Interdecadal versus interannual time-scale variations
of catch data of three anchovy fisheries distributed in the Humboldt Current
System (HCS) were analyzed during the period 1960–2002, by using first a loess
smoother. The loess residual data were considered as the interannual
variation. Interdecadal changes were highly coherent for the three fisheries
of anchovy distributed in the HCS, while there were differences in terms of
interannual variations. The north-central Peru fishery was similar to the
south Peru-northern Chile fishery in terms of the interannual component of
fluctuation of these fisheries which was significantly and negatively
related with El Niño-Southern Oscillations events occurring during the
spring of the previous year. Interdecadal synchronous variations in the
three anchovy fisheries suggest a common forcing by long-term environmental
factors in the HCS, although other causes cannot be excluded. During the
last 40 years, coherent changes in anchovy fisheries were observed, and this
synchronous pattern is out of phase with large-amplitude sardine regimes.
Long-term climate variability seems to be the main cause for interdecadal
fluctuations in anchovy fisheries in the HCS, although available time series
are too short to prove this link and exclude the hypothesis of
nonenvironmental forcing. Large-amplitude regime shifts may be more
important to consider than interannual changes since they can affect
simultaneously and more dramatically the three anchovy fisheries distributed
in the Humboldt Current System.