Economically optimal management strategies for the South Georgia Patagonian toothfish fishery

The fishery for Patagonian toothfish (Dissostichus eleginoides) around the island of South Georgia in the Southern Ocean is a profitable operation targeting a high-value, slow-growing species. We substituted the complex Bayesian age-structured model currently used for assessments with a Schaefer production model, which performs equally well as an operating model for management strategy evaluation. A number of potential effort reduction strategies are investigated, several of which would achieve better conservation objectives and higher future profits from the fishery than those predicted using the current management strategy. The article also discusses the applicability of this approach to the Australian sub-Antarctic fisheries targeting the stocks of D. eleginoides.bioeconomic model, fisheries, Patagonian toothfish, management strategy evaluation, Resource /Energy Economics and Policy,

The effect of multiple uncertainties on the performance of bioeconomic models for fishery management

An approach known as management strategy evaluation (MSE) provides a framework for identifying robust management strategies in the presence of multiple management objectives and system uncertainties, and has been increasingly used as a practical fisheries management framework in recent years. However, few examples exist that incorporate economics in MSEs. Meanwhile, there has been increased attention given to economic instruments for sustainable management of fishery resources, including the use of bioeconomic target reference points (RPs). However, investigation of the causes of errors and bias in the estimates of bioeconomic parameters is scarcely documented compared to their biological counterparts, and the implications of simplified assumptions concerning both the biological and economic parts of the bioeconomic models have not been adequately investigated. In this thesis, I used three case study fisheries to illustrate how economics can be explicitly integrated within the MSE framework, and demonstrated the usefulness of this flexible approach as a rigorous tool for the evaluation of the effect of uncertainties in key parameter estimates from bioeconomic fisheries models, as well as highlighting the merits of including economics in MSE in general. The interaction between life history characteristics, fisheries variables and economic systems strongly affect the behaviour and robustness of the bioeconomic target RPs for the case studies fisheries. It was clear from these examples that the MSE approach has the potential to radically improve the robust estimation of bioeconomic RPs as well as the construction, evaluation, and implementation of economically-oriented harvest strategies

Price relationships for imported abalone in the Japanese market

The rapid increase in abalone production and importing of farmed products may pose a serious threat to wild abalone producing countries, as it could cause negative pressure on prices. This paper investigates the price relationships for imported abalone in the Japanese market and the implications for wild abalone producing countries, using a co-integration framework. The results indicate that the fresh abalone imports from 6 major countries with different production types (wild or farmed) are within the same market: that is, there is a single market for all imported fresh abalone in the Japanese market, and thus substitution from one to another to some degree. Although no evidence was found for the farmed abalone from South Korea leading the import prices, the existence of a single market suggests that a fall in prices of one product or a country due to increased production can affect the prices of all abalone from other import countries or species in the Japanese market

Profit and equity trade-off in small pelagic fisheries: The case of the Japanese sardine fishery

The importance of small-pelagic species in marine ecosystems and their economic contribution to coastal communities are increasingly recognised by many fishery managers. However, the management of small pelagic species faces many challenges due to environmental factors that periodically impact on recruitment of the species. Delayed responses in management to these fluctuations can amplify the effects of fishing and may even result in collapse of the stock. In this paper, we examine the effectiveness of directly controlling fishing mortality and fishery closure as a means to manage a cyclically fluctuating fish stock. We develop an age-structured bioeconomic model that incorporates cyclic fluctuations in recruitment. The model is parameterised using data from the Japanese sardine Pacific stock (Sardinops melanostictus) fishery which has twice experienced the collapse of the stock since 1900. Results show that duration of the stock collapse period is mostly determined by the extent of environmental fluctuations, while the effects of such fluctuations on the fishery are heightened by the cumulative impact of fishing on the age-structure of the population. Our results further show that the closure of nursery grounds decreases the duration of the stock collapse period, but this is achieved at the expense of the decline in the overall profit of the fishery and intertemporal equality of benefits from the fishery. By contrast, a direct control of fishing mortality results in a shorter collapse period and more equal distribution of fishery benefits over time, but with less overall fisher

Bioeconomic adaptive management procedures for short-lived species: A case study of Pacific saury (Cololabis saira) and Japanese common squid (Todarodes pacificus)

Short-lived fisheries stocks are subject to large fluctuations in abundance and respond rapidly to many factors including changes in oceanographic conditions, biological interactions and fishery exploitation. Management of such species requires a flexible, adaptive framework that responds rapidly to a changing environment, although such schemes are rarely operationalized. In this article, we develop a set of bioeconomic adaptive management schemes that respond to changes in economic conditions, stock abundance and catchability, using as case studies the fisheries targeting short-lived Japanese common squid (Todarodes pacificus) and Pacific saury (Cololabis saira). We suggest that such adaptive schemes have the potential to support the successful implementation of profit maximizing (MEYbased) harvest policies for borderline profitable fisheries targeting short-lived species.Keywords: Posters and Game Demonstration Session and Reception, Fisheries Management, Fisheries Economic

Management strategy evaluation: a powerful tool for conservation?

The poor management of natural resources has led in many cases to the decline and extirpation of populations. Recent advances in fisheries science could revolutionize management of harvested stocks by evaluating management scenarios in a virtual world by including stakeholders and by assessing its robustness to uncertainty. These advances have been synthesized into a framework, management strategy evaluation (MSE), which has hitherto not been used in terrestrial conservation. We review the potential of MSE to transform terrestrial conservation, emphasizing that the behavior of individual harvesters must be included because harvester compliance with management rules has been a major challenge in conservation. Incorporating resource user decision-making required to make MSEs relevant to terrestrial conservation will also advance fisheries science.Output Type: Opinio

Cell growth of Antarctic basidiomycetous yeast on frozen condition

第2回極域科学シンポジウム/第33回極域生物シンポジウム 11月18日（金） 統計数理研究所 3階リフレッシュフロ

De Novo Mutations in GNAO1, Encoding a Gαo Subunit of Heterotrimeric G Proteins, Cause Epileptic Encephalopathy

Heterotrimeric G proteins, composed of α, β, and γ subunits, can transduce a variety of signals from seven-transmembrane-type receptors to intracellular effectors. By whole-exome sequencing and subsequent mutation screening, we identified de novo heterozygous mutations in GNAO1, which encodes a Gαo subunit of heterotrimeric G proteins, in four individuals with epileptic encephalopathy. Two of the affected individuals also showed involuntary movements. Somatic mosaicism (approximately 35% to 50% of cells, distributed across multiple cell types, harbored the mutation) was shown in one individual. By mapping the mutation onto three-dimensional models of the Gα subunit in three different complexed states, we found that the three mutants (c.521A>G [p.Asp174Gly], c.836T>A [p.Ile279Asn], and c.572_592del [p.Thr191_Phe197del]) are predicted to destabilize the Gα subunit fold. A fourth mutant (c.607G>A), in which the Gly203 residue located within the highly conserved switch II region is substituted to Arg, is predicted to impair GTP binding and/or activation of downstream effectors, although the p.Gly203Arg substitution might not interfere with Gα binding to G-protein-coupled receptors. Transient-expression experiments suggested that localization to the plasma membrane was variably impaired in the three putatively destabilized mutants. Electrophysiological analysis showed that Gαo-mediated inhibition of calcium currents by norepinephrine tended to be lower in three of the four Gαo mutants. These data suggest that aberrant Gαo signaling can cause multiple neurodevelopmental phenotypes, including epileptic encephalopathy and involuntary movements

Neural stem cells exposed to BrdU lose their global DNA methylation and undergo astrocytic differentiation

Bromodeoxyuridine (5-bromo-2′-deoxyuridine, BrdU) is a halogenated nucleotide of low toxicity commonly used to monitor DNA replication. It is considered a valuable tool for in vitro and in vivo studies, including the detection of the small population of neural stem cells (NSC) in the mammalian brain. Here, we show that NSC grown in self-renewing conditions in vitro, when exposed to BrdU, lose the expression of stem cell markers like Nestin, Sox2 and Pax6 and undergo glial differentiation, strongly up-regulating the astrocytic marker GFAP. The onset of GFAP expression in BrdU exposed NSC was paralleled by a reduced expression of key DNA methyltransferases (DNMT) and a rapid loss of global DNA CpG methylation, as we determined by our specially developed analytic assay. Remarkably, a known DNA demethylating compound, 5-aza-2′-deoxycytidine (Decitabine), had similar effect on demethylation and differentiation of NSC. Since our key findings apply also to NSC derived from murine forebrain, our observations strongly suggest more caution in BrdU uses in stem cells research. We also propose that BrdU and its related substances may also open new opportunities for differentiation therapy in oncology