News Article | December 21, 2016
The aim of the framework contract is to provide the European Commission the scientific advice they need in order to ensure the sustainable management of EU fisheries outside EU waters, which are managed by international fishery management organisation. The provision of scientific advice will especially focus on the External Dimension of the Common Fisheries Policy (excluding the Mediterranean Sea and the Black Sea). The advice and services required by the European Commission will support the implementation of the Common Fisheries Policy (CFP), especially the external policy, by applying the precautionary approach and focusing on safeguarding the entire ecosystem, and ensuring that the EU environmental laws (Marine Strategy Framework Directive) and the Integrated Maritime Policy are complied with. The EUR 4M budget for the framework contract is funded by the EU via the European Maritime and Fisheries Fund. Other organisations that are part of the consortium led by AZTI include Institut national supérieur des sciences agronomiques, agroalimentaires, horticoles et du paysage (AGROCAMPUS OUEST); Centre for Environment, Fisheries and Aquaculture Science (CEFAS); Spanish Institute of Oceanography (IEO); Institute for Marine Resources & Ecosystem Studies (IMARES); Instituto Português do Mar e da Atmosfera, I.P. (IPMA); Institut de Recherche pour le Développement (IRD); and MRAG Limited (MRAG).
Schellekens T.,IMARES |
van Kooten T.,IMARES
Journal of Theoretical Biology | Year: 2012
An organism can be defined as omnivorous if it feeds on more than one trophic level. Omnivory is present in many ecosystems and multiple omnivorous species can coexist in the same ecosystem. How coexisting omnivores are able to avoid competitive exclusion is very much an open question. In this paper we analyze a model of a community consisting of two omnivorous predators and a basal resource. The population of both predators is explicitly structured into juveniles and adults, of which juveniles only feed on basal resource and adults feed on a varied proportion of basal resource and juveniles of the other population. We thereby separate the omnivorous roles (competitor for basal resource and predator of competitors) over life history. We show in this study that persistence of multiple omnivorous predators is possible when predators differ in adult diets. In this case, coexistence occurs because community dynamics force one of the model species to act as a predator and the other to act as a consumer. We conclude that separation of omnivorous roles over life history not only offers an explanation on why systems with omnivory can persist, but also how multiple omnivores can coexist at the same trophic levels of those systems. © 2012 Elsevier Ltd.
Piet G.J.,IMARES |
ICES Journal of Marine Science | Year: 2012
This study calculates a suite of indicators reflecting the spatial extent of fishing and its impact on the seafloor and discusses the usefulness of these indicators to inform future management and the issues to consider. It explores several methods to calculate the indicators and shows that they can be informative to report on both fishing pressure and the status of the seafloor. However, although observed overall trends were robust against the specific method of calculation, the absolute values vary greatly with the calculation method. As both aspects are important from a policy perspective, agreement on the methodology to calculate the indicators is required. This study based on the Dutch Exclusive Economic Zone (EEZ) shows that it is possible to calculate indicators required to inform decision-makers on the pressure of fishing as well as the status of the seafloor pending a decision on the following issues: (i) choice of an appropriate grid cell resolution, (ii) use of interpolated VMS tracks instead of VMS position registrations, (iii) choice of an "intensity threshold" dependent on the benthic community recovery capacity, and (iv) the level of confidence required when assessing if an area is not impacted. © 2012 International Council for the Exploration of the Sea. Published by Oxford University Press. All rights reserved.
Laane R.W.P.M.,Deltares |
Slijkerman D.,IMARES |
Vethaak A.D.,Deltares |
Estuarine, Coastal and Shelf Science | Year: 2012
Policymakers and managers have a very different philosophy and approach to achieving healthy coastal and marine ecosystems than scientists. In this paper we discuss the evolution of the assessment of the chemical status in the aquatic environment and the growing rift between the political intention (precautionary principle) and scientific developments (adaptive and evidence-based management) in the context of the pitfalls and practicalities confronting the current Marine Strategy Framework Directive (MSFD).The conclusion is that policymakers and water managers should move with the times and take on board new techniques that scientists are using to assess chemical status and apply new scientific developments in assessment studies of the chemical status. These new techniques, such as bioassays, are cheaper than the classic approach of checking whether concentrations of certain individual priority compounds comply with permissible thresholds. Additionally, they give more insight into the real impacts of chemical compounds. © 2011 Elsevier Ltd.
Beare D.,Worldfish Center |
ICES Journal of Marine Science | Year: 2012
Average towing speed by Dutch beam trawlermen has fallen substantially between 2002 and 2009. Changes in towing speed are related to changes in oil price. The price of their valuable main target species (sole, Solea vulgaris) did not influence towing speed. © 2012 International Council for the Exploration of the Sea.
Smaal A.C.,Imares |
Schellekens T.,Imares |
van Stralen M.R.,MarinX |
Aquaculture | Year: 2013
In the Oosterschelde estuary, primary production has decreased by 50% in the last 15. years. Nutrient concentrations are low but primary production is nutrient limited only for short periods during the growing season. Dominant bivalve filter feeder stocks consist of mussels (Mytilus edulis), cockles (Cerastoderma edule) and the introduced Pacific oysters (Crassostrea gigas). The mussel stock, which is under control of the mussel farmers, has decreased due to shortage of mussel seed, cockle stocks have maintained and oysters have expanded. Total filtration capacity has increased, also due to the invasion of Ensis americanus.Bivalve growth and condition are food limited, as shown by a negative correlation between average mussel meat content and bivalve filter feeder stock size in a certain year. The annual growth of cockles has decreased, and the fraction picoplankton is now up to 30% of total phytoplankton. Food limitation, high filtration capacity, picoplankton abundance, and only short-term bottom-up control of primary production by nutrient limitation, point to overgrazing as a cause of primary production decline. Further expansion of shellfish stocks may induce the risk of overexploitation. © 2013 Elsevier B.V.
Floor J.R.,Wageningen University |
van Koppen C.S.A.,Wageningen University |
Journal of Sea Research | Year: 2013
The potential ecological effects of cockle fisheries and gas exploitation in the Dutch Wadden Sea and their implications for policy and management have been the topic of vigorous societal debates. Ecological science has played crucial but controversial roles in these debates. Several social science studies have been dedicated to analysing these roles and making recommendations for the improvement of science-policy interactions. In reviewing these studies, this article aims to draw lessons for (ecological) scientists and policy makers on how to understand and guide the interactions of science and policy in Wadden Sea management. Studies addressing science-policy interactions in the Dutch Wadden Sea can be grouped into three main perspectives, emphasizing the social and economic dynamics of resource management, the role of nature views and discourses in controversies, and the influence of science dynamics in policy and management debates. The review demonstrates that ecological knowledge and ecological scientists have played important roles in the controversies on cockle fisheries and gas exploitation. However, scientific knowledge was not always the most important factor in the decision-making process, and scientific insights were not always used as expected by the scientists. How scientific knowledge is used and interpreted by stakeholders was dependent on their interests, their nature views and on the dominant policy discourses. Ecological knowledge and scientists themselves became part of the policy debates, e.g. in discussions on uncertainty and reliability. The position of scientists in policy debates was strongly influenced by the policy setting and by changes in this setting, e.g. by the operation of mediators or by new interpretations of legal rules. A lesson to be drawn for scientists is that they should reflect on the sort of position - e.g. independent outsider, or engaged stakeholder - they take in a debate. They should also be aware that this position cannot be chosen at will: it is strongly influenced by the policy context. For government and other stakeholders, an important lesson is that by shaping adequate policy settings they can contribute to more productive and effective interactions with science and scientists. © 2012 Elsevier B.V.
Marine Policy | Year: 2014
The European Common Fisheries Policy (CFP) is a common policy that originates from 1983 and has been renewed every 10 years. The policy generally aims for sustainable fisheries in terms of living resources, economics and social aspects. The most recent version of the policy was agreed in co-decision by the European Parliament and the European Council of Ministers in 2013. The CFP has often been criticised for not delivering on the objectives and for developing into micro-management with very detailed regulations. In this paper, the evolution of the CFP has been analysed using a simple word-count indicator. The results show a strong increase in the number of words used to describe the basic regulation of the CFP from 3500 words in 1983 to 21,000 words in the agreed regulation in 2013. The expansion of words fits closely to an exponential growth curve. The co-decision process between the European Parliament and the Council showed a 55% increase in words and the article describing the new landing obligation showed a 360% increase in words. First reports on the new CFP have already shown that the complexity in the regulation could increase the likelihood of misunderstanding and suboptimal decisions. Word-counts are obviously a crude way to measure regulatory complexity but they are easy to generate and intuitive to understand to different audiences. The challenge is to create conceptual models that can link this intuitive indicator into an empirical framework that attempts to measure the relative regulatory complexity. © 2014.
Jansen T.,Technical University of Denmark |
Campbell A.,Marine Institute of Ireland |
Brunel T.,IMARES |
Worsoe Clausen L.,Technical University of Denmark
PLoS ONE | Year: 2013
A comparison of growth data (fish length) with latitude shows that southern juvenile mackerel attain a greater length than those originating from further north before growth ceases during their first winter. A similar significant relationship was found between the growth in the first year (derived from the otolith inner winter ring) and latitude for adult mackerel spawning between 44°N (Bay of Biscay) and 54°N (west of Ireland). These observations are consistent with spatial segregation of the spawning migration; the further north that the fish were hatched, the further north they will tend to spawn. No such relationship was found in mackerel spawning at more northerly latitudes, possibly as a consequence of increased spatial mixing in a more energetic regime with stronger currents. This study provides previously lacking support for spawning segregation behaviour among North East Atlantic mackerel - an important step towards understanding the migratory behaviour of mackerel and hence the spatiotemporal distribution dynamics around spawning time. © 2013 Jansen et al.
Jager T.,Vrije University |
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2010
The interest of environmental management is in the long-term health of populations and ecosystems. However, toxicity is usually assessed in short-term experiments with individuals. Modelling based on dynamic energy budget (DEB) theory aids the extraction of mechanistic information from the data, which in turn supports educated extrapolation to the population level. To illustrate the use of DEB models in this extrapolation, we analyse a dataset for life cycle toxicity of copper in the earthworm Dendrobaena octaedra. We compare four approaches for the analysis of the toxicity data: No model, a simple DEB model without reserves and maturation (the Kooijman-Metz formulation), a more complex one with static reserves and simplified maturation (as used in the DEBtox software) and a full-scale DEB model (DEB3) with explicit calculation of reserves and maturation. For the population prediction, we compare two simple demographic approaches (discrete time matrix model and continuous time Euler-Lotka equation). In our case, the difference between DEB approaches and population models turned out to be small. However, differences between DEB models increased when extrapolating to more field-relevant conditions. The DEB3 model allows for a completely consistent assessment of toxic effects and therefore greater confidence in extrapolating, but poses greater demands on the available data. © 2010 The Royal Society.