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This study investigated the effects of applications of international quality assurance certification at farm level on the implementation of traceability along the shrimp supply chain with evidence from Vietnam. Descriptive statistics was explored to compare products, information flows, financial efficiency, and willingness to implement traceability between certified and noncertified quality assurance shrimp farms. A binary logistics model was applied to examine the effects of applications of international quality assurance certification and other factors on the willingness to implement traceability of shrimp farmers. Found results showed that the applications of international quality assurance certification of shrimp farmers supported traceability of shrimp products among stakeholders in the supply chain. The certified farmers indicated a higher willingness to implement traceability. However, the profitability of those applications for shrimp farmers was not statistically found. The economics incentives, including farm-gate price differentiation and minimization of production costs, should be carefully considered.

Even though the cetacean tapeworm Diphyllobothrium stemmacephalum occurs in both cold and warm waters, human infections and final host occurrences have been confined to temperate areas in and near Japan. We recently obtained a strobila of this cestode that was excreted from a harbor porpoise accidentally caught offshore of Hokkaido of northern Japan. Genetic analysis of 28S rDNA and cox1 genes confirmed that the cestode was D. stemmacephalum. Our finding sets the northernmost record of D. stemmacephalum in the western Pacific, suggesting that the risk of human infections by this parasite in northern Japan deserves further attention.

Even though the cetacean tapeworm Diphyllobothrium stemmacephalum occurs in both cold and warm waters, human infections and final host occurrences have been confined to temperate areas in and near Japan. We recently obtained a strobila of this cestode that was excreted from a harbor porpoise accidentally caught offshore of Hokkaido of northern Japan. Genetic analysis of 28S rDNA and cox1 genes confirmed that the cestode was D. stemmacephalum. Our finding sets the northernmost record of D. stemmacephalum in the western Pacific, suggesting that the risk of human infections by this parasite in northern Japan deserves further attention.

The genus Anisakis is a well-known group of nematodes that parasitize cetaceans as the final host and cause mucosal damage to their stomach. However, little has been done to precisely identify the nematodes recovered from the final hosts, especially in the Western Pacific, because of taxonomic confusion about the discrimination of sibling species and the difficulties of obtaining specimens from cetaceans. We describe the results of genetic identification and histopathological observations of specimens recovered from an ulcerated lesion and stomach contents in the forestomach of a female harbor porpoise accidentally caught by a set net fishery in Usujiri, southern Hokkaido, Japan. All the specimens arbitrarily collected from the lesion and stomach contents were identified as Anisakis simplex sensu stricto according to their ITS rDNA sequences. The size of the ulcer was approximately 6.3 mm in diameter and it was infected with 119 individual nematodes, mostly consisting of L3 and L4 stage larvae (95.0%). Histological sections were characterized by a locally extensive ulcer with the parasites penetrating into the muscularis externa that caused a thickening of the surrounding mucosa.

Bycatch of harbour porpoises (Phocoena phocoena) by gillnets is a recognised threat to populations. To develop effective mitigation measures, understanding the mechanics of bycatch is essential. Previous studies in experimental conditions suggested foraging activity is an important factor influencing porpoises’ reaction to gillnets. We acoustically observed the behaviour of wild harbour porpoises around a bottom-gillnet set-up in a commercial fishing ground, especially foraging activity. Passive acoustic event recorders (A-tags) were fixed to the ends of the gillnet, and recorded for 1 392 hours. Although harbour porpoises frequently and repeatedly appeared around the net each day, incidental bycatch occurred only three times during the observations. The stomach contents of two individuals contained mainly Ammodytes sp., which were observable around the bottom-gillnet but not targeted by the fishery. A total of 276 foraging incidents were acoustically detected, and 78.2% of the foraging activity was in the bottom layer (deeper than 25 m). Porpoises appeared around the net with more frequency on the day of a bycatch incident than on the days without bycatch. These results suggest that the harbour porpoises appeared around the bottom-gillnet to forage on fish distributed in the fishing ground, but not captured by this bottom-gillnet. Thus, porpoises face the risk of becoming entangled when foraging near a gillnet, with the probability of bycatch simply increasing with the length of time spent near the net. Bycatch mitigation measures are discussed.

Traceability is considered the most important requirement for shrimp products exported to global markets. However, implementing traceability in shrimp-exporting countries is challenging because of limited production at the local supply chain and lack of financial welfare awareness. This study aims to investigate the expected farm-gate price for traceability implementation using a double-bound dichotomous choice experiment. The censored regression model is used to estimate the factors influencing the anticipated farm-gate price of shrimp farmers. The survey was conducted in Ca Mau Province, Vietnam, by interviewing 71 Penaeus monodon Fabricius, 1798, and 43 Penaeus vannamei Boone, 1931, farmers. To implement traceability, P. monodon farmers estimated the farm-gate price at 10.17 USD.kg-1, while P. vannamei farmers expected 6.18 USD.kg-1. Application of international quality assurance certifications, willingness to implement traceability, land used, culture methods, shrimp species, current farm-gate price, and variable costs affected the expected farm-gate price. The attractive anticipated farm-gate price compensated for the negative influence of applying international quality assurance certifications, indicating that the farmers were willing to implement traceability. This suggests that the application of certifications increased the ability to implement traceability in the shrimp supply chain. The attractive farm-gate price for certified shrimp products would enhance their willingness to implement the traceability of shrimp products.

Fixed closure (FC) is a standard fisheries management tool for protecting sensitive species or species requiring conservation. However, an FC might not effectively manage migratory species because of the large uncertainties of their migration. Adaptive real-time closure (ARTC) is a tool that updates closure areas according to the latest information. This study aimed to evaluate the effectiveness of ARTC to conserve sensitive species for data-limited fisheries by a series of simulations using migration models with hotspots. In the single species simulation, the conservation ratio for the sensitive species in FC varies widely at greater migration uncertainty. In ARTC, a longer duration of a hotspot resulted in a higher conservation ratio. When the mean duration of hotspots was medium or long, the conservation ratio for the sensitive species was more than 50 % in more than 99 % of the simulation trials. In multispecies fisheries, a clear trade-off was observed between the conservation ratio of sensitive species and other species. ARTC was more effective than whole closure when the proportion of sensitive species was high or without closure when the proportion was low. Conditions in which ARTC was most appropriate were described for hotspot duration, increased numbers of individuals in a hotspot, and the relative value of conservation, representing the ratio of the value of conserving sensitive species to one of catching other species.

The genus Anisakis is a well-known group of nematodes that parasitize cetaceans as the final host and cause mucosal damage to their stomach. However, little has been done to precisely identify the nematodes recovered from the final hosts, especially in the Western Pacific, because of taxonomic confusion about the discrimination of sibling species and the difficulties of obtaining specimens from cetaceans. We describe the results of genetic identification and histopathological observations of specimens recovered from an ulcerated lesion and stomach contents in the forestomach of a female harbor porpoise accidentally caught by a set net fishery in Usujiri, southern Hokkaido, Japan. All the specimens arbitrarily collected from the lesion and stomach contents were identified as Anisakis simplex sensu stricto according to their ITS rDNA sequences. The size of the ulcer was approximately 6.3 mm in diameter and it was infected with 119 individual nematodes, mostly consisting of L3 and L4 stage larvae (95.0%). Histological sections were characterized by a locally extensive ulcer with the parasites penetrating into the muscularis externa that caused a thickening of the surrounding mucosa.

Groupers (family Epinephelidae, subfamily Epinephelinae) are reef fishes of high value as food resources that generate export revenue to Sri Lanka. Yet, with less attention and poor resource management, grouper population dynamics remain understudied. This paper investigates the temporal variation of grouper species on the continental shelf of Sri Lanka in relation to seasonal, regional, and seafloor depth variables using data based on quantitative sampling of demersal fish conducted in 1978, 1979, 1980, and 2018 with a bottom trawl on the R/V Dr. Fridtjof Nansen, where the authors joined the 2018 survey. A total of 277 trawl samples were included in the analysis. The analysis of variance of all the grouper species found that the average density significantly declined from 0.89 t/NM2 (tonnes per square nautical mile) in 1979 to 0.28 t/NM2 in 2018. The contribution of groupers to the total catch (by weight) was also higher in 1979 (9.06 %) than in 2018 (1.28 %). The distribution patterns significantly differed among the six regions of the Sri Lankan shelf. In addition, seafloor depth was negatively correlated with grouper density. The results point to an urgent need for better management and conservation of the grouper resources.

Fisheries closure has been used as a fisheries management tool to protect species that need to be conserved. A commonly used type is fixed closure (FC), which specifies the closure area and period in advance and does not change after that decision is made. It has been claimed that FC is not effective for the management of migratory species, because it is difficult for FC to respond to uncertainties in the predicted distribution of species. Recently, real-time closure (RTC) has been introduced to address this issue. However, the use of RTC is still limited, because its benefits compared with FC have not been evaluated sufficiently. In this study, we conducted simple simulations to evaluate the efficiency of RTC to respond to uncertainties in the movement of migratory species. In terms of the protection of migratory species, the mean performance index of RTC was generally higher than that of FC, and the mean performance index of FC tended to decrease with greater uncertainty of species movement. We also estimated the extent of the reduction of the closure period by applying RTC instead of FC. The results of this study indicate that RTC is an efficient method of fisheries closure, and provide quantitative information to guide the use of RTC instead of FC.