7025 - Laserfiche WebLink

Home Browse Search

45 introduced species. The barrier effect of dams and the change in water flow regime and quality is certainly the largest single physical impact to native species. - With the exception of construction of large mainstem dams like Flaming Gorge, introduced species are at least equal among other impacts listed. -Nonnative fishes playa significant role in the life history of native fishes. -Introduced fishes could have the most detrimental effect on razorback sucker. It appears this species may successfully spawn but young are eaten. However, loss of habitat obviously is a factor also. Our job of helping these fish would be much easier and probably much more successful if we did not have to deal with introduced fishes. -Totally underestimated! We have done a considerable amount of work in the area of determining habitat changes and effects of habitat changes on native species, but only given lip service to the problem of nonnative impacts. The problem is, it is difficult to do, the outcome is slow, and likelihood of successful removal or elimination is difficult at best -The effect of introduced species is one of the major impacts to native species. All these impacts are cumulative, however, and "recovery" will entail dealing with all simultaneously. -Impacts from introduced fishes may be as or more important You have to view all changes as acting in a synergistic manner; it is difficult to separate one from the other. -Again, it is just one of many. In the case of Lake Powell, altered habitat and predation are having a major impact -Impacts from introduced fishes are very important because introductions are irreversible usually and results are unpredictable. They constitute a confounding variable in most studies. -All impacts are intertwined and you cannot separate one from the others. -Because these fish are present now, our efforts to negatively impact them, especially sportfish, will certainly encounter special interests that will insist or ensure that desirable sportfish persist in the system. Something is broken out there that affects rare native fishes. Mark-recapture of stocked individuals of various sizes is the only way to gain insight to, the problem in a reasonable time period (15 yr). Sure, there are probably impacts due to nonnatives, but much of the perceived problem will remain emotional in spite of the data. There is no doubt that nonnatives are part of the spectrum affecting threatened and endangered fish, but is it part of the addressable spectrum that we can in reality do something about?