Pre-recruitment abundance indices for eastern king prawn, blue swimmer crab and snapper in south-eastern Queensland

Fisheries Queensland scientists conduct an annual beam trawl survey in south-eastern Queensland to collect information on pre-recruit eastern king prawns, blue swimmer crabs and snapper. After a successful pilot study was completed in 2006, the survey commenced in 2007 and has been conducted every year since, except in 2016. The survey provides an independent estimate of pre-recruit abundance for this time series. This report assessed the analysis methods and mathematical models used to estimate abundance indices for each species, to ensure the results are useful as empirical evidence in species sustainability assessments, periodic stock assessments and for fishery management purposes. The report identifies the most appropriate mathematical models for estimating abundance indices, where and how the indices are currently used and opportunities to value add to the existing survey into the future

Stock assessment of the Australian east coast spotted mackerel (Scomberomorus munroi) fishery 2018

Australian east coast spotted mackerel, Scomberomorus munroi, is a pelagic fish species harvested by commercial, charter and recreational fishers. It forms a single genetic stock in Queensland and New South Wales. The stock is shared with NSW although over 80 per cent of the harvest is from Queensland waters. Spotted mackerel exhibit schooling behaviours that make them susceptible to overfishing. The Queensland commercial line and net fishery operates under a quota system for spotted mackerel (140 tonnes total allowable commercial catch). Recent commercial harvest (2013–2018) was around 64 tonnes per year. Catch shares (in 2013–14) in Queensland were around 55 per cent commercial and 45 per cent recreational. The formal stock assessment was requested to update the status of the stock and inform fishery management agencies and stakeholders on estimates of sustainable harvest that will build and maintain the fishery in the long term. The 2018 stock assessment combined data in an annual age-structured population model tailored for the biology, management and fishing history of spotted mackerel. The age-structured population model analysed 252 scenarios based on different combinations of input data, including harvest histories, age structures, standardised catch rates and considered both high and low estimates of natural mortality. The assessment suggests that the spotted mackerel biomass in 2016–17 is between 40 and 60 per cent of unfished biomass (all sectors and jurisdictions). The assessment provides estimates of the maximum sustainable yield (MSY) and recommends a total allowable catch to rebuild the stock to the Sustainable Fisheries Strategy (SFS) longer term target of 60% unfished biomass (as a proxy for MEY) by 2027

Stock assessment of the Queensland east coast common coral trout (Plectropomus leopardus) fishery. April 2019

Queensland’s common coral trout (Plectropomus leopardus), a species of grouper, is a line caught fish forming a single population (stock) across the Great Barrier Reef (GBR). Common coral trout are protogynous hermaphrodites (born female, many later changing sex to male) and aggregate to spawn during spring and summer. They can grow to 5 kg and 18 years of age. The stock extends north from the GBR into the eastern Torres Strait where it is under Commonwealth jurisdiction. In financial year 2017-18, the Queensland jurisdiction accounted for around 90% of the total harvest. From 2013-14 to 2017-18, the Queensland total harvest averaged 983 tonnes (t) per year. The catch breakdown is 82% commercial (806 t) and 18% recreational (177 t). The previous stock assessment estimated that in July 2012 the stock was at 60% of unfished biomass (i.e. before fishing began) over the areas commonly fished by commercial fishers. This stock assessment updates the existing model to cover the full extent of the GBR in Queensland waters and includes harvest information from the recreational sector. This stock assessment used a spatial age-structured model with a yearly time step based on financial years. The model considered twelve spatial sub-populations (“strata”) of fish based primarily on differences in coral reef habitat. The model incorporated data spanning the period from 1961-62 to 2017-18 (including commercial harvest (1988-89 to 2017-18); historical commercial (1961-62 to 1981-82); recreational harvest (1996-1997 to 2013-14); age monitoring (1994-95 to 2004-05); and underwater visual surveys (1982-83 to 2017-18)). The purpose of this report is to estimate biological reference points. The model provides estimates of the level of biomass of common coral trout relative to unfished levels, maximum sustainable yield (MSY) and the yield consistent with a biomass ratio of 68% (a proxy for maximum economic yield in this fishery)

fisheries and tourism social economic and ecological trade offs in coral reef systems

Coastal communities are exerting increasingly more pressure on coral reef ecosystem services in the Anthropocene. Balancing trade-offs between local economic demands, preservation of traditional values, and maintenance of both biodiversity and ecosystem resilience is a challenge for reef managers and resource users. Consistently, growing reef tourism sectors offer more lucrative livelihoods than subsistence and artisanal fisheries at the cost of traditional heritage loss and ecological damage. Using a systematic review of coral reef fishery reconstructions since the 1940s, we show that declining trends in fisheries catch and fish stocks dominate coral reef fisheries globally, due in part to overfishing of schooling and spawning-aggregating fish stocks vulnerable to exploitation. Using a separate systematic review of coral reef tourism studies since 2013, we identify socio-ecological impacts and economic opportunities associated to the industry. Fisheries and tourism have the potential to threaten the ecological stability of coral reefs, resulting in phase shifts toward less productive coral-depleted ecosystem states. We consider whether four common management strategies (unmanaged commons, ecosystem-based management, co-management, and adaptive co-management) fulfil ecological conservation and socioeconomic goals, such as living wage, job security, and maintenance of cultural traditions. Strategies to enforce resource exclusion and withhold traditional resource rights risk social unrest; thus, the coexistence of fisheries and tourism industries is essential. The purpose of this chapter is to assist managers and scientists in their responsibility to devise implementable strategies that protect local community livelihoods and the coral reefs on which they rely

Coscinaraea marshae corals that have survived prolonged bleaching exhibit signs of increased heterotrophic feeding

Colonies of Coscinaraea marshae corals from Rottnest Island, Western Australia have survived for more than 11 months in various bleached states following a severe heating event in the austral summer of 2011. These colonies are situated in a high-latitude, mesophotic environment, which has made their long-term survival of particular interest as such environments typically suffer from minimal thermal pressures. We have investigated corals that remain unbleached, moderately bleached, or severely bleached to better understand potential survival mechanisms utilised in response to thermal stress. Specifically, Symbiodinium (algal symbiont) density and genotype, chlorophyll-a concentrations, and δ13C and δ15N levels were compared between colonies in the three bleaching categories. Severely bleached colonies housed significantly fewer Symbiodinium cells (p < 0.05) and significantly reduced chlorophyll-a concentrations (p < 0.05), compared with unbleached colonies. Novel Symbiodinium clade associations were observed for this coral in both severely and moderately bleached colonies, with clade C and a mixed clade population detected. In unbleached colonies, only clade B was observed. Levels of δ15N indicate that severely bleached colonies are utilising heterotrophic feeding mechanisms to aid survival whilst bleached. Collectively, these results suggest that these C. marshae colonies can survive with low symbiont and chlorophyll densities, in response to prolonged thermal stress and extended bleaching, and increase heterotrophic feeding levels sufficiently to meet energy demands, thus enabling some colonies to survive and recover over long time frames. This is significant as it suggests that corals in mesophotic and high-latitude environments may possess considerable plasticity and an ability to tolerate and adapt to large environmental fluctuations, thereby improving their chances of survival as climate change impacts coral ecosystems worldwide

Lower Gascoyne land resources survey map sheet 1

Map sheet 1 from - Tille, P J, Smolinski, H J, Wells, M R, Bessell-Browne, J A, Keating, C D, Oma, V P, and Holm, A M. (2003), Lower Gascoyne land resources survey. Department of Agriculture and Food, Western Australia. Report 17.https://researchlibrary.agric.wa.gov.au/lr_images/1051/thumbnail.jp