Staff Publications

Staff Publications

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    '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.

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    Hydrography and Jack mackerel stock in the South Pacific - Final report
    Hintzen, N.T. ; Corten, A.A.H.M. ; Gerlotto, F. ; Habasque, J. ; Bertrand, A. ; Lehodey, P. ; Brunel, T.P.A. ; Dragon, A.C. ; Senina, I. - \ 2014
    IJmuiden : IMARES (Report / IMARES Wageningen UR C176/14) - 65
    trachurus trachurus - zuidelijke stille oceaan - hydrografie - visserijbeheer - visserijbeleid - visstand - duurzaamheid (sustainability) - makrelen - trachurus trachurus - south pacific - hydrography - fishery management - fishery policy - fish stocks - sustainability - mackerels
    This study aims (i) to identify the most likely population structure hypotheses of Jack mackerel, (ii) to identify management objectives for Jack mackerel, and (iii) to evaluate sustainable management strategies to achieve these objectives. These three elements were considered through literature review, statistical and population dynamics modelling. Two different conclusions were drawn: a conclusion towards most likely population structure and a conclusion towards most likely stock structure.
    Hydrography and Jack Mackerel stock in the South Pacific
    Hintzen, N.T. ; Corten, A.A.H.M. ; Gerlotto, F. ; Brunel, T.P.A. - \ 2013
    IJmuiden : IMARES (Report / IMARES Wageningen UR C156/13) - 82
    trachurus - visstand - visbestand - hydrografie - databanken - zuidelijke stille oceaan - trachurus - fish stocks - fishery resources - hydrography - databases - south pacific
    The study on Hydrography and Jack Mackerel stock (Trachurus murphyi) in the South Pacific is currently one year underway. The main achievement consisted of collecting detailed datasets on Chilean, Peruvian and European fisheries activities and information on the hydrographical / biochemical and environmental conditions present in the South Pacific. The hydrographical and environmental datasets are based on the analyses of available acoustic information collected on-board survey and fishing vessels and satellite imagery data. Jack Mackerel habitat models are being developed based on these datasets. These models will be used to produce maps of the potential habitat of Jack Mackerel, on the basis of which different stock structure hypotheses will be tested. The models developed so far are able to accurately represent the distribution of Jack Mackerel as observed by fishing and surveying activities, although some additional investigations are needed to improve the statistical fits. Good fits with hydrographical conditions have been found. The models are not yet ready to be used for testing stock structure hypotheses, but this should be the case in the near future. During the first year of the project, an extensive literature review on Jack Mackerel has also been conducted, and a synthesis has been written, giving an overview on the species biology, ecology and stock structure. The literature suggests that a meta-population structure can be seen as a potential stock structure hypothesis. The literature review also contributed to identify environmental variables that should be crucial to define the suitable habitat of Jack Mackerel. Previously published results indicate, among others, temperature and dissolved oxygen ranges in which Jack Mackerel is able to survive. Finally, a framework to derive reference points for Jack Mackerel, assuming the single stock structure as used within the SPRFMO assessment, has been developed and made available to the SPRFMO Science Committee for review. Analyses of the assessment results within this framework indicate that the fishing mortality corresponding to maximum sustainable yield might be at around 0.15 per year with a corresponding spawning stock biomass of around 10 million tonnes. Different harvest control rules have been evaluated and show little risk to overexploitation in the medium and long term, although these result heavily rely on strong incoming year classes. The tools to evaluate sustainable management options for the Jack Mackerel population, when a stock structure other than a single one is assumed, are currently under development. The design of scenarios to be tested depend on the results of the habitat modelling exercises. Therefore, preliminary results will only become available early 2014.
    Climate modulates the effects of Sardinella aurita fisheries off Northwest Africa
    Zeeberg, J.J. ; Corten, A.A.H.M. ; Tjoe-Awie, P.J. ; Coca, J. ; Hamady, H. - \ 2008
    Fisheries Research 89 (2008)1. - ISSN 0165-7836 - p. 65 - 75.
    interannual variability - upwelling systems - sea-surface - atlantic - guinea - larvae - coast - oscillation - temperature - recruitment
    The fluctuating abundance of round sardinella (Sardinella aurita) in Mauritanian waters over the past ca. 20 years can be related to environmental dynamics off Northwest Africa. Trends in the fishery are evaluated using FAO data, acoustic surveys, and catch statistics from the EU fleet (1996¿2006). Remote sensing data demonstrate rising annual sea surface temperatures, up to 3 °C higher than the long-term average in 2002¿2003, following a shift in ocean climate in 1995. Fish abundance and repeated expansion of the sardinella population in the past 10 years are attributed to favorable oceanographic conditions and increased recruitment success. Sardinella thrives with intense upwelling and high primary production during spring, and retention of waters over the shelf during summer and autumn. The stock of S. aurita over the Northwest African shelf oscillates with the cold¿warm states of the habitat. Favorable hydrographic conditions and extended habitat has resulted in unprecedented rise of sardinella abundance in the late 1990s, which was counterbalanced by the impact of fisheries. A backshift to a cold-state ecosystem, with extensive regional upwelling and decreased sardinella habitat, would topple that balance.
    Effort development in the industrial fisheries of Mauritania in the period 1992-2004
    Tjoe-Awie, P.J. ; Goudswaard, P.C. ; Ould Inejih, C.A. ; Ould Meissa, B. ; Corten, A.A.H.M. - \ 2006
    Nouadhibou : Inst. Mauritanien de Recherches Oceanographiques et des Pech (Document Technique 2) - 30 p.
    Assessment demersal fish stocks Mauritania
    Corten, A.A.H.M. ; Goudswaard, P.C. ; Heessen, H.J.L. - \ 2006
    IJmuiden : IMARES (Report / IMARES C066/06) - 52
    visstand - visbestand - demersale visserij - demersale vissen - mauritanië - fish stocks - fishery resources - demersal fisheries - demersal fishes - mauritania
    The RIVO project "Assessment of demersal fish stocks in Mauritania" was commissioned by the Ministry of Foreign Affairs of The Netherlands to produce information on the state of the demersal fish stocks (species that live near the bottom) in Mauritania, in particular octopus and shrimps. These stocks are fished by fleets from the EU, working under the fishery agreement between the EU and Mauritania. Although there are no Dutch vessels targeting demersal fish in Mauritania, the government of The Netherlands is co-responsible for the fisheries agreement with Mauritania, and thereby for a rational and sustainable exploitation of the demersal resources.
    Ondanks politieke gevoeligheden: Demersaal project Mauritanie succesvol afgerond
    Corten, A.A.H.M. - \ 2006
    Visserijnieuws 26 (2006)30. - ISSN 1380-5061 - p. 8 - 8.
    Weinig jonge Noordzeeharing : wat is de oorzaak ?
    Dickey-Collas, M. ; Corten, A.A.H.M. - \ 2006
    Visserijnieuws 26 (2006)23 special. - ISSN 1380-5061 - p. 34 - 37.
    Bycatch and release of pelagic megafauna in industrial trawler fisheries off Northwest Africa
    Zeeberg, J.J. ; Corten, A.A.H.M. ; Graaf, E. de - \ 2006
    Fisheries Research 78 (2006)2-3. - ISSN 0165-7836 - p. 186 - 195.
    leatherback turtles - atlantic - ocean - sea
    The accidental capture of large animals such as sharks, manta rays, sea turtles, and dolphins in pelagic trawler fisheries remains controversial because it threatens biological diversity in many biogeographical regions, including the subtropical eastern North Atlantic. Bycatch rates observed during more than 1400 trawl sets off Mauritania, Northwest Africa, are shown to have been considerable during the past 4 years, with high animal abundance in Summer when the Northwest African shelf is occupied by subtropical water. We demonstrate the urgency for bycatch reduction and evaluate the use of species-selective gear, a conservation method immediately available and immediately effective in waters fished through international access agreements. A modification tested in commercial trawls during the observer program guides pelagic megafauna deflected by a filter to an escape tunnel along the bottom of the trawl. This ¿excluder¿ reduces bycatch mortality of the most vulnerable megafauna species by at least 40¿100%
    Assessment of sardinella and other small pelagics in West Africa: Final report 2002-2004
    Corten, A.A.H.M. - \ 2006
    IJmuiden : RIVO (Report / RIVO C005/06) - 51 p.
    Evaluatie demersale visbestanden Mauritanie Jaarverslag 2004
    Corten, A.A.H.M. ; Goudswaard, P.C. ; Heessen, H.J.L. - \ 2005
    IJmuiden : RIVO (Rapport / Nederlands Instituut voor Visserij Onderzoek (RIVO) C045/05) - 17
    demersale vissen - visbestand - schaal- en schelpdierenvisserij - garnalen - mauritanië - demersal fishes - fishery resources - shellfish fisheries - shrimps - mauritania
    De werkzaamheden binnen het project werden in 2004 grotendeels volgens de bestaande planning uitgevoerd. Veel tijd werd gestoken in de analyse van al bestaande gegevens in de data base van het IMROP. Hoewel deze data base een aantal belangrijke tekortkomingen kent, kon op basis van de beschikbare informatie toch een redelijk beeld gevormd worden van de garnalenvisserij. De gegevens werden ook gebruikt tijdens twee workshops op het IMROP waarbij de toestand van de garnalenvisserij in Mauritanië werd geëvalueerd. Het bleek dat de garnalen in de ondiepe zone dicht onder de kust (langostino’s) al overbevist waren, terwijl dat voor de garnalen in de diepere zone (gamba’s) nog niet aantoonbaar was. Merkwaardig genoeg had de toename van de visserij inspanning op garnaal in eerste instantie niet geleid tot afname van de garnalenstand. Dit verschijnsel werd toegeschreven aan het wegvangen van de natuurlijke vijanden van de garnaal (grote vissen), waardoor er meer jonge garnalen volwassen konden worden. De gevolgen van de garnalenvisserij op andere visbestanden werden nog niet bekeken. Verwacht mag worden dat dit effect sterk negatief zal zijn.
    Evaluatie demersale visbestanden Mauritanie : jaarverslag 2003
    Corten, A.A.H.M. - \ 2004
    IJmuiden : RIVO (Rapport / RIVO C038/04) - 9 p.
    Assessment of Sardinella and other Small Pelagics in West Africa
    Corten, A.A.H.M. - \ 2004
    IJmuiden : RIVO (RIVO report C042/04) - 18
    pelagische visserij - visbestand - visstand - duurzaamheid (sustainability) - ultrasoon sporen - akoestisch sporen - mauritanië - pelagic fishery - fishery resources - fish stocks - sustainability - ultrasonic tracking - acoustic tracking - mauritania
    The year 2003 was the sixth year of the cooperation between RIVO and the Mauritanian fisheries research institute IMROP (Institut Mauritanien des Recherches Océanographiques et de Pêche). It was also the second year of the current contract between RIVO and the Dutch Ministry of Agriculture, Nature and Food Quality. The cooperation between the Dutch and Mauritanian institutes is aimed at the transfer of technology and experience in the field of pelagic stock assessment. By increasing Mauritania’s capacity for pelagic stock assessment, prospects are improved for a sustainable management of pelagic resources in the area.
    The Gulf of Guinea large marine ecosystem. Environmental forcing and sustainable development of marine resources, 2002
    Corten, A.A.H.M. - \ 2003
    Aquaculture 219 (2003)1-4. - ISSN 0044-8486 - p. 921 - 922.
    The use of CPR data in fisheries research
    Corten, A.A.H.M. ; Lindley, J.A. - \ 2003
    Progress in Oceanography 58 (2003)2-4. - ISSN 0079-6611 - p. 285 - 300.
    eastern north-atlantic - scomber-scombrus l - long-term trends - calanoid copepods - c-helgolandicus - sea - abundance - plankton - cod - zooplankton
    The Continuous Plankton Recorder (CPR) survey was initiated partly to contribute to our understanding of the variability of fish stocks and as a potential method for predicting fish distributions from the abundance and composition of the plankton. The latter objective has been superseded by technological developments in fish detection, but the former has been the subject of continuing, and in recent years expanding use of the CPR data. Examples are presented of application of the data to studies on North Sea herring, cod, mackerel, blue whiting and redfish as well as more general plankton studies relevant to fisheries research. Variations in the migration patterns of herring as well as recruitment have been related to abundances and species composition of the plankton in the CPR survey. Extensive use has been made of the CPR data in relation to cod, particularly in the development and testing of the `match-mismatch' hypothesis. Advection of sufficient numbers of Calanus from the core oceanic areas of its distribution into the areas where the cod stocks occur may partly determine the success of those stocks. The analysis of the distribution and abundances of mackerel larvae in the CPR survey have shown contrasting variations between the North Sea and Celtic Sea. The expansion of the horse mackerel fishery in the north-eastern North Sea since 1987 has been related to physical events and a `regime shift' in the plankton, described from CPR data. The oceanic spawning areas of the blue whiting and redfish were highlighted by the expansion of the CPR survey into the north-eastern and north-western Atlantic respectively. These results helped to focus the attention of fisheries scientists on stocks that have subsequently become the targets for commercial exploitation. The results of the CPR survey, particularly those on Calanus finmarchicus, the phytoplankton standing stock as measured by the CPR colour index, the overall patterns of trends in plankton abundance and distributions of indicator species have been used by fisheries scientists to interpret variations in fish stocks. Generally the CPR data can be used to determine whether changes in the distributions and growth rates of fish have resulted from changes in planktonic food, changes in strength of ocean currents and distribution of water masses and to identify trends in larval abundances. With the tightening regulation of fisheries to reduce overfishing, global climate change and changing anthropogenic inputs into the sea, the unique source of information on unexploited populations in the long-term time series of the CPR survey will be of increasing value to fisheries scientists in the study of natural variability
    The demersal fisheries of Mauritaniua in 2003: description of the fleets and assessment of resources: First report of a joint IMROP/RIVO project
    Corten, A.A.H.M. ; Inejih, C.A.O. ; Cheikna, S.Y.O. ; Meissa, B.O. ; Vlisteren, M. van; Jouffre, D. - \ 2003
    IJmuiden : RIVO (RIVO report C072/03) - 46
    beoordeling - octopus - garnalen - visserijbeleid - visserijbeheer - visstand - ecologische risicoschatting - overexploitatie - assessment - octopus - shrimps - fishery policy - fishery management - fish stocks - ecological risk assessment - overexploitation
    Demersal fisheries in the Mauritanian Exclusive Economic Zone (EEZ) are described, with a review of the state of the stocks that are exploited by these fisheries. The assessment of the various stocks is based primarily on the results of the “Groupe de Travail” (GT), held in December 2002 at the Mauritanian fisheries research institute IMROP, Nouadhibou. The conclusions of these assessments are that the octopus stock in the Mauritanian EEZ is overexploited and that fishing effort is about 30% above the optimum level. Shrimps appear to be exploited near their maximum level. Fishing mortality on hake should be reduced, and the fishing effort in the roundfish fleet should not be further increased.
    Accentverschuiving pelagisch onderzoek : RIVO-medewerkers vinden hun draai in Mauritanie
    Corten, A.A.H.M. - \ 2003
    Visserijnieuws 23 (2003)22. - ISSN 1380-5061 - p. 32 - 37.
    visserij - onderzoek - mauritanië - fisheries - research - mauritania
    Beschrijving van het leven van RIVO-onderzoekers die permanent in Mauritanië gestationeerd zijn en hun onderzoek
    Assessment of sardinella and othter small pelagics in West Africa: Progress Report 2002
    Corten, A.A.H.M. - \ 2003
    IJmuiden : RIVO (RIVO report C009/03) - 16
    west-afrika - sardines - preventie - projecties - overexploitatie - pelagische visserij - west africa - sardines - prevention - projections - overexploitation - pelagic fishery
    The co-operation between the Dutch fisheries research institute RIVO and the Mauritanian fisheries research institute IMROP (Institut Mauritanien des Recherches Océanographiques et de Pêche) in the field of pelagic stock assessment was continued in 2002. In January, a new contract was signed between RIVO and the Dutch Ministry of Agriculture, Nature Management and Fisheries (LNV) that allowed the existing co-operation to be continued and expanded for the next three years. As a consequence, RIVO project staff was increased to three scientists who worked full-time on the project. The project contributed to two major working group meetings: the FAO working group on small pelagics in West Africa (Banjul, March 2002) and the IMROP Groupe de Travail (Nouadhibou, December 2002). Both meetings concluded that there was no evidence yet for over-exploitation of small pelagics at a regional level, but that as a precautionary measure catch levels should not be further increased. The IMROP Groupe de Travail went even further and recommended a freeze on pelagic fishing effort in the Mauritanian zone. During a survey with the Mauritanian research vessel “Al Awam” in November, large concentrations of pelagic fish were observed in the coastal waters off Nouadhibou and Cap Blanc. Especially the presence of large quantities of sardines indicated the recruitment of a strong year-class and good prospects for the sardine fishing for several years to come.
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