When economy meets ecology, is it truly conflicted? A dashboard approach to assess the sustainability performance of European tropical tuna purse seine fisheries.

The development of an ecosystem approach to fisheries management makes the assessment of the sustainability performance of fisheries a priority. This study examines European tropical tuna purse seine fleets as a case study, employing a multidisciplinary dashboard approach to evaluate historical and current sustainability performances. The aim is to enhance comprehension of the interconnected dimensions of sustainability and pinpoint management policy priorities. Using 18 indicators, we assessed the environmental, economic and social sustainability performances of European tropical tuna purse seine fleets, comparing them with other industrial tropical tuna fishing fleets in the Atlantic and Indian Oceans. The analysis also explored the temporal trend of sustainability performance for European tuna purse seiners from 2009 to 2019. Our results suggest that, compared with gillnetters and longliners, purse seiners and baitboats have a greater species-based selectivity, thereby catching fewer endangered, threatened or protected species, but a lower mature tuna catch rate, thus capturing more juveniles. We identify likely gaps in bycatch data reported by fishing on fish aggregating devices (FADs), due to results regarding selectivity and discard rates that appear inconsistent in the light of the scientific literature. The greater use of FADs, likely caused by the global tuna market, by purse seiner seems result in decreased ecological performances, as suggested by an increased carbon footprint per tonne landed. At the same time, it implies a better economic performance on the short-term, with higher net profit, energy efficiency (fuel consumed relative to monetary value created) and catch. For our case study, Ecology and Economy might seem to be in conflict for short-term perspective. However, consideration of the long-term impacts of FAD fishing and market incentives for fishing on free schools should lead purse seiner fleets to reduce drifting FAD fishing and promote more sustainable fishing practices.

Improved sports image classification using deep neural network and novel tuna swarm optimization.

Sports image classification is a complex undertaking that necessitates the utilization of precise and robust techniques to differentiate between various sports activities. This study introduces a novel approach that combines the deep neural network (DNN) with a modified metaheuristic algorithm known as novel tuna swarm optimization (NTSO) for the purpose of sports image classification. The DNN is a potent technique capable of extracting high-level features from raw images, while the NTSO algorithm optimizes the hyperparameters of the DNN, including the number of layers, neurons, and activation functions. Through the application of NTSO to the DNN, a finely-tuned network is developed, exhibiting exceptional performance in sports image classification. Rigorous experiments have been conducted on an extensive dataset of sports images, and the obtained results have been compared against other state-of-the-art methods, including Attention-based graph convolution-guided third-order hourglass network (AGTH-Net), particle swarm optimization algorithm (PSO), YOLOv5 backbone and SPD-Conv, and Depth Learning (DL). According to a fivefold cross-validation technique, the DNN/NTSO model provided remarkable precision, recall, and F1-score results: 97.665 ± 0.352%, 95.400 ± 0.374%, and 0.8787 ± 0.0031, respectively. Detailed comparisons reveal the DNN/NTSO model's superiority toward various performance metrics, solidifying its standing as a top choice for sports image classification tasks. Based on the practical dataset, the DNN/NTSO model has been successfully evaluated in real-world scenarios, showcasing its resilience and flexibility in various sports categories. Its capacity to uphold precision in dynamic settings, where elements like lighting, backdrop, and motion blur are prominent, highlights its utility. The model's scalability and efficiency in analyzing images from live sports competitions additionally validate its suitability for integration into real-time sports analytics and media platforms. This research not only confirms the theoretical superiority of the DNN/NTSO model but also its pragmatic effectiveness in a wide array of demanding sports image classification assignments.

Spray drying the Pickering emulsions stabilized by chitosan/ovalbumin polyelectrolyte complexes for the production of oxidation stable tuna oil microcapsules.

The microencapsulation of polysaturated fatty acids by spray drying remains a challenge due to their susceptibility to oxidation. In this work, antioxidant Pickering emulsions were attempted as feeds to produce oxidation stable tuna oil microcapsules. The results indicated that the association between chitosan (CS) and ovalbumin (OVA) was a feasible way to fabricate antioxidant and wettable complexes and a high CS percentage favored these properties. The particles could yield tuna oil Pickering emulsions with enhanced oxidation stability through high-pressure homogenization, which were successfully spray dried to produce microcapsules with surface oil content of 8.84 % and microencapsulation efficiency of 76.65 %. The microcapsules exhibited significantly improved oxidation stability and their optimum peroxide values after storage at 50 °C, 85 % relative humidity, or natural light for 15 d were 48.67 %, 60.07 %, and 39.69 % respectively lower than the powder derived from the OVA-stabilized emulsion. Hence, Pickering emulsions stabilized by the CS/OVA polyelectrolyte complexes are potential in the production of oxidation stable polyunsaturated fatty acid microcapsules by spray drying.

Modeling tropical tuna shifts: An inflated power logit regression approach.

We introduce a new class of zero-or-one inflated power logit (IPL) regression models, which serve as a versatile tool for analyzing bounded continuous data with observations at a boundary. These models are applied to explore the effects of climate changes on the distribution of tropical tuna within the North Atlantic Ocean. Our findings suggest that our modeling approach is adequate and capable of handling the outliers in the data. It exhibited superior performance compared to rival models in both diagnostic analysis and regarding the inference robustness. We offer a user-friendly method for fitting IPL regression models in practical applications.

Efficient acid hydrolysis for compound-specific δ15N analysis of amino acids for determining trophic positions.

Compound-specific isotope analysis of nitrogen in amino acids (CSIA-AA, δ15NAA) has gained increasing popularity for elucidating energy flow within food chains and determining the trophic positions of various organisms. However, there is a lack of research on the impact of hydrolysis conditions, such as HCl concentration and hydrolysis time, on δ15NAA analysis in biota samples. In this study, we investigated two HCl concentrations (6 M and 12 M) and four hydrolysis times (2 h, 6 h, 12 h, and 24 h) for hydrolyzing and derivatizing AAs in reference materials (Tuna) and biological samples of little egret (n = 4), night heron (n = 4), sharpbelly (n = 4) and Algae (n = 1) using the n-pivaloyl-iso-propyl (NPIP) ester approach. A Dowex cation exchange resin was used to purify amino acids before derivatization. We then determined δ15NAA values using gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). The results revealed no significant differences (p > 0.05) in δ15NAA values among samples treated with different HCl concentrations or hydrolysis times, particularly for δ15NGlx (range: 21.0-23.5‰) and δ15NPhe (range: 4.3-5.4‰) in Tuna (12 M). Trophic positions (TPs) calculated based on δ15NAA at 2 h (little egret: 2.9 ± 0.1, night heron: 2.8 ± 0.1, sharpbelly: 2.0 ± 0.1 and Algae: 1.3 ± 0.2) were consistent with those at 24 h (3.1 ± 0.1, 2.8 ± 0.1, 2.2 ± 0.1 and 1.1 ± 0.1, respectively), suggesting that a 2-h hydrolysis time and a 6 M HCl concentration are efficient pretreatment conditions for determining δ15NAA and estimating TP. Compared to the currently used hydrolysis conditions (24 h, 6 M), the proposed conditions (2 h, 6 M) accelerated the δ15NAA assay, making it faster, more convenient, and more efficient. Further research is needed to simplify the operational processes and reduce the time costs, enabling more efficient applications of CSIA-AA.

Relative sarcolipin (SLN) and sarcoplasmic reticulum Ca2+ ATPase (SERCA1) transcripts levels in closely related endothermic and ectothermic scombrid fishes: Implications for molecular basis of futile calcium cycle non-shivering thermogenesis (NST).

Regional endothermy is the ability of an animal to elevate the temperature of specific regions of the body above that of the surrounding environment and has evolved independently among several fish lineages. Sarcolipin (SLN) is a small transmembrane protein that uncouples the sarcoplasmic reticulum calcium ATPase pump (SERCA1b) resulting in futile Ca2+ cycling and is thought to play a role in non-shivering thermogenesis (NST) in cold-challenged mammals and possibly some fishes. This study investigated the relative expression of sln and serca1 transcripts in three regionally-endothermic fishes (the skipjack, Katsuwonus pelamis, and yellowfin tuna, Thunnus albacares, both of which elevate the temperatures of their slow-twitch red skeletal muscle (RM) and extraocular muscles (EM), as well as the cranial endothermic swordfish, Xiphias gladius), and closely related ectothermic scombrids (the Eastern Pacific bonito, Sarda chiliensis, and Pacific chub mackerel, Scomber japonicus). Using Reverse Transcription quantitative PCR (RT-qPCR) and species-specific primers, relative sln expression trended higher in both the RM and EM for all four scombrid species compared to white muscle. In addition, relative serca1 expression was found to be higher in RM of skipjack and yellowfin tuna in comparison to white muscle. However, neither sln nor serca1 transcripts were higher in swordfish RM, EM or cranial heater tissue in comparison to white muscle. A key phosphorylation site in sarcolipin, threonine 5, is conserved in the swordfish, but is mutated to alanine or valine in tunas and the endothermic smalleye Pacific opah, Lampris incognitus, which should result in increased uncoupling of the SERCA pump. Our results support the role of potential SLN-NST in endothermic tunas and the lack thereof for swordfish.

Optimal and sustainable production of tailored fish protein hydrolysates from tuna canning wastes and discarded blue whiting: Effect of protein molecular weight on chemical and bioactive properties.

Thousands tons of discards of blue whiting (BW) and tuna heads (YT) by-products are generated each year in Europe. BW is the species most discarded by European fishing fleet and, in some canning factories, YT are processed for the retrieval of oil rich in omega-3, but producing a huge amount of solid remains and effluents disposal as wastes. The development of optimal and sustainable processes for both substrates is mandatory in order to reach clean solutions under the circular economy precepts. This work focused on the mathematical optimization of the production of tailored fish protein hydrolysates (FPH), from blue whiting and tuna residues, in terms of controlling average molecular weights (Mw) of proteins. For the modeling of the protein depolymerization time-course, a pseudo-mechanistic model was used, which combined a reaction mechanistic equation affected, in the kinetic parameters, by two non-lineal equations (a first-order kinetic and like-Weibull formulae). In all situations, experimental data were accurately simulated by that model achieving R2 values higher than 0.96. The validity of the experimental conditions obtained from modeling were confirmed performing productions of FPH at scale of 5 L-reactor, without pH-control in most of cases, at the different ranges of Mw selected (1-2 kDa, 2-5 kDa and 5-10 kDa). The results showed that FPH from BW with lower Mw led to a remarkable yield of production (12 % w/w of substrate), largest protein contents (77 % w/w of BW hydrolysate), greatest in vitro digestibility (>95 %), highest essential amino acid presence (43 %) and the best antioxidant (DPPH = 62 %) and antihypertensive (IC50-ACE = 80 mg/L) properties. Our results prove that the proposed procedure to produce sustainable FPH, with specific Mw characterisitics, could be extended to other fish waste substrates. Tailored FPH may have the potential to serve as valuable ingredients for functional foods and high-quality aquaculture feed.

Differentiation of three commercial tuna species through GC-Q-TOF and UPLC-Q/Orbitrap mass spectrometry-based metabolomics and chemometrics.

Food fraud is common in the tuna industry because of the economic benefits involved. Ensuring the authenticity of tuna species is crucial for protecting both consumers and tuna stocks. In this study, GC-Q-TOF and UPLC-Q/Orbitrap mass spectrometry-based metabolomics were used to investigate the metabolite profiles of three commercial tuna species (skipjack tuna, bigeye tuna and yellowfin tuna). A total of 22 and 77 metabolites were identified with high confidence using GC-Q-TOF and UPLC-Q/Orbitrap mass spectrometry, respectively. Further screening via chemometrics revealed that 38 metabolites could potentially serve as potential biomarkers. Hierarchical cluster analysis showed that the screened metabolite biomarkers successfully distinguished the three tested tuna species. Furthermore, a total of 27 metabolic pathways were identified through enrichment analysis based on the Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathways.

Organ-specific mercury stable isotopes, speciation and particle measurements reveal methylmercury detoxification processes in Atlantic Bluefin Tuna.

Identifying metabolism and detoxification mechanisms of Hg in biota has important implications for biomonitoring, ecotoxicology, and food safety. Compared to marine mammals and waterbirds, detoxification of MeHg in fish is understudied. Here, we investigated Hg detoxification in Atlantic bluefin tuna Thunnus thynnus using organ-specific Hg and Se speciation data, stable Hg isotope signatures, and Hg and Se particle measurements in multiple tissues. Our results provide evidence for in vivo demethylation and biomineralization of HgSe particles, particularly in spleen and kidney. We observed a maximum range of 1.83‰ for δ202Hg between spleen and lean muscle, whereas Δ199Hg values were similar across all tissues. Mean percent methylmercury ranged from 8% in spleen to 90% in lean muscle. The particulate masses of Hg and Se were higher in spleen and kidney (Hg: 61% and 59%, Se: 12% and 6%, respectively) compared to muscle (Hg: 2%, Se: 0.05%). Our data supports the hypothesis of an organ-specific, two-step detoxification of methylmercury in wild marine fish, consisting of demethylation and biomineralization, like reported for waterbirds. While mass dependent fractionation signatures were highly organ specific, stable mass independent fractionation signatures across all tissues make them potential candidates for source apportionment studies of Hg using ABFT.

Spatial distribution models for the four commercial tuna in the sea of maritime continent using multi-sensor remote sensing and maximum entropy.

The dynamic of marine environmental parameters affects the distribution of commercial tuna in the sea of the maritime continent. Hence, the objectives of this study are to develop spatial distribution models for the four main tuna species in the Maritime continent's sea with reasonable accuracy, identify their correlation with marine environmental parameters, and investigate areas of interaction between those tuna species. The study develops the distribution models for albacore (Thunnus alalunga), bigeye (Thunnus obesus), yellowfin (Thunnus albacares), and skipjack (Katsuwonus pelamis) tuna species, utilizing multi-sensor satellite remote sensing and maximum entropy. The results show models have good performance, focusing on environmental factors such as sea surface temperature (SST), chlorophyll-a (CHL), and sea surface height anomalies (SSHA), combined with eddy kinetic energy (EKE). Seasonal variations in potential tuna habitats are revealed, emphasizing the influence of those marine environmental conditions. From December to May, the four commercial tuna species were distributed in conditions characterized by SST of 26-31.5 °C, CHL levels of 0-3 mg/l, SSHA of -0.3 to 0.2 m, and EKE of 0-1 m2/s2, while from June to November, they experienced SST of 23-31 °C, CHL levels of 0-4 mg/l, SSHA of -0.5 to 0.3 m, and EKE of 0-1.1 m2/s2. The spatial persistence of the four tuna species emerged mainly around the south sea of Java, with skipjack being the most common species found in the sea of the maritime continent. With sufficient and evenly distributed tuna presence records, the results indicate the potential for extrapolation beyond the training data to estimate habitat suitability for the four commercial tuna distributions. The results also suggest potential competition between tuna species sharing ecological niches and highlight possible overlapping areas where different tuna species interact with the same fishing gear.

Discrimination of three commercial tuna species through species-specific peptides: From high-resolution mass spectrometry discovery to MRM validation.

The risk of tuna adulteration is high driven by economic benefits. The authenticity of tuna is required to protect both consumers and tuna stocks. Given this, the study is designed to identify species-specific peptides for distinguishing three commercial tropical tuna species. The peptides derived from trypsin digestion were separated and detected using ultrahigh-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOF/MS) in data-dependent acquisition (DDA) mode. Venn analysis showed that there were differences in peptide composition among the three tested tuna species. The biological specificity screening through the National Center for Biotechnology Information's Basic Local Alignment Search Tool (NCBI BLAST) revealed that 93 peptides could serve as potential species-specific peptides. Finally, the detection specificity of species-specific peptides of raw meats and processed products was carried out by multiple reaction monitoring (MRM) mode based on a Q-Trap mass spectrometer. The results showed that three, one and two peptides of Katsuwonus pelamis, Thunnus obesus and Thunnus albacores, respectively could serve as species-specific peptides.

Three cases of scombroid syndrome in Italy: clinical and preventive considerations.

Background: Foodborne diseases are common sources of morbidity and mortality worldwide. Scombroid syndrome represents a particular condition since it is not directly related to the ingestion of spoiled food but is determined by high levels of histamine, a chemical mediator naturally produced within the human body under particular conditions. In these cases, histamine is formed as a result of the bacterial activity from histidine, an amino acid present at high levels in some fish species. The resulting symptomatology can range from mild symptoms such as headache and skin rash to more severe manifestations such as hypotension and coronary spasms. Reference regulations in Italy set maximum levels of histamine in food at 200 mg/kg. Cases description: The cases described involve a family of three who, following the ingestion of a tuna dish, started to exhibit symptoms typical of an allergic reaction. In one case, hypotension, tachycardia, and electrocardiographic changes in the ST-tract suggestive of myocardial ischemia also appeared with negative myocardionecrosis enzyme dosage. All three cases experienced complete remission of symptoms in the absence of sequelae. Histamine concentrations in fish sampled three days later were 169 mg/kg. Conclusion: The cases described emphasize the importance of proper differential diagnosis as well as the importance of implementing specific controls in food hygiene.

Environmental DNA as a tool to reconstruct catch composition for longline fisheries vessels.

Global wild-capture fisheries are a large and diverse sector requiring various tools for fisheries-dependant data collection and effective Monitoring, Control and Surveillance (MCS). Here we present a novel protocol to collect eDNA from brine tanks onboard commercial longline vessels to reconstruct catch composition. We collected samples from nine vessels operating out of the Eastern Tuna Billfish Fishery, Australia, validating eDNA results with reliable catch data consisting of seven target and bycatch species. Environmental DNA was highly effective for detecting species retained on vessels without contamination or false positives. For four vessels, logbook data and eDNA were consistent with detections of all species. The remaining vessels detected all species except for rare catches of short-billed spearfish (Tetrapturus angustirostris). Similarities between rank abundance distributions of catch and eDNA reads were observed with logbook data mirrored when eDNA sequences were organised into rank order abundance. The method was effective at identifying highly abundant taxa retained in brine tanks- tuna (Thunnus spp.), swordfish (Xiphias gladius), marlin (Kajijia audax), and Atlantic Pomfret (Brama brama). Further research is required to validate how eDNA and other molecular monitoring tools can be scaled and applied to provide solutions for monitoring challenges in the fisheries sector.

Identification of Hyperuricemia Alleviating Peptides from Yellow Tuna Thunnus albacares.

The development of food-derived antihyperuricemic substances is important for alleviating hyperuricemia (HUA) and associated inflammation. Here, novel peptides fromThunnus albacares (TAP) with strong antihyperuricemic activity were prepared. TAP was prepared by alkaline protease (molecular weight <1000 Da), with an IC50 value of xanthine oxidase inhibitory activity of 2.498 mg/mL, and 5 mg/mL TAP could reduce uric acid (UA) by 33.62% in human kidney-2 (HK-2) cells (P < 0.01). Mice were fed a high-purine diet and injected with potassium oxonate to induce HUA. Oral administration of TAP (600 mg/kg/d) reduced serum UA significantly by 42.22% and increased urine UA by 79.02% (P < 0.01) via regulating urate transporters GLUT9, organic anion transporter 1, and ATP-binding cassette subfamily G2. Meantime, TAP exhibited hepatoprotective and nephroprotective effects, according to histological analysis. Besides, HUA mice treated with TAP showed anti-inflammatory activity by decreasing the levels of toll-like receptor 4, nuclear factors-κB p65, NLRP3, ASC, and Caspase-1 in the kidneys (P < 0.01). According to serum non-targeted metabolomics, 91 differential metabolites between the MC and TAP groups were identified, and purine metabolism was considered to be the main pathway for TAP alleviating HUA. In a word, TAP exhibited strong antihyperuricemic activity both in vitro and in vivo.

First record of mercury concentrations and stable isotopes (13C & 15N) in albacore (Thunnus alalunga) from the Western Equatorial Atlantic Ocean.

This paper reports the first record of total mercury (THg) concentrations in albacore (Thunnus alalunga), one of the main tuna species caught from the Western Equatorial Atlantic Ocean and presents a preliminary comparison with other regions and tuna species. Mean, standard deviation and range of concentrations in T. alalunga (515 ± 145 ng g-1 ww; 294-930 ng g-1 ww) with 92 % being of methyl-Hg, are higher than in albacore from other Atlantic Ocean subregions despite their smaller body size. These concentrations are similar to those from the Pacific and Indian oceans, but lower than in the Mediterranean. Compared to other sympatric tuna species, concentrations are higher than those in T. albacares and similar to T. obesus. These results are discussed considering the potential differences in stable isotope values (13C and 15N) of T. alalunga populations from multiple oceanic areas and compared to other tuna species worldwide.

Undervalued tuna meat (Thunus obesus and Katsuwonus pelamis lineaus) to develop sausages / Carne infravalorada de atún (Thunnus obesus y Katsuwonus pelamis linnaeus) para desarrollar salchichas

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

Antecedentes: La industria atunera se erige como uno de los sectores más importantes en la producción mundial de alimentos. Sin embargo, entre sus diversos productos, la carne comercial conocida como "lomo de atún" ostenta la mayor importancia tanto en su producción como en su comercialización. Lamentablemente, fracciones de carne provenientes de la cola y la cabeza se han desperdiciado debido a su reducido valor comercial. A pesar de poseer un notable valor tecnológico, esta carne normalmente es utilizada en la alimentación animal mediante la producción de harina, perdiendo la oportunidad de desarrollar productos alimenticios alternativos con alto valor nutricional. Objetivo: Este estudio tuvo como objetivo desarrollar y evaluar salchichas producidas con carne subutilizada de atún (carne de cola y cabeza). Métodos: Las especies de atún utilizadas fueron Big-eye (Thunus obesus) and Skip-jack (Katsuwonus pelamis lineaus). Se formularon tres (3) tipos diferentes de salchichas usando 100 % de carne de atún Big-eye (BE), 100 % de Skip-jack (SJ) y 100 % de carne de res/cerdo (Control). Se analizaron los cambios de pH en las salchichas durante el almacenamiento a 4 ± 1 oC y se compararon con el Control. También se evaluaron la composición proximal, calidad microbiológica y atributos sensoriales. Resultados: El pH mostró que los valores tendieron a disminuir en relación a la muestra Control, mientras que este valor aumentó en los dos tipos de salchicha con carne de atún. Las salchichas con carne de atún mostraron un 72 % de humedad, 18 % de proteína, 4,1 % de lípidos, 0,4 % de ceniza, 0,4 % de fibra, 4,5 % de carbohidratos. Los atributos sensoriales mostraron buena aceptabilidad de los parámetros de color, olor, sabor y textura. La aceptabilidad general se calificó como "me gusta" y el índice de aceptabilidad osciló entre el 76 % y el 86 %. Durante el periodo de almacenamiento en refrigeración, los análisis microbiológicos indicaron que el recuento de coliformes totales fue < 3 UFC/g. No se evidenció la presencia de Escherichia coli, Staphylococcus aureus y bacterias aerobias mesófilas durante 24 días de almacenamiento. Conclusión: El aprovechamiento de la carne de la cola y cabeza del atún permitió desarrollar productos emulsionados tipo gel (embutidos) que exhibieron buena calidad nutricional, sensorial y microbiológica.

Mesoscale activity drives the habitat suitability of yellowfin tuna in the Gulf of Mexico.

Yellowfin tuna, Thunnus albacares, represents an important component of commercial and recreational fisheries in the Gulf of Mexico (GoM). We investigated the influence of environmental conditions on the spatiotemporal distribution of yellowfin tuna using fisheries' catch data spanning 2012-2019 within Mexican waters. We implemented hierarchical Bayesian regression models with spatial and temporal random effects and fixed effects of several environmental covariates to predict habitat suitability (HS) for the species. The best model included spatial and interannual anomalies of the absolute dynamic topography of the ocean surface (ADTSA and ADTIA, respectively), bottom depth, and a seasonal cyclical random effect. High catches occurred mainly towards anticyclonic features at bottom depths > 1000 m. The spatial extent of HS was higher in years with positive ADTIA, which implies more anticyclonic activity. The highest values of HS (> 0.7) generally occurred at positive ADTSA in oceanic waters of the central and northern GoM. However, high HS values (> 0.6) were observed in the southern GoM, in waters with cyclonic activity during summer. Our results highlight the importance of mesoscale features for the spatiotemporal distribution of yellowfin tunas and could help to develop dynamic fisheries management strategies in Mexico and the U.S. for this valuable resource.

Risk assessment of some toxic metals in canned fish products retailed in Mansoura, Egypt.

Background: Canned fish products are widely consumed in Egypt, particularly for protein-rich meals that are quick to prepare and low in calories. Canned fish products are contaminated with toxic metals from the fish itself or from canning materials during processing. Aim: To determine the residual levels of cadmium (Cd), lead (Pb), arsenic (As), mercury (Hg), aluminum (Al), and Tin (Sn) in some canned fish products obtained from retail shops in Mansoura, Egypt. Furthermore, noncarcinogenic health risks evaluation for the Egyptian population due to hazardous metal oral intake. Methods: One hundred canned fish products (20 each of herring, mackerel, salmon, sardine, and tuna) were collected from May to September 2023, and canned fish products were obtained from Mansoura city markets in Egypt. Samples were digested in a solution composed of 60% nitric acid and 40% perchloric acid, and then an atomic absorption spectrophotometer was used for the detection of selected toxic metals. Results: It was found that the residual level of hazardous metals exceeded the acceptability level established in the European Union for Pb, Cd, and Hg by 20%, 10%, and 10%, 15%, 5%, and 20%, 35%, 30%, and 45%, 25%, 25%, and 40%, in examined herring, mackerel, sardine, and tuna, respectively. In contrast, all salmon samples were accepted for Pb and Hg, and only 5% were not accepted due to a higher Cd level than the maximum permissible limit. The average estimated daily intake of (EDI) is below the tolerable daily intakes (TDIs) for all metals. Comparatively, the EDI of Hg was 0.265 µg/kg body weight (B.W) exceeded TDIs 0.228 µg/kg B.W. The hazard index for canned tuna and sardines is more than one. Conclusion: Canned fish products are contaminated with a variety of toxic metals, especially sardine and tuna. Therefore, it is advised to decrease the consumption rate of such fish products.

Enzymatically produced acylglycerol and glycerin monostearate additives improved the characteristics of gelatin-stabilized omega-3 emulsions and microcapsules.

The impacts of enzymatically produced acylglycerol and glycerin monostearate on the characteristics of gelatin-stabilized omega-3 emulsions and microcapsules were investigated. Tuna oil was enzymatically produced and the resulting acylglycerol was mixed with tuna oil at 12.5% (w/w) to prepare a novel oil phase. This oil phase was stabilized by gelatin to prepare oil-in-water emulsions and subsequent microcapsules via complex coacervation. The tuna oil with glycerin monostearate (GMS) at 1 and 2% (w/w) were used as controls. Results showed that both acylglycerol and GMS significantly reduced the emulsion droplet size and zeta potential, while increasing the viscoelasticity and stability. The diacylglycerol/monoacylglycerol were involved in the oil/water interfacial layer formation by lowering interfacial tension and increasing droplet surface hydrophobicity. Overall, the changed emulsion properties promoted the complex coacervation and contributed to the formation of microcapsules with improved oxidative stability. Therefore, enzymatically produced acylglycerol can develop high-quality stable omega-3 microencapsulated novel food ingredients.

Fishing effort dynamics around the Galápagos Marine Reserve as depicted by AIS data.

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.