Site Fidelity and Habitat Use by Young-of-the-Year Transient Fishes in Salt Marsh Intertidal Creeks

The extensive use of salt marsh creeks by nekton is widely recognized, yet few investigations have quantified the extent to which tidal migratory nekton make repeated visits to the same location within creek networks. An improved understanding of nekton movements and fidelity can improve insights into the nursery function and value of creek habitats. We conducted tag-recapture experiments with young fishes to determine movements among intertidal creeks in the North Inlet estuary, South Carolina. In 2008, 3246 fishes were tagged with coded microwire tags. In 2012, 577 fishes were tagged with passive integrated transponder (PIT) tags. Based on percentages of recaptures, creek-specific fidelity was determined for spot (Leiostomus xanthurus) (78%), silver perch (Bairdiella chrysoura) (71%), pinfish (Lagodon rhomboides) (80%), and mullets (Mugil curema and Mugil cephalus) (77%). Recaptures occurred up to 79days after release. Rates of recapture of all tagged fishes combined varied among creeks (74% to 100%). Considering earlier research that demonstrated differences in habitat quality among local intertidal creeks, we suggest that differences in fidelity reflect differences in habitat quality among creeks. Greater rates of repeated use (higher fidelity) could help explain why some creeks consistently support more tidal migratory nekton than other creeks. Changes in the strength of fidelity over time could be a useful measure of changes in habitat quality. We suggest that site fidelity be considered as another metric to use in efforts by resource managers to identify and evaluate essential fish habitat.