High Larval Concentrations and Onshore Transport of Barnacle Cyprids Associated With Thermal Stratification

To better understand the hydrodynamic and hydrographic conditions experienced by larvae in nearshore (within 1 km of shore), role that larval behavior plays mediating shoreward transport to adult benthic habitats, we examined vertical distribution concentration barnacle cyprids a shallow, region southern California, United States. We collected high-resolution physical measurements currents temperature at 3 stations (8, 5, 4 m depths), high-frequency deep station ∼300 from shore. Larvae were sampled distinct depth intervals between surface bottom (0–1 m, 1–2 2–3 m-bottom), each hour for overnight periods ranged 13 24 h five cruises during summers 2017 2018. Barnacle Chthamalus fissus predominated all samples. Thermal stratification decreased closer shore, but when nearshore-most remained stratified (Δ°C –1 ≥ 0.1), C. cyprid concentrations high extremely abundant (exceeding 200 4,000 individuals –3 , respectively). There significant positive correlations thermal log-transformed cruise-to-cruise scales, variability cross-shore 2-day scales. Additionally, estimated was relatively greatest. Significant, albeit small, diel differences distributions also observed, with proportion increasing near night, greater day than night. Collectively, these results suggest increases supply nearshore, may enhance onshore augment chances successful settlement recruitment intertidal habitat.