Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

    Current refinement(s):

    Records 1 - 20 / 98

    • help
    • print

      Print search results

    • export

      Export search results

    Check title to add to marked list
    Economic essays on marine invasive species and international fisheries agreements
    Walker, A.N. - \ 2016
    Wageningen University. Promotor(en): Ekko van Ierland, co-promotor(en): Rolf Groeneveld; Hans-Peter Weikard. - Wageningen : Wageningen University - ISBN 9789462576308 - 165
    fisheries - fisheries ecology - agreements - biodiversity - invasive species - europe - marine fisheries - marine fishes - visserij - visserij-ecologie - overeenkomsten - biodiversiteit - invasieve soorten - europa - zeevisserij - zeevissen

    This thesis is divided into two parts, as explained in Chapter 1, which focus on different aspects of marine ecological change. Part A considers marine Invasive Alien Species (IAS), which are taxa introduced outside of their native range. The detrimental consequences of invasions for human welfare necessitate management of IAS. There are two types of IAS management. These are (i) management of the risks that an invasion will become established, termed “prevention”, and (ii) management of already established invasions, termed “control”. Chapter 2 considers prevention of invasive species with Ballast Water Management (BWM). Vessels transport invasive species in their ballast water. BWM involves treating ballast water to reduce the risk of successful invasion establishment. Chapter 2 studies the determinants of optimal ballast water treatment standards from a theoretical perspective. Chapter 3 considers control of already established invasions from a spatial and dynamic perspective. We model a non-native habitat divided into patches, where each patch may contain a population of the invasive species, and where spread of the invasion between patches is a stochastic process. In this context, we derive optimal management policies.

    The second part of this thesis: Part B, considers International Fisheries Agreements (IFAs). IFAs facilitate cooperation in the management of fish stocks. Cooperation is necessary to ensure sustainable management. Part B focuses on two issues which may affect the stability of cooperation within IFAs. These are; in Chapter 4, changes in stock location, which may occur due to climate change, and in Chapter 5, the risk of stock collapse, which may exist due to overfishing. Part B uses game theory to analyse the effects of these two issues on the stability of the Grand Coalition, which is the state of affairs where all parties cooperate to maximize their joint benefit from the fish stock.

    The methods and findings of the thesis are summarized as follows: in Chapter 2 (Part A), we construct a model to study optimal BWM standards. The model is built around the assumption that invasions arriving via ballast water are irreversible, i.e. once an invasion has arrived, it is not possible to reduce the size of the invasive population to zero. The hazard rate of invasion establishment can be reduced by setting a BWM standard. The hazard rate is also affected by the Minimum Viable Population (MVPs) of the species and the possibility of an Allee effect. An MVP exists if there is some population size below which there is an insufficient number of invasive individuals to sustain a population. An Allee effect exists if the probability that a population survives increases at an increasing rate in the size of the population. Our analysis focuses on the conditions under which a BWM standard which aims to reduce invasive populations in ballast water to below their MVPs (as is aimed for by the BWM convention) can be optimal. We find that the current aim of the BWM convention can only be optimal in the case that the hazard function (which determines the hazard rate) is not continuously differentiable around the MVP. We find that Allee effects are a requirement for a continuously differentiable hazard function. Therefore, we find that whether or not an Allee effect exists fundamentally affects whether it is optimal to aim to reduce an invasive population in ballast water to marginally below its MVP.

    In Chapter 3 (Part A), we combine aspects of previous modelling approaches to provide new generalized management insights for controlling established invasions. We employ a metapopulation network consisting of patches which are arranged one-dimensionally (i.e. in a line), which is relevant, among other cases, for invasive species spreading along coastlines. We allow for the population size of the invasion within patches to be reduced, which we term “removal”, and we allow for the probability of spread between patches to be reduced without affecting the population sizes directly, which we term “containment”. We employ numerical stochastic dynamic programming to explore how these two interventions (removal and containment) can be optimally applied to minimize the sum of damages from the invasion and the costs of removing and containing the invasion. We find that allowing for varying stock sizes within patches facilitates optimal timing of the application of containment. We also identify two novel optimal policies: the combination of containment and removal to stop spread between patches and the application of up to four distinct policies for a single patch depending on the size of the invasion in that patch.

    Chapter 4 (Part B) considers how Grand Coalitions can be stabilized in the face of changing stock location. To do so, we employ the Gordon-Schaefer fisheries model. We consider farsightedness as a mechanism by which stability of the Grand Coalition can be increased in the face of changing stock location. Farsightedness allows players to respond to deviations of other players by deviating themselves. This reduces the incentives to leave the Grand Coalition. This is in contrast to shortsightedness, whereby players cannot decide to leave the Grand Coalition in response to such a choice by another player. We begin by modifying the farsightedness concept such that it can be used in games with asymmetric players and transfer payments. We proceed to analyse the modified farsightedness concept in the case where players are symmetric (stock location does not change) in order to identify the properties of the concept in the base case. We find that farsightedness increases Grand Coalition stability with respect to shortsightedness. We proceed to analyse the extent to which farsightedness increases Grand Coalition stability, relative to shortsightedness, as fish stock location changes, using sensitivity analysis. We find that farsightedness increases the stability of the Grand Coalition, but also increases the sensitivity of stability to changes in fish stock location. Thus, for any fish stock location, a Grand Coalition is more likely to be stable if players are farsighted, but shifts between a stable and an unstable Grand Coalition will occur more frequently if players are farsighted.

    In Chapter 5 (Part B), we analyse how the stability of Grand Coalitions is affected by an endogenously determined risk of stock collapse. We do so using the Levhari and Mirman (LM) fisheries model, which is adapted such that there is a risk of stock collapse which increases as the fish stock size decreases. We numerically solve the model and calculate the stability of the Grand Coalition. We find that the effect of an endogenously determined risk of stock collapse depends heavily on the assumptions made regarding how payoffs are determined. A common assumption in the literature is that payoffs are determined at the steady state fish stock. Under this assumption, endogenous risk means that for specific discount and growth rates, a Grand Coalition is stable for any number of players. This is a very different result from the original LM model whereby Grand Coalitions can never be sustained. This is because players can essentially follow two strategies in response to the risk. Firstly, they can attempt to maintain the fish stock by fishing less. In doing so they are running the risk of collapse. Secondly, they can avoid the risk by pre-emptively depleting the fish stock, i.e. harvesting the stock to zero immediately to avoid the risk. Grand Coalitions of any number of players are stable for parameterizations for which a Grand Coalition attempts to maintain a non-zero fish stock and if a deviation from the Grand Coalition would result in pre-emptive depletion. We proceed by relaxing the assumption that payoffs are determined in the steady state by allowing for deviators to obtain payoffs in the transition between steady states. In this case, only Grand Coalitions of two players are stable, and then only for certain parameterizations. The reason is that players can now gain payoffs in the process of pre-emptively depleting the stock, i.e. payoffs are received from the process of fishing the stock down to zero. This increases the benefit of deviating from the Grand Coalition. In this case, Grand Coalitions are only stable for two players for specific parameterizations.

    Chapter 6 summarises the research questions formulated in Chapter 1 and evaluates the work of the thesis. Regarding Chapter 2, we justify our theoretical approach with the following two points. Firstly, BWM management is a global and complex problem, which means that the information required to formally calculate an optimal standard is prohibitively burdensome. Secondly, we argue that the complexity of BWM necessitates a sound theoretical understanding of the problem in order to evaluate the current BWM standard, and also to aid in future policy formulation. Similarly, in Chapter 3, we focus on deriving generalized management insights which are applicable to a variety of real-world cases, as opposed to deriving an optimal management strategy for a specific case. In addition to the data requirements necessary to derive such a management strategy, the complexity of such applied cases leads to potentially excessive computational burden. Chapter 3 analyses systems of two and three patches, which are likely to be too simple to analyse specific real world cases, but are sufficient to derive generalized management insights.

    The game theoretic methodologies in Part B are evaluated principally in terms of the assumptions about changes in stock location in Chapter 4 and the numerical method in Chapter 5. In Chapter 4, the fish stock is conceptualised as existing at a single point in space. The location of this point is determined in relation to fishing nations, which are also conceptualised as single points in space. Changes in stock location result from rises in ocean temperatures due to climate change. Such rises in temperature are likely to lead to other changes in the fish stock such as the size of the area where the fish stock can be found and increases in the maximum fish stock size which the ecosystem can support. These other aspects of changing stock location need to be considered in evaluating Chapter 4, as well as in formulating more applied models. In Chapter 5, a numerical method is adopted to analyse the effects of an endogenous risk of stock collapse. To do so, the utility function in the LM model is adapted such that it can be used in a numerical model. In order to isolate the effect of endogenous risk from changes in the utility function, a validation procedure is carried out by comparing analytically derived results in the deterministic case (without endogenous risk of stock collapse) to numerically derived results in the deterministic case. This reveals that changes to the utility function have a negligible effect and thus the results, in terms of the stability of Grand Coalitions can be attributed solely to endogenous risk of stock collapse.

    Overall, Part A of this thesis presents new insights into the determinants of optimal BWM standards. These insights demonstrate the conditions under which the current BWM standard, which aims to eliminate the risk of invasion establishment, may or may not be optimal. Part A therefore provides a novel theoretical framework which aids in the evaluation of current, and the determination of future standards. Part A also provides new insights into the control of established invasions, by extending existing spatially explicit optimal control models. Specifically, dividing space into patches and allowing for varying invasive population sizes within patches facilitates the optimal timing of management interventions and, in general, more detailed, and thus more efficient, management strategies. Part B provides a novel analysis of the effects of changing stock location on Grand Coalitions by explicitly introducing fish stock location in the analysis, and shows how farsightedness can stabilize Grand Coalitions in the face of such changes. Part B also shows how the effects of an endogenous risk of stock collapse on the stability of Grand Coalitions depends vitally on whether transition payoffs are included. These results can form the basis for more interdisciplinary analyses, analyses of different types of marine ecological change, and analyses of these changes in different settings, such as non-European countries.

    Hoe konden er tonijnen van vier meter in de Noordzee leven?
    Lindeboom, H.J. - \ 2015
    Universiteit van Nederland
    tonijn - heilbot - oesters - visserij-ecologie - boomkorvisserij - habitat vernietiging - noordzee - lesmaterialen - geschiedenis - tuna - halibut - oysters - fisheries ecology - beam trawling - habitat destruction - north sea - teaching materials - history
    Onder de zeespiegel van de Noordzee ligt een gevarieerd landschap met gebieden met mysterieuze namen. De Dodemansduim, de Doggersbank, het Friese Front en de Klaverbank bijvoorbeeld. Hoe het komt dat daar unieke planten en dieren leven, dat legt prof. dr. Han Lindeboom van de Wageningen UR uit in dit college.
    Expert judgement garnalenvisserij
    Jongbloed, R.H. ; Steenbergen, J. ; Kooten, T. van; Turenhout, M.N.J. ; Taal, C. - \ 2015
    Den Helder : IMARES (Rapport / IMARES Wageningen UR C177/14) - 82
    visserij - visserij-ecologie - garnalen - waddenzee - economische productie - overheidsbeleid - fisheries - fisheries ecology - shrimps - wadden sea - economic production - government policy
    Het Waddenfonds wil inzicht in de effectiviteit van de voorgestelde maatregelen uit het convenant en de natuurambitie met betrekking tot de garnalenvisserij in de Waddenzee. Hiertoe is aan IMARES gevraagd de op dit moment ‘best professional judgement’ te geven ten aanzien van een aantal onderdelen gerelateerd aan de garnalenvisserij in de Nederlandse Waddenzee. De onderzoeksvragen zijn: 1) Is het sluiten van gebieden voor garnalenvisserij een effectieve manier om de ecologische kwaliteiten van de Waddenzee te versterken? 2) Zou verandering van de manier waarop garnalen worden gevist een bijdrage kunnen leveren aan de verrijking van de ecologische kwaliteit van de Waddenzee? 3) Zou verandering in de (garnalen)visserij de economische kwaliteit van de visserij kunnen versterken?
    Factsheet: Pulsvisserij
    Quirijns, F.J. ; Turenhout, M.N.J. ; Paijmans, A.J. ; Taal, K. - \ 2014
    pulsvisserij - visserij-ecologie - discards - visvangsten - economische haalbaarheid - vismethoden - boomkorvisserij - zeevisserij - vangstsamenstelling - pulse trawling - fisheries ecology - discards - fish catches - economic viability - fishing methods - beam trawling - marine fisheries - catch composition
    De pulstechniek is relatief nieuw en roept veel vragen op over de mate van duurzaamheid en economische haalbaarheid. Daarom is er in de afgelopen decennia veel onderzoek gedaan naar deze visserijtechniek. Deze factsheet bevat de laatste gegevens over vangsten, discards, ecosysteem-effecten en economische haalbaarheid bij gebruik van puls in de platvisvisserij.
    Boomkorvisserij: hoe voedselweb-interacties op de zeebodem het succes van visserijmaatregelen kunnen bepalen
    Kooten, T. van - \ 2014
    IJmuiden : IMARES (Rapport / IMARES Wageningen UR C127/14) - 12
    visserij - visserij-ecologie - boomkorvisserij - onderwatergronden - bodemecologie - benthos - mariene gebieden - visserijbeheer - noordzee - voedselwebben - visbestand - visstand - aquatische ecosystemen - natuurbeheer - fisheries - fisheries ecology - beam trawling - subaqueous soils - soil ecology - benthos - marine areas - fishery management - north sea - food webs - fishery resources - fish stocks - aquatic ecosystems - nature management
    Dit document is een samenvatting, met daarbij de beleidsrelevantie, van de wetenschappelijke publicatie ‘When does fishing lead to more fish? Community consequences of bottom trawl fisheries in demersal food webs ’ geschreven door Daniel van Denderen, Tobias van Kooten en Adriaan Rijnsdorp, gepubliceerd in Proceedings of the Royal Society B, vol. 280, no. 20131883 op 4 september 2013. Het doel van deze Nederlandstalige samenvatting is het ontsluiten van de conclusies uit deze publicatie voor een breder publiek, en het schetsen van de consequenties daarvan voor het Nederlandse visserij- en natuurbeheer.
    KB WOT Fisheries 2014 - Maintaining Excellence and Innovation in Fisheries Research
    Damme, C.J.G. van; Verver, S.W. - \ 2013
    IJmuiden : Centrum voor Visserijonderzoek (CVO report / Centre for Fisheries Research (CVO) 13.009) - 103
    visserij - onderzoek - wetenschappelijk onderzoek - remote sensing - aquatische ecologie - visserij-ecologie - visserijbeheer - fisheries - research - scientific research - remote sensing - aquatic ecology - fisheries ecology - fishery management
    The KB WOT Fisheries programme is fundamental to the maintenance and development of expertise needed to carry out the statutory obligations of the Dutch WOT Fisheries monitoring and advice. The structure of the KB WOT Fisheries programme 2014 is a result of discussions on the research direction and needs between IMARES, CVO and the ministry of EZ. Important in the structure of the KB WOT Fisheries programme is the bottom up approach, where a call for proposal submission is launched ensuring innovation in the programme. However the top-down decision on the research themes within the programmes ensures that needs of both the science development within IMARES and the research questions of EZ remain covered. The KB WOT Fisheries programme will fund 17 projects in 2014 which will focus on remote sensing of the pelagic and benthic systems (acoustics and video imaging) and the interaction of ecology and fisheries, as well as new techniques for surveys and monitoring.
    Recreational fishery in the Netherlands: demographics and catch estimates in marine and fresh water
    Hammen, T. van der; Graaf, M. de - \ 2013
    IJmuiden : IMARES (Report / IMARES Wageningen UR C147/13) - 33
    sportvissen - visserij-ecologie - actieve recreatie - vangstsamenstelling - inventarisaties - schattingen - methodologie - game fishes - fisheries ecology - active recreation - catch composition - inventories - estimates - methodology
    De Nederlandse overheid heeft EU verplichtingen met betrekking tot het rapporteren van vangsten door recreatieve vissers. Het betreft gegevens over de omvang van de visserij op kabeljauw, aal, haaien en roggen. Sportvisserij Nederland was nauw betrokken bij de eerste surveys in 2010-2011. Dit rapport geeft een overzicht van de vangstschattingen van de meest gevangen zout en zoetwatersoorten uit de eerste logboek survey van 2010-2011. Daarnaast gaat het in op de methodiek hoe deze inschattingen tot stand zijn gekomen.
    Fishing activities on the Dogger Bank 2006-2011
    Bartelings, H. ; Hamon, K.G. ; Oostenbrugge, J.A.E. van - \ 2013
    The Hague : LEI, part of Wageningen UR (Memorandum / LEI : Research area Natural resources ) - 45
    visserij-ecologie - ruimtelijke verdeling - beschermingsgebieden - noordzee - visserij - vis vangen - fisheries ecology - spatial distribution - conservation areas - north sea - fisheries - fishing
    In 2008, the Minister of Agriculture, Nature and Food Quality notified four proposed Sites of Community In-terest (pSCIs) to the European Commission (for protection as Special Conservation Areas (SCAs) under the Habitats Directive). These areas are the Dogger Bank, Cleaver Bank, the Coastal Zone and the Vlakte van de Raan. The areas have been chosen, based on their specific habitats and ecological values. The objective of the current project is to give insight into the trends of the fishing activities of the Dutch and important foreign fleets (Belgian, German and UK) in the area of the Dogger Bank in the period 2006-2011. In the analyses attention is given to developments in effort, landings and economic value of the landings.
    Reisverslag van de boomkorsurvey (BTS) in 2012
    Boois, I.J. de; Bol, R.A. - \ 2012
    IJmuiden : IMARES Wageningen UR (Rapport / IMARES Wageningen UR 12.018)
    visserij - visbestand - bemonsteren - visserij-ecologie - visserijbeheer - visvangsten - boomkorvisserij - fisheries - fishery resources - sampling - fisheries ecology - fishery management - fish catches - beam trawling
    In 2012 is de beam trawl survey (BTS) uitgevoerd met de Tridens II en de Isis in opdracht van het ministerie van EL&I. De survey is onderdeel van het EU Data Collectie Programma (DCF) en valt daarmee onder de wettelijke taken die binnen IMARES worden uitgevoerd. In dit rapport staan de resultaten van de survey en de reisverslagen van de reizen op beide schepen. De gegevens van de BTS worden onder andere gebruikt in de bestandsschattingen die de ICES uitvoert voor schol en tong. Daarnaast zijn de gegevens bruikbaar voor andere vragen over het Noordzee ecosysteem. In 2012 zijn wederom vertegenwoordigers van de visserijsector mee geweest aan boord van de Tridens als waarnemer. De verslagen van deze waarnemers zijn verschenen in Visserijnieuws en verwijzingen daarnaar zijn opgenomen in dit rapport.
    Effecten uitbreiding 3 MZI locaties in Oosterschelde en Waddenzee op draagkracht
    Wijsman, J.W.M. ; Kamermans, P. - \ 2012
    Yerseke : IMARES (Rapport / IMARES Wageningen UR C156/12) - 20
    mosselteelt - visserijbeheer - visserij-ecologie - oppervlakte (areaal) - waddenzee - voordelta - mussel culture - fishery management - fisheries ecology - acreage - wadden sea - voordelta
    Deze studie bevat een update van de berekeningen van de filtratiedruk die is gemaakt in de passende beoordeling voor Mosselzaadinvang (MZI) in de Nederlandse kustwateren uit 2009. Deze update is nodig vanwege de wens tot uitbreiding van de MZI gebieden Neeltje Jans in de Oosterschelde (41 ha naar 98 ha) en Vogelzand (90 naar 150 ha) en Zuidmeep (79 naar 91 ha) in de Waddenzee.
    Het areaal aan mosselbanken op de droogvallende platen in de Waddenzee in het voorjaar van 2011
    Zweeden, C. van; Troost, K. ; Ende, D. van den; Stralen, M. van - \ 2012
    Yerseke : IMARES (Rapport / IMARES Wageningen UR C097/12) - 22
    visserij - schaal- en schelpdierenvisserij - mossels - visbestand - visserij-ecologie - waddenzee - fisheries - shellfish fisheries - mussels - fishery resources - fisheries ecology - wadden sea
    Dit onderzoek betreft één van de schelpdierinventarisaties die jaarlijks door Wageningen IMARES en MarinX worden uitgevoerd in samenwerking met de visserijsector en het Ministerie van ELI. De surveys zijn opgezet ter onderbouwing van het beleid voor de schelpdiervisserij en vormen daarbij een belangrijke bron van informatie voor verdere ecosysteem- en effectstudies. De kartering van mosselbanken vindt te voet plaats tijdens laagwater waarbij de positie van banken wordt vastgelegd met GPS-apparatuur. Daarbij worden binnen de beschikbare tijd zo veel mogelijk banken bezocht. Voor het bepalen van het totale areaal mosselbanken wordt voor de niet bezochte banken uitgegaan van gegevens in eerdere en latere jaren. Areaalschattingen voor het huidige bestand zijn daarmee voorlopig omdat zij naar aanleiding van later surveys mogelijk nog worden aangepast.
    Onderzoek effecten garnalenvisserij in natura 2000 - gebieden van start: medewerking garnalensector onmisbaar
    Tulp, I.Y.M. - \ 2012
    Visserijnieuws 32 (2012)26. - ISSN 1380-5061 - p. 7 - 7.
    garnalen - schaal- en schelpdierenvisserij - visserij-ecologie - visserijbiologie - natura 2000 - bodemfauna - bijvangst - natuurbeheer - waddenzee - noordzee - boomkorvisserij - shrimps - shellfish fisheries - fisheries ecology - fishery biology - natura 2000 - soil fauna - bycatch - nature management - wadden sea - north sea - beam trawling
    In 2009 hebben vertegenwoordigers van EL&I, de garnalen aanvoersector (Vissersbond en een aantal PO’s), de Waddenvereniging en stichting De Noordzee afspraken gemaakt voor een gezamenlijk traject naar verduurzaming van de garnalenvisserij. Onderdeel daarvan is het uitvoeren van onderzoek dat kan dienen als basis van het vergunningentraject op basis van de Natuurbeschermingswet. Na een lange voorgeschiedenis is het dan nu eindelijk zover. IMARES heeft opdracht gekregen van het ministerie van EL&I en het Productschap Vis (PVis) dit onderzoek vanaf 2012 uit te gaan voeren. Senior-onderzoeker Ingrid Tulp van IMARES geeft uitleg over het onderzoek.
    IMARES
    Imares, - \ 2012
    [S.l.] : YouTube
    visserij - visserij-ecologie - aquacultuur - aquacultuur en milieu - ecologie - mariene gebieden - toegepast onderzoek - fisheries - fisheries ecology - aquaculture - aquaculture and environment - ecology - marine areas - applied research
    Videokanaal van IMARES op YouTube. IMARES richt zich op strategisch en toegepast marien ecologisch onderzoek, met als werkvelden: ecologie, visserij, milieu en aquacultuur.
    The coevolution of renewable resources and institutions - implications for policy design
    Richter, A.P. - \ 2011
    Wageningen University. Promotor(en): Johan Grasman, co-promotor(en): D.P. van Soest. - [S.l.] : S.n. - ISBN 9789085858393 - 237
    wiskundige modellen - kabeljauw - visserijbeheer - visserijbeleid - visserij-ecologie - hulpbronnenbeheer - milieubeleid - milieueconomie - mathematical models - cod - fishery management - fishery policy - fisheries ecology - resource management - environmental policy - environmental economics

    This PhD thesis studies how natural renewable resources and institutions governing those resources mutually influence each other. Theoretical models are developed in which members of a small community have joint access to a common pool resource. We analyze under which circumstances social norms of cooperation evolve that effectively regulate resource exploitation, but also when those social norms break down, identifying obstacles for community governance. Furthermore, in the light of biological and social complexity this thesis analyzes how governmental policy should be designed if self-governance is not sufficient to protect the resource stock. The insights obtained are applied to the case of Arcto-Norwegian cod. An optimal management plan is developed that can be adapted to several policy objectives concerning the utilization of the fleet. In addition, management advice is given for the case that harvesting may trigger an evolutionary response of the fish stock.

    Distribution maps for the North Sea fisheries; Methods and application in Natura 2000 areas
    Oostenbrugge, J.A.E. van; Bartelings, H. ; Buisman, F.C. - \ 2010
    Den Haag : LEI, part of Wageningen UR (Report / LEI : Research area Natural resources ) - ISBN 9789086154593 - 122
    natura 2000 - visserij-ecologie - ruimtelijke verdeling - databanken - noordzee - natura 2000 - fisheries ecology - spatial distribution - databases - north sea
    In the study presented here a database was developed with spatial distribution pattern of fishing effort, catches and catch values of the Dutch and non-Dutch fisheries in the Dutch section of the North Sea. Distribution maps were produced on the basis of this database. In addition, estimates were made of the value of different fisheries in areas designated by the Netherlands as Natura 2000 areas.
    De ontwikkeling van een niet beviste sublitorale mosselbank
    Dankers, N.M.J.A. ; Jansen, J.M. ; Jong, M.L. de; Kersting, K. ; Couperus, A.S. ; Hoppe, M. van; Brink, A.M. van den; Smit, C.J. ; Cervencl, A. ; Brinkman, A.G. - \ 2010
    Texel : IMARES (Rapport / IMARES Wageningen UR C114/10) - 64
    mossels - biodiversiteit - beweging in de bodem - visserij-ecologie - bodembiodiversiteit - bodemecologie - verstoring - bodemmonitoring - biologische monitoring - mussels - biodiversity - movement in soil - fisheries ecology - soil biodiversity - soil ecology - disturbance - soil monitoring - biomonitoring
    Het doel van het hier gepresenteerde onderzoek is om door middel van meerjarige monitoring in voor- en najaar inzicht te krijgen in de ontwikkeling van ongestoorde sublitorale mosselbanken en de daarmee geassocieerde biodiversiteit. Voor elk van de gesloten gebieden gelden de volgende vragen: 1. Hoe is de ontwikkeling van de mosselbank wanneer er geen bodemberoerende activiteiten plaatsvinden? Kijk hiervoor naar parameters als areaal, biomassa ontwikkeling, leeftijdsklassen van mosselen en aanwas als gevolg van nieuwe broedval 2. Hoe is de ontwikkeling van de geassocieerde biodiversiteit (flora en fauna). 3. Ontwikkelt zich na sluiting voor mosselzaad- en garnalenvisserij ook andere benthos dan tot dusver op mosselvoorkomens in de Waddenzee wordt aangetroffen.
    FIMPAS project - Pre - assessment of the impact of fisheries on the conservation objectives of Dutch marine protected areas
    Deerenberg, C.M. ; Teal, L.R. ; Beare, D.J. ; Wal, J.T. van der - \ 2010
    IJmuiden : IMARES (Report / Wageningen IMARES UR C071/10) - 82
    visserij - eu regelingen - kustgebieden - visserij-ecologie - zeevisserij - natuurbeleid - habitatrichtlijn - fisheries - eu regulations - coastal areas - fisheries ecology - marine fisheries - nature conservation policy - habitats directive
    The project Fisheries Measures in Protected Areas (FIMPAS) aims to introduce by the end of 2011 fisheries measures in the marine Natura 2000 sites within the Exclusive Economic Zone of the Dutch part of the North Sea. The FIMPAS project will deal with three such areas, the Dogger Bank and the Cleaver Bank (both to be designated for protection under the Habitats Directive) and the Frisian Front (to be designated for protection under the Birds Directive). These sites are located within the Exclusive Economic Zone of the Netherlands beyond the Dutch 12 nm coastal zone. Several EU Member States fish within these areas. Therefore fisheries measures must be implemented through the Common Fisheries Policy. These marine protected areas, as well as the potential fisheries measures, are a consequence of the implementation of the European Birds and Habitats Directives and will be proposed to the European Commission by the Dutch government. The Dutch Ministry for Agriculture, Nature and Food Quality (LNV), together with Dutch environmental NGOs and the Dutch fishing industry, are cooperating within the FIMPAS project to develop the necessary fisheries measures to achieve the conservation objectives for the Dutch Natura 2000 sites of the North Sea.
    IRMM HCB and HCBD in Blankvoorn (testmaterial for reference material)
    Hoek-van Nieuwenhuizen, M. van - \ 2010
    IJmuiden : IMARES (Report / IMARES Wageningen UR no. C113/10) - 7
    waterkwaliteit - rutilus rutilus - monitoring - toxische stoffen - referentienormen - biologische monitoring - ecotoxicologie - visserij-ecologie - zeevisserij - kaderrichtlijn water - water quality - rutilus rutilus - monitoring - toxic substances - reference standards - biomonitoring - ecotoxicology - fisheries ecology - marine fisheries - water framework directive
    Blankvoorn Nieuwe Merwede (Roach, Rutilus rultilus) has been tested as a reference material for the components HCBD and HCB for biota monitoring according to the Water Framework Directive. Both components in the blankvoorn are present at moderate levels (overall average levels of respectively HCBD 1.6 μg/kg and HCB 6.2 μg/kg). These concentrations are far above reporting limits (respectively 0.1 μg/kg for HCBD and 0.2 μg/kg for HCB) and should therefore be suitable for use in a reference material.
    The impact of a potential sales ban for eel on stock and sector
    Smit, J. ; Dekker, W. ; Oostenbrugge, H. van - \ 2010
    The Hague : LEI (Report / LEI : Research area Natural resources ) - 65
    palingen - herstel - visserij - visserijbeleid - visserijbeheer - visbestand - economie van natuurlijke hulpbronnen - ecologisch herstel - herstelbeheer - visserij-ecologie - eels - rehabilitation - fisheries - fishery policy - fishery management - fishery resources - natural resource economics - ecological restoration - restoration management - fisheries ecology
    Er zijn momenteel een aantal initiatieven om het herstel van de aalstand te bevorderen. In dit rapport is een analyse gedaan in welke mate een verkoopstop voor aal in Nederland zou kunnen bijdragen aan het herstel van het Europese bestand. Vier scenario's zijn geanalyseerd waarin onderscheid is gemaakt tussen gedeeltelijke of volledige sluiting van visserij en acquacultuur. Zowel de economische consequenties voor de sector als de visserijdruk op het bestand is in kaart gebracht.
    Ex post and ex ante evaluation of the long term management plan for sole and plaice in the North Sea (part 2): ex ante
    Miller, D.C.M. ; Poos, J.J. - \ 2010
    IJmuiden : IMARES (Report / IMARES Wageningen UR no. C104/10) - 44
    visserij - visserijbeheer - schol - solea - tong (vis) - noordzee - visbestand - duurzaamheid (sustainability) - eu regelingen - effecten - visstand - visvangsten - visserij-ecologie - fisheries - fishery management - plaice - solea - dover soles - north sea - fishery resources - sustainability - eu regulations - effects - fish stocks - fish catches - fisheries ecology
    This report describes the second part of an ex post and ex ante evaluation of the multiannual plan for sole and plaice in the North Sea as laid out in Council Regulation (EC) No 676/2007. This plan has been in place since 2007. The plan aims to ensure, in its first stage, that stocks of plaice and sole in the North Sea are brought within safe biological limits, i.e. above Bpa and below Fpa. Following this, and after due consideration by the Council on the implementation methods for doing so, the plan will ensure that the stocks are exploited on the basis of maximum sustainable yield and under sustainable economic, environmental and social conditions. This report extends work previously carried out by Wageningen IMARES evaluating the multiannual plan for plaice and sole in the North Sea as described in Council Regulation EC 676/2007
    Check title to add to marked list
    << previous | next >>

    Show 20 50 100 records per page

     
    Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.