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We evaluated interannual variability and the effect of the 1997-1998 El Niño event on recruitment of intertidal mussels and barnacles along the coast of central Chile in the southeast Pacific. Monthly monitoring of recruitment at 11 sites spread over 900 km (29-34ЊS) during the 1997-1998 El Niño and over the same months in 1998-1999 and 1999-2000 allowed us to assess geographic patterns in interannual recruitment variation. The geographically most consistent interannual trend was observed for the mussel Perumytilus purpuratus, which showed overall lower recruitment rates during the 1997-1998 El Niño year. However, the magnitude of the effect at any given site was small. Interannual variation in recruitment rates of the other two intertidal mussel species, as well as two chthamaloid barnacles, were not consistent across the region, and overall, few sites exhibited significant differences among years. Differences between two and three orders of magnitude in mean annual recruitment of mussels and barnacles were observed among sites, yet the relative ranking of sites was fairly similar among years for most species. Contrary to the large positive effect that the 1997-1998 El Niño had on barnacle recruitment along the coast of central and northern California, our results show that recruitment of dominant intertidal barnacles along central Chile were not significantly altered by this strong oceanographic event. Lack of consistent trends among sites emphasizes the need to study several sites when looking at large-scale oceanographic anomalies and shows that El Niño effects on interannual recruitment variation are not predictable.

Satellite‐derived data provide the temporal means and seasonal and nonseasonal variability of four physical and biological parameters off Oregon and Washington (41°–48.5°N). Eight years of data (1998–2005) are available for surface chlorophyll concentrations, sea surface temperature (SST), and sea surface height, while six years of data (2000–2005) are available for surface wind stress. Strong cross‐shelf and alongshore variability is apparent in the temporal mean and seasonal climatology of all four variables. Two latitudinal regions are identified and separated at 44°–46°N, where the coastal ocean experiences a change in the direction of the mean alongshore wind stress, is influenced by topographic features, and has differing exposure to the Columbia River Plume. All these factors may play a part in defining the distinct regimes in the northern and southern regions. Nonseasonal signals account for ∼60–75% of the dynamical variables. An empirical orthogonal function analysis shows stronger intra‐annual variability for alongshore wind, coastal SST, and surface chlorophyll, with stronger interannual variability for surface height. Interannual variability can be caused by distant forcing from equatorial and basin‐scale changes in circulation, or by more localized changes in regional winds, all of which can be found in the time series. Correlations are mostly as expected for upwelling systems on intra‐annual timescales. Correlations of the interannual timescales are complicated by residual quasi‐annual signals created by changes in the timing and strength of the seasonal cycles. Examination of the interannual time series, however, provides a convincing picture of the covariability of chlorophyll, surface temperature, and surface height, with some evidence of regional wind forcing.