MEPS 361:253-265 (2008)  -  DOI: https://doi.org/10.3354/meps07390

ABSTRACT: An increasingly common approach for examining the movement of fish involves elemental fingerprinting, which exploits variation in the chemical composition of otoliths induced by environmental gradients. We assessed the elemental signatures of recently deposited material in the otoliths of juvenile California halibut Paralichthys californicus collected from different zones along the main axis of coastal embayments of southern California, USA, and Baja California, Mexico. From these data, we determined if unique chemical signals within embayments allowed for the reconstruction of movement patterns over small scales. Juvenile halibut were collected during 3 years (2001 to 2003) along 2 segments of coastline, including 4 embayment and 3 exposed habitats. We also compared otolith chemistry from wild-caught and caged halibut in the Punta Banda Estuary, Baja California, Mexico, and Mission Bay, California, USA; within both locations, we observed increasing concentrations of Mn and Ba in the otoliths of wild-caught and caged juveniles collected farther within embayments. However, only in Punta Banda did we find strong congruence between otolith signals from wild-caught and caged individuals. Hence, we exploited the intra-embayment variability in otolith microchemistry to chart 2 forms of movement of juvenile halibut within Punta Banda. First, within-embayment movements of juvenile fish were examined over 2 mo. Over this timescale, 8 of 14 individuals had moved among embayment zones. Second, the contribution of different embayment zones to production of adult biomass was determined. The vast majority of juveniles (82 to 89%, n = 27) that advanced to older age classes during 2002 and 2003 occupied the middle and outer zones of Punta Banda. Recognition of intra-embayment variability in otolith signals from southern and Baja California should allow for finer-scale analyses of habitat utilization, and more thorough examination of connectivity resulting from the ontogenetic migration of fish from juvenile to adult habitats.

KEY WORDS: Nursery habitat contribution · Otolith microchemistry · Embayment · California halibut · Paralichthys californicus · Caging