A better understanding of the impacts of environmental drivers on the population dynamics and abundance of key fishery species can inform flexible management decisions that pre-empt both risks of overfishing under adverse environmental conditions and opportunities for increased harvest under favourable conditions. This is increasingly important as shifting environmental dynamics drive geographical shifts in fish stocks.
This project will identify environmental variables influencing the abundance of three priority fishery species, quantify those relationships to enhance their stock assessment models, and develop a forward projection tool to inform adaptive management of each fishery. Target species - Spanner Crabs, Snapper and Pearl Perch – were selected based on key interest to management of fisheries in Queensland and NSW. Some associations between these species and certain abiotic environmental factors are already known, but there is yet to be a rigorous and comprehensive approach to this work, with the explicit goal of incorporating abiotic influences into Queensland and NSW stock assessments.
The project has three key objectives: (1) Find indices of association between measures of abundance and key environmental drivers; (2) Use these indices to enhance the existing stock assessment model for each species; and (3) Enable forecasting of environmentally driven fluctuations in targeted species’ abundance, including enhancing Management Strategy Evaluations (MSEs).
In particular, environmental correlates will be valuable to fisheries managers by: (a) reducing the uncertainty in biomass estimates, (b) explaining fluctuations in abundance, and (c) characterising what is a “bad year” for each species. Such information can be incorporated into MSEs.
The “Queensland Sustainable Fisheries Strategy 2017-2027” identifies several challenges to fulfilling its mission of ensuring the sustainability of fisheries and the economic viability of fishing sectors. The first of these is “gaps in monitoring and research, which limit the ability to make timely, evidence-based decisions”. This project will close some of these gaps and assist in formulating measures for promoting stock recovery and adaptive management.
This project studied environmental factors which may be influencing the recruitment, catchability or productivity of Snapper, Pearl Perch, and Spanner Crab stocks in Queensland. Two environmental variables: GSLA and Chl-a were found to have strong associations with either abundance or catchability across the three target species. These associations occurred at spatio-temporal scales relevant to each species’ biology. A third variable, SST, also had strong associations with Snapper.
Importantly, all three of these environment variables, GSLA, SST and Chl-a were found to have certain consistent long-term trends, with rates of change depending somewhat on the region under consideration. We demonstrated that incorporating these environmental variables into simple surplus production stock assessment models results, under some scenarios, in delays in stock recovery. This assumed that the above trends of GSLA, SST and Chl-a are sustained and the direction and strength of the identified associations are maintained.
Understanding the demographic characteristics, connectivity and stock structure of a fish species is crucial for identifying the appropriate scale and strategy for management.
Black bream is a slow growing and long-lived finfish species with reproduction confined to estuarine habitats. It is distributed in the estuaries and inshore marine waters of southern Australia, from central NSW to central west coast WA, including Tasmania. Throughout its broad distribution, black bream is thought to be composed of a number of isolated spawning stocks, with limited evidence of movements between estuaries.
In SA, black bream supports important commercial fisheries, and is highly sought-after by recreational anglers. Most of the State-wide commercial catch is taken by the Lakes and Coorong Fishery (LCF) in the Coorong estuary, with smaller contributions taken by the Marine Scalefish Fishery. In 2016, the LCF for black bream, which was historically one of Australia’s most productive black bream fisheries, was classified as ‘overfished’. It is unknown whether this status is reflective of the broader population in SA waters, or if current management arrangements for the Coorong population, which are aimed to promote stock recovery, are adequate in terms of the spatial scale that they apply.
There is a need to understand the demography, connectivity and stock structure of black bream populations across southern Australia (SA, VIC and WA). This information will assist in identifying appropriate scales and strategies for management.
‘People development’ is one of several priorities identified in the FRDC’s RD&E Plan 2015-20. The proposed project will be undertaken by a high-performing student as a PhD project. The student will undertake applied research relevant to FRDC stakeholders (scientists, fishery managers, commercial, recreational and indigenous fishers) in SA, and gain industry experience by being co-supervised by scientists from SARDI. The project will increase fisheries science capacity in SA through training of the next generation of researchers.
Much effort has been placed over the last couple of decades on the development of harvest strategies, stock assessments, risk assessments and the strategic use of ecosystem models to facilitate meeting the needs of the Commonwealth’s Harvest Strategy Policy. A focus on modelling to improve fisheries management has required effort towards method development. However, little effort has been made towards revisiting and updating the biological parameters that fundamentally underpin such modelling (e.g. growth rates, age and size at maturity, natural mortality rates, dietary information, mixing rates and stock structure) and the tools or methods used to derive them. As a result, most models now rely on parameters and community dietary data derived from information collected during the 1970s-1990s, (e.g. available maturity ogives for blue-eye trevalla are over 20 years old), or information that is borrowed from other regions or species. Whether such old or borrowed values are now representative for commercial Australian fish species is unknown but many factors point to major changes occurring in our marine environment. Australian waters in the south east and south west are climate hotspots and, overall, Australian waters have warmed faster than the global average. Key components of the productivity of marine fish (growth, maturity, and recruitment) are expected to be undergoing directional changes under a changing climate and it is entirely possible that there have been changes in fundamental productivity parameters for some Australian stocks. The reliance of current assessments on what is likely to be out-of-date information leads to increased uncertainty, which propagates into management decisions. Without an understanding of any changes in biological parameters and how any change might impact assessment frameworks, determining whether current management measures are ensuring sustainability becomes highly uncertain.
The 2012/2015 & 2017 National Recreational Fishing Conferences were highly successful, enabling the recreational fishing community to gather and discuss issues of national importance. These events also catalysed four initiatives to advance fishing in Australia: development of a charter for the sector, a national fish habitat rehabilitation plan, and renewed commitment to communicating social benefits of fishing, and delivering leadership development initiatives.
The value of regular fishing sector conferences is recognised among the fishing community, and supported by FRDC, to facilitate continued progress, coordination and recognition of achievements. The next national event for the recreational fishing community is planned for 2019.
The primary aim of this event will be to engage the largest cross-section of Australia's recreational fishing community possible in discussing key issues of relevance to their sector, developing a shared vision for the future and agreeing upon strategic actions to pursue this vision. The 2019 event will be re-focused to more directly benefit grassroots recreational fishers, involving a new format, lower cost to participants, higher levels of involvement of well-known fishing personalities in the program, a focus on increased levels of participant interaction in discussions, and a series of events designed to be both informative and entertaining. The revised approach and program of this event will seek to deliver engagement of the broader recreational fishing community on a scale not previously achieved in Australia.
