Climate change scenarios experiments predict a future reduction in small pelagic fish recruitment in the Humboldt Current system

Abstract The increasing shellfish aquaculture requires knowledge about nearshore environmental variability to manage sustainably and create climate change adaptation strategies. We used data from mooring time series and in situ sampling to characterize oceanographic and carbonate system variability in three bivalve aquaculture areas located along a latitudinal gradient off the Humboldt Current System. Our results showed pHT <8 in most coastal sites and occasionally below 7.5 during austral spring–summer in the lower (−30°S) and central (−37°S) latitudes, related to upwelling. Farmed mussels were exposed to undersaturated (Ωarag < 1) and hypoxic (<2 ml l−1) waters during warm seasons at −37°S, while in the higher latitude (43°S) undersaturated waters were only detected during colder seasons, associated with freshwater runoff. We suggest that both Argopecten purpuratus farmed at −30°S and Mytilus chilensis farmed at −43°S may enhance their growth during summer due to higher temperatures, lower pCO2, and oversaturated waters. In contrast, Mytilus galloprovincialis farmed at 37°S grows better during spring–summer, following higher temperatures and high pCO2. This knowledge is relevant for aquaculture, but it must be improved using high-resolution time series and in situ experimentation with farmed species to aid their adaptation to climate change and ocean acidification.

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Zooplankton mortality effects on the plankton community of the northern Humboldt Current System: sensitivity of a regional biogeochemical model

Biogeosciences ◽

10.5194/bg-18-2891-2021 ◽

2021 ◽

Vol 18 (9) ◽

pp. 2891-2916

Author(s):

Mariana Hill Cruz ◽

Iris Kriest ◽

Yonss Saranga José ◽

Rainer Kiko ◽

Helena Hauss ◽

...

Keyword(s):

Environmental Variability ◽

Current System ◽

Fish Predation ◽

Grazing Pressure ◽

Pelagic Fish ◽

Trophic Levels ◽

Fish Populations ◽

Biogeochemical Model ◽

Small Pelagic Fish ◽

Humboldt Current

Abstract. Small pelagic fish off the coast of Peru in the eastern tropical South Pacific (ETSP) support around 10 % of global fish catches. Their stocks fluctuate interannually due to environmental variability which can be exacerbated by fishing pressure. Because these fish are planktivorous, any change in fish abundance may directly affect the plankton and the biogeochemical system. To investigate the potential effects of variability in small pelagic fish populations on lower trophic levels, we used a coupled physical–biogeochemical model to build scenarios for the ETSP and compare these against an already-published reference simulation. The scenarios mimic changes in fish predation by either increasing or decreasing mortality of the model's large and small zooplankton compartments. The results revealed that large zooplankton was the main driver of the response of the community. Its concentration increased under low mortality conditions, and its prey, small zooplankton and large phytoplankton, decreased. The response was opposite, but weaker, in the high mortality scenarios. This asymmetric behaviour can be explained by the different ecological roles of large, omnivorous zooplankton and small zooplankton, which in the model is strictly herbivorous. The response of small zooplankton depended on the antagonistic effects of mortality changes as well as on the grazing pressure by large zooplankton. The results of this study provide a first insight into how the plankton ecosystem might respond if variations in fish populations were modelled explicitly.

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Zooplankton mortality effects on the plankton community of the Northern Humboldt Current System: Sensitivity of a regional biogeochemical model

10.5194/bg-2020-417 ◽

2020 ◽

Author(s):

Mariana Hill Cruz ◽

Iris Kriest ◽

Yonss Saranga José ◽

Rainer Kiko ◽

Helena Hauss ◽

...

Keyword(s):

Environmental Variability ◽

Current System ◽

Fish Predation ◽

Grazing Pressure ◽

Pelagic Fish ◽

Trophic Levels ◽

Fish Populations ◽

Biogeochemical Model ◽

Small Pelagic Fish ◽

Humboldt Current

Abstract. Small pelagic fish off the coast of Peru in the Eastern Tropical South Pacific (ETSP) support around 10 % of the global fish catches. Their stocks fluctuate interannually due to environmental variability which can be exacerbated by fishing pressure. Because these fish are planktivorous, any change in fish abundance may directly affect the plankton and the biogeochemical system. To investigate the potential effects of variability in small pelagic fish populations on lower trophic levels, we used a coupled physical-biogeochemical model to build scenarios for the ETSP and compare these against an already published reference simulation. The scenarios mimic changes in fish predation by either increasing or decreasing mortality of the model's large and small zooplankton compartments. The results revealed that large zooplankton was the main driver of the response of the community. Its concentration increased under low mortality conditions and its prey, small zooplankton and large phytoplankton, decreased. The response was opposite, but weaker, in the high mortality scenarios. This asymmetric behaviour can be explained by the different ecological roles of large, omnivorous zooplankton, and small zooplankton, which in the model is strictly herbivorous. The response of small zooplankton depended on the antagonistic effects of mortality changes as well as the grazing pressure by large zooplankton. The results of this study provide a first insight on how the plankton ecosystem might respond if variations in fish populations were modelled explicitly.

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Climate Change and Small Pelagic Fish

10.1017/cbo9780511596681 ◽

2001 ◽

Cited By ~ 48

Keyword(s):

Climate Change ◽

Pelagic Fish ◽

Small Pelagic Fish

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Vertical distribution of copepod eggs in the oxygen minimum zone off Mejillones Bay (23°S) in the Humboldt Current System

Marine Ecology Progress Series ◽

10.3354/meps12117 ◽

2017 ◽

Vol 571 ◽

pp. 83-96 ◽

Cited By ~ 3

Author(s):

PM Ruz ◽

P Hidalgo ◽

R Riquelme-Bugueño ◽

B Franco-Cisterna ◽

M Cornejo

Keyword(s):

Vertical Distribution ◽

Current System ◽

Oxygen Minimum Zone ◽

Humboldt Current ◽

Minimum Zone ◽

Humboldt Current System ◽

Copepod Eggs ◽

Oxygen Minimum

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Trends in sympatric otariid populations suggest resource limitations in the Peruvian Humboldt Current System

Marine Environmental Research ◽

10.1016/j.marenvres.2021.105349 ◽

2021 ◽

pp. 105349

Author(s):

Susana Cárdenas-Alayza ◽

Dimitri Gutiérrez ◽

Yann Tremblay

Keyword(s):

Current System ◽

Humboldt Current ◽

Resource Limitations ◽

Humboldt Current System

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Forecasting shifts in habitat suitability across the distribution range of a temperate small pelagic fish under different scenarios of climate change

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.150167 ◽

2022 ◽

Vol 804 ◽

pp. 150167

Author(s):

André R.A. Lima ◽

Miguel Baltazar-Soares ◽

Susana Garrido ◽

Isabel Riveiro ◽

Pablo Carrera ◽

...

Keyword(s):

Climate Change ◽

Habitat Suitability ◽

Pelagic Fish ◽

Distribution Range ◽

Small Pelagic Fish

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Coupled CO<sub>2</sub> and O<sub>2</sub>-driven compromises to marine life in summer along the Chilean sector of the Humboldt Current System

Biogeosciences ◽

10.5194/bg-9-1183-2012 ◽

2012 ◽

Vol 9 (3) ◽

pp. 1183-1194 ◽

Cited By ~ 18

Author(s):

E. Mayol ◽

S. Ruiz-Halpern ◽

C. M. Duarte ◽

J. C. Castilla ◽

J. L. Pelegrí

Keyword(s):

Current System ◽

Negative Relationship ◽

Water Layer ◽

Humboldt Current ◽

Marine Life ◽

Small Water ◽

System A ◽

Subsurface Waters ◽

Humboldt Current System ◽

Upper Mixed Layer

Abstract. Carbon dioxide and coupled CO2 and O2-driven compromises to marine life were examined along the Chilean sector of the Humboldt Current System, a particularly vulnerable hypoxic and upwelling area, applying the Respiration index (RI = log10 pO2pCO2) and the pH-dependent aragonite saturation (Ω) to delineate the water masses where aerobic and calcifying organisms are stressed. As expected, there was a strong negative relationship between oxygen concentration and pH or pCO2 in the studied area, with the subsurface hypoxic Equatorial Subsurface Waters extending from 100 m to about 300 m depth and supporting elevated pCO2 values. The lowest RI values, associated to aerobic stress, were found at about 200 m depth and decreased towards the Equator. Increased pCO2 in the hypoxic water layer reduced the RI values by as much as 0.59 RI units, with the thickness of the upper water layer that presents conditions suitable for aerobic life (RI>0.7) declining by half between 42° S and 28° S. The intermediate waters hardly reached those stations closer to the equator so that the increased pCO2 lowered pH and the saturation of aragonite. A significant fraction of the water column along the Chilean sector of the Humboldt Current System suffers from CO2–driven compromises to biota, including waters corrosive to calcifying organisms, stress to aerobic organisms or both. The habitat free of CO2-driven stresses was restricted to the upper mixed layer and to small water parcels at about 1000 m depth. Overall pCO2 acts as a hinge connecting respiratory and calcification challenges expected to increase in the future, resulting in a spread of the challenges to aerobic organisms.

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