Expanded Recruitment of Pacific Sanddab (Citharichthys sordidus) in the Nearshore Associated with El Niño Conditions

Coastal sedimentary benthic habitats, while seemingly homogeneous, are locally dynamic and affected by shorter-term upwelling variability and longer-term regime shifts. We present results of a five-year study conducted on the central Oregon coast to assess benthic fish and invertebrate communities and monitor their seasonal and inter-annual variability. From June 2010 to June 2015, sampling was conducted bi-monthly within a narrow depth range (30 to 50 m) with a 2 x 0.5 m beam trawl. Expected seasonal differences in juvenile fish communities were observed. We also observed different summer juvenile fish assemblages in the majority of our time series collected during La Niña conditions (2010 to 2013) versus that collected during El Niño conditions (summer 2014). This shift is primarily due to an increase in Pacific sanddab (Citharichthys sordidus). Prior to 2014, this species was found in low densities in the deeper end of our narrow sampling strata. Concurrent with the transition to El Niño conditions and increases in overall abundance, we also began collecting Pacific sanddab across all depth bins. Increases of juvenile Pacific sanddab in the nearshore can be an early indicator of increased recruitment to the offshore trawl fishery and increased prey for marine mammals and diving birds.