A Stochastic Metapopulation Model with Variability in Patch Size and Position

Analytically tractable metapopulation models usually assume that every patch is identical, which limits their application to real metapopulations. We describe a new single species model of metapopulation dynamics that allows variation in patch size and position. The state of the metapopulation is defined by the presence or absence of the species in each patch. For a system of n patches, this gives 2^n possible states. We show how to construct and analyse a matrix describing transitions between all possible states by first constructing separate extinction and colonisation matrices. We illustrate the model's application to metapopulations by considering an example of malleefowl, Leipoa ocellata, in southern Australia, and calculate extinction probabilities and quasi-stationary distributions. We investigate the relative importance of modelling the particular arrangement of patches and the variation in patch sizes for this metapopulation and we use the model to examine the effects of further habitat loss on extinction probabilities

Risk Assessment of Impacts of Climate Change for Key Marine Species in South Eastern Australia. Part 2: species profiles

[Extract] Blacklip and greenlip abalone form the basis of valuable fisheries in Tasmania, Victoria, South Australia and New South Wales (Figure 1.1). The Tasmanian abalone fishery is the largest wild abalone fishery in the world, producing more than 25% of the global catch (Miller et al. 2009). In 2008, the fishery had a gross landed value of $ 90 million. Blacklip abalone (BA), Haliotis rubra, is the predominant species harvested in Tasmania with 2461 t landed in 2008, compared to only 122 t of greenlip abalone (GA), H. laevigata (Tarbath and Gardner 2009). Since 2003, the BA fishery has been divided into five zones: Eastern, Western, Northern, Bass Strait, and Central West (Tarbath and Gardner 2009). The GA fishery is restricted to the north of the state and is managed by regions and separately from the BA fishery. In Victoria, approximately 1,200 t was landed in 2007/08, however, the current TAC is 774 t (2010/11). Catches are dominated by BA (96%) and the fishery is structured into three zones: Western, Central and Eastern. The South Australian fishery harvests approximately 880 t of abalone each year, about 60% of this is BA with the remainder comprising GA. Like Victoria, the South Australian fishery is divided into the Southern, Central and Western zones. Current annual catches in NSW were less than 75 t in 2009/10 and consist exclusively of BA. The commercial fisheries are assessed on a variable combination of commercial catch, effort and size-composition data, fishery-independent surveys and length-structured models. In Tasmania, 105,500 abalone were taken by recreational fishers in 2006/07, weighing an estimated 49 t. The number of recreational licenses has tripled since 1995, with 12,500 recreational diving licenses issued in 2007/08 (Lyle 2008). Recreational catches in SA are small, probably less than 1% of the TACC (Jones, 2009)

Risk Assessment of Impacts of Climate Change for Key Marine Species in South Eastern Australia. Part 2: species profiles

[Extract] Blacklip and greenlip abalone form the basis of valuable fisheries in Tasmania, Victoria, South Australia and New South Wales (Figure 1.1). The Tasmanian abalone fishery is the largest wild abalone fishery in the world, producing more than 25% of the global catch (Miller et al. 2009). In 2008, the fishery had a gross landed value of $ 90 million. Blacklip abalone (BA), Haliotis rubra, is the predominant species harvested in Tasmania with 2461 t landed in 2008, compared to only 122 t of greenlip abalone (GA), H. laevigata (Tarbath and Gardner 2009). Since 2003, the BA fishery has been divided into five zones: Eastern, Western, Northern, Bass Strait, and Central West (Tarbath and Gardner 2009). The GA fishery is restricted to the north of the state and is managed by regions and separately from the BA fishery. In Victoria, approximately 1,200 t was landed in 2007/08, however, the current TAC is 774 t (2010/11). Catches are dominated by BA (96%) and the fishery is structured into three zones: Western, Central and Eastern. The South Australian fishery harvests approximately 880 t of abalone each year, about 60% of this is BA with the remainder comprising GA. Like Victoria, the South Australian fishery is divided into the Southern, Central and Western zones. Current annual catches in NSW were less than 75 t in 2009/10 and consist exclusively of BA. The commercial fisheries are assessed on a variable combination of commercial catch, effort and size-composition data, fishery-independent surveys and length-structured models. In Tasmania, 105,500 abalone were taken by recreational fishers in 2006/07, weighing an estimated 49 t. The number of recreational licenses has tripled since 1995, with 12,500 recreational diving licenses issued in 2007/08 (Lyle 2008). Recreational catches in SA are small, probably less than 1% of the TACC (Jones, 2009)

Mathematical models of metapopulation dynamics / Jemery R. Day.

Bibliography: p. 269-279.viii, 279 p. : ill. ; 30 cm.Thesis (Ph.D.)--University of Adelaide, Dept. of Applied Mathematics, 199

Appendix 8: Quantifying the effects of environmental factors on catch rates in the Southern Eastern scalefish and shark fishery: 1986 to 2006 - Data summary and fits

The collection of basic environmental data by industry members was successful and offers a way of overcoming the problems associated with differences in scale between the environment and fisheries datasets. A simple method of collecting environmental data was developed that was only a small time burden on skippers, yet has the potential to provide very useful information on the same scale as the catch and effort data recorded in the logbooks. The success of this trial was aided by the natural interest of fishers to learn more about the environment in which they fish. The archival temperature-depth tags chosen proved robust, reliable and easy to use. While the use of large scale environmental data may not yield significant improvements in stock assessments for most SESSF species, fine-scale data collected from selected vessels using methods developed during this project may, in the longer term, be useful for incorporation into CPUE standardisations in the future..

Appendix 8: Quantifying the effects of environmental factors on catch rates in South-East fisheries: 1986-2006

The collection of basic environmental data by industry members was successful and offers a way of overcoming the problems associated with differences in scale between the environment and fisheries datasets. A simple method of collecting environmental data was developed that was only a small time burden on skippers, yet has the potential to provide very useful information on the same scale as the catch and effort data recorded in the logbooks. The success of this trial was aided by the natural interest of fishers to learn more about the environment in which they fish. The archival temperature-depth tags chosen proved robust, reliable and easy to use. While the use of large scale environmental data may not yield significant improvements in stock assessments for most SESSF species, fine-scale data collected from selected vessels using methods developed during this project may, in the longer term, be useful for incorporation into CPUE standardisations in the future..

Risk Assessment of Impacts of Climate Change for Key Marine Species in South Eastern Australia. Part 1: fisheries and aquaculture risk assessment

[Extract] The oceans are the earth's main buffer to climate change, absorbing up to 80% of the heat and 50% of the atmospheric carbon emitted. Changes in temperature, environmental flows, ocean pH, sea level, and wind regimes are all contributing to modifications in productivity, distribution and timing of life cycle events in marine species, affecting ecosystem processes and altering food webs. The south-eastern region of Australia has experienced significant oceanographic changes over recent decades and this has been reflected by changes in the associated ecosystems: range extensions have been documented in several dozen species, major distributional shifts have been recorded in barrens-forming sea urchins, bivalves and gastropods, and major declines in rock lobster recruitment have also been related to ocean warming and changing circulation patterns. The major goal of this project was to undertake a screening-level risk assessment of the potential impacts of climate change on key fishery species in the south east Australian region. Thorough literature reviews and species assessment profiles were completed for key species to underpin the ecological risk analyses. Physical drivers of climate change stressors on each fishery species were identified. Wild capture fishery and aquaculture species were ranked aaccording to their need for further assessment of their vulnerability to climate change

Risk Assessment of Impacts of Climate Change for Key Marine Species in South Eastern Australia. Part 1: fisheries and aquaculture risk assessment

[Extract] The oceans are the earth's main buffer to climate change, absorbing up to 80% of the heat and 50% of the atmospheric carbon emitted. Changes in temperature, environmental flows, ocean pH, sea level, and wind regimes are all contributing to modifications in productivity, distribution and timing of life cycle events in marine species, affecting ecosystem processes and altering food webs. The south-eastern region of Australia has experienced significant oceanographic changes over recent decades and this has been reflected by changes in the associated ecosystems: range extensions have been documented in several dozen species, major distributional shifts have been recorded in barrens-forming sea urchins, bivalves and gastropods, and major declines in rock lobster recruitment have also been related to ocean warming and changing circulation patterns. The major goal of this project was to undertake a screening-level risk assessment of the potential impacts of climate change on key fishery species in the south east Australian region. Thorough literature reviews and species assessment profiles were completed for key species to underpin the ecological risk analyses. Physical drivers of climate change stressors on each fishery species were identified. Wild capture fishery and aquaculture species were ranked aaccording to their need for further assessment of their vulnerability to climate change

Rapid assessment of fisheries species sensitivity to climate change

Climate change driven alterations in the distribution and abundance of marine species, and the timing of their life history events (phenology), are being reported around the globe. However, we have limited capacity to detect and predict these responses, even for comparatively well studied commercial fishery species. Fisheries provide significant socio-economic benefits for many coastal communities, and early warning of potential changes to fish stocks will provide managers and other stakeholders with the best opportunity to adapt to these impacts. Rapid assessment methods that can estimate the sensitivity of species to climate change in a wide range of contexts are needed. This study establishes an objective, flexible and cost effective framework for prioritising future ecological research and subsequent investment in adaptation responses in the face of resource constraints. We build on an ecological risk assessment framework to assess relative sensitivities of commercial species to climate change drivers, specifically in relation to their distribution, abundance and phenology, and demonstrate our approach using key species within the fast warming region of south-eastern Australia. Our approach has enabled fisheries managers to understand likely changes to fisheries under a range of climate change scenarios, highlighted critical research gaps and priorities, and assisted marine industries to identify adaptation strategies that maximise positive outcomes