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Prescott J.,Australian Fisheries Management Authority | Zhou S.,CSIRO | Prasetyo A.P.,Research Center for Fisheries Management and Conservation
Marine and Freshwater Research | Year: 2015

Tropical sea cucumbers are commonly exploited by small-scale, poorly managed fisheries. A fundamental problem in managing sea cucumber fisheries is the lack of basic knowledge of important life history characteristics for most species. As a result of plastic body dimensions, biological research on this group of animals becomes exceptionally challenging. To improve our understanding of essential biological parameters, we conducted a study to investigate correlations among various body measurements. We analysed a total of 18 sea cucumber species and more than 6600 individuals collected at Scott Reef in the Timor Sea, north-west Australia. We used hierarchical Bayesian errors-in-variables models to specifically take into account measurement errors that are obviously unavoidable. The measures included three types of weights (wet weight, gutted weight and dry weight) and two body dimensions (length and width). The modelling reveals that using both body length and width as independent variables, wet weight increases approximately linearly with body length, but is a power function (∼1.6) of body width, although variability exists among species. Dry weight tends to increase more slowly with body length, but has a similar power function of body width. Linear relationships are established between the three types of weights. On average, ∼11% of a live specimen and ∼16% of a gutted specimen is processed to the commercially traded dry body wall. Our results can be applied to sea cucumbers in other areas and can be useful for data standardisation and size-based fisheries management. © CSIRO 2015.


PubMed | University of Western Australia, University of Queensland, Curtin University Australia, Western Australian Museum and 4 more.
Type: | Journal: Scientific reports | Year: 2016

Creating large conservation zones in remote areas, with less intense stakeholder overlap and limited environmental information, requires periodic review to ensure zonation mitigates primary threats and fill gaps in representation, while achieving conservation targets. Follow-up reviews can utilise improved methods and data, potentially identifying new planning options yielding a desirable balance between stakeholder interests. This research explored a marine zoning system in north-west Australia-a biodiverse area with poorly documented biota. Although remote, it is economically significant (i.e. petroleum extraction and fishing). Stakeholder engagement was used to source the best available biodiversity and socio-economic data and advanced spatial analyses produced 765 high resolution data layers, including 674 species distributions representing 119 families. Gap analysis revealed the current proposed zoning system as inadequate, with 98.2% of species below the Convention on Biological Diversity 10% representation targets. A systematic conservation planning algorithm Maxan provided zoning options to meet representation targets while balancing this with industry interests. Resulting scenarios revealed that conservation targets could be met with minimal impacts on petroleum and fishing industries, with estimated losses of 4.9% and 7.2% respectively. The approach addressed important knowledge gaps and provided a powerful and transparent method to reconcile industry interests with marine conservation.


Malcolm H.A.,Australian Department of Primary Industries and Fisheries | Schultz A.L.,Southswell Marine | Sachs P.,Australian Fisheries Management Authority | Johnstone N.,Australian Department of Primary Industries and Fisheries | Jordan A.,Australian Department of Primary Industries and Fisheries
PLoS ONE | Year: 2015

Abundance and length of the highly-targeted snapper Chysophrys auratus were compared between sites in 'no take' areas (Sanctuary Zones: SZ), partial protected areas which are fished (Habitat Protection Zones: HPZ), and areas outside (Outside) the Solitary Islands Marine Park (SIMP), Australia. Baited Remote Underwater Video (BRUV) sampling on shallow rocky reef (15-25 m) was conducted annually from 2002 until 2014 in the Austral-winter, covering the decade after these marine park zones were established (2002). Additional deeper sites (25-40 m) were sampled in 2010-2011 to assess if findings were more-broadly applicable. Lengths were measured using stereo-BRUVs from 2011-2014. Snapper were significantly more abundant in SZ overall and in most years compared with the other two management types, which did not significantly differ. Snapper rapidly increased after 2-3 years protection in all management types, especially SZ. Snapper were present on more SZ deployments than HPZ and Outside after the same period. The positive SZ response in snapper abundance on shallower reef was also found at a broader spatial scale on deeper sites. Again the two fished management types did not show significant differences among each other. There was considerable variation in snapper abundance between years, with strong peaks in 2005, 2009 and 2014 especially in SZ. Abundances remained higher in SZ in the year or two following a strong peak, but decreased to similar abundances to fished areas before the next peak. Snapper length frequency distribution significantly differed between SZ and both fished management types, with more larger snapper within SZ including a higher proportion (58%) that were legal-sized (>25.7 cm FL). HPZ and Outside did not significantly differ from each other, and were dominated by individuals below legal size. Overall, SZ's have positively influenced abundance and length of snapper on these subtropical rocky reefs. © 2015 Malcolm et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


PubMed | Australian Fisheries Management Authority, Australian Department of Primary Industries and Fisheries and Southswell Marine
Type: Journal Article | Journal: PloS one | Year: 2015

Abundance and length of the highly-targeted snapper Chysophrys auratus were compared between sites in no take areas (Sanctuary Zones: SZ), partial protected areas which are fished (Habitat Protection Zones: HPZ), and areas outside (Outside) the Solitary Islands Marine Park (SIMP), Australia. Baited Remote Underwater Video (BRUV) sampling on shallow rocky reef (15 - 25 m) was conducted annually from 2002 until 2014 in the Austral-winter, covering the decade after these marine park zones were established (2002). Additional deeper sites (25 - 40 m) were sampled in 2010-2011 to assess if findings were more-broadly applicable. Lengths were measured using stereo-BRUVs from 2011-2014. Snapper were significantly more abundant in SZ overall and in most years compared with the other two management types, which did not significantly differ. Snapper rapidly increased after 2 - 3 years protection in all management types, especially SZ. Snapper were present on more SZ deployments than HPZ and Outside after the same period. The positive SZ response in snapper abundance on shallower reef was also found at a broader spatial scale on deeper sites. Again the two fished management types did not show significant differences among each other. There was considerable variation in snapper abundance between years, with strong peaks in 2005, 2009 and 2014 especially in SZ. Abundances remained higher in SZ in the year or two following a strong peak, but decreased to similar abundances to fished areas before the next peak. Snapper length frequency distribution significantly differed between SZ and both fished management types, with more larger snapper within SZ including a higher proportion (58%) that were legal-sized (>25.7 cm FL). HPZ and Outside did not significantly differ from each other, and were dominated by individuals below legal size. Overall, SZs have positively influenced abundance and length of snapper on these subtropical rocky reefs.


Prescott J.,Australian Fisheries Management Authority | Vogel C.,Murdoch University | Pollock K.,Murdoch University | Hyson S.,Australian Fisheries Management Authority | And 2 more authors.
Marine and Freshwater Research | Year: 2013

Removal methods were used to estimate key fishery parameters, abundance and exploitation rate for five species of tropical sea cucumbers harvested by Indonesian fishers at Scott Reef, north-western Australia. Detailed catch records were kept by the traditional fishers over a period of 58 days as needed for this method, whereas effort was estimated from aerial surveillance. Concurrently, ∼1007 artificial sea cucumber surrogates, were distributed and rewards were paid for recovered surrogates. Both datasets were analysed using the Huggins closed-population procedure in program MARK to obtain maximum-likelihood estimates. This procedure allowed inclusion of effort and tide covariates and an initial search phase followed by an exploitation phase. We accounted for extreme over-dispersion which is a common problem in fishery removal data. Our results strongly suggested that some surrogates became unavailable to the fishers. However, results from both datasets demonstrated strong evidence of extreme rates of exploitation on the shallow, drying reef-top habitat. Closed-removal or depletion methods are shown to be a viable method to estimate abundance and exploitation rate for sea cucumbers harvested with intense fishing pressure during a short fishing season. Journal compilation © CSIRO 2013.


Prescott J.,Australian Fisheries Management Authority | Riwu J.,Office of Marine Affairs and Fisheries | Stacey N.,Charles Darwin University | Prasetyo A.,Agency for Marine and Fisheries Research and Development
Reviews in Fish Biology and Fisheries | Year: 2016

Traditional fisheries stock assessment methods and fishery independent surveys are costly and time consuming exercises. However fishers trained in data collection and utilising other skills can reduce costs and improve fishery assessments and management. A data collection program was conducted by Australian and Indonesian scientists with small-scale Indonesian sea cucumber fishers to evaluate the approach and then capture its benefits. The data fishers recorded allowed for the first stock assessment of this trans-boundary fishery during its centuries-long existence at Scott Reef in north-western Australia. The program also included interviews with fishers capturing the social, economic, and demographic aspects of the fishery. Economic inputs to fishing were complemented by fishery revenue data voluntarily submitted when fishers returned to port and sold their catch. Catch data recorded by fishers demonstrated much higher abundances than estimates obtained using standard visual transect methods and accurately reflected the true catch composition. However, they also showed extreme rates of exploitation. Interviews revealed social and economic factors that would be important considerations if management interventions were made. The program’s approach and the time scientists spent on the fishers’ vessels were key ingredients to fishers’ participation and the utility of the results. Despite the program’s achievements the information generated has not led to improved management or had any direct benefits for the participants. Sustaining the program in the longer term requires that its value is better captured. © 2016 The Author(s)


Robertson G.,Australian Antarctic Division | Candy S.G.,Australian Antarctic Division | Hall S.,Australian Fisheries Management Authority
Aquatic Conservation: Marine and Freshwater Ecosystems | Year: 2013

Experiments were conducted on two new branch line weighting regimes designed to reduce the risk of seabird mortality in the Australian pelagic longline fishery. The experiments compared the sink rates and fish catch rates of the new regimes with that used by the fishing industry. Baited hooks on gear with a 120g lead weight 2m from the hook reduced the time to reach 2m, 5m and 8m depths by 16%, 58% and 70%, respectively, compared with industry standard gear with 60g at 3.5m. Baited hooks with 40g leads at the hook reduced the time taken to reach 2m, 5m and 8m depth by 33%, 28% and 25%, respectively. The reduction in time with a 60g lead at the hook to these depths was ~40%. There were no statistically detectable differences in catch rates of target and non-target fish between industry standard branch lines and branch lines with both 120g leads at 2m and those with 40g leads at the hook. The results contest the widely-accepted opinion that major branch line modifications, including weight at the hook, reduce fish catch. The regime with a 40g lead at or very close to (i.e. ≤ 0.5m) the hook has the most potential for adoption in fisheries due to: (i) improved crew safety; (ii) ease of port-based inspection for compliance purposes; (iii) reduced construction costs; (iv) reduced bin tangles; and (v) ease of deployment. Lead loss from shark bite-offs can be minimized by placing leads on short (≤ 0.5m) leaders. In areas of moderate to high risk to seabirds, or where the risks are unknown, the use of 60g leads either at or≤0.5m from the hook is encouraged. © 2013 John Wiley & Sons, Ltd.


Barber M.,CSIRO | Jackson S.,Griffith University | Dambacher J.,CSIRO | Finn M.,Australian Fisheries Management Authority
Ecology and Society | Year: 2015

Subsistence remains critical to indigenous people in settler-colonial states such as Australia, providing key foundations for indigenous identities and for wider state recognition. However, the drivers of contemporary subsistence are rarely fully articulated and analyzed in terms of likely changing conditions. Our interdisciplinary team combined past research experience gained from multiple sites with published literature to create two generalized qualitative models of the socio-cultural and environmental influences on indigenous aquatic subsistence in northern Australia. One model focused on the longer term (inter-year to generational) persistence of subsistence at the community scale, the other model on shorter term (day to season) drivers of effort by active individuals. The specification of driver definitions and relationships demonstrates the complexities of even generalized and materialist models of contemporary subsistence practices. The qualitative models were analyzed for emergent properties and for responses to plausible changes in key variables: access, habitat degradation, social security availability, and community dysfunction. Positive human community condition is shown to be critical to the long-term persistence of subsistence, but complex interactions of negative and positive drivers shape subsistence effort expended at the individual scale and within shorter time frames. Such models enable motivations, complexities, and the potential management and policy levers of significance to be identified, defined, causally related, and debated. The models can be used to augment future models of human-natural systems, be tested against case-specific field conditions and/or indigenous perspectives, and aid preliminary assessments of the effects on subsistence of changes in social and environmental conditions, including policy settings. © 2015 by the author(s).


Hobday A.J.,CSIRO | Hartog J.R.,CSIRO | Timmiss T.,Australian Fisheries Management Authority | Fielding J.,Australian Fisheries Management Authority
Fisheries Oceanography | Year: 2010

Reduction of bycatch through spatial management is one possible approach in fisheries management. One requirement is description of the habitat of the species in question, and this is now possible for a range of species using data collected from electronic tags. Here we report on a spatial management approach used to limit unwanted capture of southern bluefin tuna (SBT, Thunnus maccoyii) in the eastern Australia longline fishery. The approach combines a habitat model conditioned with temperature preference data from 56 pop-up satellite archival tags deployed on SBT, and an ocean model to produce near real-time habitat predictions utilized by fishery managers during the fishing season. Three habitat types based on probability of SBT occurrence are identified in the fishing region, and spatial zoning by managers is used to regulate fisher access to these zones. This management approach has been used since 2003, and despite dynamic spatial management often being resisted by fishers or managers because of perceived implementation complexity, there has been an increase in complexity of the management actions over the 6-yr period. Managers now request more habitat predictions each season, update the spatial zoning more frequently, and apply more complicated management lines dividing the habitat types. This has resulted in an improved fit to the modeled habitat predictions, and as catch per unit effort (CPUE) of SBT is related to the habitat type, has contributed to the overall success of the management approach. This implemented management approach illustrates that managers and fishers can successfully implement complex dynamic spatial zoning. © 2010 Blackwell Publishing Ltd.


Dowling N.A.,CSIRO | Dichmont C.M.,CSIRO | Venables W.,CSIRO | Smith A.D.M.,CSIRO | And 3 more authors.
Marine Policy | Year: 2013

Fishery managers are faced with the challenge of maintaining sustainable fisheries at the lowest possible cost while conforming to international and national obligations. Given that fisheries range from low to high value, there is a real need to understand how to trade ecological and economic risks, and the various costs associated with their management, against the benefits from catch. Key to this is an understanding of (a) the costs corresponding to a given level of acceptable risk, or conversely, (b) the change in risk given a change in cost investment. This paper first defines biological, economic and ecosystem risk at a whole-of-fishery level, and then develops a simple model to quantify the trade-offs between risk, cost and catch. Using as case studies Australia's federally managed fisheries that range from data-rich to data-poor, risk was quantified for target species in terms of both their limit and target reference points (defined as "biological risk" and "economic risk", respectively), and for ecosystems in terms of overall ecological impact (defined as "ecosystem risk"). A statistical linear model was used to quantify the risk-cost-catch frontier for each of the three forms of risk. The most parsimonious models were statistically significant for each. However, the management and research costs were mostly positively correlated with risk, indicating that these tended to be reactive to risk, as opposed to risk decreasing in response to increased costs. The only model where this was not the case was for the ecosystem risk, which is probably because these risks have only recently been assessed and the management response to these risks across all the fisheries has so far been limited. For target species risks, it was not possible to develop a model for proactive use. However, the method itself has merit and, if the costs were defined to a greater level of resolution, and/or a time-dynamic modelling approach considered, these issues could potentially be addressed. © 2012.

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