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Ecosystem-based fisheries management (EBFM) is often termed triple bottom line because it takes into account ecological, economic and social criteria. Effective implementation of EBFM requires development of appropriate governance structures for decision-making processes and management, so governance effectiveness and efficiency can be regarded as the fourth element in a ‘quadruple bottom line.’ Few fisheries have explicitly considered all four criteria within their resource assessments and harvest strategies. Furthermore, as some of these objectives may be in competition (e.g. employment levels, profit), a simultaneous evaluation of these criteria is required to identify the optimal level of fishing to deliver the best overall community outcome. The western rock lobster, Panulirus cygnus , resource in Western Australia is used as an EBFM case study by evaluating: sustainability of target species and effects on ecosystem and protected species; economics of the fishery; effect on employment, coastal communities and quality of recreational fishing; and governance effectiveness including explicit sectoral catch allocations, and the efficiency of monitoring and compliance systems. In 2010 the fishery moved from effort-controlled maximum sustainable yield (MSY) to a quota-controlled, maximum economic yield (MEY) system. This study explicitly examined how different levels of harvesting across the MSY to MEY range affected each of ten EBFM criteria. We confirmed that these individual objectives were maximised at different total allowable commercial catches. However an example is provided for weighting of objectives from a possible management perspective that identified the upper end of the MEY range as likely to generate the optimum outcome for this fishery. [ABSTRACT FROM AUTHOR]

The Shark Bay trawl fishery is Western Australia's most valuable prawn fishery (worth AUD$25 million in 2014). The 18-vessel fleet targets western king prawns ( Penaeus latisulcatus ), brown tiger prawns ( P. esculentus ) and also retains saucer scallops ( Ylistrum balloti ) and blue swimmer crabs ( Portunus armatus ). Increased fuel prices, falling prawn prices and lower catches of other species, following extreme environmental events, have impacted fishery profits. A biomass dynamics model with an economic component indicated that total revenue levels start to decline when annual effort increases beyond ~ 200 fishing days per boat. Annual effort required to achieve MEY, when based solely on prawn fishing, is 115–150 days per boat after accounting for fixed and variable fishing costs and annual fishing efficiency increases of 1–2%. From 2007–2014, the adjusted effort was 188–192 days per boat. Fishing occurred between March and November during 7–8 fishing periods, separated by 5–8 day (low catchability) moon closure periods. An empirical daily profit assessment (2007–2015), accounting for recruitment variation, daily prawn size compositions, monthly market prices for different prawn species and sizes, and daily fishing costs, showed vessels made profits on ~ 115–160 days and losses on ~ 15–55 days per year, when fishing occurred near the full moon. The fishery benefitted in 2013–2015 by starting later in the year and better targeting within-season effort. This management strategy within the effort-control framework, which improved profitability, maintained higher spawning stocks and reduced ecosystem fishing impacts, has wider application in prawn fishery management. [ABSTRACT FROM AUTHOR]

Catch predictions based on pre-recruit abundance have proven valuable in the stock assessment and management of major invertebrate fisheries in Western Australia for western rock lobster (Panulirus cygnus), pearl oyster (Pinctada maxima), abalone (Haliotis roei), prawn (Penaeus esculentus), scallop (Amusium balloti), and blue swimmer crab (Portunus armatus). Predictions are based on puerulus stage (post-larval) rock lobster from artificial collectors; 0+ and 1+ pearl oyster spat attached to commercial shell; dive survey of Roe's abalone; and trawl surveys of prawn (shrimp), scallop, and crab. These reliable predictions (R² = 0.67-0.97) are used in stock assessment and management harvest strategies to ensure that fishing effort or catch quotas are set so that adequate breeding stocks are maintained. This pro-active management based on predicted abundance avoids the pitfall of heavy fishing on poor recruit classes, which is a common cause of recruitment overfishing. The catch-pre-recruit relationship provides valuable information on density-dependent effects between the two life-history stages, with high levels evident in rock lobster and little evidence for prawns and crabs, which reflects the stage at which pre-recruits are measured. The review emphasizes the advantages of catch predictions based on pre-recruit abundance relative to environmental variables and the need for cost-effective pre-recruit monitoring to ensure long-term data. The pre-recruit abundance is valuable in investigating factors affecting year-class strength, including environmental factors and overfishing. The pre-recruit abundance is probably the most valuable information under climate change situations as it provides firm evidence of a change in abundance to justify management action before the change is reflected in the fishery. [ABSTRACT FROM AUTHOR]

Abstract: The western rock lobster (Panulirus cygnus) fishery has been facing significant economic pressure from increasing costs, lower prices as well as predicted reduced catches due to low recruitment. A maximum economic yield (MEY) assessment estimated the fishing effort that would maximise the net present value of profits over 2008/09–2013/14 was about 50%–70% reduction of 2007/08 effort. The assessment accounted for fixed vessel costs and the variable pot lift cost. An important component of this assessment was the use of puerulus settlement time series that provided a reliable predictor of recruitment to the fishery 3–4 years later. This can be contrasted to most MEY assessments that would use an average catch-effort relationship rather than taking into account the expected recruitment. This predictive ability has been particularly useful as there has been a period of unusually low puerulus settlements over the 5 years (2006/07–2010/11) including the lowest two settlements in the 40-year time series. Due to the low settlements, substantial management changes were implemented in 2008/09 and 2009/10 (44% and 73% reduction in nominal fishing effort, respectively compared to 2007/08) to maintain the breeding stock at sustainable levels by having a significant carryover of legal lobsters into future years of lower recruitment. These effort reductions provided a unique opportunity to assess the economic impact of a fishery moving to an MEY effort level over two years. The CPUE increased from 1.1kg/pot lift in 2007/08 to 1.7 and 2.7 in 2008/09 and 2009/10, respectively. These CPUEs were much higher than the expected levels (1.2 and 1.1, respectively) if the 2007/08 effort had been maintained in these two years. The vessel numbers declined by 14% and 36% in 2008/09 and 2009/10, respectively, compared to 2007/08. The fishery profit increased by AUS$13 and 49 million for 2008/09 and 2009/10, respectively, compared to that estimated if the 2007/08 effort level had continued. This assessment demonstrates the economic benefits of fishing at a level close to that estimated for MEY under an input management regime. The management decision-rule framework is currently based on having the egg production above a threshold reference level to ensure sustainability and now a target reference point based on MEY principles is also being considered. [Copyright &y& Elsevier]

An individual-based model, incorporating outputs of a data-assimilating hydrodynamic model, was developed to investigate the role of ocean circulation in the recruitment processes of western rock lobster () during its 9- to 11-month larval phase off the west coast of Australia. During austral summer, strong northward alongshore winds aid the offshore movement of early-stage model larvae from midshelf hatching sites into open ocean; during austral winter, eastward flows that feed the enhanced Leeuwin Current facilitate onshore movement of late-stage larvae towards nearshore habitats. Stokes drift induced by swells from the Southern Ocean is critical to retain larvae off the west coast. Diurnal migration and temperature-dependent growth are also important. Model larvae hatched in late spring - early summer grow faster because of longer exposure to warm summer temperature, which allows them to be transported towards the coast by the strong onshore flows in winter and reduces their natural mortality. Preliminary source-sink relationship indicates that the population was well mixed off the coast, with higher likelihood of settlement success from hatching sites in the north, mostly due to higher surface temperature. Weighted with the breeding stock distribution, the area between 27.5°S and 29.5°S, including the Abrolhos Islands, is the most important hatching area to the success of settlement. [ABSTRACT FROM AUTHOR]

Environmental factors such as the Leeuwin Current (influenced by the El Niño -- Southern Oscillation cycle) and westerly winds in late winter -- spring significantly affect puerulus settlement of the western rock lobster (Panulirus cygnus) fishery. Climate change is causing an increase in water temperature that is seasonally variable, a weakening of westerly winds in winter, and an increase in the frequency of El Niño events. Rising water temperatures over 35 years may have resulted in a decrease in size at maturity and size of migrating lobsters from shallow to deep water, increases in abundance of undersized and legal-sized lobsters in deep water relative to shallow water, and shifts in catch to deep water. The size of migrating lobsters is related to the water temperature about the time of puerulus settlement (four years previously). Climate change effects on puerulus settlement, catchability, females moulting from setose to non-setose, timing of moults, and peak catch rates are assessed. As climate change models project that the warming trend will continue, these biological trends are likely to continue. The changes may have negative (increasing frequency of El Niño events) or positive (increasing water temperature) implications for the fishery, which need to be taken into account in stock assessments and management. [ABSTRACT FROM AUTHOR]

There are several ways to set biological reference points (BRP) for harvest strategies, but one of the most direct methods is to use the stock-recruitment relationship (SRR). Even if the SRR is not statistically significant, it provides valuable information about the spawning stock levels that don't influence the recruitment that is relevant to setting BRP. Environmental factors, particularly extreme events such as the 2011 Western Australia (WA) marine heatwave, are typically a major driver of recruitment, so it is important to assess their influence as ignoring this effect may bias the SRR. This study examines the SRR for 13 invertebrate stocks in WA including lobster, prawn, scallop, abalone, pearl oysters and crabs. These stocks have long time series of fishery-independent juvenile abundance indices, which provide a clear signal of the year-class strength that improves the ability to assess the SRR and environmental effects. Eleven stocks showed a significant environmental effect on recruitment with seven stocks demonstrating a significant spawning stock effect. The stock-recruitment data is used to determine the BRP based on the species' specific biological information, even when the relationship is not significant. Importantly, management action in the harvest control rules is not just reactive to low spawning stock levels but is proactive based on the juvenile abundance to ensure that the level of fishing results in future spawning stocks being maintained above the BRP. This evidence-based approach to setting BRPs and the proactive management approach adopted in the harvest strategy can be invaluable to fisheries management generally. [ABSTRACT FROM AUTHOR]

Edgar, Ward, and Stuart-Smith ([2]) argue that Australian fishery stocks are suffering rapid declines and that to meet sustainability targets an expanded network of "no-fishing" reserves is required. We contend that an assessment based on 11 commercially exploited species, mainly confined to shallow waters within Queensland, is not a sound basis for extrapolating to an Australia-wide assessment of the status of fisheries that cover offshore waters with a wide array of species and habitats. An assessment of the status of Australian fisheries resources is a major exercise and requires evaluating all available information as undertaken in the peer-reviewed SAFS rather than the approach adopted by Edgar et al. ([2]). [Extracted from the article]

Fishing rights and co-management are considered important aspects of fisheries management. But with rights comes a responsibility to contribute data that improves stock assessments and harvest strategies. This responsibility should include contributing data based on fishery-independent surveys (FIS) that provide robust measures of stock abundance and greater confidence in stock assessments, reducing risks to stock sustainability and resulting in more reliable management. FIS conducted with stakeholders provides a direct link between stock abundance indices and their own experience giving them ownership and a better appreciation of stock status. We examine case studies from Western Australian fisheries in four categories: FIS conducted using research vessels; FIS conducted on recreational fisheries using citizen-science; FIS conducted using volunteer industry vessels, and FIS using chartered industry vessels. These FIS cover fisheries with different gear, management, fishing sectors, value and number of participants. The case studies demonstrate that there are a number of ways that FIS designs may be implemented, with each fishery having a unique approach with a common element that they represent standardised surveys. We consider that all fisheries require some type of FIS and this paper discusses options of how this might be achieved. However, FIS can be expensive, so surveys must be cost effective to ensure that they endure. The approach to developing FIS should include collaboration with stakeholders in a co-management agreement. The FIS could be a requirement of having fishing rights and taken into account when developing management arrangements, e.g. allocation of part of the entitlements for a FIS. • Fishers with fishing rights and co-management should support stock surveys. • Survey designs will vary depending on the objectives and fishery characteristics. • Case studies examine surveys with different gear, management, sectors and value. • Fishery-independent surveys must be cost effective to ensure that they endure. • Survey development should be part of co-management and management arrangements. [ABSTRACT FROM AUTHOR]

Abstract: Commercial blue swimmer crab (Portunus pelagicus) catches in Cockburn Sound, Western Australia, have declined significantly since 2000, due to low stock abundance resulting in closure of the fishery in December 2006. The fishery has remained closed for 3 years with predicted catches, based on juvenile recruitment indices, indicating that recovery has been slow. Like many other blue swimmer crab fisheries, management relied on a minimum legal size set well above the size at sexual maturity to allow crabs to spawn at least once before entering the fishery to presumably provide adequate protection to the breeding stock. However, a combination of biological, environmental and fishery-dependent factors contributed to a collapse and include: (1) vulnerability to environmental fluctuations as this species is at the southern extreme of its temperature tolerance, (2) a life cycle contained within an embayment and is self-recruiting, (3) a change in fishing method from gill nets to traps which increased fishing pressure on pre-spawning females in winter and reduced egg production to one age class, (4) four consecutive years of cooler water temperatures resulting in poor recruitment and (5) continued high fishing pressure during years of low recruitment resulting in low breeding stock. The strength of recruitment (juvenile 0+) from the previous season''s spawn (September to January), and the residual stock (1+) near the completion of the current fishing season, have been incorporated in an abundance index that indicates the size of the next season''s breeding stock and predicts the commercial catch. This catch prediction has been used in the development of a draft decision-rule framework for the future management of this fishery to determine the appropriate amount of fishing effort. The application of this approach to research and management may assist the sustainability of other blue swimmer crab fisheries at the extreme of their natural distributions. [Copyright &y& Elsevier]