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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />razorback suckers may not utilize these same barren shoreline habitats. Information gained this <br />year suggests juvenile suckers prefer to hide in extensive vegetative cover where seining would <br />not be effective. <br /> <br />Sampling further upstream in Canyonlands National Park has resulted in the collection of more <br />than a hundred larvae and one juvenile razorback sucker. It is quite possible razorback suckers <br />reside in the immense and remote areas of the upper reservoir. The shallow, flooded habitats <br />found in Farley and White Canyons appear physically similar to habitats used by juveniles and <br />adults elsewhere. Quite possibly these and other canyons or flooded areas in Colorado River <br />inflow area continues to support remnant numbers of suckers. <br /> <br />Some researchers suspect that razorback suckers may be imprinted to natal spawning areas. If so, <br />these fish would return to those areas upon reaching sexual maturity (Wick 1997). The capture <br />and rearing of naturally spawned razorback sucker larvae would provide researchers the <br />opportunity to test this hypothesis. If this type of research was conducted and proved successful, <br />it might lead to the discovery of additional spawning groups and areas. <br /> <br />As in the San Juan inflow area, the establishment or augmentation of a population of adult <br />razorback suckers would benefit the species. There appears to be ample habitat and the presence <br />of increased numbers might lead to upstream migration and the reestablishment or expansion of <br />riverine populations. <br /> <br />Au~mentation of Riverine Populations <br /> <br />-San Juan River-- The golf course ponds could be used to grow larger fish to support recovery in <br />river reaches in- and outside of the Glen Canyon National Park. As discussed earlier, the San <br />Juan RIP has set goals of stocking 40 cm fish, however, they have acknowledged they currently <br />do not have the resources necessary to achieve that goal. Fish reared at the golf course ponds <br />could be directed at those objectives. One possible side benefit in not releasing fish in Utah is the <br />required sacrifice of 50 or more suckers for an entry permit. The San Juan plan involves stocking <br />fish near Farmington, N.M.. It's not known what type of health certification that New Mexico <br />authorities might demand of fish entering from Arizona. This would have to be explored. <br /> <br />-Colorado River--In recent years there has been quite a bit of discussion and one actual workshop <br />devoted to the discussion of razorback sucker management in the Grand Canyon. Razorback <br />suckers have been occasionally captured in upper portions of the Grand Canyon. Little is known <br />regarding whether these fish are maintaining populations or if they represent relict individuals <br />from a pre-dam era. The constant cold releases from Glen Canyon Dam probably limits, if not <br />totally restricts, any mainstem spawning. Further downstream, below Hoover Dam, water <br />temperatures are about 12 degrees C. Scuba surveys have revealed that razorbacks constituted <br />more than 50 percent of the fish observed in the first 3 miles of river below the dam. While <br />temperatures are far from idea, razorback do successfully spawn and their eggs hatch at these <br />temperatures (Mueller 1989). <br /> <br />7 <br />