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The 2004 age-structured production model assessments and projections for the South Coast rock lobster resource

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2004 The assessment conducted in 2003 has been routinely extended, taking account of a further year’s catch, CPUE and catch-at-age data. CPUE shows a continuation of the increase that commenced in 1998. Results are generally more optimistic than ... Read more
The 2005 Age-Structured Production Model assessments and constant catch projections for the south coast rock lobster resource

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2005 The 2005 assessment was routinely extended, taking account of a further year’s catch, CPUE and catch-at-age data. CPUE shows a continuation of the increase that commenced in 1998. However, sustainable yield estimates are generally less than ... Read more
The 2006 age-structured production model assessments and projections for the South Coast rock lobster resource-routine update

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2006 The assessment conducted in 2006 has been routinely extended, taking account of a further year’s catch, CPUE and catch-at-age data. CPUE shows a continuation of the increase that commenced in 1998. The sustainable yield estimates are generally ... Read more
The 2007 Age-Structured Production Model assessments and projections for the South Coast rock lobster resource-routine update using model fitting to catch-at-age data

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2007 The assessment conducted in 2006 (WG/06/06/WCRL3) has been routinely extended, taking account of a further year’s catch, CPUE and catch-at-age data. The observed CPUE shows a slight decrease for 2005 (2005/06 season). The sustainable yield ... Read more
The 2007 age-structured production model assessments and projections for the South Coast rock lobster resource-routine update using Pope's approximation model fitting to catch-at-age data including scenarios for time-varying selectivity

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2007 The assessment conducted in 2006 (WG/06/06/WCRL3) has been routinely extended (except that the Baranov equation has been replaced by Pope’s approximation), taking account of a further year’s catch, CPUE and catch-at-age data. The observed ... Read more
2009 updated stock assessments for West Coast rock lobster

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2009 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 ... Read more
2010 Estimates of sustainable rock lobster yield for the four islands of the Tristan da Cunha group

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2010 A simple replacement yield model is fitted to CPUE and annual catch data from 1997 for the four islands of the Tristan da Cunha group. The results suggest that the current TAC be maintained, with a slight increase (perhaps 5 tons) to the ... Read more c b
2012 South coast rock lobster operating models-some initial results

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2012 Initial updated assessments are developed for the South Coast rock lobster resource incorporating the recently revised estimates of somatic growth rate by area developed by OLRAC, and fitting to area-specific CPUE and scientific catch-at-length ... Read more
2015 updated South Coast Rock Lobster assessment results

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2015 The 2013 assessment of the resource is updated given three further years of data now available. Recruitment is estimated to have been poor over the further three seasons for which this can now be estimated. The spawning biomass trajectory ... Read more
The 2016 Horse Mackerel Assessment Model

Author: Johnston, Susan J ; Butterworth, Doug S Date: Sep 2016 Furman (2014) developed and described the horse mackerel assessment model for his MSc thesis. This document extracts pertinent sections from his thesis which describe the population assessment model, and provides a description of assumptions ... Read more c b
2016 Horse Mackerel projections

Author: Johnston, Susan J ; Butterworth, Doug S Date: Oct 2016 The projections conducted in 2015 are updated to include the further data now available. The results are somewhat more positive than previously as a result of the CPUE for 2015, although still low, being higher than that for 2014. Nevertheless, ... Read more
The 2016 Horse Mackerel Updated Assessment

Author: Johnston, Susan J ; Butterworth, Doug S Date: Sep 2016 FISHERIES/2016/SEP/SWG-DM/51 provides a full description of the current stock assessment model for the South African Horse Mackerel. This document provides the updated 2016 assessment results for a number of model variants. Read more
Addendum to: Bayesian assessments of Southern Hemisphere humpback whale breeding Sub-stocks C1 and C3, including allowance for interchange on the breeding grounds.

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2009 This Addendum adds results for the Migrant and Tourist models to those reported for the Sabbatical and Resident models in the original paper. Results for the C1 sub-stock are hardly affected, but recovery is slightly less advanced for the C3 ... Read more
The Age-Structured Production Model for the south coast rock lobster population

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2005 The south coast rock lobster resource is modelled using an age-structured-productionmodel (ASPM). Read more
The Age-Structured Production Model for the South Coast rock lobster population extended to be sex- and area-specific and to fit to catch-at-length data

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2007 The south coast rock lobster resource is modelled using an age-structured-productionmodel (ASPM) which fits to catch-at-length data directly. The model is sexdisaggregated (m/f) and area-disaggregated (A=1,2,3). Read more
The Age-Structured Production Model for the South Coast rock lobster population extended to be sex- and area-specific, to fit to catch-at-length data, and to use Pope's approximation

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2008 The south coast rock lobster resource is modelled using an age-structured-productionmodel (ASPM) which fits to catch-at-length data directly. The model is sexdisaggregated (m/f) and area-disaggregated (A=1,2,3). Population equations have been ... Read more
The age-structured production modelling approach for assessment of the rock lobster resources at the Tristan da Cunha group of islands

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2011 The stock assessment approach for all four islands of the Tristan da Cunha group is to use an age-structured production model (ASPM) to fit to catch, longline standardised CPUE and catchat-length (CAL) data. The models consider only catches ... Read more c b
Allowing for time-varying selectivity in South Coast rock lobster assessments

Author: Butterworth, Doug S ; Johnston, Susan J Date: 2007 The Reference Case (RC) age-structured production model that has been used for past South Coast rock lobster assessments (ASWS/JUL07/SCRL/ASS/1) has assumed a time-invariant age-specific selectivity function. Previous work allowing the ... Read more
Assessment of the west and east Australian breeding populations of Southern Hemisphere humpback whales using a model that allows for mixing on the feeding grounds and taking account of the most recent abundance estimates from JARPA

Author: Johnston, Susan J ; Butterworth, Doug S Date: 2005 The most recent JARPA survey estimates of abundance are used to update the dynamic production model analyses of West and East Australian humpback breeding populations (Johnston and Butterworth 2002). These analyses take account of the results ... Read more
Assessment results for humpback breeding stocks D, E1 and Oceania following recommendations from SC 65a

Author: Ross-Gillespie, Andrea ; Butterworth, Doug S ; Johnston, Susan J Date: 2014 Following recommendations made at IWC 65a, 2013, a single-stock BSD (Breeding Stock D, West Australia) model has been run for a range of Antarctic catch boundaries, and some two-stock BSE1 (Breeding Stock E1, East Australia)+BSO (Breeding ... Read more

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