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Assessing the vulnerability of Torres Strait fisheries and supporting habitats to climate change
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Climate change is considered to be a major environmental threat and there is a national priority to better establish the likely effects of climate change on Australia’s fisheries. Positive and negative impacts of climate change on marine fisheries are already being observed in tropical regions, including the GBR and Pacific. In the Torres Strait region, fisheries impacts are likely to manifest in changes to species stock structure, phenology, distribution shifts, and indirectly through habitat changes. Torres Strait Islanders have a long history of association with their marine resources and fisheries species are of significant cultural, social and economic importance. Any impacts of climate change on marine fisheries stocks and the habitats that support them will affect Torres Strait communities and potentially include changes in the accessibility of target species, changes in the reliability of food supply, and reduced sustainability of fisheries. Therefore, there is an imperative for Traditional Owners, Torres Strait communities, fishers and managers to understand what these impacts are likely to be, which fisheries are expected to be most vulnerable, and to use this information to prepare for negative effects and capitalize on opportunities.We assessed the relative vulnerability of Torres Strait fisheries by conducting a vulnerability assessment on 15 key fishery species. We applied a structured semi-quantitative approach for the vulnerability assessments based on a widely-adopted framework that includes the elements of Exposure, Sensitivity and Adaptive Capacity proposed by the Intergovernmental Panel on Climate Change and United Nations Framework Convention on Climate Change. The assessments were informed by comprehensive literature reviews of Torres Strait climate (observed and projected), key fishery habitats and their vulnerability to climate change, and species reviews for 10 fishery groups that covered fishery characteristics, species life cycles and sensitivity to environmental changes. The assessments were further informed by results of interviews with Torres Strait Islanders.
The results of the vulnerability assessments identified species with high, medium and low relative vulnerability to climate change. The species identified as having the highest relative vulnerability were: black teatfish, black-lipped pearl oyster, dugong, and trochus. When vulnerability was combined with the level of importance of each species to fisheries in Torres Strait (using a measure of cultural and economic value), a priority list of five species was identified for future action by management. These species were: dugong, turtle, tropical rock lobster, trochus and gold-lipped pearl oyster.
This project concludes that there are a number of environmental changes that will be experienced in the Torres Strait by 2030, including habitat impacts that will have flow-on effects on a number of key fisheries. The main drivers are likely to be increases in sea surface temperature, increased severity of storms, and habitat changes particularly to coral reefs and seagrass meadows. The report also provides a range of recommendations on future actions and research that should arise from this project. These are grouped into three themes: (1) improving assessment accuracy, (2) extension of results to communities and decision-makers, and (3) research to address key knowledge gaps.
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... The framework described here for semi-quantitatively assessing vulnerability to climate change builds on this recent thinking to provide a framework for local assessments. The framework has evolved through applications by the author team to ecosystems [22][23][24], national industries and economies [25,26], fisheries [17,27,28], resource-dependent communities [20,26,29], and aquaculture [30]. This evolution has refined techniques for identifying and selecting indicators and for quantifying ecological responses. ...
... For example, in the Torres Strait, Johnson and Welch [20] plotted vulnerability against 'importance' for each component and used Euclidean distances to identify the highest combination of scores, and therefore highest priority components (species). In their SQA, dugong and turtle were ranked as the 3rd and 5th most vulnerable species but increased to the top two species after prioritisation as a consequence of their cultural importance as an indigenous fishery [24]. Further, weightings can be applied to different values as deemed appropriate in the calculation of overall importance values [see 20]. ...
... Torres Strait marine habitats support significant populations of dugongs, green and flatback turtles -species of conservation concern (Sobtzick et al. 2014) -as well as sharks, fish and invertebrate species, many of which are important for local fisheries, such as tropical rock lobster and sea cucumbers (Welch and Johnson 2013 ...
... Collectively, the NERP-funded projects have identified a range of potential impacts on Torres Strait resources from climate change, as well as concerns from communities on the implications for their livelihoods and tropical disease dynamics (see Section 2.3). These results are supported by additional projects that have examined the potential impacts of climate change on Torres Strait resources, including fisheries (Welch and Johnson 2013), seagrass (Coles et al. 2012, McKenzie et al. 2010, Rasheed et al. 2014, and island communities (Parnell et al. 2012, McNamara et al. 2011 including during extreme water level events (Harper 2011). The results from both NERP-funded and other research can be used to inform effective management actions and policy decisions, as well as future research investment. ...
... Black teatfish has been reliably recorded as spawning during winter (April to June) on the GBR (Shiell and Uthicke, 2006) and in New Caledonia (Conand 1993) -although it has also been recorded as spawning during the northern hemisphere summer (April to August) in Guam (Richmond, 1996), and a single record of a Black teatfish male has been recorded as spawning soon after the full moon in December on the GBR (Babcock et al., 1992). Black teatfish are one of the few holothurians that spawn in winter, with this being a key driver for assessments of high vulnerability to climate change for this species (Welch and Johnson, 2013). It may be that some spawning occurs outside the winter established period, with some mature gonads present throughout the year and limited field observations of summer spawning, though only by males (Babcock et al., 1992;Shiell and Uthicke, 2006). ...
This report sets out to provide information that may be suitable for addressing the information requirements of an NDF for Black teatfish and White teatfish in the QSCF. Most of the information was sourced from published scientific papers and reports, from fishery assessment and synthesis reports by the state and federal fishery management agencies, and from fishery commercial vessel logbook and buyer logbook data for the period 20/08/1995 to 6/12/2023 supplied by Queensland Department of Agriculture and Fisheries (DAF). Ashmore and Boot Reefs were not included in the QSCF area until 2019, but were fished under a Queensland Developmental licence (on a 3 year rotation) beginning in 2008-09 – the catches taken under the developmental licence were also supplied by DAF and are included in this analysis.
... Risk and vulnerability assessments are increasingly being used to help prioritize the management of species in the face of climate change and also to investigate the risk of not addressing evident threats (e.g. Fuentes et al. 2011;Welch and Johnson 2013). For example, an integrated climate change risk assessment was applied to sharks and rays in Australia's Great Barrier Reef (see Table 2). ...
Management of marine mega-fauna in a changing climate is constrained by a series of uncertainties, often related to climate change projections, ecological responses, and the effectiveness of strategies in alleviating climate change impacts. Uncertainties can be reduced over time through adaptive management. Adaptive management is a framework for resource conservation that promotes iterative learning-based decision making. To successfully implement the adaptive management cycle, different steps (planning, designing, learning and adjusting) need to be systematically implemented to inform earlier steps in an iterative way. Despite the critical role that adaptive management is likely to play in addressing the impacts of climate change on marine megafauna few managers have successfully implemented an adaptive management approach. We discuss the approaches necessary to implement each step of an adaptive management cycle to manage marine mega-fauna in a changing climate, highlighting the steps that require further attention to fully implement the process. Examples of sharks and rays (Selachimorpha and Batoidea) on the Great Barrier Reef and little penguins, Eudyptula minor, in south-eastern Australia are used as case studies. We found that successful implementation of the full adaptive management cycle to marine mega-fauna needs managers and researchers to: (1) obtain a better understanding of the capacity of species to adapt to climate change to inform the planning step; (2) identify strategies to directly address impacts in the marine environment to inform the designing step; and (3) develop systematic evaluation and monitoring programs to inform the learning step. Further, legislation needs to flexible to allow for management to respond.
Climate change will disrupt relationships between fishers, fisheries and fishing communities in complex ways, with final impacts on well-being highly context-dependent. We highlight these themes through three markedly distinct case-studies: small-scale, artisanal and subsistence-based fisheries of the western Indian Ocean (WIO), fishing of cultural keystone species in the Torres Strait, and commercial fishing in Australia. We note that climate change will affect various fish resources differently and that all impacts will not necessarily be adverse. Confounding factors and dynamic feedbacks will likewise depend on context: in the WIO, population growth and crop failures will further strain limited fish resources; in the Torres Strait, rising sea levels will present acute challenges; while in Australian commercial fisheries, dynamic feedbacks will be chiefly driven by changes in the global fish market. Furthermore, whereas stronger governance will likely protect fish stocks in Australian waters (possibly at the expense of fisheries elsewhere in the world), there is a likelihood of “maladaptation” in the WIO and on the Papua New Guinea side of the Torres Strait. The importance of social and cultural values is evident in each case study. Strategies that leverage these values and help strengthen social capital may have much to offer in a variety of contexts. Although pure notions of economic efficiency encapsulate well-being (formally, “social welfare”), the models that underpin much of fisheries policy incorporate only provisioning services (maximizing economic yield rather than well-being). By incorporating additional values, these models could better promote the long-term viability of a complex and dynamic socio-ecological system.
The region of eastern Australia covers a vast coastline that supports many different fisheries of cultural, economic and social importance. This vast area covers a large range in climate and climate variability and this chapter provides a synthesis of these through case studies of some of the most important fishery species. Reflecting the status of climate change research into Australian fisheries generally, these case studies focus on vulnerability assessments and the current and likely impacts of climate change on these fisheries. These studies provide the basis to inform future adaptation options. These case studies focus on the north-east and south-east regions separately and covers for each species a life history overview, their fisheries characteristics, and their sensitivity to environmental variability. For each region historic and projected climate scenarios are described which informs the summaries of how each species are most likely to be impacted by climate change, the management implications of these impacts and key information gaps for each species. Fisheries of eastern Australia are already experiencing a range of impacts under extremes in climate variability. These are expected to be amplified with longer-term climate projections with some unexpected impacts. This chapter highlights the need for further knowledge on some key species and, also highlights that the need for adaptation planning is in the present.
Climate change impacts on marine fisheries are being observed in tropical regions, including northern Australia and the Pacific. In the Torres Strait, Islanders have a long association with their sea country that holds significant cultural, social and economic importance. Future impacts of climate change on marine fisheries stocks and supporting habitats will affect Torres Strait Islander communities. We assessed the relative vulnerability of 15 key fishery species in Torres Strait using a semi-quantitative framework modified from the Intergovernmental Panel on Climate Change that integrated both ecological and social indicators of exposure, sensitivity and adaptive capacity. The assessment identified species with high, medium and low vulnerability to projected climate change in 2030. The species assessed as having the highest vulnerability were: Holothuria whitmaei (black teatfish), Pinctada margaritifera (black-lipped pearl oyster), Dugong dugon (dugong), and Trochus niloticus (trochus). A separate prioritisation process that considered the cultural and economic value of species identified three high priority species for future management focus: D. dugon, marine turtles (principally Chelonia mydas) and Panulirus ornatus (tropical rock lobster). These results can inform fishers and managers to prepare for the effects of climate change and minimise impacts. The relatively healthy condition of most fisheries in the Torres Strait is likely to assist successful adaptation.
The narrow-barred Spanish mackerel (Scomberomorus conzmerson) is widespread throughout the Indo-West Pacific region. This study describes the reproductive biology of S. commerson along the west coast of Australia, where it is targeted for food consumption and sports fishing. Development of testes occurred at a smaller body size than for ovaries, and more than 90% of males were sexually mature by the minimum legal length of 900 mm TL compared to 50% of females. Females dominated overall catches although sex ratios within daily catches vary considerably and females were rarely caught when spawning. Scomberomorus commerson are seasonally abundant in coastal waters and most of the commercial catch is taken prior to the reproductive season. Spawning occurs between about August and November in the Kimberley region and between October and January in the Pilbara region. No spawning activity was recorded in the more southerly West Coast region, and only in the north Kimberley region were large numbers of fish with spawning gonads collected. Catches dropped to a minimum when spawning began in the Pilbara region, when fish became less abundant in inshore waters and inclement weather conditions limited fishing on still productive offshore reefs. Final maturation and ovulation of oocytes took place within a 24-hour period, and females spawned in the afternoon-evening every three days. A third of these spawning females released batches of eggs on consecutive days. Relationships between length, weight, and batch fecundity are presented.
Food items identified from commercially caught adult Scomberomorus commerson showed that open water pelagic fish formed 66% of the diet with squid and penaeid prawns contributing 18%.-from Author
