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<br />o <br />C'".1 <br />t';J <br />j...\. <br />C::l <br />CD <br /> <br />Fish health personnellperformed complete necropsies on all inspection fish, as well as fish with <br />abnormalities saved by other biologists. Necropsy included: external and internal inspection for gross <br />pathology (lesions, organ deformities, unusual color, excess peritoneal fluid, etc.), bacterial sampling <br />from kidneys and lesions using sterile techniques (disinfecting the leading edge of lesions with 70 <br />percent isopropyl alcohol), and chemical fixation of various organs for histopathological examination. <br />Electrical power for light microscopic observation of skin and gill wet-mounl preparations on selected <br />fish for ectoparasites was provided by a backpack electrofishing generator. <br /> <br />Bacterial samples were isolaled on one of two standard baclerial media: brain-heart infusion agar (BHIA) <br />or trypticase soy agar (TSA). Bacterial isolates were identified in the laboratory using the Minitek™ <br />classification system. A fish was considered bacteremia-positive when bacteria was cultured from. <br />kidney tissue. Bacteremia was defined as presence of bacteria in the blood; this is considered a disease <br />state because blood and kidneys are sterile in healthy fish. <br /> <br />Tissue fixation for histology was performed In the field using Bouin's fixative or 10 percent fonnalin for <br />48 hours with subsequent transfer 10 70 percent isopropyl alcohol. Preserved tissued were sent to the <br />National Fish Health Laboratory, Biological Resources Division (USGS), Kearneysville, West Virginia, <br />for histopathological examination. Potential electrofishing-induced damage was measured by noting <br />gross physiological trauma to kidneys and by radiographing (X-ray) randomly collected fish to identifY <br />vertebral damage. Asian tapeworms, Bothriocephalus acheilognathi, were observed by dissecling fish <br />gastrointestinal tracts using stereo microscopes in the field. Virology tissues were slOred in minimal <br />essential medium (MEM) at 4' C and returned to the PFHC for viral tissue culture assays. <br /> <br />RESULTS: <br /> <br />Fish species with abnormalities: Even though C. latipinnis comprised between 50-60 percent of all <br />fish sampled during each fish survey, it accounted for 70-90 percent of all abnormalities observed. <br />Depending on the survey, C. carpio, C. discobolus, or I. punctatus ranged from I percent to 15 percent of <br />the abnormalities. <br /> <br />Abnormality types: Lesions comprised a majority of the abnormality types, but missing or defonned <br />eyes, scoliosis or lordosis, and a few tumors were found during the fourteen sampling periods. Since the <br />May 1996 survey, there has been a decrease of lesions observed that continued through May 1999. Most <br />of the abnonnalities nOled in the latter period were damaged eye tissue. Spinal deformities continued to <br />decrease each sampling period. <br /> <br />Percentage of fish with abnormalities/Fisb bealth inspection data: Randomly selected C. latipinnis <br />(inspection fish) from each designated mile are represented in Table I. Each of these fish represents a <br />complete necropsy procedure and all abnormalities were noted by fish health biologists. <br /> <br />1 <br />