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 / 688

  • help
  • print

    Print search results

  • export
    A maximum of 250 titles can be exported. Please, refine your queryYou can also select and export up to 30 titles via your marked list.
  • alert
    We will mail you new results for this query: keywords==visserij
Check title to add to marked list
New tuna regimes
Yeeting, Agnes David - \ 2017
University. Promotor(en): Simon Bush, co-promotor(en): Hans-Peter Weikard; M. Bailey. - Wageningen : Wageningen University - ISBN 9789463438308 - 154
fisheries - marine fisheries - tuna - sustainability - environmental policy - governance - economic policy - pacific ocean - environmental economics - visserij - zeevisserij - tonijn - duurzaamheid (sustainability) - milieubeleid - economisch beleid - grote oceaan - milieueconomie
governing sustainability and equity in the Western and Central Pacific Ocean
Valorisation of waste streams from by-product to worm biomass
Laarhoven, Bob - \ 2017
University. Promotor(en): Cees Buisman, co-promotor(en): Hardy Temmink; Hellen Elissen. - Wageningen : Wageningen University - ISBN 9789463438117 - 141
biomass - residual streams - animal nutrition - fisheries - organic wastes - helminths - biomassa - reststromen - diervoeding - visserij - organisch afval - wormen

There is a global demand for more feed resources to keep up with the increasing production of livestock. The hunger for resources is most urgent in the aquaculture sector, which to a large degree depends on the non-sustainable use of fish oil/ meal from wild fish. Aquatic macro invertebrates such as the freshwater worm Lumbriculus variegatus (Oligochaeta, Lumbriculidae, common name blackworms, further abbreviated as Lv) are rich in proteins, lipids, vitamins and minerals. When cultivated on safe and low-grade organic wastes they can provide a sustainable fishmeal alternative for most freshwater and marine fish.

Chapter 1 introduces the concept of aquatic worm production on waste streams. Worm biomass composition and relevant research lines are explained. Organic waste sludges from food industries are a rich source of bio-molecules and can be upgraded to (fish) feed when fed to aquatic worms. For valorisation of waste streams by aquatic worms, as proposed in this thesis, these streams preferably are free from contaminants such as organic micro pollutants, heavy metals and pathogens. For example, this would not be the case when sewage (municipal) sludge is used as a substrate for the worms. However, such contaminated sludges may still be applied for non-food applications. Thus, the quality of the waste stream that is used as a substrate for the worms determines the application potential of the worm biomass as well as the options for downstream processing and refinery.

Previous research showed that Lv can be used for reduction and compaction of sewage sludge. The consumption of (suspended) sludge particles results in a dry matter reduction of 25 - 50 % and in worm faeces that are 60 % more compact than the original waste sludge. This contributes to a significant reduction in sludge processing costs. Sludge reduction by aquatic worms is mainly studied by research groups in The Netherlands and in China. Unfortunately, it is generally accepted free swimming worms in full-scale wastewater treatment plants is extremely difficult, mainly because of large (seasonal) population fluctuations. A controlled reactor concept applying the sessile (crawling, sediment dwelling) species Lv already was developed in earlier research. The key characteristic of this reactor is a carrier material for the worms, which also functions as a separation layer between the waste stream (worm food) and a water phase used for aeration, worm harvesting and worm faeces collection. This concept also was the starting point for the development of the improved reactor concept that is described in this thesis.

The two main objectives of this thesis were: (1) to assess the potential of organic waste streams and by-products for Lv production for fish feed and (2) to develop a (cost and resource) effective bioreactor for this purpose.

In Chapter 2 a new, standardized method is described and tested that can be used for a quantitative and qualitative assessment of the effect of different substrates on worm growth. This method not only can be used to select waste streams suitable for worm production, but also is proposed as a tool is ecotoxicology studies.

The test method consists of beaker experiments with a combination of agar and sand to optimize food uptake by and growth of the worms. The effects of agar gel, sand, and food quantity were studied and evaluated for different food sources. Agar gel addition ameliorated growth conditions by reducing microbial food hydrolysis and by improving the sediment structure. This guaranteed that substrate ingestion and worm growth in the first place were the result of the food quality and the effect of other (environmental) factors was reduced. A final test with secondary potato starch sludge demonstrated the test method is appropriate for the evaluation of solid and suspended organic feedstuffs/waste streams.

In Chapter 3 the standardized method of chapter 2 was used for worm growth studies, focussing on the effect of carbon to nitrogen (C/N) ratios of diets on worm growth and reproduction. Growth and reproduction of Lv on different combinations of wheat based derivatives like gluten and gray starch was studied at fixed isoenergetic levels (expressed as chemical oxygen demand (COD) of the food), but at different C/N ratios. Growth and reproduction rates were compared to those on Tetramin, a substrate known to result in excellent worm growth. Growth was mainly controlled by the C/N ratio of the single and mixed wheat fraction diets. Lower C/N ratios of around 6-7 gave a much better performance than high C/N ratios of around 20. This probably was caused by Lv relying on the presence of proteins as carbon and energy source. Although growth and reproduction rates were not as high as on the control diet, the results were promising for development of a worm biomass production reactor, operating on by-products from wheat processing industries.

In Chapter 4 a new reactor concept for Lv cultivation on waste streams was developed and tested. In a vertical tubular reactor a centralized food compartment was surrounded by a gravel layer that mimicked the natural habitat of Lv. Secondary (biological) sludge from a potato starch processing industry was used as a clean and low value food source. The results with respect to worm growth rate, density and production and nutrient recovery were compared to the previous reactor design. Much higher worm densities were achieved (6.0 compared to 1.1 kg ww m-2 carrier material) as well as much faster Lv growth rates (4.4 - 12 compared to 1.2 % d-1). As a result the areal worm production rate was no less than 40 times higher (560 compared to 14 g ww m-2 d-1). The higher worm density, which was found to be independent of gravel size in a range of 2.4 to 8.0 mm, allowed for a significantly shorter food retention time in the reactor (~ 2.2 days compared to > 10 days for the previous reactor design). This restricted microbial mineralization of the food, making high nutrient recoveries from waste to worm biomass possible: 16-30 % COD, 19-22 % N and 9-11 % P. The high biomass density also limited the release of ammonium, which at large concentrations is toxic for the worms. However, even shorter food retention times (e.g. higher loading rates) are not recommended as a minimum microbial activity is needed for conversion of the original substrate into compounds that can be taken up by the worms.

In Chapter 5 worm growth, reproduction and biomass quality were evaluated on several waste streams and by-products of bacterial, animal and plant origin. The effect of 26 different diets, all applied at high food levels, on Lv growth, reproduction and fatty acid (FA) content and profile were investigated. For this purpose the standardized test method of Chapter 2 was used. In addition, it was discussed which diet composition and food sources would be most suitable for large scale production of Lv.

Diets consisting of single cell biomass from bacterial or plant origin with a high protein content (C/N ratio < 8.8), high P content (C/P < 50) and low in total ammonia nitrogen (TAN) (< 20 g N/kg) gave the highest growth rates and vital worms without signs of mortality. Besides the C/P ratio of the diet, worm conditions related with the difference between test and pre-culture conditions. The starting weight of the worms seemed to have an effect on the total fatty acid content of the worms. The growth potential of a diet rich in proteins and P depends on how much TAN is associated with the diet. By blending different food sources these factors to a certain extent can be manipulated. Lv seemed to have a distinct and very stable FA composition, irrespective of the diet’s FA composition. The worms were rich in poly unsaturated FAs (PUFAs), including several w3 and w6 FAs, and contained relatively high levels of C18 and C20 PUFAs. This makes them suitable as fish feed, in particular for freshwater fish.

In order to serve aquaculture feed markets with an attractive alternative to fish meal, such as aquatic worm biomass, a continuous and secure bulk production needs to be realized. In Chapter 6 the performance parameters established in chapter 4 (worm growth rate, density and biomass production rate) were used as the input for a feasibility assessment of large scale worm production on secondary sludge from the potato industry. In addition, in chapter 6 future value chains and lines of research were discussed.

A hypothetical worm production system treating the surplus secondary sludge from a potato processing factory can reduce excess sludge production by 50 % in solids and 62 % in volume. This is accompanied by a daily production of 1.6 metric ton of fresh worm biomass. With a very conservative estimation of the worm density of 1.6 kg ww/m2 carrier material a footprint of the system of 217 m2 can be realized, which is at least two times smaller than with a previous reactor design without a gravel layer. With reduced sludge processing costs and a conservative market price of 1.4 €/kg dry worm biomass, worm production can already be realized at an annual rate of return of 3 years. However, the costs are highly sensitive for worm biomass stocking, reactor construction and operation. A more accurate economic assessment should be based on the results of pilot-scale research.

Two general product types, whole biomass (as fish feed) and refined products can be distinguished and applied in two application areas (feed and non-food), depending on the quality of the organic (waste) sludge that the worms have been produced from. Valorisation for potential bulk markets needs further refinery of crude worm biomass into a lipid (worm oil) and a protein fraction (protein isolate). This can result in several new and unique business models in aquaculture, feed, chemical and agriculture sectors. Obviously, an assessment of economical and legislative boundary conditions needs to be part of such business models.

Worm biomass is a potential high quality fishmeal replacer, with a similar or even better potential than other waste based alternatives such as single cell biomass and insects. A comparison between Lv and fishmeal with respect to crude composition, essential amino acids and FAs learns that Lv is a highly suitable fish feed source. It can provide essential amino acids at sufficiently high levels. Based on its FA composition and (relatively low) fat content, Lv can best be considered a protein source. Still, worm biomass is rich in PUFA, which could be a potential high value product for feed applications. Compared to black soldier fly and bacterial production systems, Lv shows intermediate production efficiencies, while biomass harvesting and processing probably is more easy.

Additional advantages of Lv worm biomass to replace fishmeal are: 1) Lv acts as a strong natural fish attractant, 2) the growth efficiency of fish on worms is high in comparison to regular feeds, 3) the nutritional profile of worms matches that of fishmeal, 4) the worms are a natural feed source for freshwater fish and 5) the worms allow a secure and stable feed production that is independent of natural resources.

Further recommendations for future research as outlined and discussed in chapter 6 are mostly related to the technical upscaling of the reactor technology and obtaining more detailed insight in controlled worm growth in response to food characteristics, reactor design and operational conditions.

Schelpdierbestanden in de Nederlandse kustzone in 2017
Troost, K. ; Perdon, K.J. ; Zwol, J. van; Jol, J. ; Asch, M. van - \ 2017
IJmuiden : Stichting Wageningen Research, Centrum voor Visserijonderzoek (CVO) (CVO rapport 17.014) - 38
schaaldieren - visserij - natura 2000 - noordzee - ensis - spisula - visstand - biodiversiteitsbepaling - shellfish - fisheries - north sea - fish stocks - biodiversity assessment
The exploitation of wild shellfish has developed from free fisheries to a strongly regulated commercial activity, in which economic and ecological objectives are both aimed for. Within the framework of this policy an annual stock estimate is made for the economic important species: razor shell (Ensis directus) and cut-through shell (Spisula subtruncata), and other less economic species. The survey covers the entire Dutch coastal zone, and is commissioned by the Ministry of Economic Affairs. The fieldwork for the 23 th successive survey since 1995 was carried out in spring 2017. The principle objective of this survey is the assessment of the stock sizes of the economically important species Ensis directus and Spisula subtruncata in the Dutch coastal zone, including the Natura-2000 areas: “Noordzeekustzone”, “Voordelta”, “Vlakte van de Raan”, and the mouth of the Westerschelde estuary. In addition to the two most important species, we also report on the occurrence of three species of occasional economic importance: otter shell (Lutraria lutraria), striped venus clam (Chamelea striatula), and banded wedge shell (Donax vittatus). For the Dutch coastal zone the total stock size was estimated at 397.2 million kg fresh weight for razor shells, and 1,281.7 million kg fresh weight of cut-through shells. Stocks of the the other species were estimated at 18.1 million kg fresh weight for striped venus clams, 38.0 million kg fresh weight of banded wedge shells and 4,931 million individuals of otter shells. The stock of razor shells showed a sharp increase and was found to be the highest since 1995. The same can be said for the cut-through shells, where the stock of biomass increased to a level which is the highest since 1995. Also the stock of the otter shell and the banded wedge shell increased where the stock of the striped venus clam showed a slight decrease.
Wettelijke Onderzoek Taken WOT-05 Visserijonderzoek beknopte jaarrapportage 2016
Verver, S.W. - \ 2017
IJmuiden : Wageningen UR, Stichting DLO, Centrum voor Visserijonderzoek (CVO) (CVO rapport 17.003) - 38
visserij - visserijbeheer - wetgeving - jaarverslagen - nederland - fisheries - fishery management - legislation - annual reports - netherlands
Wettelijke Onderzoek Taken WOT-05 Visserijonderzoek Jaarverslag 2016
Verver, S.W. - \ 2017
IJmuiden : Stichting Wageningen Research, Centrum voor Visserijonderzoek (CVO) (CVO rapport 17.002) - 98
visserij - visserijbeheer - wetgeving - jaarverslagen - nederland - fisheries - fishery management - legislation - annual reports - netherlands
The programme WOT-05 Fishery Research is carrying out statutory research tasks related to the management of the fishery and aquaculture in the Netherlands. The programme is developed in consultation with the Ministry of Economic Affairs (EZ). The content and scope of programme has been agreed for the period 2011-2015. In September 2015 it was decided to extend the programme till 31 December 2016. This report is a technical report and summarises the progress made in carrying out the work plan of 2016. Fisheries policy makers and managers are dependent on up-todate information. The aim of this programme is to contribute to the collection of essential data needed for the management of fisheries, fish stocks and aquaculture through sampling programmes in as well marine and inshore areas. The data collection includes sampling programmes on fish species landed in fishing ports, discard and by-catch monitoring programmes on board of commercial vessels and scientific surveys using research vessels. In addition, monitoring programmes on shellfish (bivalves) are carried out in coastal waters to estimate the biomass of these resources. In national fresh waters also the eel stock and the stocks in IJsselmeer and Markermeer are monitored. The data have been used to provide advice which is also part of this programme. The advice for marine stocks and fisheries is based on analyses of international data carried out by working groups. The main frameworks in which this was done were ICES and STECF. These frameworks also play a role in the international co-ordination of the research carried out in this programme. The programme is carried out by the Centre for Fisheries Research (CVO) and the Institute for Marine Resources and Ecosystem Studies (IMARES, since September 2016 Wageningen Marine Research) in IJmuiden. The programme is financed by the Ministry of Economic Affairs and coordinated by Sieto Verver (CVO) CVO rapport 17.002 Jaarverslag WOT visserij 2016 23 of 98 The programme has been executed according to a pre-agreed work plan. It consists of eleven projects, each managed by a project manager. Each project consists of several sub-projects. This document contains two main sections: 1) a report presenting standard information requested by the Ministry discussing the progress made with the research targets set in the pre-agreed working programme and 2) an annex including technical progress reports of the individual projects. Scientific results are not discussed but references are given to the (scientific) products. Also a short version of this progress report is available All the pre-agreed targets in the work plan have been met within the available financial budget. The report format includes a financial summary over 2016. The total cost of the programme in 2016 was 6.6 million Euro. About 0.69 m€ of the 2016 budget was forwarded to 2017 part as a reservation of activities which are planned in 2017.
Overview of the international fishing activities on the Dogger Bank : update with Dutch, British, Danish, German, Belgian, Swedish and French data for 2010-2015
Hamon, Katell G. ; Hintzen, Niels T. ; Oostenbrugge, Hans J.A.E. - \ 2017
Wageningen : Wageningen Economic Research (Wageningen Economic Research memorandum 2017-050) - 35
fisheries - marine animals - fishery management - north sea - population dynamics - europe - cost benefit analysis - visserij - zeedieren - visserijbeheer - noordzee - populatiedynamica - europa - kosten-batenanalyse
This report is an update of the data and analysis on the value of the fishing activities of the Dutch, British, Danish, German, Belgian, Swedish and French fishing fleets on the proposed closed areas on the Dogger Bank. The effort, value and landings are presented for a five-year period (2010-2015) and show large variations over the last years, driven mainly by fishing opportunities for plaice for the Dutch and British fleets and sandeel for the Danish and German fleets.
Waardekaarten van: Haisborough, Hammond & Winterton, North Norfolk Sandbanks & Saturn Reef
Hintzen, N.T. - \ 2017
IJmuiden : Wageningen Marine Research (Wageningen Marine Research rapport C009/17) - 18 p.
vissen - visserij - waarden - kaarten - natura 2000 - groot-brittannië - kustgebieden - fishes - fisheries - values - maps - great britain - coastal areas
Langs de Engelse kust staan een aantal gebieden op de UK Natura 2000 agenda voor sluiting voor de Nederlandse demersale vloot. Wageningen Marine Research bestudeerde in hoeverre de Nederlandse vloot actief was in dit gebied en hoe de voorgenomen te sluiten gebieden overlappen met voor de visserij interessante visgronden. Een grotere opbrengst (factor 3) wordt gehaald uit het North Norfolk Sandbanks & Saturn Reef gebied (dit is één gebied) ten opzichte van het Haisborough, Hammond and Winterton gebied (dit is ook één gebied). Vooral tong word in dit eerste gebied gevangen terwijl scholvangsten groter zijn in het tweede gebied. De voornaamste visgronden die interessant zijn voor de Nederlandse sector zijn niet opgenomen in de voorgenomen te sluiten gebieden, waarbij juist voor de visserij interessante delen van de totale zoekgebieden niet aangemerkt zijn als te sluiten gebied.
International stakeholder dialogue on pulse fisheries : report of the second dialogue meeting, Amsterdam, 20 January 2017
Steins, Nathalie A. ; Smith, Sarah ; Strietman, Wouter Jan ; Kraan, Marloes ; Trapman, B.K. - \ 2017
IJmuiden : Wageningen Marine Research (Wageningen Marine Research rapport C016/17) - 145
pulse trawling - fisheries - fishing methods - fishery policy - stakeholders - pulsvisserij - visserij - vismethoden - visserijbeleid
Frame Survey Curaçao’s fishing fleet 2016
Kraan, Marloes - \ 2017
IJmuiden : Wageningen Marine Research (Wageningen Marine Research rapport C022/17) - 38
fishing vessels - fisheries - curacao - vissersschepen - visserij - curaçao
A brief inventory of the current fishing capacity (frame survey) of the insular fishing fleet of Curacao was conducted. Curacao is part of the Kingdom of the Netherlands. It lies in the southern Caribbean, approximately 60km off the coast of Venezuela.
Mission report Tanzania : scoping mission marine fisheries Tanzania
Hoof, Luc van; Kraan, Marloes - \ 2017
IJmuiden : Wageningen Marine Research (Wageningen Marine Research rapport C004/17) - 66
zeevisserij - visserij - voedselzekerheid - zeewieren - samenwerking - handel - tanzania - marine fisheries - fisheries - food security - seaweeds - cooperation - trade
Inspanningsadviezen voor snoekbaars, baars, blankvoorn en brasem in het IJssel-/Markermeer : visseizoen 2017/2018
Tiën, Nicola ; Hammen, Tessa van der; Vries, Pepijn de; Schram, Edward ; Steenbergen, Josien - \ 2017
IJmuiden : Wageningen Marine Research (Wageningen Marine Research rapport C018/17) - 79
snoekbaars - baars - rutilus rutilus - abramis brama - vissen - visserij - visstand - ijsselmeer - pike perch - bass - fishes - fisheries - fish stocks - lake ijssel
Het Ministerie van Economische Zaken wil komen tot wetenschappelijk onderbouwd duurzaam beheer van snoekbaars, baars, blankvoorn en brasem in het IJsselmeer en Markermeer. Voor alle vier bestanden is de beleidsdoelstelling voor visseizoen 2017/2018 geformuleerd in het document “Toekomstbeeld visstand IJsselmeer/Markermeer – synthesedocument’. Hierin wordt in ieder geval gestreefd naar ‘een evenwichtiger lengte-opbouw van de bestanden met meer grotere exemplaren en een groter aantal jaarklassen’, als ook ‘een toename van de (paai)bestanden’. Voor het behalen van deze beleidsdoelstellingen zijn inspanningsadviezen gevraagd over de staandwantvisserij en de zegenvisserij, gecombineerd voor het IJsselmeer en Markermeer.
Report on the eel stock and fishery in the Netherlands 2015/2016
Graaf, Martin de; Bos, Oscar G. - \ 2017
IJmuiden : Wageningen Marine Research (Wageningen Marine Research rapport C003/17) - 59
eels - anguilla - fish stocks - fisheries - netherlands - palingen - visstand - visserij - nederland
Knowledge production at boundaries : an inquiry into collaborations to make management plans for European fisheries
Stange, Kari - \ 2017
University. Promotor(en): Jan van Tatenhove, co-promotor(en): Judith van Leeuwen. - Wageningen : Wageningen University - ISBN 9789463430623 - 160
fishery management - european union - stakeholders - european union countries - fishery policy - multi-stakeholder processes - knowledge - knowledge transfer - environmental policy - fisheries - companies - europe - visserijbeheer - europese unie - landen van de europese unie - visserijbeleid - multi-stakeholder processen - kennis - kennisoverdracht - milieubeleid - visserij - kapitaalvennootschappen - europa

This thesis addresses how knowledge is used and produced in stakeholder-led collaborations to make long-term management plans for European fishery management. Boundary object theory is applied and developed to explain how stakeholders from the fishing industry interact with each other, and with fishery scientists and managers, in initiatives to produce management plans. Using a qualitative case study approach, two initiatives were investigated in-depth: the North Sea Advisory Council’s development of a long-term management plan for North Sea Nephrops fisheries, and the Pelagic Advisory Council’s development of a long-term management plan for a new boarfish fishery in the Northeast Atlantic. A conceptual framework with emphasis on boundary spaces was developed to analyse knowledge exchange and the interaction between actors, objects and activities. The findings point to the importance of entry points for actors to become directly involved in knowledge-production processes. Direct stakeholder engagement in management plan production created a sense of ownership of the problems identified and triggered solution-oriented ways of working. The findings highlight the multiple roles played by fishery scientists in the diverse settings where management plans for European fisheries are produced, and draw attention to the need for clear procedures to ensure that different roles are acted out transparently.

Understanding social sustainability of capture fisheries
Veldhuizen, Linda J.L. - \ 2017
University. Promotor(en): Imke de Boer, co-promotor(en): Paul Berentsen; Eddy Bokkers. - Wageningen : Wageningen University - ISBN 9789462579644 - 159
fisheries - sustainability - animal welfare - cod - haddock - fishing methods - whitefish - northeast atlantic - visserij - duurzaamheid (sustainability) - dierenwelzijn - kabeljauw - schelvis - vismethoden - houting - noordoost atlantische oceaan

Fishing companies are faced with decreasing profitability and increasing competition. These companies can try to gain a competitive advantage by differentiating their products, e.g. by marketing new product attributes that consumers are interested in such as attributes relating to sustainability. Although consumers could be considerably interested in social sustainability of fish, this sustainability dimension has received little research interest so far. The main objective of this thesis is to understand social sustainability of capture fisheries. Social sustainability can be understood by applying the framework for social sustainability assessment, which consists of stakeholder consultation and issue selection, indicator development and quantification, and interpretation of the results, to the case considered. The case considered in this thesis was capture fisheries in the northeast Atlantic. Stakeholder consultation resulted in the identification of 27 social sustainability issues relevant for capture fisheries in the northeast Atlantic. Overall, social sustainability issues concerning working conditions, employees' job fulfilment and fish welfare were seen as more important than other social sustainability issues. Indicators were defined for the most important social sustainability issues of capture fisheries in the northeast Atlantic. To interpret values for each indicator, rubrics were developed that articulated levels of performance. Application of these indicators and their accompanying rubrics to a Norwegian trawler demonstrated that the indicators and rubrics provide insight into social sustainability at the level of the vessel, which can be used to identify potential room for improvement. To determine whether social sustainability issues can be used for product differentiation, consumer interest in social sustainability issues of whitefish from the northeast Atlantic was studied. Results from a choice modelling survey demonstrated that consumers prefer the issue fish welfare over the issues product quality, worker safety and local employment. Given the lack of overview of the knowledge on fish welfare, the most important social sustainability issue for consumers, the literature on this topic was reviewed to determine how the capture process in capture fisheries affects fish welfare, using the indicators external injuries and mortality. This review showed that scale, skin and fin injuries occur more frequently in trawls, purse seines, gillnets, traps and seines than in hooks, whereas hooking injuries occur in hooks only. Pressure injuries can occur in all gear types when deployed at greater depth. Trawls, purse seines and seines result in higher mortality than gillnets, hooks and traps. Mortality appears to increase with decreasing fish length, and differs across fish species. A greater capture depth and a longer fishing duration were associated with more external injuries and higher mortality, whereas a large change in water temperature, a longer duration of air exposure and a high density in the net were associated with higher mortality only. This thesis shows that application of the framework for social sustainability assessment to capture fisheries in the northeast Atlantic leads to an understanding of social sustainability that fishing companies can use to their advantage. In addition, this thesis shows that fishing companies in the northeast Atlantic need to start paying attention to fish welfare because consumers consider fish welfare the most important social sustainability issue of capture fisheries in the northeast Atlantic.

Ankerkuilmonitoring Westerschelde: resultaten 2016
Boois, I.J. de; Asch, M. van; Couperus, A.S. - \ 2016
IJmuiden : Wageningen Marine Research (Wageningen Marine Research rapport C113/16) - 19
monitoring - visserij - visstand - westerschelde - nederland - fisheries - fish stocks - western scheldt - netherlands
Benthic development around a gas platform in the North Sea -: a small scale closure for fisheries : a trait based approach
Glorius, Sander ; Hal, Ralf van; Kaag, Klaas ; Weide, Babeth van der; Chen, Chun ; Kooten, Tobias van - \ 2016
Den Helder : Wageningen Marine Research (Wageningen Marine Research rapport ) - 42
benthos - aquatic communities - aquatic ecology - fisheries - north sea - aquatische gemeenschappen - aquatische ecologie - visserij - noordzee
This project looked at the effect of closing an area for fisheries on the development of the benthic community. An existing data set of benthic species densities sampled at different distances and angles from a platform was used for this purpose. The particular area was closed due to the installation of a gas production platform, but is likely to function as a marine protected area (MPA), with the expectation that the benthic community develops differently from the benthic community in the surrounding areas as it no longer has to cope with the impact of fisheries. Differences in development might be linked to the impact of fisheries and the effects of closure might provide an expectation for the effect of planned MPAs in similar areas.
Pulse fishing and its effects on the marine ecosystem fisheries : an update of the scientific knowledge
Rijnsdorp, Adriaan ; Haan, Dick de; Smith, Sarah ; Strietman, Wouter Jan - \ 2016
IJmuiden : Wageningen Marine Research (Wageningen Marine Research report C117/16) - 30
pulse trawling - fishing methods - fisheries - aquatic ecology - marine ecology - aquatic ecosystems - pulsvisserij - vismethoden - visserij - aquatische ecologie - mariene ecologie - aquatische ecosystemen
This report summarises the knowledge on the effects of pulse trawls used in the North Sea fishery for flatfish and brown shrimp. The report describes the electrical characteristics of the pulse trawl systems currently used (potential difference over electrode pairs, pulse frequency, pulse width, duty cycle and dimensions of the gear). The shrimp pulse applies a low frequency pulse that invokes a startle response (tailflip) in shrimps. The sole pulse applies a higher frequency that invokes a cramp response that immobilise the fish species facilitating the catching process.
Toestand vis en visserij in de zoete Rijkswateren 2015 : Deel I : Trends
Graaf, M. de; Boois, I.J. de; Bos, O.G. ; Griffioen, A.B. ; Keeken, O. van; Tien, N.S.H. ; Vries, P. de - \ 2016
IJmuiden : Wageningen Marine Research (Wageningen Marine Research rapport C114/16) - 79
vissen - visserij - zoetwaterecologie - monitoring - fishes - fisheries - freshwater ecology
Het rapport “Toestand Vis en Visserij in de Zoete Rijkswateren” bestaat uit drie verschillende delen: Deel I “Trends”, Deel II “Methoden” en Deel III “Data”. In dit rapport (Deel I) worden (i) de trends in commercieel benutte vissoorten per VBC gebied, (ii) de trends in niet-inheemse vissoorten (exoten) en (iii) de trends in ecologische kwaliteitsratio’s vis gerapporteerd. Hiervoor is gebruik gemaakt van de gegevens die binnen de verschillende vismonitoringsprogramma’s op de Zoete Rijkswateren worden verzameld, aangevuld met gegevens over bv. aanlandingen. In de rapportage zijn trendanalyses voor de verschillende commercieel benutte vissoorten en niet-inheemse vissoorten (exoten) gemaakt aan de hand van de beschikbare monitoringsgegevens. De gegevens van deze monitoringsprogramma’s worden gebruikt als indicatoren voor de ontwikkeling van de bestanden van de geanalyseerde soorten over verschillende tijdsperioden. Het rapport concentreert zich op het weergeven van data en trends.
Aanpassing programma monitoring aal ter ondersteuning beleidskader open/gesloten gebieden
Kotterman, Michael - \ 2016
IJmuiden : Wageningen Marine Research (Wageningen Marine Research rapport C084/16) - 34
palingen - monitoring - visserij - toxicologie - visserijbeleid - eels - fisheries - toxicology - fishery policy
Dit rapport beschrijft een aanpassing van het bestaande aalmonitoringsprogramma dat ingezet kan worden voor het te ontwikkelen beleidskader. De aanpassingen zijn op basis van bestaande data. Dit nieuwe protocol is voor het eerst toegepast op het aal monitoringsprogramma in 2016.
Een haalbaarheidsstudie naar integratie van elektrische voortstuwing in de visserijsector : Academic Consultancy Training
Born, Michael van den; Geurts, Joris ; Jong, Hermen de; Langezaal, Hugo ; Dreessen, Sebastiaan - \ 2016
Kenniskringvisserij.nl - 68 p.
fisheries - costs - fuels - electricity - visserij - kosten - brandstoffen - elektriciteit
De visserijsector heeft de laatste jaren te maken gehad met grote fluctuaties in visprijzen en brandstofkosten. Om de sector toekomstbestendig te maken moeten brandstofkosten worden verlaagd om zo minder invloed te hebben op de financiële resultaten. Daarnaast is het terugdringen van emissies en onafhankelijkheid van fossiele brandstoffen een steeds belangrijker thema. Daarom is in dit project onderzocht in hoeverre het mogelijk is om vissersschepen volledig elektrisch aan te drijven. De focus gelegd op drie thema’s: technische haalbaar, ecologisch verantwoord en economisch rendabel. Tevens is er een stakeholderanalyse uitgevoerd. De resultaten zijn samengevat in een sterkte-zwakte analyse.
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.