This study was conducted to gain a better understanding of fishery resources in Abbotts Lagoon, Point Reyes National Seashore. During February/March, May, August, and November 1999, fish were sampled with floating variable-mesh gill nets and small minnow traps from as many as 14 sites in the lagoon. Water temperature, dissolved oxygen, pH, total ammonia(NH3 + NH4+), salinity, turbidity, water depth, and bottom substrate composition were also measured at each site. A total of 2,656 fish represented by eight species was captured during the study. Gill nets captured Sacramento perch, Archoplites interruptus; largemouth bass, Micropterus salmoides; Pacific herring, Clupea pallasi; prickly sculpin, Cottus asper, silver surfperch, Hyperprosopon ellipticum; longfin smelt, Spirinchus thaleichthys; and striped bass, Morone saxatilis; whereas minnow traps captured Sacramento perch; prickly sculpin; and threespine stickleback, Gasterosteus aculeatus. Cluster analysis (Ward's minimum variance method of fish catch statistics identified two major species assemblages-the first dominated by Sacramento perch and, to a lesser extent, by largemouth bass, and the second dominated by Pacific herring and threespine stickleback. Simple discriminant analysis of environmental variables indicated that salinity contributed the most towards separating the two assemblages.
