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  • 1
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The free-living nematode Panagrellus redivivus is a potential source of live food for first feeding fish. The digestion and assimilation of nematodes by larval fish were investigated with the aid of a histological and stable isotope approach. Larvae of whitefish Coregonus lavaretus were reared for 8 d with nematodes and compared with an unfed control. Nematodes were readily ingested by 3-d-old larvae. Different stages of nematode digestion could be observed in transverse sections of fish larvae sampled on Day 6 at regular intervals after feeding. Nematodes were produced on corn medium. In this way nematodes with a stable carbon isotope signature clearly different from the isotopic pattern of the fish larvae could be obtained. Stable carbon isotope signatures for lipids and lipid-free matter of fish larvae sampled on Days 2 and 8 after first feeding were clearly influenced by the stable isotopic pattern of the nematodes. The high acceptance of the nematodes by Coregonus lavaretus larvae and the early onset of digestion and nutrient retention positively confirm the potential of PanagreUus redivivus as a live food for first feeding fish larvae.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The free-living nematode Panagrellus redivivus was mass produced on a solid culture medium enriched with sunflower oil or fish oil by means of a new technology. Nematodes with different fatty acid compositions were obtained. A 7-day experiment was performed in order to compare the lipid enriched nematodes with Artemia as live food for first feeding common carp (Cyprinus carpio L.) larvae. Larvae fed nematodes doubled their body mass and had a mean survival rate higher than 80%. No significant differences could be observed between the two groups fed nematodes. Fish larvae fed with Artemia showed almost no mortality and had a final body mass five times higher than larvae fed nematodes. It is concluded that mass produced nematodes are a promising food source for first feeding common carp larvae. However, further research is needed on the development of improved culture media to increase the nutritional value of P. redivivus.
    Type of Medium: Electronic Resource
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  • 3
    Publication Date: 2017-04-29
    Description: Für den deutschen Aquakultursektor existieren weitreichende europäische und nationale Vorschriften. Deren Vollzug liegt im Binnenland zu großen Teilen im Verantwortungsbereich der einzelnen Bundesländer. In diesem Rahmen werden auf Basis bestehender Rechtsgrundlagen, verschiedene Daten zur Binnenaquakultur auf unterschiedlichen Verwaltungsebenen erhoben. Systematische Datensammlungen zur Produktion und Struktur des Aquakultursektors sowie über zugeführte Wildfänge erfolgen insbesondere in Form der Aquakulturstatistik (Bundesstatistik). Ergänzende Produktionsdaten werden im Rahmen des Jahresberichtes zur Deutschen Binnenfischerei und Binnenaquakultur von den Obersten Landesfischereibehörden abgefragt. Weiterhin werden Daten über das Auftreten von anzeige- und meldepflichtigen Fischkrankheiten, die Vergrämung von Prädatoren sowie über (bisher nicht stattgefundene) Einführungen von Fremdarten, von verschiedenen Behörden jeweils zentral erfasst und teilweise veröffentlicht. Im Rahmen von Antrags- und Genehmigungsverfahren werden betriebsspezifische Daten durch die Aquakulturbetriebe an die zuständigen Behörden, zumeist Kreisbehörden, der Bundesländer übermittelt. Hervorzuheben ist hierbei die Genehmigungspflicht von Aquakulturbetrieben (Fischseuchenverordnung) und eine zumeist notwendige wasserrechtliche Zulassung. Umgekehrt finden behördliche Betriebskontrollen statt. Neben der behördlichen Datenerfassung unterliegen die Betriebe selbst bestimmten Buchführungspflichten. Diese resultieren insbesondere aus dem Tiergesundheitsrecht, Arzneimittelrecht und Lebensmittelrecht. Die aufzuzeichnenden Daten verbleiben allerdings in der Regel auf Betriebsebene. Eine Übermittlung an die zuständigen Behörden findet nur dann statt, wenn explizite Mitteilungspflichten bestehen oder durch einzelfallbezogene Auflagen vorgeschrieben sind. Zusätzliche Vorschriften zur Zertifizierung und hinsichtlich Buchführungs- und Mitteilungspflichten bestehen für die ökologische/biologische Aquakulturproduktion. Die nachhaltige Entwicklung der Aquakulturwirtschaft ist ein elementarer Bestandteil der Gemeinsamen Fischereipolitik (GFP) der EU sowie ein wesentliches Ziel des nationalen Strategieplans Aquakultur. Auch seitens der Verbraucher werden erhöhte Anforderungen an die Nachhaltigkeit der in Aquakultur erzeugten Produkte gestellt. Für eine Beurteilung der ökologischen Nachhaltigkeit und Bewertung der Zielerreichung sowie hinsichtlich eines (inter-) nationalen Vergleichs der verschiedenen Produktionsformen, werden quantifizierbare Daten zur Umweltwirkung der Aquakultur benötigt. Die vorliegende Übersicht zeigt, dass diverse umweltbezogene Datenquellen zur Binnenaquakultur, aus der Erfüllung von Rechtsanforderungen, bereits in Deutschland vorhanden sind. Eine weitergehende Nutzung dieses Datenpotenzials erfolgt jedoch in vielen Bereichen nicht, so dass derzeit keine quantifizierbare Darstellung der Umweltverträglichkeit der Binnenaquakultur anhand empirischer Daten erfolgen kann. Für eine solche Darstellung müssten bestehende Daten zugänglich gemacht und ggf. zusätzliche Daten, z.B. im Rahmen eines Netzwerks aus Modellbetrieben, erhoben werden.
    Description: German aquaculturists have to comply with manifold and far-reaching European as well as national regulations when running an aquaculture system. The implementation of these rules falls within the responsibility of the individual federal states (Bundesländer). Based on the current laws and regulations, various data on German inland aquaculture are being collected on different administrative levels, e.g. data on aquaculture production, on the structure of the aquaculture sector as well as on the utilization of animals caught in the wild (federal statistics). Additional data on aquaculture production are collected within the annual report on German inland fisheries. These data are obtained from the supreme fisheries authorities within the federal states. In addition, data on notifiable fish diseases, measures regarding the protection from predators (birds) as well as on the introduction of alien species (not applicable for German aquaculture so far) have to be reported to the respective authorities. Some of these data are released in regular intervals. Data on aquaculture operations, requested during the application and approval process of a farm as well as data, that arise due to monitoring responsibilities, are available in the individual federal states and at distinct administrative levels. These data arise due to the obligatory registration and licensing procedures of aquaculture plants as well as the required water rights approval. These data remain on the administrative level exclusively. Besides data collection via administrative bodies and data from regular on-farm auditing, aquaculturists are subjected to bookkeeping obligations that mainly arise from animal health, pharmaceutical and food law. These operational data are transferred to the authorities only if there are explicit obligations, such as concerning the occurrence of increased mortality, outbreaks of notifiable fish diseases or if notification obligations are prescribed due to individual case-related requirements (e.g. water law). Most of these data, however, remain on the individual farms. For organic aquaculture production, additional obligations on bookkeeping and reporting as well as on the certification process apply. The sustainable development of the aquaculture industry is one of the main objectives of the Common Fisheries Policy (CFP) on the European as well as on national level. In addition, consumers impose higher requirements with respect to sustainability of aquaculture products. For this purpose, quantifiable data are needed to assess environmental impacts of aquaculture production and to allow for a national and international comparison of production systems. The present overview reveals the existence of various sources of data that might be used for environmental impact assessment of German aquaculture. Most of these data, though collected, are not being used for this purpose at present. For environmental impact assessment, these data have to be made accessible. Moreover, additional data might be gathered from, e.g. model farms, completing the already existing data set.
    Keywords: ddc:630 ; Binnenaquakultur ; ökologische Nachhaltigkeit ; Datenquellen ; inland aquaculture ; environmental sustainability ; data source
    Repository Name: EconStor: OA server of the German National Library of Economics - Leibniz Information Centre for Economics
    Language: German
    Type: doc-type:report
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  • 4
    Publication Date: 2019-04-16
    Description: Environmental enrichment aims for a deliberate increase in structural complexity in otherwise plain rearing units, helping to reduce aberrant traits and promote welfare of fish kept in captivity. Before putting enrichment protocols into practice, however, practitioners like hatchery managers need clear guidelines on enrichment measures and on the substrates used. In the present study, we used rainbow trout as a model species for salmonid rearing and investigated the use of a single layer of three different gravel types, i.e., small (4–8 mm), medium (8–16 mm) and large (16–32 mm), for environmental enrichment during egg incubation, endogenous and first feeding of rainbow trout and compared this to a barren control. From the egg stage onwards, we determined mortality, fungal prevalence as well as growth of larvae and fingerlings. We found that gravel size significantly affected mortality and fungal prevalence with the smallest gravel size and the control showing the lowest incidents. Growth of larvae and fingerlings was not affected by gravel, both when compared between gravel types and to the barren control. When using gravel for environmental enrichment in salmonid hatcheries, a small gravel size should be used. Small gravel provides the fish with a more natural environment without compromising practical feasibility of enrichment in hatcheries, still allowing for easy visual inspection and manual control of the reared fish.
    Type: Article , PeerReviewed
    Format: text
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  • 5
    Publication Date: 2004-02-01
    Description: Although stable isotope ratios in animals have often been used as indicators of the trophic level and for the back-calculation of diets, few experiments have been done under standardized laboratory conditions to investigate factors influencing δ15N and δ13C values. An experiment using Nile tilapia [ Oreochromis niloticus (L.)] was therefore carried out to test the effect of different dietary protein contents (35.4, 42.3, and 50.9%) on δ15N and δ13C values of the whole tilapia. The fish were fed the isoenergetic and isolipidic semi-synthetic diets at a relatively low level. δ15N and δ13C values of the lipid-free body did not differ between the fish fed the diets with different protein contents, but the trophic shift for N and C isotopes decreased with increasing protein accretion in the individual fish, for N from 6.5‰ to 4‰ and for C in the lipid-free body from 4‰ to 2.5‰. This is the first study showing the strong influence of the individual protein balance to the degree to which the isotopic signature of dietary protein was modified in tissue protein of fish. The extrapolation of the trophic level or the reconstruction of the diet of an animal from stable isotope ratios without knowledge of the individual physiological condition and the feeding rate may lead to erroneous results. ©2004 Springer-Verlag
    Print ISSN: 0028-1042
    Electronic ISSN: 1432-1904
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
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