Humanity and Evolution

Authors: Gordon Mueller

Year: 2010 (xlii)

Abstract

Efforts to recover razorback sucker has been ongoing for more than 3 decades with little success. Federal and state hatcheries have produced and stocked millions of razorbacks; however, reintroduction efforts have failed to build, let-alone retain wild populations. Hatchery produced razorbacks have been shown to be predator naÁ¯ve and lack the survival skills and conditioning necessary to survive; a situation worsened by the practice of stocking on predator communities at carrying capacity. In spite of dismal survival, stocking continues unabated. It is well documented that natural, as well as artificially induced stressors accelerates evolutionary change. Natural selection that determines survival skills is largely absent in hatcheries which leads to domestication. Mundane rearing environments retard the process of natural selection and possibly impact inherited behaviors necessary for survival. Researchers have reported hatchery reared salmon exhibit retarded or accentuated inherited fish behavior traits; which in some cases increase aggressive behavior and reduces survival rates. The impact of hatchery production on commercial salmon stocks continues to be a key research concern in the Pacific Northwest. Similar concern for hatchery produced razorback is lacking as is an understanding of the behavioral adaptations that might also be occurring in nature. Relic populations in the Green, Yampa and Upper Colorado River; Lakes Mohave, Havasu and Roosevelt failed to adapt to human induced change and have vanished. However, a single, relic population has persisted in Lake Mead for 75 years. This oldest and last wild population has not only survived but is recruiting naturally in an environment so physically and biologically altered, it defies scientific explanation. Why there? Could behavioral adaptation within this population help explain recruitment; if so, could researchers even tell? Basin research needs to advance beyond physically based sciences to better understand issues of hatchery domestication and how inherited behavior influences survival. Management must accept the limitations, risks, and environmental ethics of stocking to merely maintain a species presence and acknowledge that hatchery razorbacks cannot survive in predator-laden habitats. Program achievement should be based on stocking survival and sustainable populations; not driven by production and stocking commitments. Conservation and recovery programs need to become more biologically accountable in terms of first securing self-sustaining communities regardless of location and minimize the ramifications of hatchery domestication. Conservation efforts should focus on those habitats and locations that have the greatest likelihood of reestablishing communities. Past research has shown that self-sustaining populations can be effectively established in off-channel, predator free habitats. An effective sanctuary plan was presented by Minckley and others (2003) nearly 8 years ago. All that remains is for agencies to find the political fortitude to implement it. Once off-channel communities are secure, the next logical step would be the most difficult task of reestablishing mainstem populations.