Drivers, dynamics and management of Eastern Baltic cod (Gadus morhua) reproduction habitat
The overall aim of my thesis was to improve our understanding of environmental drivers causing the dynamics of the Eastern Baltic cod reproduction habitat and to assess their relevance for a possible application in the sustainable stock management. A novel approach to map the reproductive habitat of...
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ftunivkiel:oai:macau.uni-kiel.de:diss_mods_00023941 2024-06-23T07:52:58+00:00 Drivers, dynamics and management of Eastern Baltic cod (Gadus morhua) reproduction habitat von Dewitz, Burkhard Reusch, Thorsten B. H. Gröger, Joachim 2018 https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-239412 https://macau.uni-kiel.de/receive/diss_mods_00023941 https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00007907/PhD_Thesis_Burkhard_von_Dewitz.pdf eng eng https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-239412 https://macau.uni-kiel.de/receive/diss_mods_00023941 https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00007907/PhD_Thesis_Burkhard_von_Dewitz.pdf https://rightsstatements.org/page/InC/1.0/ info:eu-repo/semantics/openAccess thesis ddc:570 Baltic Sea Eastern Baltic cod fisheries management environmental indicators spawning habitat oceanographic modeling dissertation Text doc-type:PhDThesis 2018 ftunivkiel 2024-06-12T14:19:39Z The overall aim of my thesis was to improve our understanding of environmental drivers causing the dynamics of the Eastern Baltic cod reproduction habitat and to assess their relevance for a possible application in the sustainable stock management. A novel approach to map the reproductive habitat of Eastern Baltic cod, the Buoyancy Depending Reproductive Layers (BDRL), was developed and used to propose an alternative stock indicator, the effective Spawning Stock Biomass (eSSB). The eSSB was found to improve the fit of a recruitment model compared to the model using the conventional Spawning Stock Biomass. Oxygen depletion was also negatively impacting the available size of nursery areas for juveniles. The mechanism was able to partly explain the observed decline of the condition of juveniles in the nursery areas, because a high population density in the remaining habitat could increase the impact of density depending effects. Furthermore, by the application of the novel approach of BDRLs the spawning habitat was shown to be sensitive to eutrophication and that this sensitivity is strongly depending on the size of the female spawner using the habitat. As predicted, the BDRL approach was superior to the “classic” approach, the Reproductive Volume (RV) because it was more sensitive to environmental change, able to incorporate stock structure, was not overestimating the spawning habitat in the eastern spawning areas and could provide estimates of other stressors depending on the female spawner size. Due to a permanently installed measurement platform in the Arkona Basin, the new methodology could be used to establish a new environmental indicator on the spawning habitat conditions. It was recommended to be used in future stock assessments. Das Ziel dieser Arbeit war unser Verständnis der treibenden Umweltparameter dieser Entwicklung und ihrer Dynamic zu verbessern und sie auf eine mögliche Nutzung im Zusammenhang mit einem nachhaltigen Management des Bestandes zu überprüfen. Entwickelt wurde eine neue Methode die ... Doctoral or Postdoctoral Thesis Gadus morhua MACAU: Open Access Repository of Kiel University |
institution |
Open Polar |
collection |
MACAU: Open Access Repository of Kiel University |
op_collection_id |
ftunivkiel |
language |
English |
topic |
thesis ddc:570 Baltic Sea Eastern Baltic cod fisheries management environmental indicators spawning habitat oceanographic modeling |
spellingShingle |
thesis ddc:570 Baltic Sea Eastern Baltic cod fisheries management environmental indicators spawning habitat oceanographic modeling von Dewitz, Burkhard Drivers, dynamics and management of Eastern Baltic cod (Gadus morhua) reproduction habitat |
topic_facet |
thesis ddc:570 Baltic Sea Eastern Baltic cod fisheries management environmental indicators spawning habitat oceanographic modeling |
description |
The overall aim of my thesis was to improve our understanding of environmental drivers causing the dynamics of the Eastern Baltic cod reproduction habitat and to assess their relevance for a possible application in the sustainable stock management. A novel approach to map the reproductive habitat of Eastern Baltic cod, the Buoyancy Depending Reproductive Layers (BDRL), was developed and used to propose an alternative stock indicator, the effective Spawning Stock Biomass (eSSB). The eSSB was found to improve the fit of a recruitment model compared to the model using the conventional Spawning Stock Biomass. Oxygen depletion was also negatively impacting the available size of nursery areas for juveniles. The mechanism was able to partly explain the observed decline of the condition of juveniles in the nursery areas, because a high population density in the remaining habitat could increase the impact of density depending effects. Furthermore, by the application of the novel approach of BDRLs the spawning habitat was shown to be sensitive to eutrophication and that this sensitivity is strongly depending on the size of the female spawner using the habitat. As predicted, the BDRL approach was superior to the “classic” approach, the Reproductive Volume (RV) because it was more sensitive to environmental change, able to incorporate stock structure, was not overestimating the spawning habitat in the eastern spawning areas and could provide estimates of other stressors depending on the female spawner size. Due to a permanently installed measurement platform in the Arkona Basin, the new methodology could be used to establish a new environmental indicator on the spawning habitat conditions. It was recommended to be used in future stock assessments. Das Ziel dieser Arbeit war unser Verständnis der treibenden Umweltparameter dieser Entwicklung und ihrer Dynamic zu verbessern und sie auf eine mögliche Nutzung im Zusammenhang mit einem nachhaltigen Management des Bestandes zu überprüfen. Entwickelt wurde eine neue Methode die ... |
author2 |
Reusch, Thorsten B. H. Gröger, Joachim |
format |
Doctoral or Postdoctoral Thesis |
author |
von Dewitz, Burkhard |
author_facet |
von Dewitz, Burkhard |
author_sort |
von Dewitz, Burkhard |
title |
Drivers, dynamics and management of Eastern Baltic cod (Gadus morhua) reproduction habitat |
title_short |
Drivers, dynamics and management of Eastern Baltic cod (Gadus morhua) reproduction habitat |
title_full |
Drivers, dynamics and management of Eastern Baltic cod (Gadus morhua) reproduction habitat |
title_fullStr |
Drivers, dynamics and management of Eastern Baltic cod (Gadus morhua) reproduction habitat |
title_full_unstemmed |
Drivers, dynamics and management of Eastern Baltic cod (Gadus morhua) reproduction habitat |
title_sort |
drivers, dynamics and management of eastern baltic cod (gadus morhua) reproduction habitat |
publishDate |
2018 |
url |
https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-239412 https://macau.uni-kiel.de/receive/diss_mods_00023941 https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00007907/PhD_Thesis_Burkhard_von_Dewitz.pdf |
genre |
Gadus morhua |
genre_facet |
Gadus morhua |
op_relation |
https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-239412 https://macau.uni-kiel.de/receive/diss_mods_00023941 https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00007907/PhD_Thesis_Burkhard_von_Dewitz.pdf |
op_rights |
https://rightsstatements.org/page/InC/1.0/ info:eu-repo/semantics/openAccess |
_version_ |
1802644424391393280 |