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13 The goal of this project is to expand the demographic range ofHBC and use warmer tributaries as growout areas for small HBC. The objective is to transplant small HBC into appropriate tributaries within Grand Canyon National Park and within tribal lands found in the Little Colorado River. The end product may be several tributaries containing HBC as they did historically and effectively expanding the current range of HBC. V. Study area Tributaries of the Colorado River within Grand Canyon National Park and Oil. tribal lands in the Little Colorado River VI. Study Methods/Approach The approach to this project will first include a review of past studies on tributaries and identification of information gaps such as discharge, habitat, water quality and existing fish densities. Biologists will be taken to the lower end of the Little Colorado River at Boulder's Camp to obtain approximately (300) 50-l00mm HBC. Near the confluence of the Colorado River, HBC are most vulnerable to being washed into the mainstem and long-teml survival is reduced. The minimum size that HBC can be elastomer marked is approximately 50mm total length. Due to the limited number of fish being moved, every opportunity to detect fish movement out of the tributaries and be able to identity translocated individuals needs to be pursed. Capture methods used will include seining, minnow traps and hoop nets. Due to the warm ambient air temperatures in the LCR during summer, all capture efforts will be conducted during early morning and late afternoon to reduce stress and mortality of captured fishes. Captured fish will be measured for length, and implanted with an elastomer tag with a unique color. During subsequent monitoring effort and pending approval by the National Park Service and the Navajo Nation, all captured nonnative fishes will be sacrificed. All other fishes will be retumed to point of capture. All captured HBC will be held in 1/8 mesh live cars in the LCR until transport. Fish will be transported to the release site in an aerated tank or cooler stored within the helicopter. At the release site, fish will be tempered both for temperature, pH and potentially C02 levels until differences between parameters are within I mg/l and I DC. Following tempering, translocated fish will be held in live cars at several locations within each tributary. At each location fish will monitored for stress and mortality for a minimum of 24 hours. Following 24 hours of monitoring, fish will be released into the tributary. Monitoring efforts and evaluation of transplant success will occur twice per year. For the initial Chute Falls translocation, the benefits of this action include introduction ofHBC into presently unoccupied habitat in the LCR. It will provide an opportunity for growth of young fish to a size where they have a higher likelihood of surviving should they be carried or dispersed to the mainstream. Risks include the probability that a flood will carry them to the mainstream before sufficient growth increases their likelihood of survivorship. There is some Ve1Y small genetic risk that a reproducing founder population with limited genetic diversity will become established. The probability that transplanted fish will remain there until reproductive age is very small, but in the event that such might occur, remedial actions can be taken to remove the population from that reach of the river or to periodically augment it with from the lower LCR to enhance genetic diversity. Created on 5/6/20035:41 PM