Laserfiche WebLink
12 <br />Temperature Observations <br />The high, low, and mean temperatures of fish with temperature- <br />sensitive transmitters and water temperatures recorded near their <br />locations are presented in Figs. 6-15. These data reflect the range of <br />temperatures available and utilized by each fish. Fish numbers 4, 8, 9, <br />10, and 12 had the most notable fluctuations in fish temperature during <br />the months of May and June. This can be related to their use of backwater <br />habitats during this period (Appendix B, Tables 3 and 4). Use of <br />backwater habitat resulted in exposure to higher temperature and appears <br />to have influenced spawning time among migrant fish. Migrant fish <br />numbers 4, 9, and 10 used backwater habitats quite extensively during <br />runoff in May and June, but fish number 5 was not recorded in a backwater <br />until early July. Fish 4, 9, and 10 began migrating before number 5 <br />did. Fish number 4 exhibited spawning behavior patterns at river km <br />26.4 (mile 16.4), one week before fish number 5 did. Fish numbers 4 and <br />5 were tagged in the same river reach on the same day (river km <br />102.2-102.7, mile 63.5-63.8). <br />Ripe males were captured in the vicinity of the spawning site <br />(river km 26.4) during the week of July 11 through 17, when the mean <br />water temperature was 18.5°C. Ripe males and females were captured at <br />the same locations between July 29 and August 8. The mean water <br />temperature recorded in the field during this period was 22.7°C. Based <br />on observations of radiotagged fish at the spawning area, the interval <br />of July 23 through August 8 was identified as the major spawning period <br />in 1982.