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I I I I I I I I I I I I I I I I I I I . water within a few minutes of being knocked out, measured and weighed. These pikeminnow recovered quickly and showed no signs of adverse effects. It is advised to use caution any time MS- 222 is used. TRANSPORTATION (LOADING, HAULING AND STOCKING) The FRH made only eight off-unit pikeminnow stocking trips. All hauls involved small fish (< 6 inches) and small amounts offish (< 70 pounds). A 250-gallon fiberglass hauling tank supplied with oxygen (1-2 liters/minute) was used in all hauls. This tank was definitely oversized, but no mortality occurred during any of the stocking trips. MARKINGAND TAGGING Fish from each 1991-92 pair-matings (lots) that were to be potential brood fish were Passive Integrated Transponder (PIT) tagged (BioSonics, Inc., Seattle, Washington). Protocol for PIT- tagging fish can be found in Prentice et al (1990). A PIT tag is a small (0.43 inches long and 0.08 inches in diameter) passive radio frequency identification tag which is programmed with a unique identification code that cannot be altered. With the use of a compatible radio frequency identification reading system, each tagged pikeminnow can easily be identified. After the tag was inserted into the pikerninnow's body, valuable information such as tag ill number, lot number, genetic parentage, length, weight, and date of tagging was recorded and later entered into a computer data base network. This network provides information on all PIT -tagged fish in the Colorado River drainage. It is recommended to only tag fish larger than 3 inches. DISEASES AND TREATMENT Inside the hatchery, fish were not exposed to and/or became infected with any fish pathogens. There were fish that were exposed to high levels of gas supersaturation and mortality did occur from gas bubble disease (see Water Quality/Dissolved Gases Criteria/Nitrogen). Outside, several 4-6 inch pikeminnow developed granulomatous lesions of apparent bacterial origin. The granulomas had a soft pulpy core (caseinous) in which a gram-negative and non-acid-fast bacterium was found. All of these fish were sent off for diagnostic work, and results were not conclusive as to the causative bacterium. LITERATURE CITED "Buterbaugh, G.L. and H. Willoughby. 1967. A feeding guide for brook, brown, and rainbow trout. Prog. Fish-Cult. 29:210-215. Prentice, E.F., T. A. Flagg, C. S. McCutcheon, D. F. Brastow, and D. C. Cross. 1990a. Equipment, methods, and an automated data-entry station for PIT tagging. American Fisheries Society Symposium 7:335-340. 15