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Kai Lorenzen - One of the best experts on this subject based on the ideXlab platform.
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trade offs between socioeconomic and conservation management objectives in Stock Enhancement of marine recreational fisheries
Fisheries Research, 2017Co-Authors: Edward V Camp, Sherry L Larkin, Robert N M Ahrens, Kai LorenzenAbstract:Abstract We used an integrated bio-economic model to explore the nature of tradeoffs between conservation of fisheries resources and their use for socioeconomic benefit, as realized through the Stock Enhancement of recreational fisheries. The model explicitly accounted for the dynamics of wild, Stocked, and naturally recruited hatchery-type fish population components, angler responses to Stocking, and alternative functional relationships that defined conservation and socioeconomic objectives. The model was set up to represent Florida’s red drum ( Sciaenops ocellatus ) fishery as a case study. Stock Enhancement produced strong trade-offs characterized by frontiers indicating that maximizing socioeconomic objectives could only be achieved at great losses to conservation objectives when the latter were based exclusively on abundance of wild-type fish. When naturally recruited hatchery-type fish were considered equivalent to wild fish in conservation value, this tradeoff was alleviated. Frontier shapes were sensitive to alternative assumptions regarding how conservation objectives were formulated, differential harvesting of Stocked and wild-type fish, and potential inherent stakeholder satisfaction from the act of Stocking. These findings make more explicit the likely opportunity costs associated with recreational Stock Enhancement and highlight the utility of trade-off frontiers for evaluating management actions.
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marine angler characteristics and attitudes toward Stock Enhancement in florida
Fisheries Research, 2017Co-Authors: Taryn Garlock, Kai LorenzenAbstract:Abstract Fisheries Stock Enhancement, the release of hatchery-reared fish into wild fish populations with the aim of improving fisheries, is a common management strategy of variable success that also involves substantial tradeoffs between fisheries management objectives. We conducted an internet-based survey to assess attitudes towards fisheries Stock Enhancement and other management measures among marine inshore anglers in Florida. A random sample of 200,000 fishing license holders was selected from Florida’s recreational saltwater license holders. The survey received a response rate of 5.2%. The survey was designed to collect information on angler participation, fishing experience, catch preferences and motivations in addition to attitudes toward management options including fisheries Stock Enhancement. The concepts of recreation specialization and consumptive orientation were used to explore diversity in management perspectives and attitudes towards fish Stocking. Hierarchical cluster analysis of five specialization variables was used to identify three groups of inshore anglers. Angler groups had different levels of participation, skill, fishing-related expenditures and management preferences including support for fisheries Stock Enhancement. Inshore anglers were generally supportive of fisheries Stock Enhancement, but less so than many alternative management strategies including habitat restoration and traditional bag and minimum size limits. The most specialized anglers showed significantly higher levels of support for Stock Enhancement and most other management measures than less specialized anglers. Regardless of specialization, anglers were largely unaware of the risks and tradeoffs inherent to Stock Enhancement.
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Stock Enhancement to address multiple recreational fisheries objectives an integrated model applied to red drum sciaenops ocellatus in florida
Journal of Fish Biology, 2014Co-Authors: Edward V Camp, Kai Lorenzen, Robert N M Ahrens, Micheal S AllenAbstract:An integrated socioecological model was developed to evaluate the potential for Stock Enhancement with hatchery fishes to achieve socioeconomic and conservation objectives in recreational fisheries. As a case study, this model was applied to the red drum Sciaenops ocellatus recreational fishery in the Tampa Bay estuary, Florida, U.S.A. The results suggest that Stocking of juvenile fish larger than the size at which the strongest density dependence in mortality occurs can help increase angler satisfaction and total fishing effort (socioeconomic objectives) but are likely to result in decreases to the abundance of wild fishes (a conservation objective). Stocking of small juveniles that are susceptible to density-dependent mortality after release does not achieve socioeconomic objectives (or only at excessive cost) but still leads to a reduction of wild fish abundance. The intensity and type of socioeconomic gains depended on assumptions of dynamic angler-effort responses and importance of catch-related satisfaction, with greatest gains possible if aggregate effort is responsive to increases in abundance and satisfaction that are greatly related to catch rates. These results emphasize the view of Stock Enhancement, not as a panacea but rather as a management tool with inherent costs that is best applied to recreational fisheries under certain conditions.
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potentials and limitations of Stock Enhancement in marine recreational fisheries systems an integrative review of florida s red drum Enhancement
Reviews in Fisheries Science, 2013Co-Authors: Edward V Camp, Kai Lorenzen, Robert N M Ahrens, Luiz R Barbieri, Kenneth M LeberAbstract:In this study, an integrative review of the potential for Stock Enhancement is conducted to support desirable management outcomes in marine recreational fisheries, focusing on the Florida, USA, red drum fishery as a case study. Here, Stock Enhancement is implicitly seen as a way of simultaneously achieving both ecological objectives of sustained wild fish populations and socioeconomic objectives of high fishing effort and/or catch rates. However, the review suggests that a fundamental tradeoff remains between these objectives in the short-term because Stocking of hatchery fish is likely to result in at least partial displacement of wild fish through biological interactions as well as increased fishing pressure. Contrary to the perception of Enhancement as a “quick fix,” successful use of the approach in the marine recreational fishery is likely to require sophisticated Stock management and some adaptation in governance. In developing the Enhancement, it will be necessary to address uncertainty in key attr...
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responsible approach to marine Stock Enhancement an update
Reviews in Fisheries Science, 2010Co-Authors: Kai Lorenzen, Kenneth M Leber, Lee H BlankenshipAbstract:Marine Stock Enhancement is a set of management approaches involving the release of cultured organisms to enhance or restore fisheries. Such practices, including sea ranching, Stock Enhancement, and reStocking, are widespread, of variable success, and often controversial. A set of principles aimed at promoting responsible development of reStocking, Stock Enhancement, and sea ranching has been proposed by Blankenship and Leber [American Fisheries Society Symposia 15: 167–175 (1995)], and has gained widespread acceptance as the ‘Responsible Approach’. Fisheries science and management, in general, and many aspects of fisheries Enhancement have developed rapidly since the responsible approach was first formulated. Here we provide an update to the Responsible Approach in light of these developments. The updated approach emphasizes the need for taking a broad and integrated view of the role of Enhancements within fisheries management systems; using a stakeholder participatory and scientifically informed, accoun...
Shuichi Kitada - One of the best experts on this subject based on the ideXlab platform.
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rigorous monitoring of a large scale marine Stock Enhancement program demonstrates the need for comprehensive management of fisheries and nursery habitat
Scientific Reports, 2019Co-Authors: Shuichi Kitada, Katsuyuki Hamasaki, Kaori Nakajima, Hirotoshi Shishidou, Robin S Waples, Hirohisa KishinoAbstract:Release of captively-bred individuals into the wild is one of the most popular tools in fisheries, forestry, and wildlife management, and introgression of hatchery-reared animals into wild populations is of global concern. However, research and monitoring of impacts on wild populations are generally lacking, and the benefit of hatcheries for long-term fisheries and conservation goals is unclear. Using spatio-temporal genetic monitoring and a four-dacade time series of catch data, we quantified the effects on the size and genetic diversity of wild populations of one of the world’s largest marine Stock Enhancement programs–the red sea bream (Pagrus major) in Kagoshima Bay, Japan. Our analyses found that the Stock Enhancement program reduced genetic diversity of the population, but the genetic effect diminished with increased size of the wild population. Increases to the seaweed communities and reduced fishing efforts were the primary factors associated with the wild population recovery; effects of aquaculture were much smaller. Our results represent crucial evidence that hatcheries for Enhancement and conservation of populations cannot be successful over the long term unless sufficient efforts are also made to reduce harvest rates and rehabilitate natural habitats.
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economic ecological and genetic impacts of marine Stock Enhancement and sea ranching a systematic review
Fish and Fisheries, 2018Co-Authors: Shuichi KitadaAbstract:Hatchery release is one of the most popular management tools in fisheries, forestry and wild life management, while its negative impacts on wild populations are a global concern. Research and monitoring of its impacts are generally lacking, and the usefulness of hatchery release for fisheries and conservation objectives is unclear. Here, I evaluated positive and negative impacts of worldwide marine Stock Enhancement and sea ranching programmes in a systematic review associated with meta‐analyses with the goal of reducing bias of the review. Vast numbers of individuals of more than 180 species are released into the wild each year, but most studies are at experimental stages to assess its potential, and empirical studies are sparse for evaluating the impact on fishery production. Most cases are economically unprofitable except for a few successful cases or unevaluated. The effects of releasing juveniles can be dwarfed by the magnitude of natural recruitment when the spawning Stock produces much larger recruitment than released juveniles. Density‐dependent growth caused by competition of food can be substantial, and growth rates of hatchery and wild fish and other competitive species can simultaneously be reduced when Stocking exceeded the carrying capacity. Relative reproductive success can vary depending on the species, seed quality and environmental factors. Empirical studies show evidence of substantial gene flow from hatcheries, but fitness reduction in Stocked populations has not been reported. The results represent the current state of worldwide marine Stock Enhancement and sea ranching activity and provide key information for growing fields of artificial propagation and conservation.
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Japanese chum salmon Stock Enhancement: current perspective and future challenges
Fisheries Science, 2014Co-Authors: Shuichi KitadaAbstract:This study reviews the present status of the Japanese chum salmon Oncorhynchus keta Stock Enhancement program and considers the ecological sustainability of wild populations while providing fishery production, exemplified by the hatchery-based Kitami region set net fishery. The return rate and the number of returns have been historically high in the Sea of Okhotsk, but have decreased in other regions since 2005. Natural spawning of chum salmon occurred in at least 160 rivers in Hokkaido. The genetic diversity of Japanese chum salmon was similar to or higher than that of other Pacific Rim populations. Numbers of alleles were high at microsatellite loci, but the loss of rare haplotypes was observed in all populations. The estimated N _ e / N ratio for the Kitami region was >0.15 % including hatchery and wild fish under the present high fishing pressure. Four regional populations were inferred in Hokkaido, however, genetic differentiation was weak and some river-populations were nested. Substantial changes in run timing were observed, but it has recovered gradually owing to the recent practice of escapement. Our analyses highlight the importance of juvenile quality and the vital roles of escapements in enhanced and non-enhanced rivers. New research is needed to minimize the genetic risks associated with hatchery programs.
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Catch Fluctuation of Kuruma Prawn, Penaeus japonicus in Japan Relative to Ocean Climate Variability and a Stock Enhancement Program
Reviews in Fisheries Science, 2013Co-Authors: Katsuyuki Hamasaki, Shuichi KitadaAbstract:The kuruma prawn, Penaeus japonicus is widely distributed in the Indo-West Pacific. The Japanese Stock Enhancement program, which produces and releases juvenile kuruma prawns into their natural habitat, started in 1964 and has expanded throughout Japan. The annual number of juveniles released ranged from approximately 240 to 300 million until the mid-1990s but then decreased steadily to approximately 105 million in 2008. National annual landings of kuruma prawns recovered to a record of 3,741 t in 1985 from 1,263 t in 1970 but then declined steadily to the historical minimum of 726 t in 2008. Thus, kuruma prawn catches have decreased dramatically despite the release of juveniles. The aim of this study is to analyze the catch fluctuation of kuruma prawns relative to ocean climate variability and the Stock Enhancement program. The effects of ocean climate on kuruma prawn Stock sizes were evaluated by generalised additive models (GAMs). In the GAMs, catch-per-unit effort and catch data transformed to reduce ...
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A review of seed production and Stock Enhancement for commercially important portunid crabs in Japan
Aquaculture International, 2011Co-Authors: Katsuyuki Hamasaki, Yasuhiro Obata, Shuichi KitadaAbstract:We reviewed the present status of seed production for Stock Enhancement and evaluated the impact of Stocking on commercial catches in Japan, of portunid crabs particularly Portunus trituberculatus and Scylla paramamosain . The mean survival rate from hatching to first-stage crabs was around 10%, and 20–30% of the larval culture trials conducted in recent years could not harvest juveniles during seed production. To achieve reliable mass seed production technologies, measures for controlling disease and the nutritional condition of larvae in seed production tanks are required to be developed. The main spawning season extends from April/May to July. Reflecting their life cycle characteristics such as high growth rates, crabs recruit to the fishery after September and largely contribute to the commercial landings until December in the hatching year. The main release season of juveniles is from June to July. Consequently, released juveniles are expected to contribute to commercial landings in the release year. Analyses of catch and release statistics in two small bays estimated the yield from released individuals (YPR, yield per release) at 2.4 g for P. trituberculatus and 3.3–7.7 g for S. paramamosain , which were similar to values reported from tagging surveys. On a major regional basis, catch and release histories of P. trituberculatus highlighted the impact of hatchery releases on commercial landings as 33.6 g YPR in the Seto Inland Sea, where catches and releases have been greatest. Although the YPR estimates were different between small bays and major regional seas, Japanese Stock Enhancement programmes should have had an impact on portunid crab production, dependent on the magnitude of the releases.
Matthew D Taylor - One of the best experts on this subject based on the ideXlab platform.
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tools and criteria for ensuring estuarine Stock Enhancement programs maximise benefits and minimise impacts
Fisheries Research, 2017Co-Authors: Craig Blount, P Odonnell, K Reeds, Matthew D Taylor, S Boyd, B Van Derwalt, Daryl Peter Mcphee, M Lincoln P SmithAbstract:Abstract New South Wales (NSW) is the first jurisdiction in Australia to approve and implement an ongoing marine Stock Enhancement program. As part of the development and consent process an Environmental Impact Statement (EIS) was prepared, and a management strategy developed to govern the activity in estuaries and control for risks outlined in the EIS. Initially, the EIS developed and used novel tools and criteria to determine which of 158 NSW estuaries were most appropriate to achieve the program’s goals for the seven recreationally-targeted species (4 fish, 2 crab and 1 prawn species). Estuaries within three release regions were selected and ranked using a multi-criteria analysis of 20 factors considered important to the success of Stock Enhancement. Estimation of the trophic impact of released species and estimates of the productivity of the selected estuaries were used to determine release rates at various sizes for the target species. Criteria were established to: (1) ensure best practice broodStock management and genetic quality of released recruits; (2) minimise disease risk through Stock Enhancement; and, (3) maximise social and economic benefits from Stock Enhancement. These tools and criteria fed into the risk assessment in the EIS and guided further controls outlined in the management arrangements for the program. In this paper, we outline this novel approach to development and assessment of Stock Enhancement activities. We discuss the potential application of this framework to marine Stock Enhancement activities in other jurisdictions.
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marine Stock Enhancement reStocking and sea ranching in australia future directions and a synthesis of two decades of research and development
Reviews in Fisheries Science, 2013Co-Authors: N R Loneragan, G I Jenkins, Matthew D TaylorAbstract:This article synthesizes information on marine and estuarine release programs in Australia and evaluates potential opportunities for Stock Enhancement. In Australia, the scale of reStocking and Stock Enhancement programs in marine environments has been low compared with other countries, particularly Japan, China, and the United States. However, since the early 1990s, a number of government and industry organizations have made significant investments in research and development for the release of a variety of species to evaluate the potential of releases to increase the productivity of fisheries. The scale of these research programs has varied from releases of tens of thousands of individuals (abalone Haliotis laevigata, barramundi Lates calcarifer, and mulloway Argyrosomos japonicus), hundreds of thousands (tiger prawns Penaeus esculentus and black bream Acanthopagrus butcheri), and millions (eastern king prawn Penaeus plebejus). These programs, which have shown a strong commitment to the responsible appr...
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using experimental ecology to understand Stock Enhancement comparisons of habitat related predation on wild and hatchery reared penaeus plebejus hess
Journal of Experimental Marine Biology and Ecology, 2010Co-Authors: F A Ochwadadoyle, N R Loneragan, Charles A Gray, Matthew D TaylorAbstract:Marine Stock Enhancement is often characterized by poor survival of hatchery-reared individuals due to deficiencies in their fitness, such as a diminished capacity to avoid predators. Field experiments were used to examine predation on Penaeus plebejus, a current candidate for Stock Enhancement in Australia. We compared overall survival of, and rates of predation on, wild P. plebejus juveniles, naive hatchery-reared juveniles (which represented the state of individuals intended for Stock Enhancement) and experienced hatchery-reared juveniles (which had been exposed to natural predatory stimuli). Predation was examined in the presence of an ambush predator (Centropogon australis White, 1790) and an active-pursuit predator (Metapenaeus macleayi Haswell) within both complex (artificial macrophyte) and simple (bare sand and mud) habitats. Overall survival was lower and rates of predation were higher in simple habitats compared to complex habitats in the presence of C. australis. However, the three categories of juveniles survived at similar proportions and suffered similar rates of predation within each individual habitat. No differences in survival and rates of predation were detected among habitats or the categories of juveniles when M. macleayi was used as a predator. These results indicate that wild and hatchery-reared P. plebejus juveniles are equally capable of avoiding predators. Furthermore, exposure of hatchery-reared juveniles to wild conditions does not increase their ability to avoid predators, suggesting an innate rather than learned anti-predator response. The lower predation by C. australis in complex habitats was attributed to a reduction in this ambush predator's foraging efficiency due to the presence of structure. Ecological experiments comparing wild and hatchery-reared individuals should precede all Stock Enhancement programs because they may identify deficits in hatchery-reared animals that could be mitigated to optimize survival. Such studies can also identify weaknesses in wild animals, relative to hatchery-reared individuals, that may lead to the loss of resident populations.
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complexity affects habitat preference and predation mortality in postlarval penaeus plebejus implications for Stock Enhancement
Marine Ecology Progress Series, 2009Co-Authors: Faith Ochwada, N R Loneragan, Charles A Gray, Iain M Suthers, Matthew D TaylorAbstract:Global attempts to offset declines in fishery populations through Stock Enhancement have had varied levels of success due to the absence of preliminary studies to determine which habi- tats best support release species and the mechanisms controlling their distribution. Habitat prefer- ence was examined as a possible mechanism driving distribution of postlarval Penaeus plebejus, a current candidate prawn for Stock Enhancement in Australia. Occupancy of complex (artificial macro- phyte) and simple (bare sand and mud) habitats by postlarvae was compared in the presence and absence of a choice between the habitats. Predation mortality was also compared amongst these habitats. P. plebejus settled into the different habitats randomly during the night, but actively selected macrophyte over the simple habitats during the day. Mortality caused by the predatory fishes Centropogan australis and Acanthopagrus australis was higher in simple habitats than in com- plex habitats, but was similar across habitats when large penaeid prawns, Metapenaeus macleayi (which are tactile rather than visual feeders), were used as predators. Postlarvae may select macro- phyte habitats during the day to lower predation risk, but because nighttime foraging efficiency is reduced in their predators, which are primarily visual hunters, this may preclude the need of postlar- vae to obtain shelter in macrophyte habitats at night. Predation mortality of Stocked P. plebejus may be minimized by releasing postlarvae directly into macrophyte habitats. Studies such as these must precede all Stock Enhancement attempts because they identify optimal release strategies and allow ecological and financial costs of Enhancement to be weighed against projected benefits, and thereby assess the practicality of Enhancement as a management option.
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responsible estuarine finfish Stock Enhancement an australian perspective
Journal of Fish Biology, 2005Co-Authors: Matthew D Taylor, P J Palmer, D S Fielder, Iain M SuthersAbstract:The responsible approach to marine Stock Enhancement is a set of principles aimed at maximising the success and benefits of artificially re-Stocking depleted fisheries. The benefits of such an approach are evident in the 400% increase in survival of Stocked striped mullet in Hawaii through refinement of release techniques, however financially or temporally constrained Stocking programs in Australia have not adhered to all principles. A pragmatic approach to address these principles is proposed, using international examples and Australian marine finfish pilot Stockings of barramundi, mulloway, sand whiting, dusky flathead and black bream. Biological ranking of candidate species by estuarine residency, a low natural-mortality to growth ratio, a large L∞ and comparison by recreational value and available rearing technologies, show that mulloway, barramundi and sea mullet are ideal species for Stocking in Australia. Australian intermittently closed opening landlocked lagoons and recreational fishing havens, especially near cities, provide experimental opportunities to apply this approach and Stock suitable species through small-scale pilot experiments. This would allow evaluation of production and carrying capacity, and density dependent processes with respect to optimal Stocking strategies unconfounded by emigration and commercial fishing practices. Twenty per cent of Australians fish each year, and harvest approximately 27 000 t of finfish. Stocking recreationally important species in Australia should give a greater financial benefit, which is spread across a larger cross-section of the community, compared to Stocking to enhance commercial fisheries. The pragmatic application of the responsible approach, and Stocking of fast growing estuarine residents into recreational fishing havens would enhance the benefit from marine Stocking.
N R Loneragan - One of the best experts on this subject based on the ideXlab platform.
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marine Stock Enhancement reStocking and sea ranching in australia future directions and a synthesis of two decades of research and development
Reviews in Fisheries Science, 2013Co-Authors: N R Loneragan, G I Jenkins, Matthew D TaylorAbstract:This article synthesizes information on marine and estuarine release programs in Australia and evaluates potential opportunities for Stock Enhancement. In Australia, the scale of reStocking and Stock Enhancement programs in marine environments has been low compared with other countries, particularly Japan, China, and the United States. However, since the early 1990s, a number of government and industry organizations have made significant investments in research and development for the release of a variety of species to evaluate the potential of releases to increase the productivity of fisheries. The scale of these research programs has varied from releases of tens of thousands of individuals (abalone Haliotis laevigata, barramundi Lates calcarifer, and mulloway Argyrosomos japonicus), hundreds of thousands (tiger prawns Penaeus esculentus and black bream Acanthopagrus butcheri), and millions (eastern king prawn Penaeus plebejus). These programs, which have shown a strong commitment to the responsible appr...
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competition between wild and captive bred penaeus plebejus and implications for Stock Enhancement
Marine Ecology Progress Series, 2012Co-Authors: F A Ochwadadoyle, N R Loneragan, Charles A Gray, Iain M SuthersAbstract:The mechanisms that drive density dependence are rarely studied in the applied context of population management. We examined the potential for competition for food and shelter and the resulting demographic density dependence to influence how well populations of the eastern king prawn Penaeus plebejus Hess can recover following marine Stock Enhancement programmes in which captive-bred juveniles are released into the wild. Specifically, manipulative laboratory experiments were used to quantify the differential effects of competition for food and competition for shelter on survival of wild and captive-bred P. plebejus as densities were increased and as each category of P. plebejus (wild or captive-bred) was supplemented with the alternate category. Increasing population densities when food and shelter were limited lowered survival for both categories. When food was limited, survival of both categories was unaffected by addition of the alternative category. Adding wild P. plebejus to their captive-bred counterparts when shelter was limited under laboratory conditions resulted in significantly higher mortality in captive-bred individuals. In contrast, adding captive-bred P. plebejus to wild individuals under these conditions did not affect wild P. plebejus. We conclude that if the current results can be extended to wild conditions, competition for shelter may lead to the loss of captive-bred P. plebe- jus, thereby reducing the intended outcomes of Stock Enhancement. This highlights the impor- tance of investigating interactions between wild and captive-bred animals prior to Stock enhance- ment to predict long-term outcomes and identify situations where Stock Enhancement could be an effective response to the loss of populations or recruitment limitation.
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using experimental ecology to understand Stock Enhancement comparisons of habitat related predation on wild and hatchery reared penaeus plebejus hess
Journal of Experimental Marine Biology and Ecology, 2010Co-Authors: F A Ochwadadoyle, N R Loneragan, Charles A Gray, Matthew D TaylorAbstract:Marine Stock Enhancement is often characterized by poor survival of hatchery-reared individuals due to deficiencies in their fitness, such as a diminished capacity to avoid predators. Field experiments were used to examine predation on Penaeus plebejus, a current candidate for Stock Enhancement in Australia. We compared overall survival of, and rates of predation on, wild P. plebejus juveniles, naive hatchery-reared juveniles (which represented the state of individuals intended for Stock Enhancement) and experienced hatchery-reared juveniles (which had been exposed to natural predatory stimuli). Predation was examined in the presence of an ambush predator (Centropogon australis White, 1790) and an active-pursuit predator (Metapenaeus macleayi Haswell) within both complex (artificial macrophyte) and simple (bare sand and mud) habitats. Overall survival was lower and rates of predation were higher in simple habitats compared to complex habitats in the presence of C. australis. However, the three categories of juveniles survived at similar proportions and suffered similar rates of predation within each individual habitat. No differences in survival and rates of predation were detected among habitats or the categories of juveniles when M. macleayi was used as a predator. These results indicate that wild and hatchery-reared P. plebejus juveniles are equally capable of avoiding predators. Furthermore, exposure of hatchery-reared juveniles to wild conditions does not increase their ability to avoid predators, suggesting an innate rather than learned anti-predator response. The lower predation by C. australis in complex habitats was attributed to a reduction in this ambush predator's foraging efficiency due to the presence of structure. Ecological experiments comparing wild and hatchery-reared individuals should precede all Stock Enhancement programs because they may identify deficits in hatchery-reared animals that could be mitigated to optimize survival. Such studies can also identify weaknesses in wild animals, relative to hatchery-reared individuals, that may lead to the loss of resident populations.
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complexity affects habitat preference and predation mortality in postlarval penaeus plebejus implications for Stock Enhancement
Marine Ecology Progress Series, 2009Co-Authors: Faith Ochwada, N R Loneragan, Charles A Gray, Iain M Suthers, Matthew D TaylorAbstract:Global attempts to offset declines in fishery populations through Stock Enhancement have had varied levels of success due to the absence of preliminary studies to determine which habi- tats best support release species and the mechanisms controlling their distribution. Habitat prefer- ence was examined as a possible mechanism driving distribution of postlarval Penaeus plebejus, a current candidate prawn for Stock Enhancement in Australia. Occupancy of complex (artificial macro- phyte) and simple (bare sand and mud) habitats by postlarvae was compared in the presence and absence of a choice between the habitats. Predation mortality was also compared amongst these habitats. P. plebejus settled into the different habitats randomly during the night, but actively selected macrophyte over the simple habitats during the day. Mortality caused by the predatory fishes Centropogan australis and Acanthopagrus australis was higher in simple habitats than in com- plex habitats, but was similar across habitats when large penaeid prawns, Metapenaeus macleayi (which are tactile rather than visual feeders), were used as predators. Postlarvae may select macro- phyte habitats during the day to lower predation risk, but because nighttime foraging efficiency is reduced in their predators, which are primarily visual hunters, this may preclude the need of postlar- vae to obtain shelter in macrophyte habitats at night. Predation mortality of Stocked P. plebejus may be minimized by releasing postlarvae directly into macrophyte habitats. Studies such as these must precede all Stock Enhancement attempts because they identify optimal release strategies and allow ecological and financial costs of Enhancement to be weighed against projected benefits, and thereby assess the practicality of Enhancement as a management option.
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reStocking and Stock Enhancement of coastal fisheries potential problems and progress
Fisheries Research, 2006Co-Authors: Johann D. Bell, Kai Lorenzen, Devin M Bartley, N R LoneraganAbstract:The demand for fish is expected to rise substantially by 2020. Although aquaculture must provide much of the additional fish, it remains to be seen whether restored or enhanced capture fisheries can also help fill the projected gap in supply. The key challenges for capture fisheries involve reducing fishing effort, removing excess fishing capacity and building the institutional arrangements needed to restore spawning biomass to more productive levels, and to reverse degradation of the supporting habitats. Two interventions, based largely on hatchery technology, have the potential to reduce the time needed to rebuild some severely over-exploited fisheries, or improve the productivity of other ‘healthy’ fisheries. These interventions are ‘reStocking’, which involves releasing cultured juveniles to restore spawning biomass to levels where the fishery can once again support regular harvests, and ‘Stock Enhancement’, which involves release of cultured juveniles to overcome recruitment limitation. However, despite the potential of these interventions, few reStocking and Stock Enhancement programmes have met expectations. The main problems have been a pre-occupation with bio-technical research at the expense of objective analysis of the need for the intervention, and failure to integrate the technology within an appropriate management scheme that has the participation and understanding of the users. The papers presented at the Special Symposium on this subject at the Seventh Asian Fisheries Forum provide a series of valuable lessons to guide objective assessment of the potential for reStocking and Stock Enhancement. They also show how to implement these interventions responsibly and effectively where they are deemed to add value to other forms of management. Above all, these studies demonstrate that reStocking and Stock Enhancement programmes are applied in complex human–environment systems, involving dynamic interactions between the resource, the technical intervention and the people who use it.
Hirohisa Kishino - One of the best experts on this subject based on the ideXlab platform.
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rigorous monitoring of a large scale marine Stock Enhancement program demonstrates the need for comprehensive management of fisheries and nursery habitat
Scientific Reports, 2019Co-Authors: Shuichi Kitada, Katsuyuki Hamasaki, Kaori Nakajima, Hirotoshi Shishidou, Robin S Waples, Hirohisa KishinoAbstract:Release of captively-bred individuals into the wild is one of the most popular tools in fisheries, forestry, and wildlife management, and introgression of hatchery-reared animals into wild populations is of global concern. However, research and monitoring of impacts on wild populations are generally lacking, and the benefit of hatcheries for long-term fisheries and conservation goals is unclear. Using spatio-temporal genetic monitoring and a four-dacade time series of catch data, we quantified the effects on the size and genetic diversity of wild populations of one of the world’s largest marine Stock Enhancement programs–the red sea bream (Pagrus major) in Kagoshima Bay, Japan. Our analyses found that the Stock Enhancement program reduced genetic diversity of the population, but the genetic effect diminished with increased size of the wild population. Increases to the seaweed communities and reduced fishing efforts were the primary factors associated with the wild population recovery; effects of aquaculture were much smaller. Our results represent crucial evidence that hatcheries for Enhancement and conservation of populations cannot be successful over the long term unless sufficient efforts are also made to reduce harvest rates and rehabilitate natural habitats.
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lessons learned from japanese marine finfish Stock Enhancement programmes
Fisheries Research, 2006Co-Authors: Shuichi Kitada, Hirohisa KishinoAbstract:Abstract We examined the efficacy of marine Stock Enhancement for coastal finfish in Japan. To do this, we used four case studies of the red sea bream Pagrus major and the Japanese flounder Paralichthys olivaceus to establish whether hatchery releases augmented total production without replacement of wild fish. The catches by age of released and wild fish showed that hatchery-reared fish contributed 36.4 ± 17.8% to total production of red sea bream and 22.6 ± 11.3% to flounder, respectively. About 50% of the variation in total catches was explained by capture of hatchery-reared fish for red sea bream, and 29–38% for flounder. However, the scope for increased production was limited by carrying capacity, particularly at release sites. Replacement of wild fish by hatchery-reared juveniles was suggested in one case. The comparative analysis of macro-scale catch history revealed that the average contribution of hatchery-reared fish was 9.5% for red sea bream and 11.7% for flounder, and the global dynamics of wild populations does not appear to be linked to Stock Enhancement activities. Our results suggest the need for a cautious approach to Stock Enhancement programmes. We also address the biological potential, the limitations, and the future prospects of marine Stock Enhancement.
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effectiveness of a Stock Enhancement program evaluated by a two stage sampling survey of commercial landings
Canadian Journal of Fisheries and Aquatic Sciences, 1992Co-Authors: Syuiti Kitada, Yasushi Taga, Hirohisa KishinoAbstract:In this study, we evaluated the effectiveness of fish Stock Enhancement programs using a two-stage random sampling survey of commercial landings. Estimators for the total number of fish landed, the ratio of the number of fish released to the total number of fish landed, the recovery rate, and the amount of income were formulated. Variance formulas for these estimators were also derived. In a case study of the flounder fishery, we obtained the conservative estimate of 36 982 recoveries from 246 300 hatchery-reared fish over 3 yr after release. The ratio of the recovery rate to the number of fish released was 0.15. The total income and benefit estimate were $260 000 and $63 000 (U.S.), respectively. We found that the Stock Enhancement program was economically profitable. We also studied several sampling strategies. We recommend that as many markets as possible be surveyed for a minimum number of days because the variation in daily landings among markets was larger than that within markets. Stratification of...
