Browsing by Subject "Hake"

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    Investigating the consequences of Marine Protected Areas for the South African deep-water hake (Merluccius paradoxus) resource
    (Oxford University Press (OUP), 2009) Edwards, Charles T T; Rademeyer, Rebecca A; Butterworth, Doug S; Plagányi, Éva E
    Protected areas are often touted as important management tools to mitigate the uncertainty inherent in marine ecosystems, and thereby improve the long-term prospects for sustainable resource use. However, although they certainly play an important role in conservation, their usefulness in improving fishery yields is contentious. We present a simulation model that explores spatial closure options, and apply it to the demersal hake trawl fishery off South Africa. The model is based on the age-structured approach used for current assessments, representing the dynamics of the deep-water hake Merluccius paradoxus within a zonally disaggregated spatial system. Fitting the model to two zones, which demarcate a potential closed area from the remaining fished area, we investigate the consequences that such a protected area could have for the fishery. Our model suggests that area closures would have a negligible benefit for the fishery, regardless of the level of hake movement between areas. This is likely the result of the model's simplicity, and we suggest additional factors that should be considered to quantify the impact of Marine Protected Areas on the fishery more reliably.
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    Resource rents and resource management policies in Namibia's post-Independence hake fishery
    (Springer, 2014) Kirchner, Carola; Leiman, Anthony
    This study reviews the nature and outcomes of policies, incentives and management procedures in the Namibian hake industry from independence in 1990 to the present. It is argued that, although based on individual quotas, Namibia's post-independence management procedures have conflicted with the State's commitment to efficiency. Its 'Namibianization' policy and its attempt to increase domestic control of the hake industry both increased fishing effort and depressed hake stocks below economically optimal levels. Despite current over-capacity, government continues to reward new investments. Industry inefficiency has been further compounded by inconsistent rights allocation policies and the fragmentation of quota shares, which have reduced right-holders' sense of stewardship over the resource. If the resulting loss of rents is to be reversed, the present policies and the associated perverse incentives will need to be re-evaluated.
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    Risk evaluation for the current South African west coast rock lobster, hake and pelagic OMPs
    (2007) Johnston, Susan J; Rademeyer, Rebecca A; Cunningham, Carryn L; Butterworth, Doug S
    The choice of OMP involved an appropriate selection of the trade-offs between the conflicting objectives of greater catches, less TAC variability and lower risks. The statistic B(13/03) was seen to evaluate biological risk. The industry were interested in assessing economic risk, and hence the use of the FE and Etrap and Ehoop statistics. The FE statistic was used as an indicator for future employment levels. In an economy were unemployment is a problem, options projecting a decrease in FE and hence employment were considered undesirable from a social/industrial perspective. Further, to limit instability to the industry as a result of large TAC changes, these were limited to maxima of 10% from one year to the next.
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    Summary of the most recent South African hake assessments
    (2006) Rademeyer, Rebecca A; Butterworth, Doug S
    In the most recent assessments (Rademeyer and Butterworth, 2006) of the South African hake resource, Merluccius paradoxus and M. capensis are treated as two separate stocks, but are assessed simultaneously within a single assessment framework and for the south and west coasts combined. This simultaneous assessment is necessary because much of the data is available in species-aggregated form only. Thus the model is one of two species and two spatial strata (see Fig. 1) with differences in the distributions by age within each stratum handled by allowing for stratum-specific commercial (in principle, though not in this particular implementation) and survey selectivities, rather than explicitly modelling movement. This follows the recommendation from the January 2004 BENEFIT/NRF/BCLME workshop (BENEFIT, 2004), though the further recommendation of that workshop to extend to four spatial strata (two by depth as well as two longshore) has yet to be implemented. The only data available which are explicitly disaggregated by species are those from research surveys that have taken place from 1986 to the present. However the framework does admit implicit disaggregation of data from the commercial fishery as summarised below.