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Eastern little tuna (Euthynnus affinis) is a commercially important species for coastal communities in the western and southern part of Indonesia. However, little is known about its characteristics. Therefore, a comprehensive and broader research of its population structure is imminent in response to conserve and manage the fishery sustainably. This study aimed to fill the gap of the lacking information on the stock separation of eastern little tuna within the Indonesian archipelagic waters and its Economic Exclusive Zone (EEZ). Population genetic approaches were used to examine population structure using the mitochondrial DNA (mtDNA) control region marker. A total of 94 samples were collected from nine landing sites between January to September 2020. Polymerase chain reaction (PCR) was used to amplify the samples, and Sanger sequencing was used to sequence them. The findings showed a mean value of 0.922 for genetic diversity (Hd) and 0.009 for nucleotide diversity (π). Both of these numbers pointed to a high level of genetic diversity. A further population analyses using Analysis of Molecular Variance (AMOVA) and Discriminant Analysis of Principal Component (DAPC) confirmed a mixing gene pool with no distinct population structure detected (ΦST value of 0.097 and p-value>0.05). [ABSTRACT FROM AUTHOR]

This study aimed to investigate histamine exposure associated with consumption of fresh tuna and tuna-like species in West Java, and to estimate risk of Scombroid Fish Poisoning (SFP) in Indonesia. A range of species, including tuna ( Thunnus spp. ) , bullet tuna ( Auxis sp. ) were collected from local markets and fish landing sites. Subsequently, histamine concentrations were determined using NMR analysis and exposure was calculated in mg/day for toddlers, children, and adults. The results showed that skipjack had the highest histamine exposure for all age groups, followed by bullet and regular tuna. The highest EDI for histamine was from skipjack consumption, accounting for 38.67; 37.77 and 20.74 percentage of exposure for toddlers, children and adults, respectively. These values are below the defined thresholds levels (ARfD), indicating no potential risk of acute health effect. Cooked bullet tuna and skipjack were estimated to cause similar illnesses, accounting for 6-7 cases per 100,000 individuals, which was higher than cooked tuna at 1-2 cases per 100,000 individuals. Considering the preparation of raw tuna in restaurants following Good Hygienic Practices (GHP), the predicted annual cases decreased significantly to 4-5 cases per million individuals. This risk estimation only considered histamine levels in fresh fish, without including data from fish preparation. Therefore, further studies were recommended to estimate the risk level in raw/fresh tuna and similar species before consumption.( Katsuwonus pelamis ) were collected from local markets and fish landing sites. Subsequently, histamine concentrations were determined using NMR analysis and exposure was calculated in mg/day for toddlers, children, and adults. The results showed that skipjack had the highest histamine exposure for all age groups, followed by bullet and regular tuna. The highest EDI for histamine was from skipjack consumption, accounting for 38.67; 37.77 and 20.74 percentage of exposure for toddlers, children and adults, respectively. These values are below the defined thresholds levels (ARfD), indicating no potential risk of acute health effect. Cooked bullet tuna and skipjack were estimated to cause similar illnesses, accounting for 6-7 cases per 100,000 individuals, which was higher than cooked tuna at 1-2 cases per 100,000 individuals. Considering the preparation of raw tuna in restaurants following Good Hygienic Practices (GHP), the predicted annual cases decreased significantly to 4-5 cases per million individuals. This risk estimation only considered histamine levels in fresh fish, without including data from fish preparation. Therefore, further studies were recommended to estimate the risk level in raw/fresh tuna and similar species before consumption.

Prices of agricultural and fisheries products have always been a concern not only by producers and consumers but also by the government in designing policies to control and stabilize these prices to protect the poor. Therefore, a study of price behavior is crucial to be scrutinized more deeply and comprehensively. This research is aimed at examining and analyzing tuna (Thunnus spp.) price behavior in terms of their seasonal, trend, variability, and instability behavior as well as their market integration. For this purpose, monthly data of tuna prices from 2011:1 to 2019:12 in five tuna production centers (provinces) in Indonesia, including North Sulawesi, West Papua, Aceh, North Maluku, and Bali, at the national level were applied. It was found that tuna prices have a positive trend and are statistically significant, excluding in West Papua. The study also found that price variability and instability were insignificant during observations. The study also concluded that the tuna price in every single province in Indonesia is formed independently. [ABSTRACT FROM AUTHOR]

The Yellowfin tuna is an economically important fish, representing a leading non-oil and gas export commodity in Morotai Island Regency. This species is highly demanded and its exploitation is intensively increasing every year. Thus, the sustainability of its resources is assumed to be under threat. To maintain this status, management efforts are required to regulate the intensity of fishing so that the level of exploitation remains optimal and sustainable. Efforts may include the estimation of population parameters and exploitation level. No documented accurate study or biological information has been recorded on the yellowfin tuna population parameters in West Morotai waters. Consequently, this research focused on the estimation and analysis of the population parameters of yellowfin tuna fish. The current data can provide informative material for local governments, fishery entrepreneurs and fishermen to attain optimal and sustainable management. Data on fish length measurement were recorded during the period from October to December 2020, followed by the analysis of the recorded values of population parameters and the level of the species exploitation using Microsoft Excel and the Physical program II. The population parameters of yellowfin tuna in the study site were as follows: maximum length (L∞= 242 cm), growth coefficient (K= 0.32 per year) and age (t0= -0.41). The rate of total mortality (Z) was 0.79, natural mortality (M) was 0.46 and fishing mortality (F) was 0.33. The current level of exploitation has reached its optimum condition with an estimated value of E 0.42. [ABSTRACT FROM AUTHOR]

Traceability is broadly understood as a technical means of understanding, communicating and steering the relations of production and trade in the global food system. Using an assemblage lens, this paper challenges this technical understanding by analysing how traceability affects and is affected by the relations that constitute global value chains. Analysing the introduction of the ThisFish traceability system in a small-scale tuna fishery in Indonesia we show how an NGO, Masyarakat dan Perikanan Indonesia (MDPI), de-stabilised existing relations and expertise around landing and trading tuna and subsequently re-stabilised these relations in a different assemblage through the collection, collation and management of fisheries data. In doing so MDPI worked through rather than reconfigured the social relations of production and trade in the implementation of traceability, thereby becoming part of the assemblage the NGO sought to change. The results demonstrate how the implementation of traceability is, in contrast to its technical framing, more accurately understood as a process of 'active embedding' by 'boundary subjects' who re-assemble contingent interactions by enacting multiple roles simultaneously. Traceability is as such contingent on the performance of these boundary subjects rather than on market incentives or objective monitoring and control. However, we also conclude that because it also dependent on the negotiated identity and function of these boundary subjects, traceability (and similar market based forms of governance) risk reinforcing rather than transforming the relations of production and trade they engage. [ABSTRACT FROM AUTHOR]

Calls for increased traceability of seafood have been frustrated by a poor understanding of the social dynamics shaping the flow of fish and information in global value chains. Contrasting with utilitarian and regulatory approaches, this article proposes a social practices intervention framework to understand the effect of traceability interventions ensuing from the EU IUU regulation and Fair Trade USA seafood certification program on fishers and traders operating in remote tuna landing sites in Indonesia. The framework demonstrates how the success or failure of traceability interventions depends on both alignments with (1) the performance of "targeted" and (2) "non-targeted" value chain practices as well as (3) "non-targeted" practices adjacent to the value chain. We conclude that the social practices intervention framework can provide improved insight and guidance on the uptake of traceability and other market-based governance approaches across a range of locally embedded fisheries landing sites. [ABSTRACT FROM AUTHOR]

Indonesia's tuna fisheries sector encounters significant challenges in its development, primarily due to illegal, unreported, and unregulated (IUU) fishing practices that have led to the depletion of tuna stocks. This depletion poses a significant threat to the Indonesian economy, given the key, pivotal role that tuna fisheries play in contributing 2.65% to the country's gross domestic product (GDP) and accounting for approximately 16% of the world's total tuna production. To highlight the threat, this research employs quantitative data collected from government institutions, supplemented with data from a literature review and analysis of media reports and selected publications that addressed IUU tuna fishing practices in Indonesia. It was noted that (1) illegal fishing practices in Indonesia include crimes against human rights (forced labor and human trafficking), corruption (monetary), and tuna smuggling; (2) unreported fishing practices at tuna fisheries include faulty documents (misreported, unrecorded catches); and (3) unregulated fishing practices at tuna fisheries include catch transshipments by both small-scale and industrial fishing fleets. Decisive law enforcement and active coordination among Indonesian law enforcement authorities, as well as fisher involvement, are factors for successful reduction and control of IUU fishing practices through the Indonesian Ocean Policy (IOP) in Indonesia. The implementation of the IOP to combat IUU fishing could have a transformative effect on the patterns of IUU fishing in Indonesia. Here, we review recent developments in IUU fishing practices, and discuss the opportunities to regulate sustainable tuna fisheries policies in Indonesia. [ABSTRACT FROM AUTHOR]

The movements, and hence stock structures, of bigeye tuna, Thunnus obesus , and yellowfin tuna, Thunnus albacares , remain poorly defined despite their importance to food security, livelihoods and government revenue in many nations. We examined the parasite fauna of juvenile bigeye tuna and juvenile yellowfin tuna from areas within and outside Indonesia to determine how far they may have moved since metamorphosis and acquisition of a piscivorous diet. Patterns in parasite data between collection areas were consistent between the two tuna species. Fish from two outlier areas, Maldives and the Solomon Islands, harboured a distinct parasite fauna from those from adjacent Indonesian areas, although occasionally showed similarity with those from within the Indonesian archipelago. Within Indonesia, the parasite data indicated that few juvenile fish moved west from the Pacific Ocean into the archipelago and few moved west from the archipelago into the eastern Indian Ocean. While sampling of adult fish is required to fully resolve the stock structure of both tuna species, the results provide a necessary first-step in examining structuring of the two tuna species in Indonesia and indicate that juveniles of both species may have more restricted movement than is recognized in current management arrangements. [ABSTRACT FROM AUTHOR]

The objectives of the present study were to determine the size distribution, growth pattern, feeding habit and stomach fullness index of bullet tuna Auxis rochei in the Makassar Strait, West Sulawesi. The research was conducted for six months between March and August 2017. Sampling collection was carried out using the handline technique. A total of 2160 fish were caught. Their total length ranged from 15.8 to 28.5 cm and weight ranged from 52.3 to 366.5 g. The total length of male fish ranged from 18.5 to 28.5 cm and weight ranged from 77.5 to 366.5 g. The total length of female fish ranged from 15.8 to 27.5 cm and weight ranged from 52.3 to 328.8 g. The growth pattern of bullet tuna for both male and female fish was classified into a positive allometry (b>3); the type of food found in the fish gut consisted of crustacean (12.50% to 25.64%), chepalopods (7.32 to 34.80%) and unidentified (47.69 to 64.51%), respectively. Nonetheless, the predominant food condition was not identified and in the gut there was generally no food present. The stomach fullness index ranged from 1.13% to 7.18%, (12.11 to 15.74%), ½ (12.27 to 23.14%) and empty (59.26 to 65.74%). The length size distribution of male bullet tuna was larger than the female with a positive allometric growth pattern. However, the growth pattern of male and female bullet tuna statistically showed no difference. [ABSTRACT FROM AUTHOR]

This study aims to identify the sources and magnitude of uncertainty in the collection and processing of catch and effort data of small- and medium-scale tuna fisheries in Indonesia, as well as the causes of uncertainty on an operational level. We identified possible sources of uncertainty through a literature review and interviews with experts. Next, we surveyed 40 small-scale (<10 GT) and medium-scale (10–100 GT) pole-and-line, purse-seine, longline and handline fishers in the oceanic fishing port Bitung, which has the largest number of tuna fisheries activities in eastern Indonesia, to estimate the magnitude of unreported catch of juvenile tuna, on-board consumption, home consumption and catch used as bait. We used logbook data from the fisheries submitted to the fishing port authorities to extrapolate survey results to the fishing port level. Uncertainties around unreported catches were due both to non-reporting by fishers to the fishing port authority and to flaws in data management in the data collection institution. After removing flaws in the logbook database we estimated that the catch by small- and medium-scale fishing vessels active in Indonesian waters could be about 33–38% higher than reported. The proportion of unreported catch, as well as the sources and range of uncertainty, varied according to the types of gear used. Finally, we discuss what aspects of data collection and processing should be improved at the fishing port level, including the identified sources of unreported catch and the processes leading to non-reporting. We hence provide a methodology for estimating unreported catches in small and medium-scale fisheries. [ABSTRACT FROM AUTHOR]

While numerous population genetics studies have investigated phylogeographic patterns of coral reef organisms in the coral triangle, few have addressed whether fishes in the pelagic environment exhibit concordant patterns of genetic subdivision. We analyzed approximately 400 base pairs of the mitochondrial control region to compare population structure and phylogeography of five pelagic tuna and mackerel within a subset of their geographic ranges (i.e., the Indonesian Archipelago). Focal species include frigate tuna [Auxis thazard (Lacépède, 1800)], kawakawa [Euthynnus affinis (cantor, 1849)], skipjack tuna [Katsuwonus pelamis (Linnaeus, 1758)], Indian mackerel [Rastrelliger kanagurta (cuvier, 1816)], and narrow-barred spanish mackerel [Scomberomorus commerson (Lacépède, 1800)]. Observed patterns of regional genetic subdivision were consistent with the role of Pleistocene vicariance in structuring populations. Divergence dates of all pelagic fish lineages dated to the Pleistocene epoch. concordant barriers to larval dispersal found near sumatra, sulawesi, and Papua suggested that the Halmahera and Mindanao eddies and the Indonesian flowthrough may be contemporary forces maintaining genetic divergence between demes of pelagic fishes. Given the economic importance of these species, we suggest that the scale of management for pelagics in Indonesia be re-evaluated to reflect regional differences in the genetic composition of fishes. [ABSTRACT FROM AUTHOR]

Sun-drying was carried out to dry fish skins of four species of seawater fish, namely yellowfin tuna, brown stingray, red snapper and white cheek shark, and the gelatins extracted from the skins were characterized in comparison to those of extracted from fresh skins. The fish skins were pretreated using 0.05 M acetic acid followed by extraction at 80°C for 2 h. The gelatin obtained was analyzed for yield, proximate composition, functional properties, and amino acid composition. Results showed that drying on brown stingray and red snapper fish skins significantly decreased gelatin yield. Gelatins from dried fish skins had higher crude protein, lower ash content and lower crude lipid. Drying led to decreased viscosity, increased gel strength, and no significant effect on melting point. Gelatin from dried skins showed a higher turbidity and darker appearance. It was observed that drying did not interfere with amino acid composition. This study showed that sun-drying seems to be a prospective method for preservation of fish skins. [ABSTRACT FROM AUTHOR]

Abstracts: The illegal, unreported and unregulated (IUU) fisheries catch in Raja Ampat, Eastern Indonesia is estimated in the paper. The history of regulatory, technological, political and market changes from 1960 to present to estimate trends in the relative rate of misreporting of fisheries catch was analyzed. Trends were converted to absolute values using anchor points: known rates of misreporting from the literature from the region, and based on expert opinion. A Monte Carlo analysis was used to estimate the likely quantity of IUU catch with associated error ranges for six fisheries: reef fish, tuna, anchovy, shark, sea cucumber and lobster. Results show that illegal and unreported catch exceeded the reported catch by more than 40 thousand tonnes (or a factor of 1.5) for the year 2006. The value of the illegal and unreported catch in 2006 is 40 million USD. The catch missing from official records presents challenges for fishery managers, threatens the longterm sustainability of fisheries and thus the livelihoods in the region. [Copyright &y& Elsevier]

Indonesian salted-boiled fish (pindang) is a popular traditional food in Indonesia, which is made from Scombroid fish such as tuna and mackerel. As with other traditionally prepared fish products, pindang has important economic and social values, especially for those living in the coastal areas of Indonesia. However, pindang is a major cause of histamine fish poisoning (HFP) for consumers. Klebsiella aerogenes T124, a relatively high histamine-producing isolate from pindang , was used to describe lag time (λ), growth rate (μ max), maximum population density (N max), and histamine production in histidine broth and artificially contaminated Grey mackerel. Broth was adjusted to 1.5, 6, 10 and 20% w / v NaCl; mackerel was treated with 6% w /w NaCl, a level common to Indonesian industry practice, or not treated with additional NaCl. Samples were incubated at 10, 15, 20 and 30 °C. In broth, μ max and N max were significantly affected by temperature and NaCl, respectively, with λ influenced by both parameters. In control fish, μ max was significantly affected by temperature and NaCl, except at 10 and 15 °C; for 6% NaCl treatment, growth was only observed at 20 and 30 °C. Under similar incubation conditions for broth and fish, histamine formation was markedly affected by NaCl concentration. In broth, −5.1 to −6.6 log μg of histamine was produced per CFU, versus −4.6 to −6.6 log μg per CFU in fish. This study demonstrated that mackerel treated with 6% NaCl and stored at 10–15 °C prevents growth of K. aerogenes strain TI24 and formation of toxic levels of histamine. • μ max and N max were significantly affected by temperature and NaCl, respectively. • Histamine production was affected by NaCl, with higher levels of histamine in broth. • In broth, −5.1 to −6.6 log μg histamine/CFU observed versus −4.6 to −6.6 log μg/CFU in fish. • 6% NaCl and at 10–15 °C prevented growth and toxic histamine levels in fish. [ABSTRACT FROM AUTHOR]

Abstract: This paper provides some of the only fisheries and quantitative biological data for the Mobulidae (manta and devil rays), a group of large pelagic species that are widely distributed in tropical and warm temperate waters. The data were derived from 409 mobulids that were taken as bycatch of drift gillnet fisheries for the skipjack tuna Katsuwonus pelamis and subsequently examined at fish landing sites in Indonesia. The most abundant of the five species was Mobula japanica (∼50%), followed by Mobula tarapacana (∼24%), Manta birostris (∼14%), Mobula thurstoni (9%) and Mobula cf kuhlii (2%). The four most abundant species were represented by a wide size range of each species and, in the case of Mobula japanica, by embryos, neonates and fully mature individuals. The disc width at maturity (DW50) of males, derived from the proportion of males at each size class with fully calcified claspers, ranged from 1538mm for Mobula thurstoni to 3752mm for M. birostris. As the claspers of males become calcified over a relatively narrow size range, the process of maturation is presumably relatively rapid. There is an increasing demand for various body parts of mobulids. Branchial filter plates, which are used for traditional Chinese medicines, are the most valuable, fetching as much as 30 $US a kilo (dry weight). The skins are dried and deep fried and the flesh salted and dried and these are used for human consumption, while cartilage is dried for export as a filler for shark-fin soup. The very low fecundity of the large and probably long-lived mobulid rays make the stocks of their species particularly susceptible to further increases in fishing. [Copyright &y& Elsevier]

This paper is a study of stakeholders' perceptions of the reliability of landings data obtained by governments on fish stocks. The case studied is the tuna fishery in Indonesia, which is the country's most important fisheries sector in terms of income and employment, but poses particular difficulties for landings data collection because Indonesia is an archipelago made up of 17,500 islands making data collection a very complex, time-consuming, and costly process because of the large number of ports and the need to employ a considerable team of enumerators to collect the data. This study is not an enquiry into whether the officially recorded data are reliable, but whether fishers and other stakeholders believe them to be reliable. We carried out a survey of 921 respondents (724 tuna fishers; 154 live-bait fishers; 16 policy makers; 16 public sectors and 11 private sectors) to investigate their perceptions of the way landings data on tuna are obtained and collated by Indonesian government officials. The results indicate there is considerable scepticism about the accuracy of these fisheries data. Respondents said there was inadequate funding for data collection; the enumerators were poorly trained; and there were few incentives for checking the results of surveys. These and other criticisms raise serious doubts about the efficacy of the management of the tuna fisheries in Indonesia. Stakeholders' perceptions on how to improve their confidence in the data collected include greater involvement of individual fishers and the private sector. [ABSTRACT FROM AUTHOR]

Indonesia is the second-largest contributor of microplastics (MPs) pollution in the marine ecosystem. Most MPs pollution-related studies in Indonesia focus on seawater, sediment, with less information found on the commercially important fish species used for human consumption. Skipjack Tuna (Euthynnus affinis) is one of the major exporting fishery commodities from Indonesia. This exploratory study aimed to determine MPs presence in the digestive tract of Skipjack Tuna from the Southern Coast of Java, Indonesia. The fish samples were collected from five different fish traditional auction market along the Southern Coast of Java, Indonesia, namely Pangandaran, Pamayang Sari, Ciletuh, Santolo, and Palabuhan Ratu. The gastrointestinal tract of Skipjack tuna was pretreated using alkaline destruction and filtered. The presence of MPs in the treated samples was visually identified using an optical microscope, while Polybrominated diphenyl ethers (PBDEs) contaminants were analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). A total of 19 suspected MPs particles were found in the form of filament (84%), angular (11%), and round (5%). This result would provide a better indication of the MPs contamination in marine life species in the Southern Coast of Java, Indonesia, as useful information for marine environmental monitoring program in the future., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Seafood is increasingly subject to traceability requirements set by importing countries and global buyers. These demands place significant pressure on value chain actors to change seafood production and trade practices to align to the standardized norms around legality and food safety. While processing companies are recognized as critical players in facilitating access to global markets there is currently a lack of understanding about how they respond to traceability demands. To address this gap, this paper employs a social practices perspective to analyse how and why the actual practices performed by tuna processing companies in Indonesia change in response to BRC certification and the EU IUU regulation catch certification requirements. The results demonstrate that responses are determined by the performance and embeddedness of existing social practices that make up tuna value chains. Furthermore, our findings showcase short term adaptive responses for practices within the direct control of processing companies while practices beyond the control of processing companies, for example those performed by middlemen and government officials, were more rigid and required new social and material arrangements to be developed. With traceability demands likely to expand, conceptualizing value chains as sets of interrelated social practices offers a novel way to understand the uptake of traceability demands. - We present a novel perspective for understanding how processing companies respond to transparency demands. - Responses to interventions in global value chains are neither singular or linear - Traceability uptake depends on the degree of control processing companies exercise over chain practices [ABSTRACT FROM AUTHOR]

• We examine the oceanographic biophysical conditions at traditional anchored fish aggregating device in eastern Indonesia. • Catch-per-unit relationship with biophysical conditions were analysed with correlation and GAM analyses. • Tuna pole-and-line fishery at the research sites heavily depends on the installations of traditional anchored fish aggregating devices, called rumpon. The research was conducted to investigate the oceanographic characteristics at three traditional anchored Fish Aggregating Device (FADs) sites for tuna pole-and-line fishery in eastern Indonesia. The FADs locations, and sea surface temperature (SST) and chlorophyll-a (chl-a), salinity (sal), wave height (wav), wind (win) current (cur) were examined using a geographic information system (GIS). Relationships between Catch-per-Trip (CPT) with oceanographic characteristics (SST, chl-a, sal, wav, win and cur), were analysed using correlation and generalised additive models (GAMs) analyses. Correlation analyses was used in order to determine how strongly pairs of variables were related to one another, and generalised additive models (GAMs) were used in order to model relationships between Catch-per-Trip (response variable) and the oceanographic variables SST, chl-a, sal, wav, win and cur (predictor variables). Correlation analyses showed that significantly negative correlations were found in entire locations between SST and chl-a while in contrarily, the lowest correlation was found between CPT and chl-a. Furthermore, the GAM plots indicated that a positive association was observed between catch-per-trip and SST with approximately >26.5 °C, chl-a was <0,4 mg/m3, salinity was observed between>33 to < 34.5 (psu) for entire sites while wav was found at>0.23 for Sorong and >0,87 (m) in Larantuka and <0.64 in Pulau Bacan. Win variable had positive effects at>4.1 m/s in entire research sites while cur had a positive effect on CPT occurred at <56 (m/s) for entire locations. The GAM models showed that SST explains up to 20 % whereas chl-a explains as the lowest variable (up to 0.78 % of the deviances) in skipjack CPT relationships, and the addition of predictor variables resulted in an increase in the deviance explained. This research provides evidence that skipjack tuna CPT has relationship with oceanographic variables in eastern Indonesia. [ABSTRACT FROM AUTHOR]