels of limestone and other elements that are needed to produce hatches of steam insects. The insects are there, but not in the numbers that are found in many northern and western streams of the same size. The low number of insects in the small headwaters streams is one reason almost all Georgia stream-bred trout are small. Wild brook trout in Southern Appalachian and Georgia headwaters streams generally reach about 3 to 4 inches by the end of their first year. By their second year in these cold, nutrient-poor mountain streams, brook trout are around 5 inches long. Brook trout in Georgia rarely exceed 8 inches in total length, due to the short growing season and limited food supply in high-elevation headwater streams.

At a year-old wild brookies are just 3 to 4 inches long.

Both brown and brook trout spawn about the same time of year and the same way. Both species of trout spawn when the water temperature is in the 40s. The water temperature is probably the most important factor. Nature is hard to pin point on a calendar and extended warm spells in the fall and early winter can delay spawning. There is probably some biological thermostat that slows egg growth until the water is consistently cold enough for the highest survival rate of eggs and the young fry.

A male trout usually swims upstream until he hinds what his hormone- and instinct-controlled brain thinks is the perfect site for a female to build her redd or nest. The male will defend the area from other males and will welcome a female. The male and female will interact in what is sometimes referred to as courting.

When the water gets cold enough, the female and male will stay almost side by side, with the female releasing eggs and the female releasing milt or sperm. The female will lie on her side and, with her tail, force gravel to cover the fertilized eggs. The male will run other trout away and stay and guard the eggs.

I used to visit brook trout streams when snow was on the ground. The snow is beautiful and seeing the “jewels of the mountains” on a white background is spectacular.