Browsing by Subject "West coast rock lobster"

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    Sensitivity of the west coast rock lobster length-based stock assessment to a consistently higher somatic growth rate
    (2005) Johnston, Susan J; Butterworth, Doug S
    A recent study by Dubula et al. (2005) on the effect of tagging on the subsequent growth rate of rock lobsters has shown that there may be an appreciable reduction in the growth rate of male rock lobsters as a result of tagging. The amount of somatic growth reduction that might be occurring is of the order 2-3 mm per annum. A key question then to consider is what implications this might have for the sustainable productivity from the resource.
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    West coast rock lobster 2010 updated assessments
    (2010) Johnston, Susan J; Butterworth, Doug S
    The 2010 updated assessment involved included new (2009) data in the likelihood, as well as using updated FIMS data (a recent review of the methodology had produced new FIMS CPUE, catch-at-length and F% (percentage of the catch by number which is female) data series). Updated somatic growth data are also included. The historic catch series were slightly modified to take recent updates into account.
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    West coast rock lobster updated stock assessment results for the length-based model for both area-aggregated and area-disaggregated approaches
    (2005) Johnston, Susan J; Butterworth, Doug S
    This document presents updated assessments of the west coast rock lobster resource using the length-based model and the most recent available data. Results are shown for both area-aggregated and area-disaggregated approaches, and for two scenarios for historic recruitment trends (RC1 and RC2). Fits of the models to the data are shown. In most instances, the area-aggregated results are quite similar to the corresponding sums of the area-disaggregated estimates.
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    West coast rock lobster: the 2013/2014 recreational season
    (2014) Johnston, Susan J; Butterworth, Doug S
    The telephone survey of recreational West Coast rock lobster fishers has been carried out since the 1991/1992 season. Currently this is the only survey conducted to monitor the recreational fishers. No telephone survey was conducted during the 2013/2014 season due to budget constraints. During the 2013/14 WCRL recreational season fishers were permitted to catch their bag limit of four lobsters per day during the period 15th November 2013 – 17th November 2013, 14th December 2013 to 31st December 2013 and from the 18th April 2014 to 21st April 2014 (a total of 26 fishing days). This document reports available statistics, and suggests a possible method of extrapolating these statistics to estimate the recreational take for the 2013 season. The recreational take each year depends mainly on two factors: i) the season length i.e. the number of days allocated to recreational fishers ii) the number of actual recreational fishers. The number of recreational fishers can be estimated by assuming these to be linked (either directly or proportionally in some way) to the number of rock lobster permits sold in the season. Table 1 reports the available statistics relating to the recreational sector since 1991. The missing value is the 2013 telephone survey estimate of recreational take.