Area Use and Dispersal of White Croaker Genyonemus lineatus in the Los Angeles and Long Beach Harbors

Understanding fish movements in relation to areas of contaminated sediment is important for management and remediation.  In this study, the movements of white croaker in the Los Angeles and Long Beach Harbors are studied using both active and passive acoustic telemetry tracking.  Daily area use for 20 actively tracked fish averaged 94,720 ± 78,720 m² (± SD) and was smallest in the vicinity of the most highly contaminated sediments in the harbor, with activity spaces shifting from day to day.  Only one white croaker transited between harbor regions during a 24hr active tracking period.  Long-term dispersal of 93 passively tracked white croaker followed significantly non-random patterns.  Fifty-five (59.1%) of passively tracked fish were detected outside of the region of the harbor in which they were tagged, and these transitions took an average of 4.7 ± 4.1 weeks to complete.  Dispersal throughout the harbor was significantly faster than what was predicted by an individual-based random walk model generated from short-term white croaker movements, indicating that long-term dispersal is likely the result of sporadic emigrations rather than random daily shifts in activity spaces.