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Göteborg, Sweden

Westerberg H.,Swedish Board of Fisheries | Westerberg K.,Lund University
Fisheries Research | Year: 2011

The formation of an odour trail can be broken down into a chain of events: first, the emission of the attractant from the bait, second, a turbulent mixing into the immediate surroundings and third, a downstream advection and dispersion of the attractant by the current flowing past the bait. In this work, a simple analysis of the physical processes governing the first two stages shows that the release of attractant will decline as the inverse of the square root of time. The decline curve will be similar for all solid natural baits within a realistic size range during normal soak times.Experiments were performed to measure typical diffusion constants of odour substances in fish tissue and it is shown that due to the low diffusivity just a thin surface layer will release its content of odour substances during a fishing operation using pieces of fish as bait. Moreover, the initial concentration of attractant when a plume is formed will be independent of the size of a solid bait and only depend on the ratio of the surface area to the cross-section area of the bait. To increase the maximum concentration of odour substance in the plume and utilize a given amount of bait optimally, a solid bait should be cut into smaller pieces. The effect of current speed on the initial odour concentration in the plume is strong. Due to speed variations during the soak time the effectiveness of the attraction will vary in time.To extend the analysis and develop models for optimization of the range of the olfactory signal from a bait it is necessary to know both the concentration of the attractant in the bait and the target species detection threshold. When such data become available it will be possible to estimate the range of attraction of baits under different environmental conditions. © 2011 Elsevier B.V. Source


Waldo S.,Swedish University of Agricultural Sciences | Paulrud A.,Swedish University of Agricultural Sciences | Jonsson A.,Swedish Board of Fisheries
Marine Policy | Year: 2010

The cod stocks in the Baltic Sea are important not only for fisheries but for the entire ecosystem utilized by numerous stakeholders around the coast. All such activities have economic values. In this note the economics of the Swedish Baltic Sea cod fishery is estimated in relation to the sector's interaction with other users of the Baltic Sea ecosystem. The results show a negative resource rent for the fishery, € -5 million without public expenses (subsidies and administrative costs), and € -13 million including public expenses. The interactions between the fisheries and tourism, seal population, carbon dioxide emissions, recreational fishing, and discards are discussed, and when monetary estimates are available these are related to the estimated resource rent. © 2009 Elsevier Ltd. All rights reserved. Source


Ratner B.D.,WorldFish | Asgard B.,Swedish Board of Fisheries | Allison E.H.,University of Washington
Global Environmental Change | Year: 2014

A review of case law and other documentation of human rights issues in fishing communities highlights forced evictions, detention without trial, child labour, forced labour and unsafe working conditions, and violence and personal security, including gender-based violence, as key areas of concern. We argue that human rights violations undermine current attempts to reform the fisheries sector in developing countries by increasing the vulnerability and marginalization of certain groups. Citing cases from India, the Philippines, Cambodia, and South Africa, we show how human rights advocacy can be an effective element of support for development in fisheries. Finally, we outline how fisheries reform can better address human rights issues as an essential complement to the equitable allocation of fishing rights, contributing to improved resource management and human wellbeing. © 2014 The Authors. Source


Daverat F.,IRSTEA | Beaulaton L.,Onema | Poole R.,Marine Institute of Ireland | Lambert P.,IRSTEA | And 7 more authors.
Ecology of Freshwater Fish | Year: 2012

A cooperative effort gathered a large European length-at-age data set (N=45,759, Lat. 36S-61N Long. 10W-27E) for Anguilla anguilla, covering one century. To assess the effect of global warming during the last century and habitat effects on growth, a model was fitted on the data representing the conditions met at the distribution area scale. Two GLMs were designed to predict eel log(GR): one model was fitted to the whole data and the other was fitted to the female data subset. A model selection procedure was applied to select the best predictors among sex, age class, five temperature parameters and six habitat parameters (depth, salinity and four variables related to the position in the catchment). The yearly sum of temperatures above 13°C (TempSUP13), the relative distance within the catchment, sex, age class, salinity class and depth class were finally selected. The best model predicted eel log(GR) with a 64.46% accuracy for the whole data and 66.91% for the female eel data. Growth rate (GR) was greater in habitats close to the sea and in deep habitats. TempSUP13 variable had one of the greatest predictive powers in the model, showing that global warming had affected eel growth during the last century. © 2012 John Wiley & Sons A/S. Source


Hedman J.E.,Swedish Museum of Natural History | Rudel H.,Fraunhofer Institute for Molecular Biology and Applied Ecology | Gercken J.,Institute of Applied Ecology Ltd. | Bergek S.,Swedish Board of Fisheries | And 6 more authors.
Marine Pollution Bulletin | Year: 2011

The implementation of the EU Marine Strategy Framework Directive necessitates the development of common criteria and methodological standards for marine environmental monitoring and assessment across Europe. Eelpout (Zoarces viviparus) is proposed as a key indicator organism in the Baltic and North Sea regions. This benthic fish species is widely used in ecotoxicological studies and as a bioindicator of local pollution due to its stationary behavior. Eelpout is included in the environmental monitoring program of several Baltic States, covering both chemical and biological effects measurements, and samples have been archived in environmental specimen banks for >15. years. A method for evaluating the frequency of larval aberrations has been suggested as a standardized assessment tool. The large scientific knowledge-base and considerable experience of long-term chemical and biological effects monitoring and specimen banking, make eelpout a suitable species for the assessment of Good Environmental Status in the Baltic and North Seas. © 2011 Elsevier Ltd. Source

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