Combined fishing and climate forcing in the southern Benguela upwelling ecosystem: an end-to-end modelling approach reveals dampened effects

 

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dc.contributor.author Travers-Trolet, Morgane en_ZA
dc.contributor.author Shin, Yunne-Jai en_ZA
dc.contributor.author Shannon, Lynne J en_ZA
dc.contributor.author Moloney, Coleen L en_ZA
dc.contributor.author Field, John G en_ZA
dc.date.accessioned 2016-01-02T05:06:45Z
dc.date.available 2016-01-02T05:06:45Z
dc.date.issued 2014 en_ZA
dc.identifier.citation Travers-Trolet, M., Shin, Y. J., Shannon, L. J., Moloney, C. L., & Field, J. G. (2014). Combined fishing and climate forcing in the southern Benguela upwelling ecosystem: an end-to-end modelling approach reveals dampened effects. PloS one, 9(4), e94286. doi:10.1371/journal.pone.0094286 en_ZA
dc.identifier.uri http://dx.doi.org/10.1371/journal.pone.0094286 en_ZA
dc.identifier.uri http://hdl.handle.net/11427/16170
dc.description.abstract The effects of climate and fishing on marine ecosystems have usually been studied separately, but their interactions make ecosystem dynamics difficult to understand and predict. Of particular interest to management, the potential synergism or antagonism between fishing pressure and climate forcing is analysed in this paper, using an end-to-end ecosystem model of the southern Benguela ecosystem, built from coupling hydrodynamic, biogeochemical and multispecies fish models (ROMS-N 2 P 2 Z 2 D 2 -OSMOSE). Scenarios of different intensities of upwelling-favourable wind stress combined with scenarios of fishing top-predator fish were tested. Analyses of isolated drivers show that the bottom-up effect of the climate forcing propagates up the food chain whereas the top-down effect of fishing cascades down to zooplankton in unfavourable environmental conditions but dampens before it reaches phytoplankton. When considering both climate and fishing drivers together, it appears that top-down control dominates the link between top-predator fish and forage fish, whereas interactions between the lower trophic levels are dominated by bottom-up control. The forage fish functional group appears to be a central component of this ecosystem, being the meeting point of two opposite trophic controls. The set of combined scenarios shows that fishing pressure and upwelling-favourable wind stress have mostly dampened effects on fish populations, compared to predictions from the separate effects of the stressors. Dampened effects result in biomass accumulation at the top predator fish level but a depletion of biomass at the forage fish level. This should draw our attention to the evolution of this functional group, which appears as both structurally important in the trophic functioning of the ecosystem, and very sensitive to climate and fishing pressures. In particular, diagnoses considering fishing pressure only might be more optimistic than those that consider combined effects of fishing and environmental variability. en_ZA
dc.language.iso eng en_ZA
dc.publisher Public Library of Science en_ZA
dc.rights This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. en_ZA
dc.rights.uri http://creativecommons.org/licenses/by/4.0 en_ZA
dc.source PLoS One en_ZA
dc.source.uri http://journals.plos.org/plosone en_ZA
dc.subject.other Biomass (ecology) en_ZA
dc.subject.other Marine fish en_ZA
dc.subject.other Predation en_ZA
dc.subject.other Marine ecosystems en_ZA
dc.subject.other Phytoplankton en_ZA
dc.subject.other Zooplankton en_ZA
dc.subject.other Ecosystems en_ZA
dc.subject.other Fish physiology en_ZA
dc.title Combined fishing and climate forcing in the southern Benguela upwelling ecosystem: an end-to-end modelling approach reveals dampened effects en_ZA
dc.type Journal Article en_ZA
dc.rights.holder © 2014 Travers-Trolet et al en_ZA
uct.type.publication Research en_ZA
uct.type.resource Article en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Marine Research (MA-RE) Institute en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Travers-Trolet, M., Shin, Y., Shannon, L. J., Moloney, C. L., & Field, J. G. (2014). Combined fishing and climate forcing in the southern Benguela upwelling ecosystem: an end-to-end modelling approach reveals dampened effects. <i>PLoS One</i>, http://hdl.handle.net/11427/16170 en_ZA
dc.identifier.chicagocitation Travers-Trolet, Morgane, Yunne-Jai Shin, Lynne J Shannon, Coleen L Moloney, and John G Field "Combined fishing and climate forcing in the southern Benguela upwelling ecosystem: an end-to-end modelling approach reveals dampened effects." <i>PLoS One</i> (2014) http://hdl.handle.net/11427/16170 en_ZA
dc.identifier.vancouvercitation Travers-Trolet M, Shin Y, Shannon LJ, Moloney CL, Field JG. Combined fishing and climate forcing in the southern Benguela upwelling ecosystem: an end-to-end modelling approach reveals dampened effects. PLoS One. 2014; http://hdl.handle.net/11427/16170. en_ZA
dc.identifier.ris TY - Journal Article AU - Travers-Trolet, Morgane AU - Shin, Yunne-Jai AU - Shannon, Lynne J AU - Moloney, Coleen L AU - Field, John G AB - The effects of climate and fishing on marine ecosystems have usually been studied separately, but their interactions make ecosystem dynamics difficult to understand and predict. Of particular interest to management, the potential synergism or antagonism between fishing pressure and climate forcing is analysed in this paper, using an end-to-end ecosystem model of the southern Benguela ecosystem, built from coupling hydrodynamic, biogeochemical and multispecies fish models (ROMS-N 2 P 2 Z 2 D 2 -OSMOSE). Scenarios of different intensities of upwelling-favourable wind stress combined with scenarios of fishing top-predator fish were tested. Analyses of isolated drivers show that the bottom-up effect of the climate forcing propagates up the food chain whereas the top-down effect of fishing cascades down to zooplankton in unfavourable environmental conditions but dampens before it reaches phytoplankton. When considering both climate and fishing drivers together, it appears that top-down control dominates the link between top-predator fish and forage fish, whereas interactions between the lower trophic levels are dominated by bottom-up control. The forage fish functional group appears to be a central component of this ecosystem, being the meeting point of two opposite trophic controls. The set of combined scenarios shows that fishing pressure and upwelling-favourable wind stress have mostly dampened effects on fish populations, compared to predictions from the separate effects of the stressors. Dampened effects result in biomass accumulation at the top predator fish level but a depletion of biomass at the forage fish level. This should draw our attention to the evolution of this functional group, which appears as both structurally important in the trophic functioning of the ecosystem, and very sensitive to climate and fishing pressures. In particular, diagnoses considering fishing pressure only might be more optimistic than those that consider combined effects of fishing and environmental variability. DA - 2014 DB - OpenUCT DO - 10.1371/journal.pone.0094286 DP - University of Cape Town J1 - PLoS One LK - https://open.uct.ac.za PB - University of Cape Town PY - 2014 T1 - Combined fishing and climate forcing in the southern Benguela upwelling ecosystem: an end-to-end modelling approach reveals dampened effects TI - Combined fishing and climate forcing in the southern Benguela upwelling ecosystem: an end-to-end modelling approach reveals dampened effects UR - http://hdl.handle.net/11427/16170 ER - en_ZA


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This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Except where otherwise noted, this item's license is described as This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.