Escapement and Productivity of Spring Chinook and Summer Steelhead in the John Day River Basin, Technical Report 2004-2005 PDF Download

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Languages : en
Pages : 98

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Book Description
The objectives are: (1) Estimate number and distribution of spring Chinook salmon Oncorhynchus tshawytscha redds and spawners in the John Day River subbasin; and (2) Estimate smolt-to-adult survival rates (SAR) and out-migrant abundance for spring Chinook and summer steelhead O. mykiss and life history characteristics of summer steelhead. Spawning ground surveys for spring (stream-type) Chinook salmon were conducted in four main spawning areas (Mainstem, Middle Fork, North Fork, and Granite Creek System) and seven minor spawning areas (South Fork, Camas Creek, Desolation Creek, Trail Creek, Deardorff Creek, Clear Creek, and Big Creek) in the John Day River basin during August and September of 2005. Census surveys included 298.2 river kilometers (88.2 rkm within index, 192.4 rkm additional within census, and 17.6 rkm within random survey areas) of spawning habitat. We observed 902 redds and 701 carcasses including 227 redds in the Mainstem, 178 redds in the Middle Fork, 420 redds in the North Fork, 62 redds in the Granite Creek System, and 15 redds in Desolation Creek. Age composition of carcasses sampled for the entire basin was 1.6% age 3, 91.2% age 4, and 7.1% age 5. The sex ratio was 57.4% female and 42.6% male. Significantly more females than males were observed in the Granite Creek System. During 2005, 82.3% of female carcasses sampled had released all of their eggs. Significantly more pre-spawn mortalities were observed in Granite Creek. Nine (1.3%) of 701 carcasses were of hatchery origin. Of 298 carcasses examined, 4.0% were positive for the presence of lesions. A significantly higher incidence of gill lesions was found in the Granite Creek System when compared to the rest of the basin. Of 114 kidney samples tested, two (1.8%) had clinical BKD levels. Both infected fish were age-4 females in the Middle Fork. All samples tested for IHNV were negative. To estimate spring Chinook and summer steelhead smolt-to-adult survival (SAR) we PIT tagged 5,138 juvenile Chinook and 4,913 steelhead during the spring of 2005. We estimated that 130,144 (95% CL's 97,133-168,409) Chinook emigrated from the upper John Day subbasin past our seining area in the Mainstem John Day River (river kilometers 274-296) between February 4 and June 16, 2005. We also estimated that 32,601 (95% CL's 29,651 and 36,264) Chinook and 47,921 (95% CL's 35,025 and 67,366) steelhead migrated past our Mainstem rotary screw trap at river kilometer (rkm) 326 between October 4, 2004 and July 6, 2005. We estimated that 20,193 (95% CL's 17,699 and 22,983) Chinook and 28,980 (95% CL's 19,914 and 43,705) steelhead migrated past our Middle Fork trap (rkm 24) between October 6, 2004 and June 17, 2005. Seventy three percent of PIT tagged steelhead migrants were age-2 fish, 13.8% were age-3, 12.7% were age-2, and 0.3% were age 4. Spring Chinook SAR for the 2002 brood year was estimated at 2.5% (100 returns of 4,000 PIT tagged smolts). Preliminary steelhead SAR (excluding 2-ocean fish) for the 2004 tagging year was estimated at 1.61% (60 returns of 3,732 PIT-tagged migrants).