7908 - Laserfiche WebLink

Home Browse Search

2-10 . Chapter 2 more efficient with little perceptible injury to the fish. However, angling was used to catch actively- feeding rainbow trout for stomach analysis to assess predation on young-of-year (YOY) and juvenile humpback chub in the vicinity of the LCR inflow. FISH HANDLING METHODS Care and Processina Fish were placed in live wells to minimize stress and to enhance their recovery from handling. Live wells consisted of 127-L insulated coolers located on each netting and electrofishing boat, 13-L bail buckets carried by seining crews, and 1.2 m x 1.8 m x 1.3-cm mesh (4 ft x 6 ft, 0.5-in) holding pens placed in the river. Fresh river water was used in all live wells and water was changed frequently when holding time was prolonged or when large numbers of fish were being held. Fish showing signs of stress (e.g., increased or irregular gill movements, loss of equilibrium, dramatic color change, reddened fms, excessive slime) were isolated in fresh water carefully monitored, and treated with a 5% sal~ solution to minimize electrolytic losses (Hattingh et al. 1975, Bulkley et al. 1981). Fish with extended lethargy or obvious injuries were appropriately treated (e.g., Betadine™was applied to wounds) and released upon recovery. Dead fish were preserved in an appropriately labeled container and transferred to the ichthyology collection at Arizona State TECHNIQUES NATIVE SPECIES (FM, BHI" TL, SL, WT - All Sizes PeT Ta - > 150mm TL NON.NATlVE SPECIES (RB. BR, SB, CCI' TL, SL, WT . All Sizes Slomach Sam les - RB, BR, SB, CC Final Report University. Incidental mortality of humpback chub from this investigation did not exceed 10 per year, which was the number allowed under BlW's federal collecting permit. From October 1990 through July 1991, all humpback chub captured were transported to a central processing station near each camp and returned to their respective capture locations for release--a one-way distance of up to 6.4 kIn (4 mi). This protocol prolonged holding time and unnecessarily stressed the fish. It was modified in August 1991 so that humpback chub were processed and released near their capture location, and only adults destined for radio-implant were transported to a central processing station. A number of fish processing procedures were used during the course of this investigation. Some were initiated by the original study design and modified or discontinued, while others were implemented as a result of specific data needs or at the request of the ACT (Fig. 2-6). Humpback chub were measured for total length (TL), standard length (SL), and fork length (FL) in millimeters, weighed wet in grams, and gender was determined for each fish. From October 1990 through July 1991, the left side of every humpback chub 200 mm TL or longer was photographed (35-mm color slide and VHS video) on a white plasticized board; the board was marked with a l-cm grid to provide a spatial reference scale :TL= Iotal length, SL= standard length, FL= forked length, WT= lNeighl FM= flannelrrouth sucker, BH= b1uehead sucker , RB= rainbJw trout, BR= brown troLi, SB= striped bass, CC= charnel catfish Fig. 2-6. Schedule of fish processing procedures conducted by BIOIWEST.