250 years of sardine and anchovy scale deposition record in Mejillones Bay, northern Chile

Valdés, Jorge; Ortlieb, Luc; Gutiérrez, Dimitri; Marinovic, Luis; Vargas, Gabriel; Sifeddine, Abdelfettah

doi:10.1016/j.pocean.2008.10.002

Cited by 62 publications

(34 citation statements)

References 27 publications

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“…During the last 50 yr, both species showed high levels of biomass, but with apparent different periods of high and low biomass (Chavez et al 2003). When looking farther in the past, paleostudies show that while anchovy scale deposition rates fluctuated over periods of 25 to 40 yr, only 2 peak periods of sardine occurred during the last 250 yr, suggesting that their biomass variations depend on other ocean-climatic factors than those which control the biomass of anchovy (Valdés et al 2008). Also, during the 400 yr of the Little Ice Age (1400 to 1800s) neither anchovy nor sardine was abundant ).…”

Section: Introductionmentioning

confidence: 97%

Long-term changes in zooplankton size distribution in the Peruvian Humboldt Current System: conditions favouring sardine or anchovy

Ayón¹,

Swartzman²,

Espinoza³

et al. 2011

Mar. Ecol. Prog. Ser.

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Changes in the size distribution of zooplankton in the Humboldt Current System have been hypothesized to underlie observed changes in sardine and anchovy populations, the dominant pelagic fish species. To examine this hypothesis, the size distribution of over 15 000 zooplankton data samples collected since the 1960s was qualitatively determined. Dominance of each size group of zooplankton (small, medium and large) and of euphausiids was modelled using generalized additive models as a function of year, latitude, time of day, distance from the 200 m isobath (a surrogate for onshelf versus off-shelf), sea surface temperature and salinity. The temporal (yr) pattern for euphausiid dominance was highly cross-correlated (i.e. was in phase) with the time series for estimated biomass of anchovy, and small zooplankton dominance with that for estimated sardine biomass. This supports the focal hypothesis based on feeding-energetic experiments, which showed energetic advantages to sardine filter feeding on smaller zooplankton and to anchovy bite feeding on larger copepods and euphausiids. Although euphausiids predominate offshore from the shelf break, anchovy biomass is generally highest on the shelf, suggesting a possible mismatch between anchovy feeding and euphausiid dominance. However, evidence concerning the offshore expansion of the anchovy range in cooler conditions, where both anchovy and euphausiids predominate, somewhat alleviates this apparent contradiction. A strong diel component to euphausiids and large zooplankton indicated diel migration for these zooplankton groups. That anchovy will preferentially eat euphausiids when they are more available (i.e. during the night and offshore) is supported by anchovy diet data.

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Section: Introductionmentioning

confidence: 97%

Long-term changes in zooplankton size distribution in the Peruvian Humboldt Current System: conditions favouring sardine or anchovy

Ayón¹,

Swartzman²,

Espinoza³

et al. 2011

Mar. Ecol. Prog. Ser.

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“…On the one hand this caused growth and extension of the Andean glaciers (Vuille et al, 2008) and on the other it enabled human settlements in the presently hyperarid southern Peruvian Andes (Unkel et al, 2007). In the upwelling areas off Peru and the western South American shelf regions, the main consequence of these climatic conditions during the LIA was a deepening of the nutricline and a strongly diminished biological productivity (Vargas et al, 2007;Sifeddine et al, 2008;Valdés et al, 2008;Gutiérrez et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Nutrient utilisation and weathering inputs in the Peruvian upwelling region since the Little Ice Age

et al. 2015

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Abstract. For this study two sediment cores from the Peruvian shelf covering the time period between the Little Ice Age (LIA) and present were examined for changes in productivity (biogenic opal concentrations (bSi)), nutrient utilisation (stable isotope compositions of silicon (δ 30 Si opal ) and nitrogen (δ 15 N sed )), as well as in ocean circulation and material transport (authigenic and detrital radiogenic neodymium (ε Nd ) and strontium ( 87 Sr / 86 Sr) isotopes).For the LIA the proxies recorded weak primary productivity and nutrient utilisation reflected by low average bSi concentrations of ∼ 10 %, δ 15 N sed values of ∼ 5 ‰ and intermediate δ 30 Si opal values of ∼ 0.9 ‰. At the same time, the radiogenic isotope composition of the detrital sediment fraction indicates dominant local riverine input of lithogenic material due to higher rainfall in the Andean hinterland. These patterns were most likely caused by permanent El Niño-like conditions characterised by a deeper nutricline, weak upwelling and low nutrient supply. At the end of the LIA, δ 30 Si opal dropped to low values of +0.6 ‰ and opal productivity reached its minimum of the past 650 years. During the following transitional period of time the intensity of upwelling, nutrient supply and productivity increased abruptly as marked by the highest bSi contents of up to 38 %, by δ 15 N sed of up to ∼ 7 ‰, and by the highest degree of silicate utilisation with δ 30 Si opal reaching values of +1.1 ‰. At the same time, detrital ε Nd and 87 Sr / 86 Sr signatures documented increased wind strength and supply of dust to the shelf due to drier conditions. Since about 1870, productivity has been high but nutrient utilisation has remained at levels similar to the LIA, indicating significantly increased nutrient availability.Comparison between the δ 30 Si opal and δ 15 N sed signatures suggests that during the past 650 years the δ 15 N sed signature in the Peruvian upwelling area has to a large extent been controlled by surface water utilisation and not, as previously assumed, by subsurface nitrogen loss processes in the water column, which only had a significant influence during modern times (i.e. since ∼ AD 1870).

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“…Por otra parte, durante períodos cálidos, se ha observado un cambio en la estructura de la comunidad planctónica (Alheit & Ñiquén, 2004), con una reducción de la abundancia de copépodos y eufáusidos (González et al, 1998). Estas obser-vaciones pesqueras (registro de los últimos 40 años) contrastan con lo señalado por Valdés et al, 2008, quienes encontraron respuestas no alternantes en algunos períodos de los 250 años reconstruidos mediante el análisis de escamas en depositación. Es decir, ambas especies se hallaron en momentos positivos de abundancia, a veces una dominando sobre la otra.…”

Section: Zona Norteunclassified

Variabilidad ambiental y recursos pesqueros en el Pacifico suroriental: estado de la investigacion y desafios para el manejo pesquero

Parada¹,

Yannicelli²,

Hormazábal³

et al. 2013

lajar

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250 years of sardine and anchovy scale deposition record in Mejillones Bay, northern Chile

Cited by 62 publications

References 27 publications

Long-term changes in zooplankton size distribution in the Peruvian Humboldt Current System: conditions favouring sardine or anchovy

Long-term changes in zooplankton size distribution in the Peruvian Humboldt Current System: conditions favouring sardine or anchovy

Nutrient utilisation and weathering inputs in the Peruvian upwelling region since the Little Ice Age

Variabilidad ambiental y recursos pesqueros en el Pacifico suroriental: estado de la investigacion y desafios para el manejo pesquero

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