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.-~. ... PHYSICAL MEASUREMENTS, LIGHT TRAPPING AND NETTING Methods Physical water quality parameters were measured using a Hydrolab each trip. Readings were taken by boat at 1-m depth intervals at the ponds deepest location. Light traps were set to determine the presence of fish larvae, however, their use was restricted to periods following telemetry work because it was believed their presence could affect fish behavior. Light traps were set near suspected spawning areas for intervals of two hours and overnight. Samples were examined in the field. Fish larvae were separated from other organisms and preserved for later analysis. CHLP was surveyed on July 23, 2003 and a resulting bathometry map was produced (Map 1). This map will be further refined to show submergent vegetation, information that will be presented next year. Trammel nets were set March 17 to capture adult bonytail for the telemetry study. Only large-meshed (7.5-cm stretched bar) nets were used to avoid capturing small fish. We also set nets following the study to recapture study fish in order to examine and remove transmitters. Immediately following the study (May 7) we set trammel nets parallel to the High Levee at 04:00 hours to intersect fish returning to their cavities. Realizing our opportunity to recapture large bonytail, we collected gut samples from fish <40 cm using a nonlethal method of stomach and intestinal irrigation that was developed for adult humpback and roundtail chub (Wasowicz and Valdez 1994, Valdez and Hoffnagle 1999). We duplicated this technique using vinyl tubing and a hand water pump (Wasowicz and Va1dez 1994). Water was forced through the intestinal track, which flushed consumed material out ofthe fish's anal vent. The samples were collected, preserved, and are being examined in the laboratory. Results and Discussion HydrolabMeasurements. Limnological parameters all appeared normal. CHLP remained generally well mixed and parameters remained within acceptable limits. Temperatures ranged between 16 and 30 DC, dissolved oxygen ranged from 7.7 to 10.8 mglL, conductance ranged from 1207 to 1234 !-un/cm, and pH ranged from 7.1 to 7.6. Fish Larval Collections. Larval light traps were periodically set to determine the presence of fish larvae. Last year we were unable to collect any razorback sucker larvae and with the absence of juvenile razorback suckers in the collection, we speculated that either spawning or larval survival had not been successful. Light traps were again used, except during the bonytail telemetry study. We discovered that adult bonytail avoided 12