Effects of seasonal variability in across- and alongshore transport of anchoveta (Engraulis ringens) larvae on model-based pre-recruitment indices off central Chile

Authored by Carolina Parada, Francois Colas, Samuel Soto-Mendoza, Leonardo Castro

Date Published: 2012

DOI: 10.1016/j.pocean.2011.07.015

Sponsors: No sponsors listed

Platforms: No platforms listed

Model Documentation: Other Narrative Mathematical description

Model Code URLs: Model code not found

Abstract

An individual-based model (IBM) of anchoveta (Engraulis ringens) larvae was coupled to a climatological hydrodynamic (Regional Oceanic Modeling System, ROMS) model for central-southern Chile to answer the question as to whether or not across- and alongshore transport off central-southern Chile enhances retention in the spawning areas during the winter and summer reproductive periods, using model-based pre-recruitment indices (simulated transport success to nursery areas). The hydrodynamic model validation showed that ROMS captures the mean Seas Surface Temperature and Eddie Kinetic Energy observed in satellite-based data over the entire region. The IBM was used to simulate the transport of eggs and larvae from spawning zones in central Chile (Constitucion, Dichato, Gulf of Arauco and Lebu-Corral) to historical nursery areas (HRZ, region between 35 degrees S and 37 degrees S). Model results corroborated HRZ as the most successful pre-recruitment zone (particles originated in the Dichato and Gulf of Arauco spawning areas), as well as identifying Lebu-Corral as a zone of high retention with a high associated pre-recruitment index (particles originated in the Lebu-Corral spawning zone). The highest pre-recruitment values were mainly found in winter. The Constitucion and Dichato spawning zones displayed a typical summer upwelling velocity pattern, while the Gulf of Arauco in summertime showed strong offshore and alongshore velocity components. The Lebu-Corral region in winter presented important near-surface cross-shore transport towards the coast (associated with downwelling events), this might be one of the major mechanisms leading to high retention levels and a high pre-recruitment index for Lebu-Corral spawning zone. The limitations of the modeling approach are discussed and put into perspective for future work. (C) 2011 Elsevier Ltd. All rights reserved.

Tags

Diel vertical migration Continental-shelf Pelagic fish eggs Southern benguela 1997-1998 el-nino Upwelling region Yolk-sac larvae Sardine strangomera-bentincki Humboldt current system Oceanographic conditions