Rodríguez Sánchez, R., H., Villalobos & S., Ortega-García (2022). Spatial Dynamics of the Pacific sardine (Sardinops sagax) in the California Current system: Connecting seasonal, interannual, and long-term movements. International Symposium Small pelagic fish: New frontiers in science and sustainable management. Lisboa, Portugal, noviembre 7 - 11, 2022, 47.
Rubén Rodríguez Sánchez 1, Héctor Villalobos 1 y Sofía Ortega-García 1
To understand how Pacific sardine (PS) movements on minor spatial-temporal (S-T) scales interrelate with largescale, long-term changes in PS abundance, we reconstructed their seasonal migrations during the different stages of the interannual ENSO variability over the course of the last warming period (1980-1997), when the bulk of PS biomass and the center of distribution of the population moved northward of the California Current (CC). Based on analyses of relative abundance indices, a continuous change in the seasonal patterns was identified. The location, importance, and number of seasonal geographic groupings shifted northwards of the CC, with less important groups remaining in the south, suggesting a dynamic evolution of suitable habitats (SH) for recruitment. In the long term, when environmental conditions are favorable for PS to achieve the greatest latitudinal expansion and population size, even though PS could take advantage of SH in the large domain of a heterogeneous ecosystem, two distant but transient geographic groups are favored. Potential climatic drivers of S-T sardine shifts are not discussed. The absence/inconsistency of long-term data is problematic to identifying climate drivers in the extension of CC. Thus, a fundamental assumption underlying the S-T changes is the implicit association with seasonal-scale, and interannual changes in temperature associated with the different stages of ENSO events, and the regime shift toward warm ocean conditions that began in the mid-1970s. The spatial dynamics described here may help us think about the latitudinal reduction of SH in a cooling climate scenario, which would force the PS to shift southward.
Palabras clave: Spatial-temporal scales; seasonal scale; interannual scale; long-term scale; migrations; Movements; sardine stocks
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