Papers by Henrik Gislason
The impacts of industrial fisheries on the prey of salmon: From: The Atlantic Salmon as predator and prey. Report of the special Session of the Council, NASCO. Gothenburg Sweden, 13 June 1996
All additional text, figures, and tables cited in the main analysis are present in this document
General information Publication status: Published Organisations: National Institute of Aquatic Re... more General information Publication status: Published Organisations: National Institute of Aquatic Resources, Section for Ecosystem based Marine Management, Public Sector Consultancy, Section for Monitoring and Data, Section for Freshwater Fisheries Ecology Contributors: Gislason, H., Dalskov, J., Dinesen, G. E., Egekvist, J., Eigaard, O. R., Jepsen, N., Larsen, F., Poulsen, L. K. , Sørensen, T. K., Hoffmann, E. Number of pages: 83 Publication date: 2014
Fishing patterns and yield variations
An integrated end-to-end modeling framework for testing ecosystem-wide effects of human-induced pressures in the Baltic Sea
induced pressures in the Baltic Sea DTU Orbit (29/12/2018) An integrated end-to-end modeling fram... more induced pressures in the Baltic Sea DTU Orbit (29/12/2018) An integrated end-to-end modeling framework for testing ecosystem-wide effects of human-induced pressures in the Baltic Sea We present an integrated end-to-end modeling framework that enables whole-of ecosystem climate, eutrophication, and spatial management scenario exploration in the Baltic Sea. The framework is built around the Baltic implementation of the spatially-explicit end-to-end ATLANTIS model, linked to the high-resolution coupled physical-biological model HBMERGOM and the fisheries bio-economic FishRent model. We investigate ecosystem-wide responses to changes in human-induced pressures by simulating several eutrophication scenarios that are relevant to existing Baltic Sea management plans (e.g. EU BSAP, EU CFP). We further present the structure and calibration of the Baltic ATLANTIS model and the operational linkage to the other models. Using the results of eutrophication scenarios, and focusing on the relative ...
Menneskeskabte påvirkninger af havet – Andre presfaktorer end kvælstof og klimaforandringer
General information Publication status: Published Organisations: Danish Shellfish Centre, Nationa... more General information Publication status: Published Organisations: Danish Shellfish Centre, National Institute of Aquatic Resources, Section for Ecosystem based Marine Management, Section for Marine Living Resources, Section for Oceans and Arctic, Aarhus University Contributors: Petersen, J. K. (ed.), Holm, A. S., Christensen, A., Krekoukiotis, D., Jakobsen, H., Sanderson, H., Andreasen, H., Gislason, H., Strand, J., Behrens, J., Hansen, J. W., Svendsen, J. C., Timmermann, K., Møller, L. F., Bach, L., Larsen, M. M., Zrust, M., Nielsen, M. M., Eigaard, O. R., Nielsen, P., Stæhr, P. A., Høgslund, S., Nielsen, T. G. Number of pages: 118 Publication date: 2018
Ecological Indicators, 2020
Machine Learning (ML) has seen massive progress in the last decade and as a result, there is a pr... more Machine Learning (ML) has seen massive progress in the last decade and as a result, there is a pressing need for validating ML-based systems. To this end, we propose, design and evaluate CALLISTO-a novel test generation and data quality assessment framework. To the best of our knowledge, CALLISTO is the first blackbox framework to leverage the uncertainty in the prediction and systematically generate new test cases for ML classifiers. Our evaluation of CALLISTO on four real world data sets reveals thousands of errors. We also show that leveraging the uncertainty in prediction can increase the number of erroneous test cases up to a factor of 20, as compared to when no such knowledge is used for testing. CALLISTO has the capability to detect low quality data in the datasets that may contain mislabelled data. We conduct and present an extensive user study to validate the results of CALLISTO on identifying low quality data from four state-ofthe-art real world datasets.
Proceedings of the Royal Society B: Biological Sciences, 2019
The relationship between biodiversity and ecosystem functioning (BEF) is a topic of considerable ... more The relationship between biodiversity and ecosystem functioning (BEF) is a topic of considerable interest to scientists and managers because a better understanding of its underlying mechanisms may help us mitigate the consequences of biodiversity loss on ecosystems. Our current knowledge of BEF relies heavily on theoretical and experimental studies, typically conducted on a narrow range of spatio-temporal scales, environmental conditions, and trophic levels. Hence, whether a relationship holds in the natural environment is poorly understood, especially in exploited marine ecosystems. Using large-scale observations of marine fish communities, we applied a structural equation modelling framework to investigate the existence and significance of BEF relationships across northwestern European seas. We find that ecosystem functioning, here represented by spatial patterns in total fish biomass, is unrelated to species richness—the most commonly used diversity metric in BEF studies. Instead...
The natural mortality of exploited fish populations is notoriously difficult to estimate. It is t... more The natural mortality of exploited fish populations is notoriously difficult to estimate. It is therefore often inferred from Pauly's equation using estimates of growth parameters and ambient temperature. However, contrary to the results derived from multispecies and size-spectra models, Pauly's equation assumes that natural mortality is independent of individual size. This assumption has large implications for size-based fish population models and for the success of size-dependent management measures such as mesh-size regulations. Here we reanalyze the existing empirical estimates of natural mortality using a model where individual size, growth characteristics and ambient temperatures are all accounted for. We find natural mortality to scale significantly with individual body size, asymptotic size, and the von Bertalanffy growth parameter K, and our parameter estimates are not significantly different from those derived from a sizebased fish-community model.
J. (2017). Analysis of marine protected areas-in the Danish part of the North Sea and the Central... more J. (2017). Analysis of marine protected areas-in the Danish part of the North Sea and the Central Baltic around Bornholm. Part 2: Ecological and economic value, human pressures, and MPA selection. DTU Aqua Report No.
Does whiting play a central role in the food web of the western Baltic Sea
Scientific quality is undoubtedly the most important aspect of a contribution to a symposium, but... more Scientific quality is undoubtedly the most important aspect of a contribution to a symposium, but the value of a contribution is also greatly heightened by a vivid and stirring presentation, and the discussion it stimulates. In order to underline the importance of the latter in com municating scientific results, it was decided to give awards for the “best presentations” . On the basis of a plenary vote, the awards were presented to H. Gislason (paper) and to M. Tasker, R. Furness, M. Harris, and R. S. Bailey (poster) for their excellent use of audio visual aids. The Co-conveners would like to express their grati tude to J. Harwood (U K ), A . Laurec (France), J. G. Pope (U K ), and H. Sparholt (Denmark), who put great effort into the organization of the Symposium as mem bers o f the Steering Committee. In addition, they would like to thank the referees of the papers selected for publication for their invaluable contribution and ex pertise in formulating many suggestions for imp...
Scavenging strategies of hagfish in the Kattegat
En revision af traditionelle koncepter i fiskeriet. Er balanceret fiskeri en mulig forvaltningsstrategi
Supplementary material from "Biodiversity–ecosystem functioning relationships in fish communities: biomass is related to evenness and the environment, not to species richness
Global analysis of fish growth rates shows weaker responses to temperature than metabolic predictions
Global Ecology and Biogeography
Aim: Higher temperatures increase the metabolic rate of ectothermic organisms up to a certain lev... more Aim: Higher temperatures increase the metabolic rate of ectothermic organisms up to a certain level and make them grow faster. This temperature-sensitivity of growth is frequently used to predict the long-term effects of climate warming on ectotherms. Yet, realized growth also depends on ecological factors and evolutionary adaptation. Here we study whether faster growth is observed along temperature clines within and between marine fish species from polar to tropical regions. Location: Global. Time period: The sampling or publication year is for 718 observations before 1980, 1,073 observations between 1980 and 2000, and 390 observations after 2000 (for 336 observations no year was recorded). Major taxa studied: Marine teleost fish and elasmobranchs. Methods: The effects of temperature on fish growth are studied using 2,517 growth observations, representing 771 species in 165 marine ecoregions. The effects of temperature are presented with a Q10, describing relative increase in the rate of growth for each 10 °C increase. Results: We find weak within- and between-species effects of temperature on growth. The typical within-species effect of temperature has a Q10 of 1.1. The between-species effect is a little higher (Q10 = 1.4, or Q10 = 1.2 when corrected for phylogenetic relationships). When analysed per fish guild, growth responses vary from nearly independent of temperature in large demersals (Q10 = 1.1) to positive in small pelagics (Q10 = 1.6) and elasmobranchs (Q10 = 2.3). Average growth is higher in ecoregions with high primary production. Main conclusion: The change in average growth along temperature clines is weaker than predicted by metabolic theory, suggesting that the metabolic predictions are not sustainable in an ecosystem context. The long-term response of fish to the increase in temperature associated with climate change may hence be shaped more by local environmental and ecological dynamics than by the physiological temperature response of the species currently present.
Marine biota is redistributing at a rapid pace in response to climate change and shifting seascap... more Marine biota is redistributing at a rapid pace in response to climate change and shifting seascapes. While changes in fish populations and community structure threaten the sustainability of fisheries, our capacity to adapt by tracking and projecting marine species remains a challenge due to data discontinuities in biological observations, lack of data availability, and mismatch between data and real species distributions. To assess the extent of this challenge, we review the global status and accessibility of ongoing scientific bottom trawl surveys. In total, we gathered metadata for 283,925 samples from 95 surveys conducted regularly from 2001 to 2019. 59% of the metadata collected are not publicly available, highlighting that the availability of data is the most important challenge to assess species redistributions under global climate change. We further found that single surveys do not cover the full range of the main commercial demersal fish species and that an average of 18 sur...
Bottom trawling may adversely affect the ecological functioning of marine habitats and associated... more Bottom trawling may adversely affect the ecological functioning of marine habitats and associated macrobenthos communities. While several studies have assessed the variability and sensitivity of invertebrate taxa and biodiversity indices to human impacts, few ecological indicators have proven sensitive to bottom trawling. In a recent study, trawling intensity explained more of the variation in total macrobenthos density than in species density and derived biodiversity indices; however, changes in ecological functioning were not tested. The aim of this study was to investigate whether trawling induced variation in total macrobenthos density translates into changes in ecological functioning by using 35 modalities across 8 response and effects traits. Quantitative macrobenthos time series data (2006-2015) from a complex, northern European sea (the Kattegat connecting the North Sea and Baltic Sea) were analysed to decipher ecosystem responsiveness to trawling intensity and 6 key environ...
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Papers by Henrik Gislason