The reason rainbow trout survived and spawned successfully is the same reason they live in so many different habitats out west and around the world. They have a very plastic ability to live in a broad range of habitats and water temperatures. They are able to withstand water temperatures from just above freezing to almost 80 degrees, and more importantly, they are capable of spawning from early winter through late spring. Once spawned, the rainbow eggs can survive and hatch in water temperatures from the mid-30s to above 60 degrees. Other trout species like brook trout, lake trout and cutthroat trout are unable to survive water temperatures much above 68 degrees and require spawning temperatures below 50 degrees.
Brown trout are an exception.
They survive and grow very well in our spring branches, but their spawning and hatching requirements are much more critical. Browns do not spawn successfully in Missouri's spring branches. Studies by the Department of Conservation and the U.S. Park Service show that the newly spawned eggs die about 13 days after fertilization because of water temperatures higher than 52 degrees. This precludes them becoming established in any of our spring branches. They do spawn successfully in the White River below Bull Shoals Dam and will probably spawn in Lake Taneycomo.