. Bulletin - Southern California Academy of Sciences. Science. STATUS OF STEELHEAD TROUT IN MALIBU CREEK â ^ "fr '9 7'>*G ' 'i â *b ~*b ^ ^ ^» ^ ^? ^? "** "«V "%- "^ ^ ""%> ^* -6> -^> â¢$? -^ -^ vy *<? ^ ^ "iS" *?â "&â â j" Temperature {degrees C} Fig. 6. Frequency of occurrence of water temperatures measured at 15-30 minute intervals in steelhead occupied pools in Malibu Creek, 2005, 2006, 2008 (2005 N= 1,791; 2006 N=4,445; 2008 N=8,750). during the fish die-off time frame. Ammonia-nitrogen levels were ppm
. Bulletin - Southern California Academy of Sciences. Science. STATUS OF STEELHEAD TROUT IN MALIBU CREEK â ^ "fr '9 7'>*G ' 'i â *b ~*b ^ ^ ^» ^ ^? ^? "** "«V "%- "^ ^ ""%> ^* -6> -^> â¢$? -^ -^ vy *<? ^ ^ "iS" *?â "&â â j" Temperature {degrees C} Fig. 6. Frequency of occurrence of water temperatures measured at 15-30 minute intervals in steelhead occupied pools in Malibu Creek, 2005, 2006, 2008 (2005 N= 1,791; 2006 N=4,445; 2008 N=8,750). during the fish die-off time frame. Ammonia-nitrogen levels were ppm during August 2006, and orthophosphate levels were ppm. A summary of all data is found at Dissolved oxygen levels were only directly measured mid-day at the surface, and were found to be 10 mg/1. No continually recorded DO data sets are available for Malibu Creek. No evidence could be found for any toxic spills or acute pollution event. Toxicity testing of the grab sample collected on September 21, 2006 by the LVMWD was negative. Bti application by the LACVC followed the same procedures as previous years, with a volume of liters per event released at each of four locations within the study reach. Two of these locations received applications at the normal rate between June and August 2006 (M6 and M11)(LACVC 2006). Sediment Toxicity At the request of the Technical Advisory Committee, a sample of sediment was collected on 14 December 2006, refrigerated and shipped to Nautilus Environmental Bioassay Laboratory, San Diego for analysis. Mean survival of the amphipod Hyallela Table 2. Percentage of logged time that water temperatures occurred in Malibu Creek between June 13-September 12 2005, 2006, 2008. (2005 N= 1,791; 2006 N=4,445; 2008 N=8,750). Degrees C 2005 0% 1% 21% 50% 25% 4% 0% 2006 0% 1% 9% 35% 35% 16% 5% 2008 0% 0% 9% 53% 29% 8% 1%. Please note that these images are extracted from scanned pag
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