@article{13d8856374964f8e9597b0a938236102,
title = "Environmental factors shaping fish fauna structure in a temperate mesotidal estuary: Periodic insights from the Elbe estuary across four decades",
abstract = "Anthropogenic perturbations paired with increasing climatic changes, affect the biota composition and ecosystem services provided by highly productive estuarine transitional ecosystems worldwide. To determine driving forces affecting fish stocks in an estuarine habitat, we created a periodic time series over the last four decades (1984–2022) combining fish species compositions and densities with environmental conditions along the course of the temperate mesotidal Elbe estuary. We detected major changes in the species composition alongside with changes in life cycle guilds composition. With a relative increase of marine-estuarine opportunists and reduction of diadromous species, the fish fauna of the Elbe estuary has become more similar in guild structure compared to macro tidal estuaries in Europe. Improvements in water quality in the 1990s were accompanied by increased fish densities, specially smelt (Osmerus eperlanus), until 2010. Anthropogenic hydromorphological interventions, however, could have led to an increase in suspended particular matter until 2022, which combined with reduced river runoff and poor oxygen concentrations in summer months acted as poor environmental conditions for fishes in the estuary. Mean fish densities dropped by over 91 % compared to 2010 to an all-time low in the data. This reduction was primarily a result of a decline of the key species smelt in the system along with declines of twaite shad (Alosa fallax), flounder (Platichthys flesus), ruffe (Gymnocephalus cernua), common bream (Abramis brama) and other species. On the contrary, marine species herring (Clupea harengus) and whiting (Merlangius merlangus) densities increased. Overall, the time-series provides insight into the strong impact of human intervention that are however expected to lead to further stressors.",
keywords = "Estuary, Fish assemblage, Guild composition, Fish stocks, Environmental influences",
author = "Jesse Theilen and Victoria Sarrazin and Elena Hauten and Raphael Koll and Christian Moellmann and Andrej Fabrizius and Ralf Thiel",
year = "2025",
month = jul,
day = "15",
doi = "10.1016/j.ecss.2025.109208",
language = "English",
volume = "318",
journal = "Estuarine, Coastal and Shelf Science",
issn = "0272-7714",
publisher = "Academic Press",
}
@article{56648fb33a59452bbdc5309b26d0059c,
title = "Inter- and Intra-Estuarine Comparison of the Feeding Ecology of Keystone Fish Species in the Elbe and Odra Estuaries",
abstract = "Food webs in estuarine ecosystems serve as important biological indicators. The feeding ecology of four keystone fish species, pikeperch (Sander lucioperca L.), smelt (Osmerus eperlanus L.), ruffe (Gymnocephalus cernua L.) and flounder (Platichthys flesus L.), in the Elbe and Odra estuaries was analyzed using stomach content analyses. Important prey of pikeperch were fishes and mysids in both estuaries. Amphipods were especially important as prey for smelt in the Elbe estuary, whereas smelt caught in the Odra estuary mainly consumed mysids. Ruffe fed mainly on amphipods in the Elbe estuary, while annelids (lower section) and insect larvae (upper section) were the most important prey in the Odra estuary. Flounder favored copepods as prey in the Elbe estuary, while bivalves were preferred in the Odra estuary. Higher dietary overlaps were found in the Elbe estuary between smelt vs. ruffe, pikeperch vs. ruffe, and pikeperch vs. smelt. In the Elbe estuary, a shift in the diet composition of pikeperch, smelt, and ruffe was observed from 2021 to 2022 compared to food analyses from the 1990s. These shifts included an increased consumption of amphipods, while mysids and copepods had recently decreased in their diets. These changes indicate a restructuring of the food web, potentially linked to environmental changes, which highlights the sensitivity of estuarine ecosystems.",
author = "Jesse Theilen and Sarah Storz and Sof{\'i}a Amieva-Mau and Jessica Dohr and Elena Hauten and Raphael Koll and Christian M{\"o}llmann and Andrej Fabrizius and Ralf Thiel",
year = "2025",
month = apr,
doi = "10.3390/fishes10040161",
language = "English",
volume = "10",
journal = "Fishes",
issn = "2410-3888",
publisher = "MDPI",
number = "4",
}
@article{cb83dedfbd9149419a65c0fb62de87f6,
title = "Spatial and temporal patterns of zooplankton trophic interactions and carbon sources in the eutrophic Elbe estuary (Germany)",
abstract = "Zooplankton in estuaries encounter complex physical and biogeochemical processes that affect the quantity, quality, and origin of their food sources. The knowledge about how zooplankton deal with highly variable organic matter sources is sparse. Here, we investigated the spatial and temporal patterns of zooplankton trophic dynamics and carbon sources in the intensively dredged, eutrophic Elbe estuary. For this purpose, we applied elemental and stable isotope analysis (δ13C and δ15N) on particulate organic matter (POM) and dominant meso- and macrozooplankton species, including ichthyoplankton, from five stations along the entire salinity gradient of the estuary in 2022. The δ13C values of POM (−29.2 to −23.0 ‰) indicated a mixture of riverine, terrestrial, and coastal carbon sources used by most taxa for their diet. Eurytemora affinis (−34.0 to −23.3 ‰) and Mesopodopsis slabberi (−22.2 to −20.0 ‰) exhibited a broader range in δ13C than POM, suggesting selective feeding on single POM components depending on the season. In winter and autumn, under high suspended matter loads and limited availability of high-quality autochthonous phytoplankton, zooplankton showed increased tendency for carnivory (higher δ15N values). Our study revealed a high trophic plasticity of estuarine Elbe zooplankton to buffer hydrological-related alterations in their food source by dietary niche partitioning and a flexible switch in their feeding behaviour.",
keywords = "Elbe estuary, estuarine zooplankton, Trophodynamics, stable isotopes, Allochthonous and autochthonous carbon, selective feeding",
author = "Johanna Biederbick and Christian M{\"o}llmann and Elena Hauten and Vanessa Russnak and Niko Lahajnar and Thomas Hansen and Jan Dierking and Rolf Koppelmann",
year = "2024",
month = dec,
day = "31",
doi = "10.1093/icesjms/fsae189",
language = "English",
journal = "ICES Journal of Marine Science",
issn = "1054-3139",
publisher = "Oxford University Press",
}
@article{771646a9324b4606b997d44214065728,
title = "A climate vulnerability assessment of the fish community in the Western Baltic Sea",
abstract = "Marine fisheries are increasingly impacted by climate change, affecting species distribution and productivity, and necessitating urgent adaptation efforts. Climate vulnerability assessments (CVA), integrating expert knowledge, are vital for identifying species that could thrive or suffer under changing environmental conditions. This study presents a first CVA for the Western Baltic Sea's fish community, a crucial fishing area for Denmark and Germany. Characterized by a unique mix of marine, brackish, and freshwater species, this coastal ecosystem faces significant changes due to the combined effects of overfishing, eutrophication and climate change. Our CVA involved a qualitative expert scoring of 22 fish species, assessing their sensitivity and exposure to climate change. Our study revealed a dichotomy in climate change vulnerability within the fish community of the Western Baltic Sea because traditional fishing targets cod and herring as well as other species with complex life histories are considered to face increased risks, whereas invasive or better adaptable species might thrive under changing conditions. Our findings hence demonstrate the complex interplay between life-history traits and climate change vulnerability in marine fish communities. Eventually, our study provides critical knowledge for the urgent development of tailored adaptation efforts addressing existing but especially future effects of climate change on fish and fisheries in the Western Baltic Sea, to navigate this endangered fisheries systems into a sustainable future.",
keywords = "Climate change, Climate vulnerability assessment, Fish community, Trait-based sensitivity, Western Baltic Sea",
author = "Dorothee Moll and Harald Asmus and Alexandra Bl{\"o}cker and Uwe B{\"o}ttcher and Jan Conradt and Leonie F{\"a}rber and Nicole Funk and Steffen Funk and Helene Gutte and Hinrichsen, {Hans Harald} and Paul Kotterba and Uwe Krumme and Frane Madiraca and Meier, {H. E.Markus} and Steffi Meyer and Timo Moritz and Otto, {Saskia A.} and Guilherme Pinto and Patrick Polte and Riekhof, {Marie Catherine} and Victoria Sarrazin and Marco Scotti and Rudi Voss and Helmut Winkler and Christian M{\"o}llmann",
note = "Publisher Copyright: {\textcopyright} The Author(s) 2024.",
year = "2024",
month = dec,
doi = "10.1038/s41598-024-67029-2",
language = "English",
volume = "14",
journal = "Scientific Reports",
issn = "2045-2322",
publisher = "Springer Nature",
number = "1",
}
@article{a567e5fcd1eb447388c5dc0d8174c22b,
title = "Spatio-temporal plasticity of gill microbiota in estuarine fish",
abstract = "Coastal marine and estuarine systems are subject to enormous endogenous and exogenous pressures, particularly climate change, while at the same time being highly productive sources and nurseries for fish populations. Interactions between host and microbiome are increasingly recognized for their importance for fish health, with growing evidence indicating that increasing environmental pressures impact host resilience and favor the raise of opportunistic bacterial taxa. The microbial composition of the gill mucus reflects environmental conditions and represents an entry route for pathogens into the fish body. High-throughput sequencing of prokaryotic populations from 250 samples of two fish species with highly different habitat preferences, as well as seasonal and spatial distributions in the Elbe estuary system, allowed us to describe the variation of the microbiota along a salinity gradient and under fluctuating environmental conditions. The analysis of estuarine fish core microbiota in relation to variable bacterial components indicated dysbiotic states under sustained hypoxia and high nutrient loads largely driven by increased prevalence of facultatively aerobic (Acinetobacter) and anaerobic heterotrophs (Shewanella, Aeromonas). By correlating bacterial abundances with environmental and physiological parameters in a co-occurrence network approach, we describe plasticity in microbiota composition, identify potential biomarkers for fish health monitoring and reconstruct movement patterns of the fish. Our results can help to shape future minimal-invasive and cost-effective monitoring programs, and identify factors that need to be controlled in the estuary to promote fish and stock health.",
author = "Raphael Koll and Elena Hauten and Jesse Theilen and Corinna Bang and Michelle Bouchard and Ralf Thiel and Christian M{\"o}llmann and Woodhouse, {Jason Nicholas} and Andrej Fabrizius",
note = "Copyright {\textcopyright} 2024. Published by Elsevier B.V.",
year = "2024",
month = nov,
day = "11",
doi = "10.1016/j.scitotenv.2024.177505",
language = "English",
volume = "957",
pages = "177505",
journal = "Science of The Total Environment",
issn = "0048-9697",
publisher = "Elsevier B.V.",
}
@article{aee08ea044d24e6d92d808ee38c7d0a3,
title = "Exploring the adaptive capacity of a fisheries social-ecological system to global change",
abstract = "Global change challenges coupled natural-human systems such as fisheries social-ecological systems (SES) because they are confined by spatial and functional ecosystem boundaries. Understanding the capacity of an SES to adapt to changing environmental or socio-economic conditions is complex and entails an analysis of the system's properties such as resilience, resistance, vulnerability, and adaptive capacity. We used a modified Ostrom framework to structure our analyses and to define the SES components, attributes and indicators of the German mixed demersal fishery SES operating in the southern North Sea. Combining analyses of 20-year time series of environmental and socio-economic data with network analysis and semi-structured interviews allowed for a detailed description of past SES adaptations. Hence, our analysis revealed autonomous adaptations of the SES to environmental and socio-economic change, which entailed a shift in target species, fishing strategies as well as a distinct decrease in number of actors. We found that the adaptive capacity of the SES has declined over time, and that the SES is now on the brink of being unable to withstand future environmental and socio-economic change. It is therefore captured in an undesirable state, reflecting a social-ecological trap where social and environmental feedbacks negatively reinforce each other. The main barriers to the adaptive capacity of the SES are related to fishing cultures, economic structures, policy frameworks and increasing conflicts over the use of marine space. An in-depth understanding of the linkages between the identified key SES components and related indicators is a prerequisite for developing future management approaches to enhance the adaptive capacity of SES to global change. Our findings highlight the need for tailored and context-specific co-management approaches for all decision-making processes affecting SES.",
author = "Vanessa Stelzenm{\"u}ller and Jonas Letschert and Benjamin Blanz and Alexandra Bl{\"o}cker and Joachim Claudet and Roland Cormier and Kira Gee and Hermann Held and Andreas Kannen and Maren Kruse and Henrike Rambo and J{\"u}rgen Schaper and Camilla Sguotti and Nicole Stollberg and Emily Quiroga-G{\'o}mez and Christian Moellmann",
year = "2024",
month = sep,
day = "25",
doi = "10.1016/j.ocecoaman.2024.107391",
language = "English",
volume = "258",
journal = "Ocean & Coastal Management",
issn = "0964-5691",
publisher = "Elsevier BV",
}
@article{41187e3377a243b99d665b3eb71b6393,
title = "Network-based integration of omics, physiological and environmental data in real-world Elbe estuarine Zander",
abstract = "Coastal and estuarine environments are under endogenic and exogenic pressures jeopardizing survival and diversity of inhabiting biota. Information of possible synergistic effects of multiple (a)biotic stressors and holobiont interaction are largely missing in estuaries like the Elbe but are of importance to estimate unforeseen effects on animals' physiology. Here, we seek to leverage host-transcriptional RNA-seq and gill mucus microbial 16S rRNA metabarcoding data coupled with physiological and abiotic measurements in a network analysis approach to decipher the impact of multiple stressors on the health of juvenile Sander lucioperca along one of the largest European estuaries. We find mesohaline areas characterized by gill tissue specific transcriptional responses matching osmosensing and tissue remodeling. Liver transcriptomes instead emphasized that zander from highly turbid areas were undergoing starvation which was supported by compromised body condition. Potential pathogenic bacteria, including Shewanella, Acinetobacter, Aeromonas and Chryseobacterium, dominated the gill microbiome along the freshwater transition and oxygen minimum zone. Their occurrence coincided with a strong adaptive and innate transcriptional immune response in host gill and enhanced energy demand in liver tissue supporting their potential pathogenicity. Taken together, we show physiological responses of a fish species and its microbiome to abiotic factors whose impact is expected to increase with consequences of climate change. We further present a method for the close-meshed detection of the main stressors and bacterial species with disease potential in a highly productive ecosystem.",
keywords = "Estuary, Holobiont, Hypoxia, Network analysis, Transcriptomics and Metabarcoding",
author = "Raphael Koll and Jesse Theilen and Elena Hauten and Woodhouse, {Jason Nicholas} and Ralf Thiel and Christian M{\"o}llmann and Andrej Fabrizius",
note = "Publisher Copyright: {\textcopyright} 2024 The Authors",
year = "2024",
month = sep,
day = "10",
doi = "10.1016/j.scitotenv.2024.173656",
language = "English",
volume = "942",
journal = "Science of The Total Environment",
issn = "0048-9697",
publisher = "Elsevier B.V.",
}
@article{2de50bce5a97471d8d6d80be0917c237,
title = "Robust fisheries management strategies under deep uncertainty",
abstract = "Fisheries worldwide face uncertain futures as climate change manifests in environmental effects of hitherto unseen strengths. Developing climate-ready management strategies traditionally requires a good mechanistic understanding of stock response to climate change in order to build projection models for testing different exploitation levels. Unfortunately, model-based projections of fish stocks are severely limited by large uncertainties in the recruitment process, as the required stock-recruitment relationship is usually not well represented by data. An alternative is to shift focus to improving the decision-making process, as postulated by the decision-making under deep uncertainty (DMDU) framework. Robust Decision Making (RDM), a key DMDU concept, aims at identifying management decisions that are robust to a vast range of uncertain scenarios. Here we employ RDM to investigate the capability of North Sea cod to support a sustainable and economically viable fishery under future climate change. We projected the stock under 40,000 combinations of exploitation levels, emission scenarios and stock-recruitment parameterizations and found that model uncertainties and exploitation have similar importance for model outcomes. Our study revealed that no management strategy exists that is fully robust to the uncertainty in relation to model parameterization and future climate change. We instead propose a risk assessment that accounts for the trade-offs between stock conservation and profitability under deep uncertainty.",
keywords = "Animals, Climate Change, Conservation of Natural Resources/methods, Decision Making, Fisheries, Gadus morhua, Models, Theoretical, Uncertainty",
author = "Jan Conradt and Steffen Funk and Camilla Sguotti and Rudi Voss and Thorsten Blenckner and Christian Moellmann",
year = "2024",
month = jul,
day = "23",
doi = "10.1038/s41598-024-68006-5",
language = "English",
volume = "14",
journal = "Scientific Reports",
issn = "2045-2322",
publisher = "Springer Nature",
number = "1",
}
@article{cc76f4ab65024887ab0f82d323fb4df9,
title = "Spatial structuring of Mediterranean fisheries landings in relation to their seasonal and long-term fluctuations",
abstract = "The Western Mediterranean fisheries significantly contribute to the regional blue economy, despite evidence of ongoing, widespread overexploitation of stocks. Understanding the spatial distribution and population dynamics of species is crucial for comprehending fisheries dynamics combining local and regional scales, although the underlying processes are often neglected. In this study, we aimed to (i) evaluate the seasonal and long-term spatio-temporal fluctuations of crustacean, cephalopod, and fish populations in the Western Mediterranean, (ii) determine whether these fluctuations are driven by the spatial structure of the fisheries or synchronic species fluctuations, and (iii) compare groupings according to the individual species and life history-based groups. We used dynamic factor analysis to detect underlying patterns in a Landing Per Unit Effort (LPUE) time series (2009–2020) for 23 commercially important species and 33 ports in the Western Mediterranean. To verify the spatial structure of ports and species groupings we investigated the seasonal and long-term spatio-temporal fluctuations and common LPUE trends that exhibit non-homogeneous and species-specific trends, highlighting the importance of life history, environmental and demographic preferences. Long-term trends revealed spatial segregation with a north-south gradient, demonstrating complex population structures of Western Mediterranean resources. Seasonal patterns exhibited a varying spatial aggregation based on species-port combinations. These findings can inform the Common Fishery Policy on gaps challenging their regionalisation objectives in the Mediterranean Sea. We highlight the need for a nuanced and flexible approach and a better understanding of sub-regional processes for effective management and conservation – a current challenge for global fisheries. Our LPUE approach provides insight into population dynamics and changes in regional fisheries, relevant beyond the Mediterranean Sea.",
keywords = "Benthopelagic communities, Commercial fisheries, Dynamic factor analysis, Seasonality, Spatio-temporal trends, Synchrony",
author = "Konstancja Wo{\'z}niacka and Georgios Kerametsidis and Luc{\'i}a L{\'o}pez-L{\'o}pez and Christian M{\"o}llmann and Manuel Hidalgo",
note = "Publisher Copyright: {\textcopyright} 2024 The Authors",
year = "2024",
month = may,
doi = "10.1016/j.marenvres.2024.106453",
language = "English",
volume = "197",
journal = "Marine Environmental Research",
issn = "0141-1136",
publisher = "Elsevier Limited",
}
@article{2608bb8675c449cbaed67f47fd3361e7,
title = "Operationalizing a fisheries social-ecological system through a Bayesian belief network reveals hotspots for its adaptive capacity in the southern North sea",
abstract = "Fisheries social-ecological systems (SES) in the North Sea region confront multifaceted challenges stemming from environmental changes, offshore wind farm expansion, and marine protected area establishment. In this paper, we demonstrate the utility of a Bayesian Belief Network (BN) approach in comprehensively capturing and assessing the intricate spatial dynamics within the German plaice-related fisheries SES. The BN integrates ecological, economic, and socio-cultural factors to generate high-resolution maps of profitability and adaptive capacity potential (ACP) as prospective management targets. Our analysis of future scenarios, delineating changes in spatial constraints, economics, and socio-cultural aspects, identifies factors that will exert significant influence on this fisheries SES in the near future. These include the loss of fishing grounds due to the installation of offshore wind farms and marine protected areas, as well as reduced plaice landings due to climate change. The identified ACP hotspots hold the potential to guide the development of localized management strategies and sustainable planning efforts by highlighting the consequences of management decisions. Our findings emphasize the need to consider detailed spatial dynamics of fisheries SES within marine spatial planning (MSP) and illustrate how this information may assist decision-makers and practitioners in area prioritization. We, therefore, propose adopting the concept of fisheries SES within broader integrated management approaches to foster sustainable development of inherently dynamic SES in a rapidly evolving marine environment.",
keywords = "Adaptive capacity (potential), Bayesian belief network, Fisheries management, Marine spatial planning, Offshore renewables, Social-ecological system (SES)",
author = "M. Kruse and J. Letschert and Roland Cormier and H. Rambo and K. Gee and A. Kannen and J. Schaper and C. M{\"o}llmann and Vanessa Stelzenm{\"u}ller",
note = "Publisher Copyright: {\textcopyright} 2024",
year = "2024",
month = apr,
doi = "10.1016/j.jenvman.2024.120685",
language = "English",
volume = "357",
journal = "Journal of Environmental Management",
issn = "0301-4797",
publisher = "Academic Press",
}