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South eastern Australia is a global warming hotspot, and is also home to ~70% of Australia's population and one of Australia's largest fisheries—the South East Scalefish and Shark Fishery. This fishery spans shelf to deep waters, subtropical to temperate waters, employs many gears, and interacts with over 100 species. Despite following best practice fisheries management principles, including taking an ecosystem perspective to overall fisheries interactions, management interventions have failed to arrest or recover the decline of some focal species. Using an Atlantis ecosystem model developed for the fishery over the past 20 years, this paper presents simulations that suggest climate change may be a major contributor to the trajectories seen for a number of species—such as jackass morwong (Nemadactylus macropterus), blue warehou (Seriolella brama), and gemfish (Rexea solandri). This kind of climate influence poses many challenges for fisheries management into the future, raising questions about what to do when climate change undermines or overrides fisheries management actions and objectives. [ABSTRACT FROM AUTHOR]

Fishery-independent scientific surveys are highly valuable for monitoring lobsters and other fisheries. Yet, there are relatively few long-term monitoring surveys to support the provision of management advice. A number of challenges can prevent the continuity of long-term monitoring series. This paper uses the 35-year continuous annual dive surveys for Australia's Torres Strait tropical rock lobster (TRL) to overview strengths and limitations of a long-term scientific survey, as well as lessons learnt from having overcome a range of challenges. Fishery-independent surveys are more reliable than fishery-dependent data and are more robust to external shocks such as market drivers and fuel prices. The primary purpose of the surveys is to provide a reliable index of stock abundance together with data to inform on size and age structure, plus model parameters and reference points. Here, we also highlight additional survey benefits including: yielding positive gains relative to cost, facilitating an adaptive management approach that serves as an early warning system, reducing and resolving inter-sector conflicts, reduced frequency of stock assessments, providing data from associated habitat monitoring, improved stakeholder buy-in, utility for development of Operating Models for Management Strategy Evaluation, contribution to achieving certification, contributing to biodiversity agreements and consistent cross-jurisdictional monitoring. We analyse lessons learnt from challenges such as changes in resource management, budget cuts, increased health and safety requirements, maintenance of capability and staff capacity, stakeholder buy-in, need to validate survey results, a pandemic and changing climate. Our experiences highlight why long-term scientific surveys are considered the gold standard for fisheries monitoring and we provide insights for building and maintaining key marine monitoring series. [Display omitted] • Fishery-independent surveys are valuable but challenging to maintain long-term. • Challenges include costs, capacity, management changes, COVID19, climate change. • Survey data robust to extreme events and external system shocks. • Benefits include reliability, positive benefit:cost, habitat data, science buy-in. • Long-term scientific surveys considered the gold standard for fisheries monitoring. [ABSTRACT FROM AUTHOR]

Responsible stock enhancement initiatives require baseline data of wild population demographic conditions that can be used in testing management outcomes. This study provides the first fishery-independent assessment of length- and age-based biological characteristics of exploited populations of Platycephalus fuscus in eastern Australia prior to stock enhancement. Sampling was conducted over seven estuaries spanning seven degrees of latitude and the geographical range of proposed stock enhancements. Populations in all estuaries showed evidence of length and age truncation, especially those subject to commercial fisheries where young individuals of both sexes dominated populations. Maximum longevities were 12 and 11 years for females and males respectively, but few females >5 years and males >3 years were generally sampled. Females dominated populations, and on average, the mean lengths and ages of females were greater than males within each estuary and across all age classes. Sexually dimorphic variation in growth was evident across all estuaries, with females attaining greater maximum lengths than males. Estuary-specific differences in individual growth were not identified. On average, over 50% of females sampled in each estuary were > the minimum legal length (MLL), but the opposite was evident for males. In contrast, over 25% of males in each estuary were > the mean length at maturity (L50), whereas in all but one estuary <13% of the females were > the L50. Stocked male and female P. fuscus should recruit to the fishery in 2 and 3 years, and contribute to the spawning stock in 1.5 and 4.5 years, respectively. This study provides important historical baseline data that can contribute to testing stock enhancement outcomes on populations. [ABSTRACT FROM AUTHOR]