Seasonal Abundance, Distribution, and Population Size-Structure of Fishes in SanJuan River Secondary Channels; 1991-1997. San Juan River Implementation Program

摘要

Between Shiprock, New Mexico and Chinle Creek, Utah, secondary channels are acommon feature of the San Juan River. Prior to initiation of the San Juan River Seven-Year Research Program no studies specific to secondary channels had been conducted. As part of the Seven-Year Research Program, research was initiated in 1991 to characterize the fish fauna of San Juan River secondary channels, to discern seasonal-use patterns of secondary channels by common fishes, to evaluate the effects of different flow regimes on common fish species, and to characterize use of secondary channels by rare fishes (roundtail chub, Colorado pikeminnow, and razorback sucker). Summer inventories of secondary channels were initiated in 1991 and spring and autumn inventories began in 1993. Research on secondary channels occurred in Geomorphic Reaches 5, 4, and 3. Flows of 1500 cfs wetted most secondary channels and flows of 2500 cfs inundated almost all.