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Browsing by Author "Plagányi, Éva E"

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Abalone poaching confiscation trends for Zones A-D up until 2007

Author: Plagányi, Éva E Date: 2007 Poaching confiscation data have been updated using all data currently available up until the end of May 2007. The data have been reworked in terms of a standard Model year y that is taken to run from October of year y-1 to September of year ... Read more
Abalone spatial- and age-structured assessment model preliminary results for Zones A, B, C and D in 2007

Author: Plagányi, Éva E Date: 2007 This document provides preliminary results from fitting the abalone spatial- and agestructured production model (ASPM) to Zones/Subareas A, B, CNP, CP and D in combination (hereafter referred to as the “combined ABCD model”) using the updated ... Read more
Abalone spatial- and age-structured assessment model preliminary results for Zones A, B, C and D in 2008

Author: Plagányi, Éva E Date: 2008 A summary is presented of the results obtained from the 2008 Reference-case model that was fit to Zones A, B, CNP, CP and D in combination (hereafter referred to as the “combined ABCD model”). The full details of the spatial- and age-structured ... Read more
Abalone spatial- and age-structured assessment model results for Zones A, B, C and D in 2005

Author: Plagányi, Éva E ; Butterworth, Doug Date: 2005 A summary is presented of the results obtained from the 2005 Reference-case model that was fit to Zones A, B, CNP, CP and D in combination (hereafter referred to as the “combined ABCD model”). The full details of the spatial- and age-structured ... Read more
Aspects of modelling Robben Island African Penguin Spheniscus demersus populations

Author: Plagányi, Éva E ; Butterworth, Doug Date: 2006 Crawford et al. (2006) present relationships between the breeding success of Robben Island African penguins Spheniscus demersus and the abundances of both anchovy Engraulis encrasicolus and sardine Sardinops sagax. Based on their analysis, ... Read more
Assessing the adequacy of current fisheries management under changing climate: a southern synopsis

Author: Plagányi, Éva E ; Weeks, Scala J ; Skewes, Tim D ; Gibbs, Mark T ; Blamey, Laura K ; Soares, Muri ; Robinson, William M L ; Poloczanska, Elvira S ; Norman-Lopez, Anna Date: 2011 Climate change is likely to have a significant impact on both target and non-target marine stocks worldwide, with the concomitant need for management strategies capable of sustaining fishing in future. We use several southern hemisphere ... Read more
Assessing the adequacy of current fisheries management under changing climate:a southern synopsis

Author: Plagányi, Éva E ; Weeks, Scala J ; Skewes, Tim D ; Gibbs, Mark T ; Blamey, Laura K ; Soares, Muri ; Robinson, William M L ; Norman-Lopez, Anna Date: 2012 Climate change is likely to have a significant impact on both target and non-target marine stocks worldwide, with the concomitant need for management strategies capable of sustaining fishing in future. We use several southern hemisphere ... Read more
Assessment of the South African Hake resource taking its two-species nature into account

Author: Rademeyer, Rebecca A ; Butterworth, Doug S ; Plagányi, Éva E Date: 2008 The commercially valuable hake fishery off South Africa consists of two morphologically similar species, the shallow-water Cape hake Merluccius capensis and the deep-water Cape hake M. paradoxus. Because catch-and effort statistics collected ... Read more
A brief introduction to some approaches to multispecies/ecosystem modeling in the context of their possible application in the management of South African fisheries

Author: Butterworth, Doug S ; Plagányi, Éva E Date: 2004 Aspects of the potential application of multispecies/ecosystem modelling to advise the management of South African fisheries are discussed. In general, reliable predictive ability from such models is likely to be achieved sooner for top ... Read more
A comparison between ADAPT-VPA and ASPM-based assessments of the Gulf of Maine cod stock

Author: Butterworth, Doug S ; Rademeyer, Rebecca A ; Plagányi, Éva E Date: 2005 ADAPT-VPA and ASPM assessment methods are applied to the same data set for the Gulf of Maine cod stock to attempt to ascertain the reasons for the rather different results provided by past applications of the two approaches. A number of ... Read more
Conditioning SMOM using the agreed calendar of observed changes in predator and krill abundance: a further step in the development of a management procedure for krill fisheries in area 48

Author: Plagányi, Éva E ; Butterworth, Doug S Date: 2008 The updated version of the Spatial Multi-species Operating Model (SMOM) of krill-predatorfishery dynamics described in an accompanying paper is conditioned using the WG-SAM set of reference observations for Area 48 (the SAM calendar). Results ... Read more
A critical look at the potential of Ecopath with ecosim to assist in practical fisheries management

Author: Plagányi, Éva E ; Butterworth, Doug S Date: 2004 Ecosystem-orientated thinking is increasingly incorporated into fishery management. Given the complexity of ecosystem processes, there is a need to evaluate the tools used to steer this thinking critically. ECOPATH with ECOSIM (EwE), an ... Read more
Data inputs for the African Penguin Spheniscus demersus model to be coupled to the pelagic OMP

Author: Plagányi, Éva E ; Robinson, William Date: 2008 This document serves as an updated compilation of all data currently available as inputs to the African penguin spatial model which is to be coupled to the pelagic OMP. The data are presented here together with some comments as to how they ... Read more
Ecosystem modelling provides clues to understanding ecological tipping points

Author: Plagányi, Éva E ; Ellis, Nick ; Blamey, Laura K ; Morello, Elisabetta B ; Norman-Lopez, Anna ; Robinson, William M L ; Sporic, Miriana ; Sweatman, Hugh Date: 2014 Ecological thresholds, associated with abrupt changes in the state and organisation of ecosystems, challenge both scientists and managers. Adaptive response to such changes, and planning for their occurrence, requires an understanding of the ... Read more
Further results using the 2008 abalone assessment model for Zones A, B, C and D

Author: Plagányi, Éva E Date: 2008 A summary is presented of the results obtained from the 2008 Reference-case model and three variants that was fit to Zones A, B, CNP, CP and D in combination (hereafter referred to as the “combined ABCD model”). The full details of the spatial- ... Read more
A history of recent bases for management and the development of a species-combined Operational Management Procedure for the South African hake resource

Author: Rademeyer, Rebecca A ; Plagányi, Éva E ; Butterworth, Doug S Date: 2010 The bases for historical catch limits placed on the hake fishery are reviewed in brief for earlier years and then in some depth over the period from 1991 when the Operational Management Procedure (OMP) approach was introduced for this fishery. ... Read more
Illegal and unreported fishing on abalone—Quantifying the extent using a fully integrated assessment model

Author: Plagányi, Éva E ; Butterworth, Doug ; Burgener, Markus Date: 2011 Illegal, unregulated and unreported (IUU) fishing is a major problem in many of the world's fisheries. The stocks most severely impacted centre on those characterised by high economic value, such as abalone, as well as long lived and slow ... Read more
Illustrative outputs of the age-structured model of African penguin populations for linking to the pelagic OMP testing process

Author: Robinson, William M L ; Plagányi, Éva E ; Butterworth, Doug Date: 2008 Given the move towards adopting an ecosystem approach to fisheries in the pelagic sector, the new joint OMP needs to be tested in the light of not only the risk parameters as considered previously, along with catch statistics, but also ... Read more
An indirect investigation of the possible influence of port on the estimation of observer effects on catch rates in the pelagic fishery

Author: Somhlaba, S ; Brandão, Anabela ; Plagányi, Éva E ; Butterworth, Doug S Date: 2006 Earlier GLM analyses of catch per hour data for sardine and anchovy to determine observer effects have suggested statistically significant increases in this catch rate with observers on the vessels over January-to June for the sardine ... Read more
Investigating the use of interview data regarding the illegal sector in the stock assessments for abalone in Zones E and G

Author: Edwards, Charles ; Hauck, Maria ; Plagányi, Éva E Date: 2007 Read more

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