Developing and validating novel methods to estimate age- and size-at-maturity in South Eastern Australian fisheries
We submit this EOI to the priority ‘Biological parameters for stock assessments in South Eastern Australia – a information and capacity uplift’
Empirical observations from around the world have shown that intense fisheries harvest and oceanic warming can both lead to individuals reaching sexual maturity at younger ages and smaller sizes (Waples and Audzijonyte 2016). We know that younger and smaller mothers produce fewer eggs that may be of poorer quality than those from older and larger mothers (Barneche et al. 2018). Further, young mothers often need to build up their energy reserves before spawning each year, meaning that they experience a constrained spawning season. A shorter spawning window reduces the likelihood that their offspring will encounter an environment favourable for growth and survival (Wright and Gibb 2005). Harvest-induced declines in age and size at maturity have, for example, been implicated as one of the main drivers underpinning the collapse of Canadian Atlantic cod stocks (Hutchings and Rangeley 2011).
Environmental stress can also lead to poorer conditioned fish that lack the resources to spawn at all. The prevalence of ‘skip spawning’, as it is known, is hard to ascertain in wild populations but could be as high as 30% of the sexually mature biomass in some years (Rideout and Tomkiewicz 2011). Earlier maturity and skip spawning both have the potential to significantly impact on the biomass of sexually mature individuals in a stock and overall levels of recruitment success. Failure to properly account for these reproductive phenomena can lead to significant under- or over-estimation of SSB, which in turn leads to ineffective management advice that may heighten the risk of stock decline, unnecessarily limit catches, or impede stock recovery.
The rapid warming of southeast Australian waters has already been implicated in driving significant increases in the juvenile growth rates of harvested species, including tiger flathead, redfish and jackass morwong (Thresher et al. 2007, Morrongiello and Thresher 2015). It is plausible that these growth changes (predicted by eco-physiological theory, Atkinson 1994) are linked to commensurate, yet unknown, declines in age and size at maturity. Further, warmer waters may be stressing spawning adults (Portner and Farrell 2008), leading to an increased prevalence of skip spawning in southeast Australian fishes. Importantly, in recent times the biomass of several SESSF species has failed to recover despite significant management intervention. There is a real and pressing need to update the maturity parameters used in assessment models to reduce uncertainty in stock projections.
Our two-part project will refine and validate novel otolith-based methods to estimate an individual’s age at maturity and spawning dynamics from information naturally recorded in its otolith, and then apply this to existing otolith collections. AFMA already invests significant resources into the routine collection of otoliths for ageing purposes. In Part One of our project, we propose to value-add to these existing monitoring programs by developing new maturity and spawning assays that can be readily integrated into stock assessments to reduce model uncertainty and improve harvest strategies (FRDC strategic outcome 2 & 4), in turn bolstering community trust in projections (FRDC strategic outcome 5). In Part Two of our project, we will develop unprecedented insight into the reproductive history of SESSF stocks by recreating time series of maturity using archived otoliths that are currently sitting idle in storage.
Postgraduate students and early career researchers will play a central role in the development and delivery of our project. This experience will help provide a clear pathway for graduates into fisheries science. Our project will bolster the capacity and capability of fish ageing laboratories across Australia to deliver improved monitoring services to fisheries managers (FRDC enabling strategy IV).
More generally, we believe that our novel maturity and spawning assays have the potential to impact on fisheries assessment in other jurisdictions across the world that experience the same time and cost impediments we face here in Australia. Perhaps most excitingly, our assays have the potential to provide much needed maturity information to data poor and emerging fisheries across the Info-Pacific region using information in already collected otoliths.
References
Atkinson, D. 1994. Temperature and organism size: a biological law for ectotherms? Advances in ecological research 25:1-58.
Barneche, D. R., D. R. Robertson, C. R. White, and D. J. Marshall. 2018. Fish reproductive-energy output increases disproportionately with body size. Science 360:642-645.
Hutchings, J. A., and R. W. Rangeley. 2011. Correlates of recovery for Canadian Atlantic cod (Gadus morhua). Canadian Journal of Zoology 89:386-400.
Morrongiello, J. R., and R. E. Thresher. 2015. A statistical framework to explore ontogenetic growth variation among individuals and populations: a marine fish example. Ecological Monographs 85:93-115.
Portner, H. O., and A. P. Farrell. 2008. Physiology and climate change. Science 322:690-692.
Rideout, R. M., and J. Tomkiewicz. 2011. Skipped spawning in fishes: more common than you might think. Marine and Coastal Fisheries 3:176-189.
Thresher, R. E., J. A. Koslow, A. K. Morison, and D. C. Smith. 2007. Depth-mediated reversal of the effects of climate change on long-term growth rates of exploited marine fish. Proc. Natl. Acad. Sci. U.S.A. 104:7461-7465.
Waples, R. S., and A. Audzijonyte. 2016. Fishery-induced evolution provides insights into adaptive responses of marine species to climate change. Front. Ecol. Environ. 14:217-224.
Wright, P. J., and F. M. Gibb. 2005. Selection for birth date in North Sea haddock and its relation to maternal age. Journal of Animal Ecology 74:303-312.
Measuring non-commercial fishing catches (traditional fishing) in the Torres Strait in order to improve fisheries management and promote sustainable livelihoods
Following the initial groundwork to assess community support and approaches for a non-commercial fishery monitoring program in the Torres Strait (Bedford et al 2021 - https://www.pzja.gov.au/sites/default/files/final_report_-_monitoring_the_non-commercial_catch_in_torres_strait_update_06042021.pdf ), the following five steps were proposed:
1. Community consultation and sign on (engaging community re support for the suggested monitoring method).
2. Assess self-reporting web-based tool/APP platform design and development options (including data collection and storage options), through co-design with communities and Government to meet stakeholder needs.
3. Develop self-reporting web-based tool/APP platform, database and data flow infrastructure.
4. Community rollout – pilot (in some communities).
5. Community rollout – full-scale (to all communities).
The Torres Strait Scientific Advisory Committee (TSSAC) recommended that steps 1 and 2 (above) be undertaken first and they form the scope of this proposal.
As also noted in the TSSAC committee meeting of June 2021, the project was an initiative of the quota working group subcommittee of the Torres Strait Regional Authority Board, and identified as a priority by the Traditional Inhabitants (https://www.pzja.gov.au/sites/default/files/tssac_79_meeting_record_final.pdf). In particular, by ‘improving estimates of non-commercial catch of commercial species to inform stock assessment and set sustainable catch levels, as well as determine the catch sharing between the sunset sector, and how much to allocate for community consumption, in order to protect Traditional non-commercial catches and help ensure sustainable management.’
As noted in the ‘Opportunity’ section of this proposal, this project help fill a range of needs for Torres Strait communities, including:
• More accurate assessment of the Recommended Biological Catches of commercial species from all sources of fishing in the Torres Strait
• Reliable assessments of ongoing catches from the substantial non-commercial sectors in the Torres Strait, including knowledge of future change in catches that may be due to pressures from fishing, coastal industry, climate change, other ecosystem regime change
• Stronger ownership of marine resource management by Torres Strait communities, including ownership of non-commercial catch information, and supported by improved knowledge of the temporal and spatial dynamics of non-commercial catches.
The previous project also concluded that a non-commercial fishery monitoring program would have the best chance of success by gaining broad and committed acceptance by local communities and their leaders, with a strong co-design component. The need for this level of consultation was re-iterated by Traditional Inhabitants in several PZJA fishery management fora, including the TSSAC. This project is designed to meet that need.
The proposed project aligns strongly with the Torres Strait Fisheries Strategic Research Plan (https://www.pzja.gov.au/sites/default/files/tssac_srp_2018-2022_post_tssac_final.pdf). In particular:
• Theme 1: Protecting the Torres Strait marine environment for the benefit of Traditional Inhabitants; which is based on improving effective management of fishery stocks in order to support Traditional Inhabitant social and economic needs; which is an expectation of the improved fishery data outputs from the project.
• Theme 2: Social and Economic Benefits; which promotes social and economic benefits for Traditional Inhabitants from Torres Strait fisheries; for example, through increased capacity required to manage the program and increased knowledge of any future changes in catches through space and time in the Torres Strait.
• Theme 3: Technology and Innovation; which promotes the development of technology to support the economic, environmental and social benefits from the fishing sector.
This research project is co funded by the Australian Fisheries Management Authority of the Australian Government. Project co- investigators are Kenny Bedford, David Brewer and Timothy Skewes.
Final report
The long-term sustainability of all fisheries in the Torres Strait region requires reliable catch data from all sectors, including commercial and non-commercial (traditional and recreational). This data is not only a priority for managing key commercial species, such as Spanish Mackerel (Scomberomorus commerson), coral trout (Plectropomus spp) and Tropical (Ornate) Rock Lobster (Panulirus ornatus), also caught by traditional and recreational sectors, but also for the many other traditionally fished species that communities rely on. Commercial fisheries have management programs in place and data contributes to assessments that are central to management decisions. However, fish catches from the traditional and recreational fishery sectors are largely unquantified, except for some historic snapshot surveys and are either currently not monitored, or only in a very limited way. Torres Strait Islanders have expressed concern for their traditional fisheries and the need to protect them to ensure food security needs. Monitoring traditional fishing catches from both traditional and recreational fishing sectors has also been identified as a high priority in numerous Protected Zone Joint Authority (PZJA) fisheries committees over recent years. This project aimed to contribute knowledge to support a future monitoring program to address these data gaps.
The project presents two primary recommendations. The first applies to the development and support of a pilot program for a bespoke traditional fishing app in the Torres Strait (separate from the recreational fishery program); and the second, to support concurrent promotion of the Queensland Government recreational fishing monitoring app (currently using the Qld fishing 2.0 app) program to monitor the Torres Strait recreational fishery.
Project products
Approaches for incorporating Indigenous Rights, practices and catch into resource sharing and harvest strategy frameworks, based on international experiences
Project need from the call for applications (summarised):
Across the globe, First Nations and Indigenous Peoples have been and continue to negotiate recognition of their fishing rights and for their knowledge and interests to be directly accounted for in intersectoral allocation and fisheries management. Recognition of Indigenous fishing rights into current fisheries management, in resource sharing policies and allocation is in various stages of development across Australia's states, territories, and the Commonwealth. At the same time and at the more operational level, harvest strategies are being developed which include Indigenous and cultural fishing, but greater guidance is required regarding harvest strategy settings which recognise the importance and account for the cultural, social, and economic impacts on local abundance and availability of fish stocks for Traditional Owners and local Indigenous communities. However, there is a gap in knowledge of possible approaches to address this, and the ability to generalise is still needed. To this end, this project will undertake a review of approaches and policies developed internationally and domestically for incorporating Indigenous Rights, knowledge, practices and catch (Cultural-Customary and Cultural-Commercial) into resource sharing and harvest strategy frameworks. It will identify possible approaches available for Australian fisheries management agencies, Traditional Owners, and Indigenous communities, while recognising the different historical, cultural, and legal contexts of different jurisdictions.
Summary of UTS approach:
The UTS project team will meet this need through convening a highly experienced team of Indigenous and non-Indigenous researchers, each with relevant expertise and experience in Australia and internationally. The existing work of the research team on multiple Indigenous harvest strategies and Indigenous led natural resource management initiatives will be drawn on to provide a sound basis for a survey of relevant examples. Importantly, senior Indigenous researchers guiding the project already have strong international networks and up to date knowledge on relevant international developments, that will be mobilised to guide this work, and to broker the knowledge and linkages of a range of expert participants into the project.
The research design for this proposal includes a thorough desktop study of the field, including mobilisation of UTS developed databases of specific relevance to the topic area, as well as detailed consultation with Australian and international experts throughout the process. The project will also involve co-production of knowledge with relevant experts/end users, through research activities designed to identify the parameters that influence what approaches are 'fit-for-purpose' in Australian settings.