Skipjack Research Articles

How technical change has boosted fish aggregation device productivity in the Indian Ocean tuna fishery

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.

Spatiotemporal Patterns in the Distribution of Albacore, Bigeye, Skipjack, and Yellowfin Tuna Species within the Exclusive Economic Zones of Tonga for the Years 2002 to 2018

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.

Real-time multi-month forecasting of skipjack tuna (Katsuwonus pelamis) habitat in the western and central Pacific Ocean for improved fishing efficiency and fisheries management

Abstract 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.

The effect of climate oscillations on skipjack tuna (Katsuwonus pelamis) in the Indian Ocean

Skipjack tuna (Katsuwonus pelamis) (SKJ) is one of the most commercially important marine fish species distributed throughout the world's tropical and subtropical oceans. The Indian Ocean is a main fishing ground for SKJ, whose exploitation rate is just below the maximum sustainable yield. Therefore, SKJ stocks may potentially be significantly affected by climate change. In this study, climatic oscillation indices related to the Indian Ocean, including the Indian Ocean Dipole (IOD), the mean water temperature anomaly in the Eastern Indian Ocean (EIO) and Western Indian Ocean (WIO), the Madden-Julian Oscillation Index at 80°E (MJO80) and the Arctic Oscillation Index (AOI), were associated with SKJ catch per unit effort (CPUE). This study aimed to understand the effect of these five climatic oscillations on SKJ, with the goal of optimizing the utilization of skipjack tuna in the Indian Ocean. We combined gradient forest analysis (GFA) and generalized additive models (GAMs) to evaluate the importance of each climatic index with a 0–5 year lag on the impact of SKJ CPUE and to establish an optimal prediction model. The GFA results show that MJO80 is the most important climatic index influencing SKJ CPUE, followed by MJO80_1, AOI_2, IOD_4, WIO_2, etc. The best GAM model includes MJO80, AOI_2, and WIO_2, which could be related to the recruitment and larval survival of SKJ by influencing water temperature. Meanwhile, there is a significant negative correlation between SST and SKJ CPUE in the tropical regions of the western and central Indian Ocean. Our results suggest that climate oscillations have a 0–2 year lag effect on the SKJ fishery in the Indian Ocean, which can be used to predict resource changes in SKJ over the next 2 years.

Studies on blocking the JAK2/STAT3 signaling pathway with elastin peptides from skipjack tuna (Katsuwonus pelamis) bulbus cordis to alleviate osteoarthritis

Osteoarthritis (OA) is a chronic disease associated with bone and muscle degeneration that causes great disturbances to daily lives. Skipjack tuna elastin peptides (STEP) is a kind of small molecule mixed peptides extracted from skipjack tuna bulbus cordis that have multiple active functions, including anti-inflammatory activity. However, it is ambiguous whether STEP reduce OA inflammation. Zebrafish served as a model in the present research for verifying the anti-inflammatory efficacy of STEP. Then, the composition of STEP was figured out by LC-MS/MS analysis, and the potential anti-inflammatory peptides were screened by molecular docking and microscale thermophoresis (MST). Finally, in vitro experiments were conducted on the potential peptides. According to the in vivo findings, STEP protected the cartilage tissues of zebrafish and regulated the expression of inflammatory factors and the JAK2/STAT3 signaling pathway. The in vitro results showed that the potential peptides (LGVGSPPGK, GFDPSR and PGAPGGGFDI) positively regulated the inflammatory responses and the JAK2/STAT3 signaling pathway and were effective in inhibiting extracellular matrix (ECM) degeneration and chondrocyte apoptosis. As a consequence, STEP possess anti-inflammatory and chondroprotective effects and could be a functional product for the alleviation of OA.

Potential fishing grounds of Skipjack tuna (Katsuwonus pelamis) in western water of Sumatera using remotely sensed data and maximum entropy model

The fishery of skipjack tuna (Katsuwonus pelamis) was collected from the vessel monitoring system (VMS) as well as satellite oceanographic data for salinity, chlorophyll-a (chl-a) concentrations, and sea surface temperature (SST) used to determine the effects of oceanographic factors on potential fishing grounds for skipjack tuna in the western water of Sumatera (WWS). Salinity, chl-a and SST data were downloaded from the INDESO project website. The relationship between these parameters and the potential skipjack fishing area was analyzed using a maximum entropy (maxent) model. The Maxent model demonstrated its potential to predict the spatial distribution of skipjack, expressed as the area under the 0.852 curve value. In addition, jackknife test results indicate that the spatial pattern of fishery potential was influenced mainly by chl-a (0.50), followed by salinity (0.43) and SST (0.10). The integration of multi-sensor remote sensing data and modelling methods provides an ingenious way to determine a potential skipjack catch in the western water of Sumatera.

Bioactive peptide prediction of skipjack tuna (Katsuwonus Pelamis) hydrolysates using in silico

Katsuwonus pelamis or locally called skipjack tuna has been used as food for centuries by different populations. It is one of the important sources of protein for human health. Hydrolysate is one of the ways to utilize the primary function of protein as a natural protein source. The hydrolysate is known to have many bioactivates that may benefit human health such as immunodulators, anticancer, antihypertensive, antioxidant and anti-inflammatory. The current study aimed to explore the potential of Katsuwonus pelamis hydrolysate as a potential bioactivity agent. Gene bank of Katsuwonus pelamis obtained from NCBI then analyzed using BIOPEP. The software can predict the potential biopeptides as a bioactive agent. Furthermore, the BIOPEP also capable of predicting the contributing sensory taste based on peptides from Katsuwonus pelamis. The toxicity of promising peptides is then analyzed using ProTox II to determine the exact LD50 of each potential peptide. Results show that the most dominant bioactivities of Katsuwonus pelamis is ACE inhibitor followed by DPP IV inhibitor. Sensory analysis shows that the most contributing taste on Katsuwonus pelamis peptides is bitter followed by sour taste. The potential peptides are dominated by class V toxicity levels with LD50 value of 2000<LD50≤5000 mg/kg. The research suggests that Katsuwonus pelamis hydrolysates are proven to be a potential bioactive agent that can be utilized as a functional food for human health benefits

Volatile Compounds Detected by SPME-GC-MS in Fish Viscera Extracts with Attractant Activity Against House Fly Musca Domestica from Chemometric FTIR Fingerprints

Fish viscera has been locally applied as fly attractant in North Moluccas. The objective of this study was to evaluate the efficacy of attractant from fish viscera extracts and to determine the indispensable active extracts with chemometric FTIR fingerprints, as well as to characterize volatile compounds of the extracts. Attractant activity against house fly Musca domesctica and FTIR spectra were analyzed for the ethanol, acetone and hexane extracts of stomach, intestines, liver, and combination of the viscera from skipjack tuna stored for 1-2 days at room temperature. SPME-GC-MS analysis was applied for active extracts to determine volatile compounds. OPLS analysis result showed that FTIR spectra were correlated with the attractant activity (R2 0.974 and Q2 0.89), and compounds with functional groups S-H, N-H, O-H, and C-O have the strong correlation. Ethanol and acetone extracts of mixed viscera from 2 days storage are the active extracts. The volatile compounds in the extract through the SPME-GC-MS analysis belong to ketone, amine, phenol, heterocyclic, aromatic aldehyde, fatty acid, fatty acid ester and sulfur compounds are reported.

Ecosystem Management Policy Implications Based on Tonga Main Tuna Species Catch Data 2002–2018

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.

Is Mushy Tuna Syndrome a Growing Problem for the Tuna Industry?

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.

Re-evaluating age estimation using daily increments on otoliths of the skipjack tuna Katsuwonus pelamis

This study compared the microstructures of transverse sections and surface of the otoliths of skipjack tuna. Pairs of otoliths were extracted from the same individuals (fork length [FL]: 6.5–77.5 cm) to examine the difference in the counts of the daily increments between the sections. The increments counted on the transverse section were less than those on the surface section, and the difference between the two sections increased with body size. Even high-resolution scanning electron microscopy did not enhance the difference between the two sections. Increments in the transverse section would not occur daily, which makes otoliths from this section unsuitable for age estimation. Subsequently, we re-evaluated the age estimated using the surface reading with new criteria and compared them with the results of a reference study. Despite successful age estimates using surface otoliths exposed by an etching method, practical difficulties in the method and vague criteria for reading increments have been raised against their reliability for age estimation. By reproducing detailed procedures of the etching method and using reading criteria, we estimated the ages of individuals at various life stages. In applying the criteria, the coefficient of variation (CV) for increment counts among readers decreased. In particular, the criteria reduced the CV for the transition area where the width between increments gradually narrows after the 50th–90th increment. The age estimates (FL < 40 cm) using the criteria are reasonably fit to the growth curve reported in the reference study with validation of daily increment deposition for surface reading. Thus, the new criteria are suitable for estimating age estimation in skipjack tuna up to an FL of 40 cm.

Present Status and Future Developmental Perspectives of Pole and Line Fishery in Sri Lanka

Present Status and Future Developmental Perspectives of Pole and Line Fishery in Sri Lanka

The Effect of Different pH Conditions on Peptides' Separation from the Skipjack Dark Meat Hydrolysate Using Ceramic Ultrafiltration.

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.

ANALISIS POTENSI Chlorella Sp. DI PANTAI BASE-G SEBAGAI BAHAN BIODIESEL DENGAN UJI PROKSIMAT

Background: Phytoplankton is one of the microalgae that has great potential as an energy source, one of which is Chlorella sp.. Chlorella sp. is the largest producer of protein compared to other types of phytoplankton. The lipid and fatty acid content in microalgae is a source of energy that plays a role in the process of making biodiesel. Phytoplankton type Chlorella sp. easy to cultivate and breed. Supporting breeding in the process is supported by the use of fertilizers that are rich in nutrients so that it will optimize the growth of these phytoplankton. Generally fertilizer is divided into two, namely inorganic fertilizer and organic fertilizer. The aim of this research was to determine the fat content of Chlorella sp. which was obtained from the results of culture with the treatment of giving skipjack tuna fertilizer through a proximate test. Methods: This research was conducted by taking samples of Chlorella sp. At Base-G Beach. Samples were cultured and added liquid fertilizer from skipjack fish waste at a concentration of 4;8;12 ml/L. Chlorella sp. The culture results were calculated for cell density and tested for fat content through proximate fat analysis. Results: The study showed that the density of microalgae cells produced ranges from 0.21 x106 cells/ml to 0.51x106 cells/ml. The average proximate analysis of fat in microalgae was 0.022%-0.039% (w/w). The application of skipjack tuna waste fertilizer affected the proximate fat value of Chlorella sp. (p&lt;0.05). Conclusion: The proximate fat content in Chlorella sp samples from Base-G beach which were cultured with the addition of liquid skipjack tuna waste fertilizer was 0.022-0.039% (w/w).

Assessing the Activity under Different Physico-Chemical Conditions, Digestibility, and Innocuity of a GAPDH-Related Fish Antimicrobial Peptide and Analogs Thereof.

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.

Optimization the Management of Tihu Village Resources to Increase the Income of Village Communities

Geographically Tihu village is located on the coast where the majority of its residents work as fishermen. Skipjack tuna is a type of fish that is abundant in Tihu village. The habit of fishermen distributing their catch to consumers causes the economic value of sales to be less than optimal. Processing skipjack tuna into shredded fish and nuggets will support the increased income of the society of Tihu village. This society service provides training to the Tihu village society to make floss, nuggets and coconut cookies according to BPOM standards as well as packaging and online marketing method. This training was carried out so that the Tihu village society could optimize their natural resources to increase their income.

Application of coconut shell liquid smoke on dried skipjack tuna (Katsuwonus pelamis) quality

Liquid smoke is produced from incomplete combustion, contains various compounds with functional properties that can provide aroma, taste, and color. Liquid smoke can be used as a preservative because it contains phenols and acids as anti-bacterial and antioxidant. Application of liquid smoke as a preservative can be done in the drying process using an oven. The purpose of this study was to determine the effect of the use of liquid smoke on the quality and organoleptic of dried skipjack tuna. The use of liquid smoke in the study was 0.5%, 1% and 1.5% consisting of 3 replications. Using a completely randomized design (CRD) and the smallest real test (BNJ). Parameters observed include water content, protein content, ash content and organoleptic test consisting of 25 panellists. The results showed that the lowest water content and the highest protein were found in the A2 treatment (use of liquid smoke 1%) at 47.7% and 50.71%, respectively. The highest ash content was found in treatment A1 (0.5% liquid smoke) at 4.56%. While the highest overall organoleptic assessment of color, taste, texture and aroma were the dried Skipjack Tuna with 1,5% liquid smoke with a score of 4.4.

Characterization and evaluation of antioxidant properties of skipjack (Katsuwonus pelamis) tuna skin gelatin Hydrolysate

The present society is extremely conscious of the lifestyle-related ailments and the serious consequences that result from an unhealthy diet and lifestyle. A holistic approach to incorporating nutraceuticals into one's lifestyle has become the current trend. Protein hydrolysates with antioxidant potential have gained critical commercial importance. Protein hydrolysates are produced from food industrial remnants in order to reduce production costs and achieve sustainable resource management. The food industry generates a greater proportion of waste from fisheries, and with the consistent requisite for fish-based products, utilisation of remnants remains a critical concern. Fish hydrolysates have been discovered to have exceptional physical, chemical, and functional properties. It is noteworthy that fish hydrolysates have strong antioxidant properties against reactive oxygen species. In the current research, gelatin prepared from the processing waste of skipjack tuna (Katsuwonus pelamis) skin were hydrolysed by proteolytic enzyme papain. The obtained gelatin hydrolysate showed ~33% degree of hydrolysis (DH). The surface-active properties of Skipjack tuna skin gelatin hydrolysate (SSGH) revealed pronounced foaming and emulsion properties at low protein concentrations. SSGH demonstrated higher antioxidant efficacy by in vitro antioxidant assays. In conclusion, the resulting hydrolysates demonstrated remarkable antioxidant potential, as well as great development prospects for a variety of applications. Further studies with regard to isolation, purification and identification of and peptide sequences improve the quality of functional foods.

Purse Seiner non grata: Privy Council Wades into Pacific fisheries

William Framhein & another v Attorney General [of the Cook Islands] was heard by the Judicial Committee of the Privy Council on 17 November 2021, with the judgment released on 28 February 2022. The case concerned a judicial review of three decisions made by the Cook Islands Government in relation to the establishment of its purse seine fishery in 2013, which is subject to international management arrangements made by the Western and Central Pacific Fisheries Commission. The three decisions at issue were the making of the Skipjack Tuna Purse Seine Fishery Plan 2013, the promulgation of the Marine Resources (Purse Seine Fishery) Regulations 2013, and the adoption and signature of the Sustainable Fisheries Partnership Agreement and Implementation Protocol with the European Union. The case was brought by a private citizen and traditional leader, Mr William Framheim, together with a local environmental NGO, Te Ipukarea Society. The Applicants brought the case to the High Court of the Cook Islands in 2017 and, following the Court’s dismissal of their claim, appealed to the Court of Appeal in 2018. Both parties appealed elements of the Court of Appeal’s decision to the Privy Council, which is the Cook Islands’ highest appeal court. Ultimately, the government prevailed on its cross-appeal to the Privy Council, and the Applicants’ appeal was dismissed. The case centers on the interaction between customary international law, the international fisheries legal regime, and domestic law (including indigenous customary law). The findings are significant not just for the Cook Islands, but for all Commonwealth countries engaged in fishing that rely on the Privy Council as a final court of appeal.

Production and Characterization of Heme Iron Polypeptide from the Blood of Skipjack Tuna (Katsuwonus pelamis) Using Enzymatic Hydrolysis for Food Supplement Application.

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.