Influence of El Niño and La Niña on the population dynamics of Calanus chilensis in the Humboldt Current ecosystem of northern Chile

From a time-series of sea surface temperature (SST) and zooplankton data from December 1991 through January 1998, and using a temperature-dependent model, we studied the growth rate (g), female size, generation time (GT), and number of generations per year of Calanus chilensis from the Mejillones Pe...

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Bibliographic Details
Published in:ICES journal of marine science Vol. 57; no. 6; pp. 1867 - 1874
Main Authors: Escribano, R., Hidalgo, P.
Format: Journal Article
Language:English
Published: Oxford University Press 01.12.2000
Subjects:
Calanus
Calanus chilensis
El Niño
growth
Humboldt Current
Marine
temperature
ISE, Chile, Antofagasta, Mejillones Peninsula
ISE, Pacific, Humboldt Current
temperature
growth
Humboldt Current
ISSN:1054-3139, 1095-9289
Online Access:Get full text
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Summary:From a time-series of sea surface temperature (SST) and zooplankton data from December 1991 through January 1998, and using a temperature-dependent model, we studied the growth rate (g), female size, generation time (GT), and number of generations per year of Calanus chilensis from the Mejillones Peninsula, northern Chile. Female size was negatively related to SST on both seasonal and interannual scales, and abundance was positively correlated to SST through seasons, though not associated with warm (El Niño) or cold (La Niña) years. The model predicted that cold and warm years may have a substantial effect on annual abundance of this species. Mean annual abundances of C. chilensis were not consistent with those predicted by the model, however, suggesting that factors other than temperature may regulate interannual differences in population size. For instance, changes in mortality rates between warm and cold years and advective losses under strong coastal upwelling may be implicated in the variation. Despite smaller population size in years subject to ElNiño conditions, predicted annual means of g and GT showed little variability, as expected for fairly stable/constant annual mean SST. The overall g was 0.33 d−1, while GT was 18.1 d under an overall mean SST of 17.7°C. The lack of evidence for food-shortage effects during El Niño conditions and the influence of temperature on a seasonal scale suggest that temperature-dependent growth may be a mechanism regulating population size by adjusting growth and development to stable temperature regimes on an annual basis.
Bibliography:istex:C424F63CCF9FD70DA6F50FD3B950C32638B2F449
ark:/67375/HXZ-TGNTM54J-L
ArticleID:57.6.1867
ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
content type line 23
ISSN:1054-3139
1095-9289
DOI:10.1006/jmsc.2000.0953