ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    In:  http://aquaticcommons.org/id/eprint/12791 | 9595 | 2013-12-21 22:44:49 | 12791 | Gulf and Caribbean Fisheries Institute
    Publication Date: 2021-07-05
    Keywords: Fisheries ; GCFI
    Repository Name: AquaDocs
    Type: conference_item
    Format: application/pdf
    Format: application/pdf
    Format: 18-26
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    facet.materialart.
    Unknown
    In:  http://aquaticcommons.org/id/eprint/12923 | 9596 | 2013-12-19 18:38:53 | 12923 | Gulf and Caribbean Fisheries Institute
    Publication Date: 2021-07-07
    Keywords: Fisheries ; GCFI
    Repository Name: AquaDocs
    Type: conference_item
    Format: application/pdf
    Format: application/pdf
    Format: 152-162
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    facet.materialart.
    Unknown
    In:  http://aquaticcommons.org/id/eprint/12932 | 9596 | 2013-12-19 18:37:15 | 12932 | Gulf and Caribbean Fisheries Institute
    Publication Date: 2021-07-07
    Keywords: Fisheries ; GCFI
    Repository Name: AquaDocs
    Type: conference_item
    Format: application/pdf
    Format: application/pdf
    Format: 106-116
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    facet.materialart.
    Unknown
    NOAA/National Marine Fisheries Service | Silver Spring, MD
    In:  http://aquaticcommons.org/id/eprint/14566 | 403 | 2014-02-20 18:26:54 | 14566 | United States National Marine Fisheries Service
    Publication Date: 2021-06-28
    Description: This report argues for greatly increased resources in terms of data collection facilities and staff to collect, process, and analyze the data, and to communicate the results, in order for NMFS to fulfill its mandate to conserve and manage marine resources. In fact, the authors of this report had great difficulty defining the "ideal" situation to which fisheries stock assessments and management should aspire. One of the primary objectives of fisheries management is to develop sustainable harvest policies that minimize the risks of overfishing both target species and associated species. This can be achieved in a wide spectrum of ways, ranging between the following two extremes. The first is to implement only simple management measures with correspondingly simple assessment demands, which will usually mean setting fishing mortality targets at relatively low levels in order to reduce the risk of unknowingly overfishing or driving ecosystems towards undesirable system states. The second is to expand existingdata collection and analysis programs to provide an adequateknowledge base that can support higher fishing mortality targets while still ensuring low risk to target and associated species and ecosystems. However, defining "adequate" is difficult, especially when scientists have not even identified all marine species, and information on catches, abundances, and life histories of many target species, and most associated species, is sparse. Increasing calls from the public, stakeholders, and the scientific community to implement ecosystem-based stock assessment and management make it even more difficult to define "adequate," especially when "ecosystem-based management" is itself not well-defined. In attempting to describe the data collection and assessment needs for the latter, the authors took a pragmatic approach, rather than trying to estimate the resources required to develop a knowledge base about the fine-scale detailed distributions, abundances, and associations of all marine species. Thus, the specified resource requirements will not meet the expectations of some stakeholders. In addition, the Stock Assessment Improvement Plan is designed to be complementary to other related plans, and therefore does not duplicate the resource requirements detailed in those plans, except as otherwise noted.
    Keywords: Biology ; Ecology ; Fisheries ; Management
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 140
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    facet.materialart.
    Unknown
    In:  http://aquaticcommons.org/id/eprint/15054 | 403 | 2014-05-27 14:25:32 | 15054 | United States National Marine Fisheries Service
    Publication Date: 2021-07-01
    Description: The dynamics of the survival of recruiting fish are analyzed as evolving random processes of aggregation and mortality. The analyses draw on recent advances in the physics of complex networks and, in particular, the scale-free degree distribution arising from growing random networks with preferential attachment of links to nodes. In this study simulations were conducted in which recruiting fish 1) were subjected to mortality by using alternative mortality encounter models and 2) aggregated according to random encounters (two schools randomly encountering one another join into a single school) or preferential attachment (the probability of a successful aggregation of two schools is proportional to the school sizes). The simulations started from either a “disaggregated” (all schools comprised a single fish) or an aggregated initial condition. Results showed the transition of the school-size distribution with preferential attachment evolving toward a scale-free school size distribution, whereas random attachment evolved toward an exponential distribution. Preferential attachment strategies performed better than random attachment strategies in terms of recruitment survival at time when mortality encounters were weighted toward schools rather than to individual fish. Mathematical models were developed whose solutions (either analytic or numerical) mimicked the simulation results. The resulting models included both Beverton-Holt and Ricker-like recruitment, which predict recruitment as a function of initial mean school size as well as initial stock size. Results suggest that school-size distributions during recruitment may provide information on recruitment processes. The models also provide a template for expanding both theoretical and empirical recruitment research.
    Keywords: Ecology ; Fisheries
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 349-365
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2010-11-01
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Springer Nature
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2007-02-13
    Print ISSN: 1054-3139
    Electronic ISSN: 1095-9289
    Topics: Biology , Geosciences , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2009-09-16
    Description: Brooks, E. N., Powers, J. E., and Cortés, E. 2010. Analytical reference points for age-structured models: application to data-poor fisheries. – ICES Journal of Marine Science, 67: 165–175. Analytical solutions for biological reference points are derived in terms of maximum lifetime reproductive rate. This rate can be calculated directly from biological parameters of maturity, fecundity, and natural mortality or a distribution for this rate can be derived from appropriate metadata. Minimal data needs and assumptions for determining stock status are discussed. The derivations lead to a re-parameterization of the common stock–recruit relationships, Beverton–Holt and Ricker, in terms of spawning potential ratio. Often, parameters in stock–recruit relationships are restricted by tight prior distributions or are fixed based on a hypothesized level of stock resilience. Fixing those parameters is equivalent to specifying the biological reference points. An ability to directly calculate reference points from biological data, or a meta-analysis, without need of a full assessment model or fisheries data, makes the method an attractive option for data-poor fisheries. The derivations reveal an explicit link between the biological characteristics of a species and appropriate management. Predicted stock status for a suite of shark species was compared with recent stock assessment results, and the method successfully identified whether each stock was overfished.
    Print ISSN: 1054-3139
    Electronic ISSN: 1095-9289
    Topics: Biology , Geosciences , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2008-08-21
    Description: Powers, J. E., and Brooks, E. N. 2008. Penalties and rewards for over- and underages of catch allocations. – ICES Journal of Marine Science, 65: 1541–1551. Many fisheries are managed using a total allowable catch (TAC) that is subsequently sub-allocated to different fisheries sectors. These allocations are then monitored separately to ensure the adherence of each fishery to its particular allocation quota and to the overall TAC. In some management arenas, there are systems of “payback” where over- and underages are punished or rewarded using particular decision rules. Differences between fishing gear, the sizes and ages of fish being targeted by those gears, and the spatio-temporal distribution of the fishers using those gears can lead to different precision, accuracy, and cost of monitoring the allocation, affecting the probability that an overall management objective is reached. Weaknesses in monitoring may be exploited by user groups in their competition for larger catches and, subsequently, bigger allocations, so differential monitoring precision and accuracy can lead to both short- and long-term reallocations, i.e. a new set of winners and losers. Simulations in a management strategy evaluation framework were used to demonstrate the implications of alternative decision rules regarding payback on conservation and sustainability objectives and rebuilding time frames. The efficacy of the rules under alternative monitoring systems was also examined. Decision rules allowing payback prolong rebuilding (compared with perfect implementation or more precautionary TACs), especially if monitoring is biased (catches misreported) or imprecise. When precision of reported catches was increased and/or bias decreased, better yields and stock abundance resulted. When overages were penalized and underages not rewarded, recovery was achieved earlier. Conversely, policies in which transgressions were ignored and underages rewarded did not perform well. Underreporting by one nation may result in stocks that are well below the stock size conservation standards, yet produce substantial gains in yield for that nation, unless other nations retaliate by underreporting.
    Print ISSN: 1054-3139
    Electronic ISSN: 1095-9289
    Topics: Biology , Geosciences , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2014-01-31
    Description: Natural mortality (M) rates are difficult to measure empirically and are often specified in stock assessments based on life history characteristics. More recently, these specifications have included M as a function of the size or age of a fish. However, natural mortality is a dynamic parameter that will change with the suite of predators and, thus, indirectly with cohort size and age. As an alternative, a density-dependent M rate function is derived and compared with the commonly used Lorenzen model, where M at age forms an allometric relationship with weight-at-age. The density-dependent model expresses M as a function of two parameters: one density dependent and one density independent. Properties of the two models (size-based vs. density-dependent) were explored to indicate conditions where the results are and are not similar. Associated catch equations, equilibrium analyses, and non-linear replacement lines in stock–recruitment theory are examined. Just as with density-independent values of M, most assessment data are not sufficient to provide precise estimates of density-dependent M parameters. However, the density-dependent model provides a basis for incorporating ecological variability into single-species assessments, noting the differing dynamics between short- and long-lived species. The incorporation of dynamic natural mortality has implications when estimating abundance trends and stock status, and ultimately setting management reference points.
    Print ISSN: 1054-3139
    Electronic ISSN: 1095-9289
    Topics: Biology , Geosciences , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...