The USGS Branch of Analytical Services' Biological Quality-Assurance Unit (Biological QA Unit) located at the National Water-Quality Laboratory provides verification of taxonomic identifications through the collection of voucher specimens and the establishment of a fish reference collection. At each sampling reach, voucher specimens (representatives of taxonomically difficult nongame species collected from each sampling reach) are collected, fixed, and preserved to document and verify species identifications. Occasionally, game fish species may be included as voucher specimens in the unlikely event of questions regarding taxonomy of game fish. However, game fish species generally should not be included as voucher specimens because of their economic and recreational value. If a wide range of sizes occurs for a species collected within a sampling reach, two voucher specimens for that species should be collected--a small-size individual and a larger specimen. Preserved voucher specimens are shipped to the Biological QA Unit for verification and establishment of a reference collection.
A fish reference collection is maintained to corroborate the correct identification of a reported species. A reference collection is necessary because of changes in taxonomy, questions regarding taxonomically difficult specimens, and the fact that there are still new species native to the United States that are occasionally discovered (Jenkins, 1976; Lundberg and McDade, 1990). The importance of establishing a reference collection is further described by Crossman (1980), Haedrich (1983), and Lundberg and McDade (1990).
Field data sheets should be printed on waterproof paper using water-, formalin-, and alcohol-resistant inks. Recommendations are provided for two data sheets--a fish sampling equipment data sheet (fig. 7) and a fish species data sheet (fig. 8).
The fish sampling equipment data sheet (fig. 7) is divided into two sections--site information and equipment use information. Site information includes the study unit designation, the sampling date, the station name and identification number, investigators, reach conditions, reference location, reach length, and water-quality information. Equipment use information includes specific information about the types of sampling gear used. The purpose of the fish equipment data sheet is to provide a record of all methods and gear used at a sampling reach. One fish equipment data sheet is completed per sampling reach.
The first component of the site information section is the study unit designation. The four-letter code of the study unit name (table 1) is recorded for the NAWQA study unit designation (for example, ALBE for Albemarle-Pamlico Drainage). The sampling date is entered in numeric format for month, day, and year (for example, December 1, 1992, is 12-01-92). The station name may be a descriptive name (for example, Yakima River at Kiona,