Trends in carbon flux to seabirds in the Peruvian upwelling system: effects of wind and fisheries on population regulation

By J. Jahncke, D. Checkley, G. Hunt. 2004

114 citations recorded by the source corpus.

We hypothesized that change in the annual population size of guano-producing seabirds (cormorant, Phalacrocorax bougainvillii; booby, Sula variegata; pelican, Pelecanus thagus) is a response to changes in primary and secondary production of the Peruvian upwelling system. We tested this hypothesis by modeling nitrate input through upwelling to the upper layers of the ocean off Peru between 6° and 14°S using data on wind stress and sea surface temperature. The model predicted the amount of carbon fixed by primary production each year from 1925 to 2000, which was then apportioned to the Peruvian anchovy (Engraulis ringens) biomass and ultimately to the seabird population and the anchovy fishery, the largest single-species fishery on Earth. The model predicted a marked increase in primary production as a consequence of increasing wind stress. It overestimated the anchovy biomass after the collapse of the fishery in 1972, but closely predicted the growth of seabird populations from 1925 to the mid-1960s, and their decline thereafter, explaining about 94% of the variation in seabird numbers from 1925 to 2000. The model indicates the seabirds consumed 14.4% of the available anchovies and, thus, that seabirds consumed 2.3% of the new production, before the development of the anchovy fishery, and only 2.2% of the available anchovies and 0.3% of the new production after the development of the fishery. The model results clarify the roles that environmental and anthropogenic factors may have had in regulating the guano-producing seabird populations. It indicates that the growth of seabird populations from 1925 to 1955 was likely a response to increased productivity of the Peruvian upwelling system and that the subsequent drastic decline in seabird abundance was likely due to competition for food with the fishery, which caught ∼85% of the anchovies, which otherwise would have been available for the seabirds. This model also shows that an increase in oceanic primary production promotes reproductive success and population growth in higher trophic level organisms.

Subfields: Global and Planetary Change, Oceanography

View Paper: https://www.semanticscholar.org/paper/40c70415730f60221d7a87b004024ffd5e604cb4

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Global and Planetary Change

1. M. Peck
2. J. Pinnegar
3. A. Bertrand
4. Erasmo C. Macaya
5. W. Arntz
6. E. Acuña
7. G. Engelhard
8. S. Bograd

In Oceanography

1. Erasmo C. Macaya
2. W. Arntz
3. E. Acuña
4. M. Peck
5. P. Espinoza
6. M. Thiel
7. A. Bertrand
8. William J. Sydeman

Citations in the corpus

• Linking predators to seasonality of upwelling: Using food web indicators and path analysis to infer trophic connections (2012, background): “The variety of predators and response variables examined makes this study unique with respect to physical–biological coupling and predator–prey interactions in the California Current, and upwelling ecosystems more generally (Cury and Shannon, 2004; Jahncke et al., 2004; Chavez and Messie, 2009).”
• Influence of seabird guano and camelid dung fertilization on the nitrogen isotopic composition of field-grown maize (Zea mays) (2012, background): “, 1987), largely as a consequence of variations in upwelling conditions and primary productivity (Jahncke et al., 2004).”
• Revisiting Peruvian anchovy (Engraulis ringens) trophodynamics provides a new vision of the Humboldt Current system (2008, background): “Yet all trophic models of the HCS developed to date, even recently, still consider that the anchoveta consumes at least as much carbon from phytoplankton as from zooplankton (e.g. Jahncke et al., 2004; Neira et al., 2004).”
• Resolving the effect of climate change on fish populations (2009, background): “On a qualitative level, the increase in average and extreme winds over European marine areas may increase upwelling, enhance primary production, and eventually increase fish productivity (Dickson et al., 1988; Jahncke et al., 2004; Rykaczewski and Checkley, 2008).”
• The humboldt current system of northern and central chile : Oceanographic processes, ecological interactions and socioeconomic feedback (2007, background): “It seems that the anchovy fishery has taken up the superabundance of food, which in the past permitted the seabirds from the HCS to cope with the recurring crashes induced by oceanographic perturbations (Jahncke et al. 2004).”