The Optimal Environmental Window Hypothesis in the ICES Area: The example of the Iberian Sardine

English. In upwelling areas, the relationship between upwelling intensity and pelagic fish recruitment success appears to be sometimes positively and sometimes negatively correlated. The Optimal Environmemal Window (OEW) hypothesis offers an interpretation for these apparently contradictory results. The OEW hypothesis suggests that a dome shaped relationship exists between recruitment success and upwelling intensity: recruitment success increases with upwelling intensity in areas where wind speed is low or moderate,food availability is then the limiting factor; recruitment success decreases with upwelling intensity in areas of strong wind where physical constraints are the main determinants of larvae mortality rates. Several studies have shown that the relationship between recruitment success of small pelagic fish stocks located in upwelling areas is dome shaped and in agreement with the OEW hypothesis. The limiting factors defined by the OEW hypothesis are also able to account for apparent contradictory patterns observed between reproductive strategies of related species located in geographically distinct areas. The OEW hypothesis applies to eastern boundary current ecosystems located in tropical or subtropical areas where trade winds are responsible for the upwelling process. The applicability of the OEW 10 higher latitude areas like the ICES regions is discussed and an example of an ICES region where upwelling events take place is presented.

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Spanish; Castilian. Versión del editor