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<br />2400 hours. Water velocity was recorded at each location and sampling <br />period with a Marsh-McBirney1 current meter. Backwaters were sampled for <br />larval fish with 1.0 x 1.0 m seine with 0.63 mm2 mesh at weekly intervals <br />during July and August, 1981-88, in the two nursery areas. <br />Backwater sampling was conducted in September and October, 1979- <br />1985, 1987-1988, in the two nursery areas. Backwaters were sampled using <br />a systematic design: a random starting place was selected, the river was <br />divided into 8 km sections, and the first two backwaters were sampled in <br />each respective section. Selected backwaters were sampled with a 5.0 x <br />1.0 m seine of 3.2 x 4.8 mm woven mesh. Two seine hauls were made in <br /> <br />backwaters less than 20 m in length and at least three hauls were made in <br />backwaters longer than 20 m. Colorado squawfish were counted and total <br />length (TL) measured to the nearest mm. All other species were counted <br />and divided into 10 mm length classes. Colorado River chubs (presumably <br />Gila robusta but may also contain ~. ~ and ~. eleqans) were <br />collectively identified as Gila and all small suckers (< 30 mm TL) were <br />identified as Catostomus (presumably ~. latioinnis and ~. discobolus, but <br />may also contain ~. commersoni). Larval fishes were preserved in 5% <br />formalin and sent to the Larval Fish Laboratory at Colorado State <br /> <br />University for identification. After seining, the area sampled, maximum <br />depth, temperature, and backwater configuration were recorded. Maximum <br />depth was defined as the deepest depth measured during seining. <br />Data analysis. Species associations were examined by calculating a <br />correlation coefficient matrix of loge (index of abundance + 1) for all <br /> <br />1Mention of trade names does not constitute endorsement of <br />commercial products by the Fish and Wildlife Service. <br /> <br />5 <br />