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| Titel |
Changes in the diet of hake associated with El Niño 1997-1998 in the northern Humboldt Current ecosystem |
| VerfasserIn |
J. Tam, S. Purca, L. O. Duarte, V. Blaskovic, P. Espinoza |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7340
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| Digitales Dokument |
URL |
| Erschienen |
In: 1st Alexander von Humboldt International Conference ; Nr. 6 (2006-01-09), S.63-67 |
| Datensatznummer |
250003238
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| Publikation (Nr.) |
 copernicus.org/adgeo-6-63-2006.pdf |
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| Zusammenfassung |
| Hake (Merluccius gayi peruanus) predation plays an important role in the dynamics of the Humboldt
Current ecosystem (HCE). Changes in the hake trophic habits associated with
physical variability are expected to impact prey populations and to
propagate through the food web. Time series (1995–2002) of (a) stomach
contents of hake, (b) biomass estimations of fish prey species of hake, and
(c) depth of the 15°C isotherm was analysed with the aim of exploring
the impacts of El Niño 1997–1998 on the diet of hake. Biomass
estimations of fish prey species were used to indicate resource
availability, and depth of the 15°C isotherm to represent variability
associated with the ENSO cycle in the physical environment of hake. The
richness of prey species increased during the months when 15°C isotherm
reached its deepest position, supporting the hypothesis of increased
biodiversity (tropicalization) of the HCE during El Niño events. An
increased variability in stomach fullness of hake was detected after 1999
which could indicate high heterogeneity in the food supply as a consequence
of impacts of the warm event in the biotic community structure of the HCE, a
physiological impairment of hake or an effect of the abrupt reduction in the
mean total length of hake, postulated as a compensatory response to fishery
pressure. Hake can be characterized as an opportunist predator according to
the observed changes in its diet during 1995–2002. Overall, the diet of hake
in the northern HCE exhibited transitory (e.g. increased richness of prey
species in the stomach contents) and medium term (e.g. increased variability in
feeding activity) responses associated with El Niño 1997–1998, which
should be incorporated both in population dynamics and food web analyses. |
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