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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.), and skipjack (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. [ABSTRACT FROM AUTHOR]

The study aims to investigate the impact of various drying techniques on the quality of sulfated polysaccharides (SP) extracted from Skipjack tuna (Katsuwonus pelamis) skin. Three drying methods, namely microwave drying (M‐KPP), freeze‐drying (F‐KPP), and hot air drying (HA‐KPP), are examined. The chemical and monosaccharide compositions of SP are significantly affected by the drying methods. The extraction yields for M‐KPP, F‐KPP, and HA‐KPP are 3.30%, 3.11%, and 2.50%, respectively (P < 0.05). Additionally, HA‐KPP, with 10.67% moisture content, exhibits the lowest moisture level among the dried samples (P < 0.05). Furthermore, the structural properties of SP remain consistent across different drying methods, as indicated by FTIR, XRD, and DSC analyses. F‐KPP demonstrates the highest antioxidant properties. The functional and antimicrobial activities of SP are significantly influenced by the drying technique, with hot air drying resulting in increased foaming capacity and microwave drying showing enhanced antimicrobial activity. In conclusion, the findings demonstrate that the functionality and bioactivity of SP from tuna skin are greatly influenced by the drying technique employed, suggesting that the selection of the optimal method should be tailored to the desired properties of the SPs and given careful consideration. [ABSTRACT FROM AUTHOR]

Summary: Nanoliposomes (NL) containing different levels (1%, 2%, and 5%; w/w) of EPA/DHA‐enriched oil (n3FAO) from skipjack tuna eyeballs were prepared using 1%, 2.5%, and 5% (w/v) of soy phosphatidylcholine lecithin (SL) as a wall material. Then, the impact of ultrasonication at different amplitudes (40% and 50%) and sonication time (5 and 10 min) on encapsulation efficiency (EE) of selected NL was also investigated. NLs prepared without ultrasonication treatment using 2.5% SL and 2% n3FAO (WU‐NL) showed the highest EE (88%) than the remaining concentrations. When ultrasound at 40% amplitude for 5 min was applied, NLs (US‐NL) having the maximum EE of 98% were achieved. Ultrasonication employed at all conditions showed increased particle size (31.6–67.2 nm) than the WU‐NL (22.8 nm). Microstructure suggested the formation of particles with smooth surfaces and homogenous distribution. When NL powders were incorporated into the fresh cow milk at various levels (2.5% and 5.0%; w/v), likeness for aroma, mouthfeel, taste, and aftertaste slightly decreased, especially at higher levels (5%) for all samples. Nevertheless, the likeness score remained within acceptable levels (≥5.0). The fatty acid profile of the milk fortified with 2.5% (w/w) NLs showed a significant increase in polyunsaturated fatty acids (PUFAs), including EPA and DHA. Therefore, the findings indicated that ultrasonication improved the EE of liposomes, which could be successfully incorporated into milk and other food items with a lower content of PUFAs, boosting their nutritional profile while maintaining their taste and sensory attributes. [ABSTRACT FROM AUTHOR]

Bio-calcium derived from fish frames may offer several advantages for osteoporosis prevention. This study aimed to evaluate the effects of bio-calcium derived from skipjack tuna frames on bone loss in ovariectomized rats. Tuna bio-calcium was prepared through enzymatic hydrolysis, defatting, bleaching, and grinding processes. The bioavailability of calcium was tested using the Caco-2 cell monolayer model, showing that 13% of tuna bio-calcium was absorbed, compared to 10% for calcium carbonate. Rats were divided into the five following groups: (1) OVX, (2) sham-operated, (3), OVX + estrogen-treated (4) OVX + calcium carbonate-treated, and (5) OVX + tuna bio-calcium-treated. All groups were raised for eight weeks. Tuna bio-calcium was able to increase BV/TV by 26% in the femur and 29% in the tibia, compared to 13% and 17% in the OVX group, respectively. Trabecular thickness in the femur upsurged to 360 µm in the tuna group, while a thickness of 290 µm was observed in the control. Additionally, osteoclast numbers were reduced to 5 N.Oc/mm in the femur and 6 N.Oc/mm in the tibia in the tuna group, compared to 35 and 45 N.Oc/mm in the control. Overall, tuna bio-calcium effectively prevented bone loss and can serve as a promising natural alternative for managing osteoporosis. [ABSTRACT FROM AUTHOR]

Taiwan Bank (TB) is located in the southern Taiwan Strait (TS). The uplifted continental slope and bottom currents in this area result in the formation of upwelling areas, which serve as crucial fishing grounds. Climate-induced fluctuations in fish populations occur in the TS. However, how predation and competition affect the interspecies relationships in the TB ecosystem warrants clarification. In this study, we collected high-grid-resolution data on fishery activity (2013–2019) and constructed ecosystem models using Ecopath with Ecosim (EwE). Three mass-balanced models for determining the influence of El Niño–Southern Oscillation (ENSO) events on the TB ecosystem were constructed using EwE. A range of groups, including representative pelagic, benthic, and reef species, were collected for analyzing the relationship between migratory and sedentary species in terms of ecosystem structure variation due to climate change. The results demonstrated that the total system throughput (TST) was 10,556–11,122 t km−2 year−1, with an average transfer efficiency of 12.26%. According to the keystoneness index, calculated through mixed trophic impact analysis, Polydactylus sextarius and Scomber japonicus were the key species with top–down control and relatively high impact on the ecosystem in normal years. The keystone species also shifted to the predator fish Thunnus albacares and Katsuwonus pelamis during El Niño and La Niña events, respectively. Moreover, total biomass, TST, consumption, and respiration were noted to increase during ENSO events. However, during La Niña events, the diversity and connectance indexes were relatively low but pelagic species' biomass was relatively high, whereas the biomass of most benthic and reef species was relatively high during El Niño events. [ABSTRACT FROM AUTHOR]

One of the main issues in the agro-industry supply chain is identifying and ranking different risk factors to maintain business continuity. This study discusses the agro-food supply chain risk assessment for smoked skipjack tuna in Ambon. Related literature and expert interviews identify risk factors that arise along the supply chain. These risk factors are contained in internal risk, company external operational risk, and macro-level risk. This research aims to evaluate comprehensively the risk factors of the smoked skipjack agro-industry supply chain, which are a priority to be addressed. The decision-making framework uses the BWM (Best Worst Method) to determine each risk factor's relative weight, followed by a sensitivity analysis to determine how robust the outcome is. Experts pick the risk factor assessment, and then an optimization model is modelled to obtain the weight of each risk factor, which is calculated with the help of Lingo software. The findings show that three risk factors will be prioritized to be addressed out of the eleven risk factors assessed, namely "Quality of the final product," "Financial instability," and "degradation of fish populations." Sensitivity analysis was also carried out to see the overall robustness of the results achieved. The weight of the selected risk factor ("final product quality (R1c)") has its weight value changed from 0.1 to 0.9 with an increase of 0.1. These findings are expected to help smoked skipjack tuna agro-industry managers make decisions to reduce supply chain risks and better administration management to maintain the sustainability of their business processes. [ABSTRACT FROM AUTHOR]

This study aimed to establish the preparation process of peptide–calcium chelates (TMP-Ca) using skipjack tuna meat and investigate the function and mechanism of TMP-Ca in an osteoporosis model of rats. The results indicated that trypsin is more suitable for preparing the Ca-chelating hydrolysates of tuna meat, and the optimal hydrolysis conditions were derived as follows: digestion time 4 h, material–liquid ratio 1:10, and enzyme dose 3%. The conditions for chelating Ca with tuna meat hydrolysate were optimized to be chelation time 50 min, temperature 50 °C, pH 8.0, and a peptide–Ca ratio 1:10. The prepared hydrolysate was subjected to ultrafiltration, and the fraction (TMP) (MW <1 kDa) showed the highest Ca chelation rate (51.27 ± 1.42%) and was made into the peptide–Ca chelates (TMP-Ca). In osteoporotic rats, TMP-Ca significantly improved the decrease in ovarian indexes caused by retinoic acid. It also elevated serum Ca, phosphorus, and bone turnover indexes, increased the number of bone trabeculae, and improved bone microstructure. In addition, we confirmed that TMP-Ca could regulate the OPG/TRAF6 pathway to reduce osteoclast differentiation, inhibit bone resorption, and promote bone formation. Therefore, TMP-Ca could significantly ameliorate osteoporosis, and this study provides a functional component for the preparation of healthcare products using skipjack tuna meat to treat osteoporosis. [ABSTRACT FROM AUTHOR]

Managing populations of wild harvested species requires the ability to regularly provide accurate abundance assessments. For most marine species, changes in abundance can only be monitored indirectly, using methods reliant on harvest-based indices, with significant inherent limitations surrounding the estimation and standardization of harvest effort. Tropical tunas are some of the most exploited marine species in the world and are among several species in critical need of alternative methods for estimating abundance. Addressing this concern, we developed the Associative Behaviour-Based abundance Index (ABBI), designed to provide direct abundance estimates for animals, which exhibit an associative behaviour with aggregation sites. Its implementation in the western Indian Ocean on skipjack tuna (Katsuwonus pelamis), yellowfin tuna (Thunnus albacares) and bigeye tuna (Thunnus obesus), revealed similar trajectories in their relative abundance. The ABBI stands as a potentially promising alternative to enhance traditional tropical tuna stock assessments methods, as well as a new opportunity to assess the abundance of other wild species that display an associative behaviour with physical structures found in their natural environment. [ABSTRACT FROM AUTHOR]

Seafood plays an important role in sustainably feeding the world and is one of the most traded food products globally. However sustainability improvements are often focused on its production (e.g., aquaculture, fishing) rather than trade. Here, we quantify the magnitude and extent of global 'redundant two-way' seafood trade–the exchange of the same quantity of the same taxonomic species between two countries–to examine its prevalence and potential implications across the seafood supply chain. We focused on wild-caught seafood trade and found that redundant two-way trade has increased by 43%, between 2000 and 2015, making up 3.2% (7.7 Mt) of global seafood trade during that period. Although most countries were involved in redundant two-way seafood trade (111 of 212 analyzed), the majority occurred between five trade partners: Canada and the United States (15%), Germany and the Netherlands (11.8%); Denmark and Sweden (10.6%); Germany and Denmark (7.1%); and France and Norway (7%). Nearly 50% of redundant trade is made up of just four species including Atlantic herring, Atlantic cod, Skipjack tuna and Atlantic mackerel. While deficiencies in global seafood trade data mask seasonal and product heterogeneity, redundant trade could have implications for meeting conservation and sustainable development goals. Future research should build upon these findings to explore specific environmental, economic, and social implications associated with redundant two-way trade to benefit producers and consumers within the seafood supply chain. [ABSTRACT FROM AUTHOR]

Exploring the effects of water temperature on egg development in skipjack tuna (Katsuwonus pelamis) has substantial implications for evaluations of wild spawning habitats. In the present study, we examined the hatching success and duration as a function of temperature from 21 to 33°C under captive environments. A high hatching rate of over 50% between 23 and 31°C was observed, with the shortest hatching duration at 31°C. Because the egg period is vulnerable to predators, a shortened hatching duration with warming water would be ecologically advantageous for K. pelamis, as its main spawning grounds are located in tropical areas. [ABSTRACT FROM AUTHOR]

Tropical tuna fisheries support some of the largest artisanal and industrial fisheries worldwide. Approximately 37% of the tropical tuna catch by industrial purse seiners is obtained from tuna associated with drifting fish aggregating devices (DFADs), where three tuna species coexist: skipjack (Katsuwonus pelamis) , bigeye (Thunnus obesus), and yellowfin tuna (Thunnus albacares) , with stocks subject to different health status. Purse seine fishers heavily rely on acoustic technology to detect and assess the quantity of tuna at DFADs. Yet, accurately distinguishing between species using solely acoustic methods is limited by insufficient knowledge about each species' acoustic response across frequencies. This study was carried out on six swimbladdered individuals belonging to two sets with mean lengths of 51.9 ± 9.5 and 52.9 ± 2 cm. It focuses on the frequency response obtained from ex situ measurements of yellowfin tuna recorded at 38, 70, 120, and 200 kHz, which revealed a flat response across frequencies, with b20 values of −72.4 ± 9, −73.2 ± 8, -72.3 ± 8, and −72.3 ± 9 dB, respectively. These results, contrast with previous findings on bigeye and skipjack, demonstrating the discrimination potential of acoustics in these three species. To harness this potential, a discrimination algorithm was developed. [ABSTRACT FROM AUTHOR]

The regulations imposing sanctions for violations of provisions regarding the conformity of fishing grounds and areas for catching fish have not been fully complied with by fishing vessels based at the Sibolga Archypelago Fishing Port. The number of violations committed by purse seine vessels, categorized by size, is as follows: 34 violations for vessels sized 30-100 GT and 23 violations for vessels sized 100-200 GT. The purpose of this research is to analyze the status and conformity of purse seine fishing grounds at PPN Sibolga with fisheries management regulations. This research was conducted at the Sibolga Archypelago Fishing Port from January to March 2024. The research is quantitative in nature, using a descriptive method. Respondents are skippers and boat masters of purse seine vessels. Sample determination in the research was done through incidental sampling. Data analysis was conducted using scoring, weighting, and comparison. The results indicate that the potential status and conformity of Fishing Ground are as follows: Fishing grounds within <12 miles for small pelagic purse seine fishermen with vessel sizes of 30-100 GT are classified as potential but not in conformity with Ministerial Regulation No. 58 of 2020. Meanwhile, potential FGAs for small pelagic purse seine fishermen targeting skipjack tuna with vessel sizes of 30-100 GT and for large pelagic purse seine fishermen targeting skipjack tuna with vessel sizes of 100-300 GT are in conformity with Ministerial Regulation No. 58 of 2020. [ABSTRACT FROM AUTHOR]

This work aimed to describe the morphological, histological, and histochemical adaptations in the tubular part of the digestive tube of skipjack tuna (Katsuwonus pelamis) according to its feeding and dietary preferences. Fish samples were gathered from Abu Galum, Aqaba Gulf, the Red Sea, Egypt, in May 2022. The morphological, histological, and histochemical structure of the oesophagus, stomach, and intestine of fish were photographed and described. The results showed that the esophagus of K. pelamis was described as a flexible tube with irregular mucosal folds, comprising multiple layers of mucus cells containing strong acid mucopolysaccharides (MPS) and weak sulphomucins. Submucosa consisted of fibrous connective tissue with variations in mesh size, and the muscularis layer was dense with circular muscle fibers. The stomach has a bag shape. It is separated into three regions cardiac, fundic, and pyloric. The cardiac region exhibited broad folds with dense stomach glands containing weakly acid MPS and sulphomucins. Its submucosa contained blood vessels dispersed in fibrous connective tissue, while the muscular layer comprised of inner circular and outer longitudinal muscle fibers. In the fundic region, numerous primary rugae were observed with abundant gastric glands. The pyloric region showed irregular mucosa without gastric glands. Its submucosa consisted of thicker areolar connective tissue. The intestine appeared as a small tube with folded duodenal mucosa containing deep crypts. Its epithelial mucosa consisted of columnar and mucus cells containing strong acid MPS and sulphomucins. The submucosa was thinner compared to other parts and contained fibrous connective tissue with lymphatic vessels and blood vessels. The muscular layer was dense, especially in ilial regions with long folds and abundant mucus glands. It was concluded that the tubular parts of digestive tube skipjack tuna were adapted to diet and food behaviors, as evidenced from the related functional mechanisms of fish digestive physiology. [ABSTRACT FROM AUTHOR]

The waters around the Galápagos Marine Reserve (GMR) are important fishing grounds for authorized artisanal vessels fishing within the reserve as well as for national and foreign industrial fleets operating in the wider Ecuadorian Insular Exclusive Economic Zone (IEEZ). Although it was not originally designed for fisheries management, Automatic Identification System (AIS) data provides useful, open access, near real-time and high-resolution information that allows for increased monitoring, particularly around Marine Protected Areas (MPAs) and in Areas Beyond National Jurisdiction. This study uses AIS data provided by Global Fishing Watch to assess the spatial distribution and seasonal dynamics of fishing effort by vessel flag within the GMR and the IEEZ from 2012 to 2021. Based on kernel density estimation analysis, we determinate the core-use areas (50%) and spatial extent (95%) of fishing activities by fleets (Ecuadorian and foreign), gear types and seasons (warm, from December to May; and cold, from June to November). Our results show that the Ecuadorian fleet recorded the most observed fishing hours in the study area, with 32,829 hours in the IEEZ and 20,816 hours within the GMR. The foreign flags with the most observed fishing hours in the IEEZ were Panama (3,245 hours) and Nicaragua (2,468.5 hours), while in the GMR were the 'Unknown flag' (4,991.4 hours) and Panama (133.7 hours). Vessels fished employing different fishing gears, but the waters of the GMR and IEEZ were mostly targeted by tuna purse-seiners and drifting longlines. The spatial distribution of the fishing effort exhibits marked seasonal variability, likely influenced by seasonal migrations of target species such as tunas (e.g., Thunnus albacares, T. obesus and Katsuwonus pelamis), marlins (e.g., Makaira nigricans) and sharks (e.g., Alopias pelagicus). The collection and use of this type of spatial and seasonal information is an essential step to understand the dynamics of fishing activities in national waters and improve fisheries management, particularly in less studied areas and fisheries. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the physico-chemical quality of fishmeal produced by four companies in different states of the Republic (Baja California Sur, Jalisco, and Sinaloa). Design/methodology/approach: The analyzed fishmeals were from six batches, sardine meal from California pilchard and Pacific thread herring (S. sagax and O. libertate), and skipjack tuna and (K. pelamis) processed by different Mexican companies. Proximal chemical analysis was carried out at the Centro de Investigaciones Biológicas del Noroeste (CIBNOR). Results: The fishmeal’s quality parameters analyzed in this study showed similar values to those reported in the literature. The variations observed in their proximate chemical composition allow them to be classified according to the results of the analyses. Limitations on study/implications: Considering that four of the six flours were produced from the same raw material, S. sagax, the high variability in their physico-chemical quality parameters indicates a lack of standardization in both production methods and quality controls among the producing companies. Findings/conclusions: K. pelamis by-products can produce meals of equal or better physico-chemical quality than those produced from S. sagax. The development of official regulations establishing quality standards to fishmeal production at national level is desirable for competitiveness. [ABSTRACT FROM AUTHOR]

The presence of microplastics (MPs) in marine ecosystems is widespread and extensive. They have even reached the deepest parts of the ocean and polar regions. The number of articles on plastic pollution has increased in recent years, but few have investigated the MPs from oceanic islands which are biodiversity hotspots. We investigated the possible microplastic contamination their source and characteristics in surface waters off Kavaratti Island and in the gastrointestinal tract (GT) of skipjack tuna, Katsuwonus pelamis collected from Kavaratti Island of the Lakshadweep archipelago. A total of 424 MP particles were isolated from the surface water samples collected from off Kavaratti Island with an average abundance of 5 ± 1nos./L. A total of 117 MPs were recovered from the GT of skipjack tuna from 30 individual fishes. This points to a potential threat of MP contamination in seafood around the world since this species has a high value in local and international markets. Fiber and blue color were the most common microplastic morphotypes and colors encountered, respectively, both from surface water and GT of fish. Smaller MPs (0.01–1 mm) made up a greater portion of the recovered materials, and most of them were secondary MPs. Polyethylene and polypropylene were the most abundant polymers found in this study. The Pollution Load Index (1.3 ± 0.21) of the surface water and skipjack tuna (1 ± 0.7) indicates a minor ecological risk for the coral islands, while the Polymer Hazard Index highlights the ecological risk of polymers, even at low MP concentrations. This pioneer study sheds preliminary light on the abundance, properties, and environmental risks of MPs to this highly biodiverse ecosystem. [ABSTRACT FROM AUTHOR]

Bio-calcium derived from fish frames may offer several advantages for osteoporosis prevention. This study aimed to evaluate the effects of bio-calcium derived from skipjack tuna frames on bone loss in ovariectomized rats. Tuna bio-calcium was prepared through enzymatic hydrolysis, defatting, bleaching, and grinding processes. The bioavailability of calcium was tested using the Caco-2 cell monolayer model, showing that 13% of tuna bio-calcium was absorbed, compared to 10% for calcium carbonate. Rats were divided into the five following groups: (1) OVX, (2) sham-operated, (3), OVX + estrogen-treated (4) OVX + calcium carbonate-treated, and (5) OVX + tuna bio-calcium-treated. All groups were raised for eight weeks. Tuna bio-calcium was able to increase BV/TV by 26% in the femur and 29% in the tibia, compared to 13% and 17% in the OVX group, respectively. Trabecular thickness in the femur upsurged to 360 µm in the tuna group, while a thickness of 290 µm was observed in the control. Additionally, osteoclast numbers were reduced to 5 N.Oc/mm in the femur and 6 N.Oc/mm in the tibia in the tuna group, compared to 35 and 45 N.Oc/mm in the control. Overall, tuna bio-calcium effectively prevented bone loss and can serve as a promising natural alternative for managing osteoporosis.

Oxidation in living organs causes dangerous diseases, including cancer, and in food, it causes spoilage and heavy economic losses. Synthetic antioxidants have adverse and dangerous effects on human health, therefore identifying natural antioxidant compounds is one of the main needs of the food industry. In fish processing industries, about 50-70% of fish, which are potential sources of valuable nutritional com such as essential amino acids, are produced as waste. Therefore, finding a way to optimally use these wastes and produce healthy compounds with high added value such as bioactive peptides has great importance. In this research, the effect of hydrolysis conditions (time: 30-300 min and enzyme concentration 0.5-3 %) and type of protease (alcalase and pancreatin) on the degree of hydrolysis and antioxidant properties (DPPH radical scavenging activity, Fe chelating activity, nitric oxide radical inhibition, total antioxidant capacity and Fe reducing power) of protein hydrolysate from skipjack viscera was investigated using the response surface methodology. The results showed that the optimum conditions for achieving the most antioxidant properties with alcalase and pancreatin were: hydrolysis time of 146.9 and 171.67 minutes and enzyme concentration of 1.94 and 2.17%; in these conditions, the degree of hydrolysis of the produced protein hydrolysates was 25.12% and 20.35%, respectively. Comparing the antioxidant properties of hydrolysates produced by both proteases showed that the alcalase enzyme led to the production of protein hydrolysates with stronger antioxidant properties than pancreatin. Therefore, it can be concluded that the protein hydrolysate of the skipjack fish viscera using alcalase enzyme as a healthy and value-added product can be used in the production of functional products and health supplements. [ABSTRACT FROM AUTHOR]

In a balanced diet, regular fish consumption provides positive outcomes for human health. On the other hand, the seafood supply chain faces a significant food safety risk due to the presence of potentially toxic elements (PTEs). In the present study, to assess the risk for Italian consumers, the concentrations of five PTEs, namely lead, chromium, cadmium, mercury, nickel, and aluminum, were determined in the three most consumed preserved fish in Italy: tuna (Thunnus albacares, Katsuwonus pelamis), mackerel (Scomber scombrus) and anchovy (Engraulis encrasicolus). Samples were collected from the national market, and the instrumental analysis was performed by inductively coupled plasma mass spectrometry (ICP-MS). The analyzed PTEs were found in all the species that were investigated. However, after considering the target hazard quotient (THQ) and the hazard index (HI), it was observed that the three fish preserves did not pose any risk of chronic toxicity for the average consumer, even at the highest concentrations detected. However, for significant consumers, mercury detected in tuna samples represented almost 90% of the tolerable weekly intake (TWI) reported by the European Food Safety Authority (EFSA), representing a matter of concern for consumers, particularly regarding developmental neurotoxicity, whose HI exceeded 111%. The acute toxicity of nickel was also considered for significant consumers at the highest concentration detected, and the margin of exposure (MOE) calculated was above 7000, much higher than the value of 30 indicated by EFSA. Due to the lack of data on non-professional carcinogenicity or human intake through foods with low cancer risk, this toxicity was not considered in the analysis of PTEs. [ABSTRACT FROM AUTHOR]

Tuna is an excellent food product, relatively low in calories, that is recommended for a balanced diet. The continuously increasing demand, especially for bluefin-tuna-based food preparations, and its relatively high market price make adulteration by intentionally mixing with other lower-priced tunas more prospective. The development of rapid methods to detect tuna adulteration is a great challenge in food analytical science. We have thus developed a simple, fast, and low-cost molecular rapid test for the visual detection of tuna adulteration. It is the first sensor developed for tuna authenticity testing. The three species studied were Thunnus thynnus (BFT), Thunnus albacares, and Katsuwonus pelamis. DNA was isolated from fresh and heat-treated cooked fish samples followed by PCR. The PCR products were hybridized (10 min) to specific probes and applied to the rapid sensing device. The signal was observed visually in 10–15 min using gold nanoparticle reporters. The method was evaluated employing binary mixtures of PCR products from fresh tissues and mixtures of DNA isolates from heat-treated tissues (canned products) at adulteration percentages of 1–100%. The results showed that the method was reproducible and specific for each tuna species. As low as 1% of tuna adulteration was detected with the naked eye. [ABSTRACT FROM AUTHOR]

Human milk lipids generally have the maximum long-chain fatty acids at the sn-2 position of the glycerol backbone. This positioning makes them more digestible than long-chain fatty acids located at the sn-1, 3 positions. These unique fatty acid distributions are not found elsewhere in nature. When lactation is insufficient, infant formula milk has been used as a substitute. However, the distribution of most fatty acids ininfant formula milk is still different from human milk. Therefore, structured lipids were produced by the redistribution of medium-chain fatty acids from commercial butterfat (CBF) and n-3 and n-6 long-chain fatty acids from skipjack tuna eyeball oil (STEO). Redistribution was carried out via transesterification facilitated by Asian seabass liver lipase (ASL-L). Under the optimum conditions including a CBF/STEO ratio (3:1), transesterification time (60 h), and ASL-L unit (250 U), the newly formed modified-STEO (M-STEO) contained 93.56% triacylglycerol (TAG), 0.31% diacylglycerol (DAG), and 0.02% monoacylglycerol (MAG). The incorporated medium-chain fatty acids accounted for 18.2% of M-STEO, whereas ASL-L could incorporate 40% of n-3 fatty acids and 25–30% palmitic acid in M-STEO. The 1H NMRA and 13CNMR results revealed that the major saturated fatty acid (palmitic acid) and unsaturated fatty acids (DHA and EPA) were distributed at the sn-2 position of the TAGs in M-STEO. Thus, M-STEO enriched with medium-chain fatty acids and n-3 fatty acids positioned at the sn-2 position of TAGs can be a potential substitute for human milk fatty acids in infant formula milk (IFM). [ABSTRACT FROM AUTHOR]

Background: The tuna industry is one of the most essential sectors in global food production. Nevertheless, commercial meat known as "tuna loin" holds the utmost significance in producing and marketing its various products. Regrettably, fractions like tail and head meat have been overlooked and wasted due to their comparatively lower commercial value. Despite possessing notable technological value, this meat is typically reutilized into animal feed through flour production, missing the chance to create alternative high-value food products. Objective: This study aimed to develop and evaluate the sausages produced with the underutilized cuts of tuna (tail and head meat). Methods: The tuna utilized were Big-eye (Thunus obesus) and Skip-jack (Katsuwonus pelamis lineaus). Three (3) different types of sausages were formulated using 100% of Big-eye (BE), 100% of Skip-jack (SJ) tuna meat, and 100% of beef/pork meat (Control). The sausage pH changes during storage at 4 ± 1oC were analyzed and compared with the control. Proximal, microbiological, and sensory characteristics were evaluated. Results: The pH of sausages showed that the values tended to decrease in control, while this value increased in two types of tuna. The formulated tuna sausages yielded 72% moisture, 18% protein, 4.1% lipid, 0.4% ash, 0.4 % fiber, and 4.5% carbohydrates. Sensory attributes showed excellent acceptance regarding color, smell, flavor, and texture. Overall acceptability was qualified as "liked," and the acceptability index ranged from 76% to 86%. During the refrigeration storage, the microbiological analyses indicated that the total coliform count was < 3 CFU/g. Escherichia coli, Staphylococcus aureus, and mesophilic aerobic bacteria in tuna sausage showed absence during 24 days of storage. Conclusion: Using tuna tail and head meat enabled the development of gel-type emulsified products (sausages) that exhibited good nutritional, sensory, and microbiological quality. [ABSTRACT FROM AUTHOR]

Marine fish experience shifts in their distribution due to changes in the physical and biological environments. These shifts pose challenges for fishery businesses and management in international fisheries organizations. In the western and central Pacific Ocean, changes in the spatial distribution of skipjack tuna (Katsuwonus pelamis) due to climate variability often influence fishing activities and economic benefits. This study provides an operational forecast to enhance the decision-making process for fishery managers and fishermen by informing them about fish distributions in the coming months. Monthly forecasts of skipjack tuna habitat are generated utilizing a species distribution model (boosted regression trees) in combination with real-time environmental forecasts. An alternative method (dynamic time warping) is proposed to improve monthly chlorophyll forecasts, which are crucial for enhancing skipjack tuna habitat forecasting. To assess the prediction skills of the model, a retrospective analysis was conducted, forecasting skipjack tuna distribution over 9-month periods and comparing the forecasts with observed occurrences. The results demonstrate that 67.9% of the observed skipjack tuna catches occurred within the forecasted habitats, indicating that the forecast model skillfully predicted skipjack tuna movements 9 months in advance. These monthly updated forecasts can serve as a potential tool for resource managers in developing effective management strategies and fishers in planning fishing operations sustainably and responsibly. [ABSTRACT FROM AUTHOR]

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This research has utilized fish bone wastes of tuna (Katsuwonus pelamis) collected at the Lampulo fish market in Banda Aceh. Inorganic oxides have been derived from those fish bone wastes through the decomposition method at high temperatures, namely the calcination process in air atmosphere at 900ᴼC for 4 hours. The physicochemical properties of obtained inorganic oxides were characterized using XRD and SEM-EDS techniques. The characterization results indicated that the composition of the calcined fish bone contained hydroxyapatite, CaCO3, and CaO, in which the hydroxyapatite phase has been the major component. Furthermore, the calcination process positively impacts improving the physical morphology and crystalline phase of inorganic oxides. Finally, those obtained inorganic catalysts based on fish bone waste have been applied for transesterifying Coconut oil with methanol, resulting in three main compounds: trimethyl borate, methyl laurate, and methyl octanoate. [ABSTRACT FROM AUTHOR]

The Makassar Strait is one of the Indonesian Throughflow (ITF) branches that transports warm water masses from the Pacific Ocean to the Indian Ocean. These water masses have a significant impact on oceanographic parameters, which in turn affects the skipjack tuna distribution. Satellite-derived oceanographic factors from January 2015 to December 2020 included sea surface temperature (SST), chlorophyll-a, salinity, sea surface height (SSH), surface current, and surface wind are used to predict the potential habitat of skipjack tuna (Katsuwonus pelamis) in the Makassar Strait using the maximum entropy (MaxEnt) model. The SSH was the most important oceanographic variable affecting the skipjack tuna catch, contributing 49.7% to the model gain. An increasing skipjack tuna catch was observed within the following oceanographic variable ranges: 0.48–0.58 m of SSH, 34–35 ppt of salinity, 0.1–1.2 m/s of surface current, 29–30 °C of SST, 5–6 m/s of surface wind, and 0.1–0.5 mg/l of chlorophyll-a concentrations.

Excess harvesting power can threaten the long-term sustainability of fisheries. Indicators of excess harvesting capacity must include input–output-based estimates of economic production efficiency. The increasing use of drifting Fish-Aggregating-Devices (DFADs) has boosted fishing productivity in high-seas tuna fisheries, perhaps beyond the biological capacity of the stocks, and is an object of global debate. We carried out a Data Envelopment Analysis (DEA) of relative changes in production efficiencies of the French purse-seine fleet targeting tropical tuna in the western Indian Ocean using two fishing strategies: (1) on floating objects (FOB) and (2) free swimming schools (FSC) using tuna catch and effort data spanning 1992–2019. We show that FOB fishing evolved dramatically through time with an estimated change of 3.6%yr−1 (8.0%yr−1 2007–2019), in contrast to 2.1%yr−1 for FSC. While the efficiency level in combining and using inputs has barely changed for FOB fishing, it means that all the growth in productivity comes from technical change for this strategy. The dynamics is different for the FSC with a mixture of innovation and higher efficiency. Immediate plans to improve input-based management in this region are needed to prevent further risks of overfishing to yellowfin (Thunnus albacares) and skipjack (Katsuwonus pelamis) tunas. [ABSTRACT FROM AUTHOR]

In this study, the osteogenic properties and anti-osteoporosis activity of calcium hydroxyapatite (HA) obtained from Katsuwonus pelamis tuna bone and water-soluble structured forms of HA, such as the structured HA chloride citrate compound (HA-Cl-Ci) and the structured HA hydroxide lactate compound (HA-OH-Lac), were investigated. There was no significant cytotoxicity towards MC3T3-E1 pre-osteoblast and Caco-2 cells. HA enhanced osteogenic proliferation and differentiation after 7, 14, and 21 days of treatment, as demonstrated by alizarin red staining, alkaline phosphatase (ALP) activity, and qRT-PCR. Also, the anti-osteoporosis efficiencies of HA, HA-Cl-Ci, and HA-OH-Lac were evaluated in dexamethasone-induced MC3T3-E1 osteoblasts. HA, HA-Cl-Ci, and HA-OH-Lac had the potential to prevent glucocorticoid-induced osteoporosis effects. In addition, the transcellular transport of these compounds across the Caco-2 cell monolayers was investigated. Ca, P, and Mg derived from HA, HA-Cl-Ci, and HA-OH-Lac were absorbed in the intestinal tract. The absorption of these minerals may have resulted in the osteogenic proliferation, differentiation, and anti-osteoporosis activity. [ABSTRACT FROM AUTHOR]

Concentrations of heavy metals in Yellowfin and Skipjack tuna fishes from the Laccadive sea were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES) to evaluate the human health hazards via their consumption. The samples were collected from different atolls of Maldives to ensure a good representation of sample distribution. The metal concentration in tuna fish is found to be below the maximum tolerable limit set by different international organisations. The target hazard quotient values for individual metals were well below the limiting value of 1, indicating an insignificant health risk via the dietary intake of fish. The maximum targeted cancer risk value was 10 −4, indicating low carcinogenic risk from the consumption of tuna fish from the Maldives. Hence, the consumption of tuna from the Laccadive Sea is safe for human health. [ABSTRACT FROM AUTHOR]

Katsuwonus pelamis, or skipjack, is a vital resource in purse seine fishing across the Central and Western Pacific. Identifying skipjack distribution hotspots and coldspots is crucial for effective resource management, but the dynamic nature of fish behavior means these spots are not constant. We used Chinese fishing logbook data from 2010 to 2019 to analyze skipjack resource hotspots and coldspots in a space-time cube. The study revealed 13 spatiotemporal patterns in skipjack Catch per Unit Effort (CPUE). Hotspots (36.53%) were concentrated in the central area, predominantly showing oscillating hotspots (21.25%). The significant effect of the eastern oscillating hotspot continues to be enhanced and extends to the east. Coldspots constituted 63.47% of the distribution, mainly represented by intensifying coldspots (25.07%). The no-pattern-detected type (10.53%) is distributed between coldspots and hotspots. The fishing grounds exhibited longitudinal oscillations of 3°–6° and latitudinal oscillations of 1°–2°. The spatial autocorrelation of cold and hot spot distribution was strong, and the spatiotemporal dynamic changes in skipjack resources were closely related to the El Niño-Southern Oscillation (ENSO) phenomenon. Notably, during 2011–2016, hotspots exhibited an eastward expansion trend, which continued from 2017–2019 due to the influence of fishery management measures, such as the Vessel Day Scheme (VDS) system. [ABSTRACT FROM AUTHOR]

The increase in sea surface temperature (SST), a consequence of climate change, may lead to large-scale redistributions of global fish catch, including tuna in the Eastern Pacific Ocean (EPO). This paper applies the production function approach for modeling catch and SST using high-resolution gridded data for yellowfin and skipjack tuna catch in the EPO. We find a positive but nonlinear (i.e., logarithmic and quadratic) relationship between SST and the carrying capacity of tuna fisheries. The marginal product varies across species, distance from the equator, and the fishing method. For yellowfin tuna, the largest increase in catch occurs for unassociated and dolphin sets in the Northern EPO, while for skipjack tuna the largest increases in catch occur for unassociated and floating object sets in the Southern EPO. These thermal responses to ocean warming may lead to more segregated distribution and increased specialization in effort across the Eastern Pacific. [ABSTRACT FROM AUTHOR]

The Tongan fisheries targeting the species of albacore (Thunnus alalunga), bigeye (Thunnus obesus), skipjack (Katsuwonus pelamis), and yellowfin tuna (Thunnus albacares), comprising the main tuna catch landed, within the EEZ of Tonga is critical to the economy of Tonga. Thus, it is crucial to study the spatiotemporal pattern of their catch and the influence of environmental and physical variables, in addition to the month and year of the catch. To this end, sets of eight generalized additive models were applied to model the distribution of these four species. Selection among competing models was carried out based on k-fold cross-validation, using RMSPE prediction error as a measure of model predictive performance. The following sets of predictors were considered; sea surface temperature, sea surface chlorophyll, bottom depth, month, and year. In addition, to assess the influence of fronts, gradients in SST and Chl-a were computed and used as predictors. Catch year was the most important variable for all, except Albacore tuna, for which month was the important variable. The third most important variable was SST for albacore and bigeye tuna, whereas bottom depth was the most important variable for skipjack and yellowfin tuna. A standardized index of CPUE indicates mostly inter-annual variation in CPUE for albacore and bigeye tuna, whereas a it indicates a general increase in CPUE for skipjack and yellowfin tuna. Hotspots of albacore tuna catches are around the northern and southern edges of the exclusive economic zone and typically during the months of June to August. The bigeye tuna hotspots were concentrated on the eastern side of the islands, in waters overlying trenches; this was most obvious during the months of January to June. Skipjack tuna hotspots were near the edges of the exclusive economic zone, although it is caught in smaller amounts to the three tuna species considered and higher catch rates were observed only after 2014. For yellowfin tuna, the highest catch rates were concentrated around the islands and descending towards the southern edge of the EEZ. As part of the initiative of this study to support national optimal resource management, this study generated standardized CPUE (indices of abundance), an important input in stock assessment, and also looked into the potential influence of environmental and physical variables on the CPUE of these valuable tuna stocks within the EEZ of Tonga. [ABSTRACT FROM AUTHOR]

Despite the crucial role played by international and regional tuna fisheries in facilitating the successful implementation of the ecosystem approach to fisheries management, there exist disparities in viewpoints among these stakeholders, resulting in gaps between regional fisheries management and local communities. Nevertheless, the Tongan government, under the Ministry of Fisheries, is dedicated to the efficient management of its tuna resources, aiming to establish it as the preferred and optimal approach for ensuring the long-term sustainability of its tuna fisheries and the ecosystem services they provide to the community. Recognizing that an appropriate legal, policy and institutional framework is in place for sustainable management of tuna, the first part of this paper presents a review of current Tonga fisheries laws and policies for its tuna fisheries. This review reflects the implementation of an information-based management framework, namely the Tonga National Tuna Fishery Management and Development Plan. The tuna fisheries in Tonga mainly catch albacore (Thunnus alalunga), bigeye (Thunnus obesus), skipjack (Katsuwonus pelamis), and yellowfin (Thunnus albacares) tuna. These tuna species are caught within Tonga's exclusive economic zones and play a crucial role in the country's economy; hence, it is crucial to examine the spatio-temporal distributions of their catch in relation to their environmental conditions. In pursuit of this goal, the tasks of mapping (i) the spatio-temporal distribution of catch landed at ports and (ii) the spatio-temporal of environmental conditions were performed. The study utilizes longline catch per unit effort data spanning from 2002 to 2018 for albacore, bigeye, skipjack, and yellowfin tuna. It also incorporates data on environmental conditions, including sea surface temperature, sea surface chlorophyll, sea surface current, and sea surface salinity. Additionally, the El Nino Southern Oscillation Index is mapped in relation to catch data to examine the potential effects of climate change on the tuna catch. Results show that bigeye, skipjack, and yellowfin CPUE show a central–northernmost distribution and are primarily caught between latitudes 14° S–22° S, while albacore, shows a central–southern distribution. The highest CPUE for all species are in latitudes 15.5° S–22.5° S and longitudes 172.5° W–176.5° W. The data indicate that sea surface current velocities range from −0.03 to 0.04 ms−1, sea surface salinity ranges from 34.8 to 35.6 PSU, sea surface chlorophyll concentration varies from 0.03 to 0.1 mg m−3, and sea surface temperature fluctuates seasonally, ranging from 18 °C to 30 °C. Mapping also reveals that times of reduced catches in Tonga coincide with periods of moderate to strong El Nino events from 2002 to 2018. [ABSTRACT FROM AUTHOR]

Copyright of South China Fisheries Science is the property of South China Fisheries Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of South China Fisheries Science is the property of South China Fisheries Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of South China Fisheries Science is the property of South China Fisheries Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Reducing food loss and waste is crucial for a sustainable global food system and an efficient use of natural resources. Fast-growing tuna provides a key contribution to global nutrition targets; however, reports suggest that an appreciable proportion of the catch is lost from its value chain due to flesh quality issues, one of which is Mushy Tuna Syndrome (MTS). MTS-affected tuna flesh becomes soft and pasty, unfit for canning or human consumption, resulting in high wastage of partially processed material. We investigated the prevalence of MTS globally by surveying the tuna industry using a questionnaire. Of the responses from 32 companies across 14 nations, 97% acknowledged MTS as an issue that predominantly affects skipjack (Katsuwonus pelamis) tuna. The cost of rejects reported by participants from 2017 to 2019 varied greatly, from less than 1000 USD per year to over 1 million USD. The median cost was over 60,000 USD and the average rejection rate was 1.8%. The occurrence of MTS was noted to be seasonal, mainly in the summer months. More than half of the respondents who experience MTS reported an increasing trend of occurrence. Industry perceptions suggest MTS causes are associated with environmental, physiological, and biological factors. The survey results highlight that MTS is prevalent in the industry and demonstrate the need to identify amelioration strategies for the fishers and processors to minimise loss and maximise resource efficiency. [ABSTRACT FROM AUTHOR]

The conversion of Skipjack (Katsuwonus pelamis) dark meat into a hydrolysate via enzymatic hydrolysis is a promising approach to increase the value of tuna by-products as a source of bioactive peptides. Skipjack dark meat hydrolysate (SDMH) contains various sizes and sequences of peptides. To obtain and concentrate the targeted small peptides from SDMH, ultrafiltration, a key unit operation process, was employed to fractionate the protein hydrolysate due to its simplicity and productivity. The objective of this study was to investigate the effect of the feed pH on the membrane performance based on the permeate flux and the transmission of peptides. The fractionation of SDMH was performed using a ceramic membrane (molecular weight cut-off of 1 kDa) with three different pH values (5, 7, and 9) at various transmembrane pressures (TMP) (2.85, 3.85, and 4.85 bar). A high permeate flux and transmission were obtained at pH 9 due to the repulsive interactions between peptides and the membrane surface, leading to the reduction in concentration polarization that could promote high transmission. In addition, the combination of low TMP (2.85 bar) and pH 9 helped to even minimize the fouling formation tendency, providing the highest peptide transmission in this study. The fractionation process resulted in the enhancement of small peptides (MW < 0.3 kDa). The amino acid profiles were different at each pH, affirming the charge effect from the pH changes. In conclusion, the performance of the membrane was affected by the pH of the hydrolysate. Additionally, the ultrafiltration method served as an alternate method of peptide separation on a commercial scale. [ABSTRACT FROM AUTHOR]

To limit climate warming to 2°C above preindustrial levels, most economic sectors will need a rapid transformation toward a net zero emission of CO2. Tuna fisheries is a key food production sector that burns fossil fuel to operate but also reduces the deadfall of large‐bodied fish so the capacity of this natural carbon pump to deep sea. Yet, the carbon balance of tuna populations, so the net difference between CO2 emission due to industrial exploitation and CO2 sequestration by fish deadfall after natural mortality, is still unknown. Here, by considering the dynamics of two main contrasting tuna species (Katsuwonus pelamis and Thunnus obesus) across the Pacific since the 1980s, we show that most tuna populations became CO2 sources instead of remaining natural sinks. Without considering the supply chain, the main factors associated with this shift are exploitation rate, transshipment intensity, fuel consumption, and climate change. Our study urges for a better global ocean stewardship, by curbing subsidies and limiting transshipment in remote international waters, to quickly rebuild most pelagic fish stocks above their target management reference points and reactivate a neglected carbon pump toward the deep sea as an additional Nature Climate Solution in our portfolio. Even if this potential carbon sequestration by surface unit may appear low compared to that of coastal ecosystems or tropical forests, the ocean covers a vast area and the sinking biomass of dead vertebrates can sequester carbon for around 1000 years in the deep sea. We also highlight the multiple co‐benefits and trade‐offs from engaging the industrial fisheries sector with carbon neutrality. [ABSTRACT FROM AUTHOR]

The antimicrobial activity of SJGAP (skipjack tuna GAPDH-related antimicrobial peptide) and four chemical analogs thereof was determined under different physicochemical conditions, including different pH values, the presence of monovalent and divalent cations, and after a heating treatment. The toxicity of these five peptides was also studied with hemolytic activity assays, while their stability under human gastrointestinal conditions was evaluated using a dynamic in vitro digestion model and chromatographic and mass spectrometric analyses. The antibacterial activity of all analogs was found to be inhibited by the presence of divalent cations, while monovalent cations had a much less pronounced impact, even promoting the activity of the native SJGAP. The peptides were also more active at acidic pH values, but they did not all show the same stability following a heat treatment. SJGAP and its analogs did not show significant hemolytic activity (except for one of the analogs at a concentration equivalent to 64 times that of its minimum inhibitory concentration), and the two analogs whose digestibility was studied degraded very rapidly once they entered the stomach compartment of the digestion model. This study highlights for the first time the characteristics of antimicrobial peptides from Scombridae or homologous to GAPDH that are directly related to their potential clinical or food applications. [ABSTRACT FROM AUTHOR]

Organic heme iron in the form of heme iron polypeptide (HIP) is a bioavailable form of iron that can be used for dietary supplements. However, one practical challenge with HIP is that the quality of HIP prepared with different batches of raw material could lead to HIP products with inconsistent characteristics. In this study, skipjack tuna blood, a by-product in canned tuna industry, was converted to HIP at different degrees of enzymatic hydrolysis. The variation in HIP physical–chemical characteristics from different batches was evaluated, including composition, solubility, and molecular weight distribution. It was found that the batch variation had no effect on HIP composition and solubility; however, the degree of hydrolysis (DH) and the size of peptides that interact with heme greatly influenced HIP solubility at pH 2. Tuna-HIP with a low DH (DH, 8%) had 1.76-fold greater solubility than tuna-HIP with a high DH (DH, 32%). High-performance liquid chromatography (HPLC) revealed that tuna-HIP with a low DH had a molecular weight ranging from 1 kDa to 5 kDa. In summary, HIP-derived tuna blood was found to contain 70.54 ± 3.22 mg/100 g of iron and exhibit good solubility at 58.0 ± 2.16% at pH 2. Thus, tuna-HIP with a low DH might be a suitable functional ingredient for iron fortification of food. [ABSTRACT FROM AUTHOR]

Due to the continuous exploitation of skipjack tuna in the waters of Ternate Island, using active pole and line fishing gears, the skipjack tuna population is suspected to experience degradation in the waters of Ternate Island. Therefore, this research was conducted with the aim of analyzing the status of skipjack tuna populations in the waters of Ternate Island based on population dynamics studies, including parameters of growth, mortality, recruitment and exploitation rate. Experimental fishing methods were implemented to measure fish length which was then analyzed to determine the pattern of growth, mortality, exploitation rate and yield per recruit. The results showed that the parameter of the skipjack tuna population studied had an asymptote length (L∞) of 77.7 cm, with a growth coefficient of 0.4 per year and a t0 of -0.41. Furthermore, natural mortality (M) was 1.75, while the fishing mortality was determined as 1.60, and the current exploitation rate (E) showed a value of 0.48. These values indicate that the management of skipjack tuna in Ternate Island waters is close to optimum conditions (E = 0.5). [ABSTRACT FROM AUTHOR]

The potential impacts of climate change on the distribution of tuna in Pacific Island countries' exclusive economic zones have yet to be investigated rigorously and so their persistence and abundance in these areas remain uncertain. Here, we estimate optimal fisheries areas for four tuna species: albacore (Thunnus alalunga), bigeye (Thunnus obesus), skipjack (Katsuwonus pelamis), and yellowfin (Thunnus albacares). We consider different climate change scenarios, RCP 2.6, RCP 4.5, RCP 6.0, and RCP 8.5, within a set of tuna catch records in the exclusive economic zone of Tonga. Using environmental and CPUE datasets, species distribution modelling estimated and predicted these fisheries areas in the current and future climatic scenarios. Our projections indicate an expansion in area and a shift of productive areas to the southern part of this exclusive economic zone of Tonga. This is an indication that future climatic scenarios might be suitable for the species under study; however, changes in trophic layers, ocean currents, and ocean chemistry might alter this finding. The information provided here will be relevant in planning future national actions towards the proper management of these species. [ABSTRACT FROM AUTHOR]

The goal of the current study was to create a fast soup powder from Skipjack tuna (Katsuwonus pelamis). Tuna soup powder was prepared using three different traditional recipes and one recipe among them was selected based on taste panel's judgment. By combining dried tuna powder, wheat flour, milk powder, salt, black pepper, tomato, onion, garlic, ginger, coriander, fennel, carrot, sweetcorn and oil, formulations of tuna soup powder were created. This formulation were then subjected to proximate analysis. This formulation were then subjected to biochemical quality parameters analysis, microbiological quality analysis, sensory analysis were determined during 50 days of storage period and also workout economics of tuna soup powder. Tuna soup powder had 13.48% moisture, 38.43% protein, 0.0518% fat on dry basis, 12.65% ash during 50 days of storage at chilled condition. pH, water activity, TBA, TVB-N content of tuna soup powder increased during 50 days of storage and it remained at the level of acceptability. Tuna soup powder had a total plate count of 700 cfu/ml (0.7 X 10³ cfu/ml) at 0th day, at two months, there was a rise in the number of total plate count 1411 cfu/ml (1.411 × 10³ cfu/ml) in samples at 50th days of storage. Even though the trend was increasing until the storage period of 50 days, stayed within the limitations. Tuna soup powder samples were free of mould and yeast growths. Sensory analysis was observed from hedonic scale 9 to 8 in tuna soup powder during 50 days of storage. According to the results of research on shelf life evaluation, including moisture content, sensory assessment and microbiological investigation, tuna soup powder could be kept for two months without losing quality. The cost of production analysis' findings showed that the unit (11 grams) price and tuna soup powder were 12 rupees. [ABSTRACT FROM AUTHOR]