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  • 1
    Keywords: Hochschulschrift
    Description / Table of Contents: In der vorliegenden Arbeit wird die Freßaktivität der Kliesche in der Kieler Bucht druch zwei 24-Std-Fischereien auf der Schleppstrecke Süderfahrt im Juli und November 1985 untersucht. Zur Klärung des Nahrungsangebotes erfolgte im Juli udn Okotber eine benthosprobennahme. Es wurden im Juli 1519 sowie im November 1632 Därme bearbeitet. Die Bestimmungen des Füllungsgrades des Magendarmtraktes sowie die festgestellten Artenhäufigkeiten bzw. - längen im Magen der Kliesche wurden analysiert. - Ein jahreszeitlich abhängiges Freßverhalten der Kliesche ist lediglich bei der Nahrungszusammensetzung und bei der Nahrungsmenge feststellbar. - Die Nahrungsaufnahme der Kliesche findet tagsüber statt. Die größte Freßaktivität ist kuzr vor oder nach Sonnenuntergang anzutreffen. Ein größenabhängiges Freßverhalten ist nicht festzustellen. Im Spätherbst ist, im Gegensatz zum Sommer, eine verminderte Nahrungsaufnahme zu erkennen. - Die Crustaceen gefolgt, von den Polychaeten und den Molluscen, stellen die größten Anteile der Nährtiere für die Kliesche dar. Sonstige Hauptgruppen sind unbedeutend. Die Cumacee D. rathkei ist die häufigste Art im Magen. Im Julie dienten weiterhin die Polychaeten H. sarsi sowie A. maculata, ferner die Siphos der Muschel A. alba der Kliesche als Nahrung. Im November wurden die Mysidacee G. spinifer sowie die Polychaeten P. koreni und H. sarsi bevorzugt aufgenommen. - Mit Ausnahme der Klieschen 〈10cm und 〉30cm liegt bei den verbleibenden Größen ein ähnliches Artenspekturm im Magen vor. - Eine tageszeitlich anhängige Nahrungszusammensetzung ist bei der Kliesche nicht festzustellen. - Die Übereinstimmung der Häufigkeiten der Arten im Benthos und in den Mageninhalten der Kliesche ist gering. Eine Ausnahme bildet hier die Cumacee D. rathkei. - Ein durchgehender Anstieg der Beutelänge mit zunehmender Klieschegröße liegt mit Ausnahme der Probennahme im November (ohne die Berücksichtigung des häufigsten Beutetieres D. rathkei) nicht vor.
    Type of Medium: Online Resource
    Pages: 1 Online-Ressource (92 Seiten = 6 MB) , Karte, Illustrationen, Graphen
    Edition: 2020
    Language: German
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  • 2
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    In:  (Diploma thesis), Christian-Albrechts-Universität Kiel, Kiel, Germany, 86 pp
    Publication Date: 2020-09-28
    Description: In der vorliegenden Arbeit wird die Freßaktivität der Kliesche in der Kieler Bucht druch zwei 24-Std-Fischereien auf der Schleppstrecke Süderfahrt im Juli und November 1985 untersucht. Zur Klärung des Nahrungsangebotes erfolgte im Juli udn Okotber eine benthosprobennahme. Es wurden im Juli 1519 sowie im November 1632 Därme bearbeitet. Die Bestimmungen des Füllungsgrades des Magendarmtraktes sowie die festgestellten Artenhäufigkeiten bzw. - längen im Magen der Kliesche wurden analysiert. - Ein jahreszeitlich abhängiges Freßverhalten der Kliesche ist lediglich bei der Nahrungszusammensetzung und bei der Nahrungsmenge feststellbar. - Die Nahrungsaufnahme der Kliesche findet tagsüber statt. Die größte Freßaktivität ist kuzr vor oder nach Sonnenuntergang anzutreffen. Ein größenabhängiges Freßverhalten ist nicht festzustellen. Im Spätherbst ist, im Gegensatz zum Sommer, eine verminderte Nahrungsaufnahme zu erkennen. - Die Crustaceen gefolgt, von den Polychaeten und den Molluscen, stellen die größten Anteile der Nährtiere für die Kliesche dar. Sonstige Hauptgruppen sind unbedeutend. Die Cumacee D. rathkei ist die häufigste Art im Magen. Im Julie dienten weiterhin die Polychaeten H. sarsi sowie A. maculata, ferner die Siphos der Muschel A. alba der Kliesche als Nahrung. Im November wurden die Mysidacee G. spinifer sowie die Polychaeten P. koreni und H. sarsi bevorzugt aufgenommen. - Mit Ausnahme der Klieschen 〈10cm und 〉30cm liegt bei den verbleibenden Größen ein ähnliches Artenspekturm im Magen vor. - Eine tageszeitlich anhängige Nahrungszusammensetzung ist bei der Kliesche nicht festzustellen. - Die Übereinstimmung der Häufigkeiten der Arten im Benthos und in den Mageninhalten der Kliesche ist gering. Eine Ausnahme bildet hier die Cumacee D. rathkei. - Ein durchgehender Anstieg der Beutelänge mit zunehmender Klieschegröße liegt mit Ausnahme der Probennahme im November (ohne die Berücksichtigung des häufigsten Beutetieres D. rathkei) nicht vor.
    Type: Thesis , NonPeerReviewed
    Format: text
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  • 3
    Publication Date: 2024-02-07
    Description: Understanding the drivers behind fluctuations in fish populations remains a key objective in fishery science. Our predictive capacity to explain these fluctuations is still relatively low, due to the amalgam of interacting bottom-up and top-down factors, which vary across time and space among and within populations. Gaining a mechanistic understanding of these recruitment drivers requires a holistic approach, combining field, experimental and modelling efforts. Here, we use the Western Baltic Spring-Spawning (WBSS) herring (Clupea harengus) to exemplify the power of this holistic approach and the high complexity of the recruitment drivers (and their interactions). Since the early 2000s, low recruitment levels have promoted intense research on this stock. Our literature synthesis suggests that the major drivers are habitat compression of the spawning beds (due to eutrophication and coastal modification mainly) and warming, which indirectly leads to changes in spawning phenology, prey abundance and predation pressure. Other factors include increased intensity of extreme climate events and new predators in the system. Four main knowledge gaps were identified related to life-cycle migration and habitat use, population structure and demographics, life-stage specific impact of multi-stressors, and predator–prey interactions. Specific research topics within these areas are proposed, as well as the priority to support a sustainable management of the stock. Given that the Baltic Sea is severely impacted by warming, eutrophication and altered precipitation, WBSS herring could be a harbinger of potential effects of changing environmental drivers to the recruitment of small pelagic fishes in other coastal areas in the world.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
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  • 4
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    In:  cornelius.hammer@vti.bund.de | http://aquaticcommons.org/id/eprint/4198 | 1240 | 2012-11-10 18:44:43 | 4198 | Bundesforschungsanstalt für Fischerei
    Publication Date: 2021-06-30
    Description: Financial support is going to be applied for from the European Commission in order to establish the European Fish Ageing Network (EFAN). The project, which was planned andinitiated from Norway (Floedevigen) is supposed to be a concerted action from 14 European Countries involving about 35 institutions. The primary aim of the network is to coordinate the research in age reading, especially the improvement of data bases for reference material, the transformation of research (e.g. daily ring formation in otoliths) to each interested reader. Moreover, the applied financial support is supposed to be preliminary spent fortravel of researcher and technicians to other institutes where the same fish species are aged. Reference material is supposed to be sent to the institutes for check-reading. Specific workshops will be held in cases where heterogeneousresults occur from check-reading the reference material.
    Description: Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery research in 2010
    Keywords: Fisheries ; congress report ; use of methods ; image analysis ; concerted action
    Repository Name: AquaDocs
    Type: article , FALSE
    Format: application/pdf
    Format: application/pdf
    Format: 98-100
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  • 5
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    In:  hans-joachim.raetz@vti.bund.de | http://aquaticcommons.org/id/eprint/2946 | 1240 | 2011-09-29 18:09:37 | 2946 | Johann Heinrich von Thünen-Institut, Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei
    Publication Date: 2021-06-30
    Description: The cod stock in the Western Baltic Sea is assessed to be overfished regarding the definitions of the UN World Summit on Sustainable Development at Johannesburg in 2002. Thus, the European Fisheries Council enforced a multi-annual management plan in 2007. Our medium term simulations over the future 10 years assume similar stock productivity as compared with the past four decades and indicate that the goals of the management plan can be achieved through TAC and consistent effort regulations. Taking account of the uncertainty in the recruitment patterns, the target average fishing mortality of age groups 3 – 6 years of F = 0.6 per year as defined in the management plan is indicated to exceed sustainable levels consistent with high long term yields and low risk of depletion. The stipulated constraint of the annual TAC variations of ±15% will dominate future fisheries management and implies a high recovery potential of the stock through continued reductions in fishing mortality. The scientific assessment of sustainable levels of exploitation and consideration in the plan is stronglyadvised, taking account of uncertainties attributed to environmental and biological effects. We recommend our study to be complemented with economic impact assessments including effects on by-catch species, which have been disregarded in this study. It is further demonstrated, that the goals of the management plan can alternatively be achieved by mesh size adaptations. An alternative technical option of mesh size increases to realize the required reductions in fishing mortality provides avoidance of discards of undersized fish after a few years by means of improved selectivity, another important element of the Common Fisheries Policy. However, it is emphasized that technical regulations since 1990 failed to affect the by-catch and discards of juvenile cod. In any way, the meaningful implementation of the multiannual management plan through stringent control and enforcement appears critical.
    Description: Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung - Information Fishery research in 2010. European Commission, Joint Research Centre, Institute for Protection and Security of the Citizen, Maritime Affairs Unit G.04; Johann Heinrich von Thünen-Institut, Institut für Seefischerei; Johann Heinrich von Thünen-Institut, Institut für Ostseefischerei
    Keywords: Management ; Conservation ; Fisheries ; stock management ; Baltic Sea ; Cod ; Dorsch ; Bestandsmanagement
    Repository Name: AquaDocs
    Type: article , FALSE
    Format: application/pdf
    Format: application/pdf
    Format: 36-44
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  • 6
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    In:  christopher.zimmermann@vti.bund.de | http://aquaticcommons.org/id/eprint/3130 | 1240 | 2012-04-30 20:10:09 | 3130 | Bundesforschungsanstalt für Fischerei
    Publication Date: 2021-06-25
    Description: During the autumn session of the ICES Advisory Committee for Fisheries Management (ACFM) 58 stocks assessed in 7 Working Groups have been analyzed and reviewed, among these the demersal stocks in the North Sea and the Mackerel stock. As in previous years, ICES recommends a reduction in fishing mortality for a number of stocks or even the establishment of recovery and management plans, to safeguard a continuous development of the stocks towards safe biological limits. ICES reiterated last year’s recommendation to close the directed cod fishery and any fishery taking cod as by-catch in the North Sea, west of Scotland and in the Irish Sea. This year, the stocks of plaice in the North Sea, southern hake and southern anglers are (among others) in a critical state and in urgent need of protecting or rebuilding measures. This will again have an enormous impact on almost all mixed fisheries in the European Union.
    Description: Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery Research in 2010.
    Keywords: Management ; scientific advice ; stock management ; sustainable fishery
    Repository Name: AquaDocs
    Type: article , FALSE
    Format: application/pdf
    Format: application/pdf
    Format: 144-162
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  • 7
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    In:  tomas.groehsler@vti.bund.de | http://aquaticcommons.org/id/eprint/3102 | 1240 | 2012-04-27 13:11:32 | 3102 | Bundesforschungsanstalt für Fischerei
    Publication Date: 2021-07-01
    Description: During the spring session of the ICES Advisory Committee for Fisheries Management (ACFM) 48 stocks assessed by 7 Working Groups have been analyzed and reviewed, among these all herring stocks in the ICES area, blue whiting and most demersal stocks in the Baltic, Arctic and North-Western area. As in previous years, ICES recommends a reduction in fishing mortality for a number of stocks or even the establishment of recovery and management plans, to safeguard a continuous development of the stocks towards safe biological limits. ICES recommended a 90% reduction of the cod fishery in the Baltic Sea, while most of the herring stocks are in good condition.
    Description: Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery Research in 2010.
    Keywords: Management ; fishery management ; scientific advice ; stock management ; TAC
    Repository Name: AquaDocs
    Type: article , FALSE
    Format: application/pdf
    Format: application/pdf
    Format: 98-121
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  • 8
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    In:  tomas.groehsler@vti.bund.de | http://aquaticcommons.org/id/eprint/3188 | 1240 | 2012-05-02 13:31:03 | 3188 | Bundesforschungsanstalt für Fischerei
    Publication Date: 2021-06-25
    Description: The spring session of ACFM gave advice for a number of stocks in the North Atlantic, North Sea and Baltic. The present assessment of the situation is given here for stocks of importance for the German fishery. These are: Blue Whiting: the stock size is rapidly decreasing due to high catches; ICES recommends a closure of the fishery. Herring (Atlanto-Scandian, Norwegian spring spawner): Stock is within save biological limits, weak recruitment of the recent years will lead to a further reduction of biomass. Herring (North Sea): revision of the assessment led to a different perception of the stock: SSB was in 2000 below Blim. Excellent recruitment will lead to an increase of SSB over Blim within this year, but ICES recommends to reduce fishing mortality on adults significantly. Herring (Baltic spring spawner in 22–24, IIIa): Still no increasing tendency is detectable. Herring (VIaNorth): stable. Redfish: generally further decreasing tendency observed, a reduction of the fishery is recommended. Signs of recovery visible only for two units. Greenland Halibut: State of the stock not quite clear, but slightly positive tendencies. The present fishing intensity should be reduced. Cod (Kattegat): Weak recruitment, outside safe biological limits. ICES recommends a closure of the fishery. Cod (22–24, Western Baltic): Stock situation unclear due to extensive migrations. F should be reduced by at least 10%.
    Description: Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery Research in 2010.
    Keywords: Management ; scientific advice ; stock management ; sustainable fishery ; EU regulation
    Repository Name: AquaDocs
    Type: article , FALSE
    Format: application/pdf
    Format: application/pdf
    Format: 95-113
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  • 9
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    In:  http://aquaticcommons.org/id/eprint/3257 | 1240 | 2012-05-08 16:46:11 | 3257 | Bundesforschungsanstalt für Fischerei
    Publication Date: 2021-06-26
    Description: The spring session of ACFM gave advice for a numberof stocks in the North Atlantic, North Sea and Baltic.The present assessment of the situation is given here forstocks of higher importance for the German fishery.These are: Blue Whiting: the stock is still relatively high,this, however, will not last very long, due to too intensefishing. Cod in Kattegat: stock is outside safe biologicallimits. No immediate recovery in sight. Cod in 22–24(Baltic): stock is inside save biological limits. F, however, is above the recommendation of the IBSFC. GreenlandHalibut: state of the stock not quite clear. The presentfishing intensity seems to be sustainable. Herring (Atlanto-scandian, Norwegian spring spawner): stock is within safe biological limits, weak recruitment of the recent years will lead to a reduction of biomass. Herring: for Baltic spring spawner in 22–24 and IIIa still no increasing tendency detectable. North Sea Herring: furtherincreasing tendency, with 900 000 t over B lim, goodrecruitment. Herring in VIa: stable. Redfish: generallydecreasing tendency observed, a reduction of the fisheryis recommended. Signs of recovery, however, visible for some units
    Keywords: Fisheries ; fisheries management ; scientific advice ; stock management ; sustainable fishery ; North-East Atlantic ; North Sea ; Baltic Sea
    Repository Name: AquaDocs
    Type: article
    Format: application/pdf
    Format: application/pdf
    Format: 111-126
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  • 10
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    In:  tomas.groehsler@vti.bund.de | http://aquaticcommons.org/id/eprint/3292 | 1240 | 2012-11-10 17:38:35 | 3292 | Bundesforschungsanstalt für Fischerei
    Publication Date: 2021-06-27
    Description: Information is given about the results of the latest meeting of the Herring Assessment Working Group for the Area South of 62° N and the Baltic Fisheries Assessment Working Group, which were conducted in March and April at ICES headquarters in Copenhagen. The actual stock development and the catch options estimated for different assessment units of herring and sprat are presented. The spawning stock size of North Sea herring reached in 1998 for the first time since 1991 a level above the Minimum Biological Acceptable Level (MBAL) of 800 000 t. Keeping the fishery at the present level the spawning stock size should reach in 1999 a level of about 1.2 mio. t. For the Western Baltic Spring spawning herring stock no actual stock estimate was presented. Due to uncertainties in splitting the catches in North Sea autumn and Baltic spring spawners no analytical assessment was accepted.
    Description: Johann Heinrich von Thünen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung = Information on Fishery research in 2010.
    Keywords: Management ; Fisheries ; fisheries management ; scientific advice ; stock management sustainable fisheries ; herring ; sprat stocks ; Baltic Sea ; North Sea ; Channel ; western British waters
    Repository Name: AquaDocs
    Type: article , FALSE
    Format: application/pdf
    Format: application/pdf
    Format: 17-23
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