Spatial and Temporal Ecology of Fish Larvae in Seasonal and Perennial Tributaries of The Sacramento River, Calfiornia

ABSTRACT\ud SPATIAL AND TEMPORAL ECOLOGY OF FISH LARVAE IN\ud SEASONAL AND PERENNIAL TRIBUTARIES OF THE\ud SACRAMENTO RIVER, CALIFORNIA\ud by\ud Rebecca C. Walther\ud Master of Science in Biological Sciences\ud California State University, Chico\ud Spring 2009\ud Many studies have shown the benefits of off-channel habitats, such as floodplains,\ud for the early life stages of fishes, but little work has examined the differences in\ud the abundance and distribution of fish larvae between seasonal and perennial stream\ud habitats. To examine this, drift nets were used to compare the spatial and temporal distribution\ud of fish larvae among two seasonal and two perennial tributaries of the Sacramento\ud River, California, during the winter and spring of 2004. Additionally, a detailed\ud examination of the distribution of fish larvae in Mud Creek, a seasonal stream, was conducted\ud in 2006 and 2007. Higher temperatures and an earlier date of first occurrence of\ud fish larvae in the seasonal streams were observed. In addition, Mud Creek produced extremely\ud high numbers of fish larvae and had the greatest diversity and species richness\ud xii\ud among the four sample streams. Taken together, the findings suggest that seasonal\ud streams in the Central Valley are used as spawning and rearing habitat, and the associated\ud warmer water temperatures may elicit earlier adult spawning. These same factors\ud may also contribute to increased fitness and survival of fish larvae, which in turn can\ud enhance recruitment success and year class strength for native fishes, many of which\ud are in decline.CSU, Chic