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41 <br />THE SPAWNING HABITAT AND BEHAVIOR OF SALMO GILAE MILLER, A <br />RARE SOUTHWESTERN SALMONID. <br />John Rinne, Rocky Mountain Forest and Range Experiment Station, <br />Tempe, Arizona. <br />The spawning season of Salmo gilae in three streams in <br />the Gila National Forest, New Mexico commenced in early April 14 <br />and persisted through June, dependent upon stream elevation. <br />Water temperature and streamflow interacted to induce spawning, <br />however, the former was more important. Spawning commenced <br />at water temperatures ofti8° C. <br />Normally a single or a pair of fish occupied a redd, but <br />three to four fish was not uncommon. Most spawning activity <br />occurred between midday and late afternoon (1100-1600 hours). <br />Fry emerged in 8 to 10 weeks at 15 to 20 mm in size and in- <br />habited riffle areas. Avoidance of pools by fry indicated <br />that cannibalism may occur. <br />Redds were normally located about a quarter the distance of <br />stream width from a bank in waters averaging from 6.0 to 15.0 <br />cm in depth. Fine gravel (2 to 9 mm in size) comprised the <br />greatest percentage (by weight) of substrate materials. Spawn- <br />ing fish selected redd sites more based on depth of water and <br />substrate than they did on velocity. Normally, cover was less <br />than 5 m from a redd site. Redds ranged in size from less than <br />0.1 m2 to near 2.0 m2. Redd depressions averaged 3 to 4 cm <br />in depth.