Browsing by Subject "West Coast rock lobster"

Now showing 1 - 8 of 8
  • Thumbnail Image
    Item
    Open Access
    2009 updated stock assessments for West Coast rock lobster
    (2009) Johnston, Susan J; Butterworth, Doug S
    The west coast rock lobster assessment of 20061 based on data to 2004 is updated to include data up to 2008. Over the last four years the exploitable biomass trend is upwards for Areas 7 and 8 and the resource as a whole, but downwards for Areas 5+6 and almost level for Areas 1+2 and 3+4. The overall increase since 2006 is significant at the 5% level. While better than median projections at the time the current OMP developed, the increase remains within the 95% probability intervals calculated at the time.
  • Thumbnail Image
    Item
    Restricted
    The new West Coast rock lobster OMP based on an area-disaggregated approach
    (2007) Johnston, Susan J; Butterworth, Doug S
    The OMP currently being developed for the West Coast Rock Lobster is different from the three previous OMPs applied to manage the resource (see Johnston and Butterworth 2005), in that this new OMP will provide TACs for each of the five super-areas on an annual basis. During 2006, considerable work was focussed on the development of assessment models for each super-area. These assessment models now form the “operating models” which are used for testing alternate OMP candidates and are described in ANSW/JUL07/WCRL/ASS/1 and 2. The new OMP uses data (trap and hoop CPUE, FIMS, somatic growth rate) from each area (where available), combines these data into a single index (for each data type), produces a global TAC, and then uses a series of rules to split this global TAC into TACs at the super-area level. At the same time, estimates of recreational catch for each super-area are taken into account, as well as ensuring that super-area TACs will allow the allocations to the limited rights holders (smaller scale operators restricted to a particular super-area) to be taken each year.
  • Thumbnail Image
    Item
    Open Access
    OMP 2007 re-cast results for West Coast rock lobster
    (2008) Johnston, Susan J; Butterworth, Doug S
    OMP 2007 re-cast is an update from OMP-2007 which will be used to set the TACs for the West Coast rock lobster fishery for the 2008+ seasons. OMP 2007 re-cast has been tuned to give the same median biomass recovery (in terms of male lobsters) over the 2006-2015 period as OMP 2007. OMP 2007 re-cast differs from OMP 2007 in three ways: i) the actual 2006 catches are taken into account, rather than assume the TAC values, ii) the 2007 interim relief tonnage of 175.06 MT is taken into account, and iii) the near shore rights holders TACs are allowed to vary from year to year in a manner similar to the recreational fishers. Johnston and Butterworth (2008) provides more details of these modifications.
  • Thumbnail Image
    Item
    Open Access
    OMP 2007 re-cast to be used for setting TACs for the West Coast rock lobster fishery for the 2008+ seasons
    (2010) Johnston, Susan J; Butterworth, Doug S; Glazer, Jean Patricia
    This document first gives the reasons why the OMP agreed for West Coast rock lobster in 2007 (OMP-2007) was “re-cast” the following year, listing the modifications then introduced. It then provides details of the three main components of “OMP-2007 re-cast”: 1) how data are combined across the five super-areas (Area 1-2, Area 3-4, Area 5-6, Area 7 and Area 8) for input into the OMP; 2) the OMP formulae which provide the global TAC recommendation; and 3) the manner in which the global TAC is split amongst super-areas and resource usergroups
  • Thumbnail Image
    Item
    Open Access
    OMP 2011 re-tuned to be used for setting TACs for the West Coast rock lobster fishery for the 2013+ seasons
    (2013) Johnston, Susan J; Butterworth, Doug S; Brandão, Anabela
    This document provides full specifications of OMP 2011 re-tuned to be used to set allocations for various sectors and super-areas for the 2013+ seasons for the West Coast rock lobster fishery. This OMP is implemented slightly differently for the first season (2011), and also differs from OMP 2011 as intended to be implemented for 2012+. The management objective is to increase the male biomass above 75mm CL by 35% by 2021 relative to the 2006 level in median terms. OMP 2011 re-tuned retains this management objective by adjusting for the TAC set for the 2012 season being higher than recommended under OMP 2011. This document provides details of the three main components of OMP 2011 re-tuned: 1) how data are combined across the five super-areas (Area 1-2, Area 3-4, Area 5-6, Area 7 and Area 8+) for input into the OMP; 2) the OMP formulae which provide the global TAC recommendation; and 3) the manner in which the global TAC is split amongst the super-areas and different sectors.
  • Thumbnail Image
    Item
    Open Access
    Results for final set of candidate OMPs for the new OMP 2011 for West Coast rock lobster
    (2011) Johnston, Susan J; Butterworth, Doug S
    Results of the final set of alternate candidate OMPs are presented here. All results are presented for the full 1000 simulations. The OMP candidates reported here have three main new features compared with the current OMP 2007 re-cast: 1) Allowance of the inter-annual TAC downward constraint to be changed from the baseline 10% to as much as 30% if circumstances require (RULE 1) 2) Allowance for exceptional circumstances to be invoked in a super-area which results in all fishing in that super-area being suspended (EC rule). 3) After the initial total offshore TACs area calculated, a further adjustment is made, where 20% of the offshore A8+ TAC is transferred to A3+4, A5+6, and A7. This 20% removal from A8+ is phased in over four years (i.e. will only be 5% in first season 2011). Each year a fixed 20 MT is given to A5+6, and the remainder of the transferred tonnage from A8+ is split between A3+4 and A7 in a ratio 30:70. The idea underlying the “EC rule” is not to suggest that this complete closure would occur in practice. Rather, what would need happen is an early OMP review with shifting of effort by nearshore, commercial and interim relief/subsistence to other super-areas. The reason underlying presenting calculation results in this extreme form is to demonstrate that if the situation became “so bad” in a super-area, it remains possible to achieve some reasonable extent of recovery by appreciable reductions in future catches from that super-area. Results all assume the “alternative” sector split method proposed, except for one model which shows results for the “current” sector split.
  • Thumbnail Image
    Item
    Restricted
    Results for the new West Coast rock lobster OMP
    (2007) Johnston, Susan J; Butterworth, Doug S
    The results presented here are for the current “best-performing” OMP. Results included using the “observed” 2005 somatic growth data provided by James Gaylard (OLRAC). (Note: 2005 refers to the 2005/06 season.) The OMPs presented here are meant to be tuned so that the average commercial TAC over the 10-year period is either 2000 MT, 2200 MT, 2400 MT or 2600 MT. Due to lack of time, the current tuning is approximate with these values actually being 2030 MT, 2245 MT and 2401 MT and 2596 MT. The OMP presented assumes that 5% of the A8 commercial TAC is transferred to super-areas A34 and A7 with a ratio of 0.20:0.80 respectively. The rationale behind this selection of TAC transfer is to attempt to get a more even spread of resource depletion/recovery across all five super-areas.
  • Thumbnail Image
    Item
    Open Access
    TAC 2008 for West Coast rock lobster using OMP 2007 re-cast
    (2008) Johnston, Susan J; Butterworth, Doug S; Glazer, Jean Patricia
    OMP 2007 re-cast is an adjusted version of OMP-2007 which will be used to set the TACs for the West Coast rock lobster fishery for the 2008 to 2010 seasons (note: “2008” refers to the 2008/9 season) . The results for the anticipated outcomes from application of OMP-2007 re-cast were presented in Johnston and Butterworth (2008).