Nature, Ecology and Special Critters 2009

September 9

Saving a Beautiful California Native -- The Paiute Cutthroat Trout

I decided to take a break today from writing about evolution, to write about one of my favorite topics -- Trout, particularly, the preservation of the Paiute Cutthroat Trout. Anyway, this topic also relates to evolution.

I first heard of these fish many years ago. They were said to be beautiful and rare, living only in a few small creeks in one small drainage on the Eastern slope of California's Sierra Nevada mountain range. Since I grew up fishing farther south in the Sierras, I was intrigued by these fish. When the internet came into being, one of my early searches was to look for a picture of one. It was striking, with large, purple parr marks on a spotless body. Looking up more pictures of these fish recently, I saw that they vary consderably in color, with most of them being a light pink color with purple parr marks, but some having a more yellowish or grayish hue. What they all have in common is a lack of black spots on their bodies, except for up to six on the area near their tails. Some have no spots at all. In any case, they have fewer spots than another native California beauty, the famous Golden Trout of the Golden Trout Creek strain, which has been widely transplanted.

The native home of the Paiute Cutthroat Trout is the Silver King Creek drainage, a tributary of the Carson River. When I think of California Trout, I do not usually think of Cutthroat Trout, but this region of the Sierra's Eastern slope, including the Walker, Carson, and Truckee River drainages, are native Cutthroat territory. The strain of Cutthroats found throughout most of these 3 drainages is called the Lahonton Cutthroat Trout, also a beautiful fish many of which are red over most of their bodies. Their numbers have been decimated -- primarily by the planting of non-native species -- in much of their range, but they still thrive in many places. Fortunately, the Lahontan Cutthroats can thrive in very alkaline waters, being uniquely suited to two large lakes in Nevada with no outlets -- Walker Lake (where the Walker River ends up), and Pyramid Lake (where the Truckee River ends its journey). However, they have virtually disappeared from Lake Tahoe, where they used to grow to over 10 pounds regularly, and provided a commercial fishery before other species took over. Another strain of Cutthroats in California are the Coastal Cutthroats along the far Northern Coast of California. The Coastal Cutthroat is a sea-run strain which is found throughout the Pacific Northwest.

In contrast to the Lahontan Cutthroat, the Paiute Cutthroat were never very common due to their limited range. They are presumed to have evolved from the Lahontan Cutthroat, living in isolation for many thousands of years due to downstream waterfalls on Silver King Creek, which prevented the Lahontan Cutthroats from migrating upstream. These waterfalls were apparently formed during the ice ages, either through volcanic activity, or glacial activity. The similarities between the two strains of Cutthoat, Lahontan and Paiute, are evident in their appearance -- the lack of spots, the distinct red slash under the throat which gives Cutthroats their name, their relatively solid colors. The differences are the large purple oval shaped parr marks along the midline of the Paiute's bodies, even fewer spots, and their more pinkish, grayish, or yellowish coloration. The Paiute Cutthroat Trout probably also have different habits and diet, since they evolved in relatively small streams. As it turns out, a Basque Shepherder in 1912 caught some of these beautiful fish from Silver King Creek, was enamored with them, and so, transplanted some of them upstream to some tributaries of Silver King Creek, above yet another waterfall called Llewallyn Falls. This move probably saved the pure strain from extinction, because not long afterward, some nitwit put Rainbow Trout in the part of Silver King Creek which provided the Paiute Cutthroat's native habitat. The Rainbows, which technically speaking are conspecific with both Cutthroat Trout and Golden Trout, interbred with the Paiute fish, creating a hybrid strain with individuals varying widely in appearance. The Paiute strain was not native above Llewallyn Falls; that area was originally fishless, but thanks to the Basque Shepherder, this area is now inhabited by pure-strain Paiute Cutthroat Trout. These creeks, which require a hike of many miles just to reach, have long been closed to fishing, however, to protect the fish, so few people have ever caught or even seen a live Paiute Cutthroat Trout.

As it also turns out, my brother Bruce grew up to major in Soil Science, and got a Ph.D. in this topic. Subsequently, he was hired as a scientist by the California State Water Quality Control Board, at their office in South Lake Tahoe. As part of his job, he works with fisheries experts on water quality issues. During the past few years, the California Department of Fish and Game, as part of its efforts to preserve and restore native species, and with the support of conservation and fishing groups, has been determned to restore the Paiute Cutthroats to their native home. My brother has been a consultant to this project. After much debate, it has been determined that Rotenone would be used to eliminate all fish from the native range of the Paiute Cutthroat. Subsequently, the plan is to reintroduce purebred Paiute Cutthroats from above Llewallyn Falls to areas below the falls to which they were native. Rotenone is a poison derived from Chysanthemum plants which suffocates aquatic life, then biodegrades. Some conservationists were concerned that irreparable damage would be done by the Rotenone to other species such as Salamanders and Frogs in the area, but the Rotenone advocates won the argument. For awhile, Bruce was telling me that people would be encouraged to simply fish out all of the hybrid trout though sportfishing, but that was ultimately deemed impracticle. (In fact, he was encouraging me to go fishing there, which involves a six mile hike to reach even the lower part of Silver King Creek where the trail first reaches the creek.) At this time, the Rotenone has not yet been used in Silver King Creek, but if successful, eventually, the range of the Paiute Cutthroat will be extended to their original range, and perhaps beyond, and fishing for these beauties may be allowed.

I await further word from my brother and news sources regarding the outcome of this project. I have never caught a Cutthroat Trout in California, of any strain, but the point of this post is not to lament the fact that I have never caught one; rather, I celebrate the very existence of these beautiful fish. Although they are not sentient beings in the sense that we are, I love them as beautiful marvels of the natural world, and fellow inhabitants of our planet, who have struggled to survive, and succeeded. Now that we have invaded and changed their environment, they deserve our help.