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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Environmental and resource economics 13 (1999), S. 75-94 
    ISSN: 1573-1502
    Keywords: bioeconomics ; cod ; cannibalism ; harvest allocation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Economics
    Notes: Abstract Political and economic factors usually determine the harvest sharesallotted to heterogeneous fisher groups harvesting upon the same fishstock. Given that the fishers harvest upon different segments of a fishstock with, for instance, cannibalistic tendencies, the shares allottedmay have considerable effect upon the well-being of the stock and theeconomics of the fishery. This paper analyses an existing allocationrule defining harvest shares allotted to two vessel groups (trawlers andcoastal vessels) in the Norwegian cod fishery. We apply a model with twointeracting age groups within a single fish stock, where the interactionhas both biological and economic implications. Requiring a first bestapproach to an optimal stock size results in no harvest in the firstyears studied. In order to ensure harvest amounts close to the historicharvest, we design a second best model giving optimal biological sharesin the build-up phase of the stock, and bioeconomic optimal shares atthe optimum fish stock level. The second best model recommends that foran increasing stock size the trawlers should obtain decreasing shares.We find that the actual allocation rule functions in a manner oppositeto the second best model, since this rule allocates an increasing shareto the trawlers for an increasing stock size.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of bioeconomics 2 (2000), S. 99-115 
    ISSN: 1573-6989
    Keywords: biology ; economics ; cooperative ; non-cooperative harvesting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Economics
    Notes: Abstract This paper shows how intra-stock relations such as cannibalism and growth enhancement, determine the economically optimal sharing of a fish resource between heterogeneous harvesting agents. The sharing of resources between different vessel groups is often left for political decision making. Nonetheless, such decisions may have both biological and economic consequences. This becomes quite clear when different harvesting groups exploit different sections (age groups) of a stock that has intra-stock interactions in the form of cannibalism. A two-agent bioeconomic model with cannibalism is developed and used to determine (i) optimal annual harvest sizes (TACs) for cod, and (ii) the optimal proportion of the TAC that should be harvested by the different vessel groups in the fishery. Applying biological and economic data in a numerical procedure, and comparing the results obtained to previous studies, it is shown that intra-stock interactions such as the presence of cannibalism has a significant impact on who should take what proportion of the TAC, and hence, the standing stock size and discounted economic rent achievable. In contrast to other studies, we find that the optimal harvest requires that both trawlers and coastal vessels should harvest the fish resource. In addition, the results indicate that, from a bioeconomic perspective, the existing trawler fleet’s harvest share in the cod fishery is too high.
    Type of Medium: Electronic Resource
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  • 3
    Publication Date: 2019-02-01
    Description: Increasing interest in deep-seabed mining has raised many questions surrounding its potential environmental impacts and how to assess the impacts’ significance. Under the United Nations Convention on the Law of the Sea (UNCLOS), the International Seabed Authority (ISA) is charged with ensuring effective protection of the marine environment as part of its responsibilities for managing mining in seabed areas beyond national jurisdiction (the Area) on behalf of humankind. This paper examines the international legal context for protection of the marine environment and defining the significant adverse change that can cause “serious harm”, a term used in the ISA Mining Code to indicate a level of harm that strong actions must be taken to avoid. It examines the thresholds and indicators that can reflect significant adverse change and considers the specific vulnerability of the four ecosystems associated with the minerals targeted for mining: (1) manganese (polymetallic) nodules, (2) seafloor massive (polymetallic) sulphides, (3) cobalt-rich (polymetallic) crusts and (4) phosphorites. The distributions and ecological setting, probable mining approaches and the potential environmental impacts of mining are examined for abyssal polymetallic nodule provinces, hydrothermal vents, seamounts and phosphorite-rich continental margins. Discussion focuses on the special features of the marine environment that affect the significance of the predicted environmental impacts and suggests actions that will advance understanding of these impacts.
    Type: Article , PeerReviewed
    Format: text
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