Skipjack Fisheries Research Articles

The MSC approach for developing harvest strategies and harvest control rules for Regional Fisheries Management Organisations (RFMOs)

Well-designed and robust harvest strategies are a key governance tool to achieve long term sustainability of target stocks. In some fisheries, however, such as those governed by Regional Fisheries Management Organisations (RFMOs), the development and adoption of harvest strategies can be challenging. Seafood eco-labelling programs, such as the Marine Stewardship Council (MSC), can be one way of incentivising fisheries to advocate for the adoption of harvest strategies and harvest control rules (HCRs). Here we illustrate the process through which the MSC Fisheries Standard was recently revised to guide the development and implementation of harvest strategies tested using management strategy evaluation, with particular focus on RFMOs. We identify three case studies that highlight the challenge of harvest strategy and HCR adoption: Indian Ocean skipjack tuna fisheries, Western and Central Pacific Ocean tuna fisheries, and North-East Atlantic mackerel fisheries. We discuss the problem statement that highlighted the challenges present when applying the previous MSC Fisheries Standard to stocks managed by RFMOs, and how the revised requirements within the MSC Fisheries Standard aim to overcome those challenges. These revised requirements provide an operational framework within the MSC Fisheries Standard for how RFMO-managed fisheries can implement ‘state-of-the-art' harvest strategies through management strategy evaluation. When applied by MSC certified fisheries, the new requirements are expected to contribute to delivering positive change with respect to implementing robust harvest strategies and HCRs across RFMOs, particularly in cases where there is a strong interest in the market benefits of certification.

Optimizing chlo and sst for skipjack tuna fisheries in the banda sea and its surroundings using GAM and ECDF

This study aims to determine the optimal values of chlorophylla (Chlo) and Sea Surface Temperature (SST) for skipjack fishing (Katsuwonus pelamis) in the Banda Sea and its surroundings using the GAM model and ECDF function. The GAM model yields the formula CPUE = 33.07 + s(Chlo, edf = 7.14, Ref.df = 8.09) + s(SST, edf = 8.95, Ref.df = 8.99), with a significant value for Chlo of 0.58 mg/m3 and an SST of 28.26°C, as well as the highest CPUE value of 51.84. Due to the low performance of the GAM model, ECDF is used to determine the optimal values of Chlo and SST. The results of the Kolmogorov-Smirnov test on the ECDF value showed a p-value for Chlo of 0.0016 and SST of 4.45e-14 (p < 0.05). Thus, there was a significant difference between the f(t) and g(t) distributions at Chlo = 0.28 mg/m3 and SST = 30.57°C. K-Means analysis shows that the optimal value range for Chlo is 0.075 - 0.33 mg/m3 and for SST is 29.47 - 30.47°C. The optimal months are January to June as well as October, where the combination of SST and Chlo concentrations reaches levels that support the productivity of skipjack fishery. However, from July to September, lower SSTs begin to dominate, which can reduce fishery optimality, although some regions still have supportive Chlorophyll. In November and December, SSTs reach very high levels, potentially reducing productivity efficiency.

Supporting regional co-operation in the South China Sea with an initial assessment of the data-limited skipjack tuna fishery

The 1982 United Nations Convention on the Law of the Sea (UNCLOS) requires coastal states of semi-enclosed seas, like the South China Sea (SCS), to coordinate in the management and conservation of marine environments and living resources, specifically highly migratory trans-national stocks. One of the world’s top five fishing grounds, sovereignty disputes continue to bedevil joint fisheries management in the SCS. To develop new norms and standards for regional cooperation, and to support parallel domestic fisheries policymaking, scientists from China, Indonesia, Malaysia, the Philippines and Vietnam overcame political constraints and data limitations, to develop a Common Fisheries Resource Analysis (CFRA) of skipjack tuna (SKJ). A valuable highly migratory species SKJ is fished extensively by SCS states, but regionally, was previously, unassessed. Applying Length-Based Spawning Potential Ratio assessment to evaluate catch size compositions within a Weight of Evidence framework, we conclude fishing targeted at adult stocks would probably be sustainable, but for the continuing intensification of fishing for juveniles. Fishing pressure is apparently eroding SCS food webs and serially depleting local stocks. We conclude, domestic policies need to be developed to halt the continuing expansion of fishing fleets, and reduce fishing pressure, particularly on juvenile fish. The challenge of policy development and implementation requires the support of international frameworks, like Regional Fisheries Management Organisations (RFMOs), to regularise cooperation between government and non-government scientists of coastal states The existing Western Central Pacific Fisheries Commission (WCPFC) could provide that framework, unfortunately, intensifying geopolitical competition makes that extremely unlikely.

Satellite-Based Ocean Color and Thermal Signatures Defining Habitat Hotspots and the Movement Pattern for Commercial Skipjack Tuna in Indonesia Fisheries Management Area 713, Western Tropical Pacific

Understanding the mechanisms that determine the critical habitat of commercial species is one of the significant challenges in marine science, particularly for species that inhabit the vast ocean worldwide. Previous investigations primarily focused on determining skipjack habitats without considering the feasible size for sustainable fisheries. To define habitat hotspots and movement patterns for decently sized skipjack tuna (≥50 cm) in Indonesia Fisheries Management Area (IFMA) 713, Indonesia, we examined the remote sensing of synoptic sea surface temperature (SST) and chlorophyll-a concentration (Chl-a) measurements with catch data from 2007 to 2016. A new skipjack tuna habitat model was developed based on the link between the key satellite-based environmental data and the best tuna fishery performance using a combination of generalized additive models (GAMs) and kernel density estimates. The findings reveal that feasible skipjack catch sizes were found in approximately 27% of total fishing grounds and were significantly captured in areas with a Chl-a of 0.15–0.28 mg m−3 and an SST of 29.5–31.0 °C, corresponding with an elevated skipjack habitat index (SHI). The habitat hotspots for the commercial skipjack were particularly produced by favorable Chl-a and SST, in association with Chl-a front and anticyclonic and cyclonic eddies, especially in October, which coincided with the highest skipjack catch per unit effort (CPUE). Skipjack distributions were mostly found within 10 km of favorable feeding habitats. They used the hotspot area as an indicator of their dynamics and movement pattern in the environment. The observed CPUEs cross-validated the predicted SHI values, suggesting that the model provided a reliable proxy for defining the potential habitats and the spatial movement of mature skipjack schools. Our findings have global significance for locating ecological hotspots, monitoring sustainable skipjack fisheries, and tracking skipjack migration, especially within the western tropical Pacific.

Utilization status and bioeconomic performance of skipjack tuna (Katsuwonus pelamis) fishery in the south coast of Malang waters, East Java, Indonesia

Skipjack tuna (Katsuwonus pelamis) is one of high economic valued pelagic fish on the south coast of Malang waters. This fish is usually caught by purse seine. This study was conducted at Sendang Biru Coastal Fishing Port Malang Regency from February to May 2021, aiming to find out the utilization rate and bioeconomic conditions of the skipjack tuna fishery. The study used descriptive methods. Statistical data on catches from 2011 to 2020 were used to apply bioeconomic analysis to calculate the maximum sustainable yield (MSY), maximum economic yield (MEY), total allowable catch (TAC), and free access equilibrium (FAE). Results showed that values of catch and effort at MSY level were 1,800 tons and 3,191 trips respectively with a value of TAC as much as 1,440 tons. While values of catch and effort at MEY reached 1,774 tons and 2,814 trips respectively with the highest profit obtained as much as IDR 34.12 billion. In addition, catch and effort at FAE level took place at 751 tons and 5,627 trips respectively. The utilization rate of skipjack tuna (K. pelamis) was 123%. In conclusion, the fish is in over-exploited condition hence the amount of effort must be decreased to maintain resources sustainability.

Bioeconomic analysis of skipjack tuna fisheries in North Gorontalo Regency, Indonesia

The model of the skipjack tuna resource management that can provide maximum rent can be done with a clear ownership regime (sole owner) or in the condition of MEY balance. However, the management and utilization of skipjack tuna resources must also consider the factors that can result in overfishing of both biological and economics overfishing. This study aims to assess the management and utilization of skipjack tuna fisheries resources in North Gorontalo Regency using a bioeconomic approach. Data processing is done by approaching the bioeconomic model using skipjack tuna fisheries biological and economic parameters. The results showed that the maximum rent obtained in skipjack fisheries in North Gorontalo Regency was at the MEY regime compared to the MSY and OA regime. However, based on the actual data obtained, it is known that the average production of skipjack tuna in North Gorontalo Regency has not reached the optimum catch value in the equilibrium condition of MSY (hMSY ), but in some period the actual catch value has passed the optimal catch value (hMSY ), this means that skipjack tuna has overfished (biological overfishing). While the actual production value of skipjack tuna catches in North Gorontalo Regency has passed the production of optimum MEY (hMEY ). This condition indicates that actually skipjack tuna resources have experienced an economic overfishing.

Mapping spatial-temporal skipjack tuna habitat as a reference for Fish Aggregating Devices (FADs) settings in Makassar Strait, Indonesia

Abstract. Hidayat R, Zainuddin M, Mallawa A, Mustapha MA, Putri ARS. 2021. Mapping spatial-temporal skipjack tuna habitat as a reference for Fish Aggregating Devices (FADs) settings in Makassar Strait, Indonesia. Biodiversitas 22: 3637-3647. Skipjack tuna (Katsuwonus pelamis) has a high economic value in the international market. Catching skipjack tuna using fish aggregating devices (FADs) without knowing its habitat characteristics can damage the ecosystem. This study aimed to determine suitable fishing areas for setting skipjack’s FADs. The data used included that on catch, sea surface temperature (SST), and sea surface chlorophyll-a (SSC) in the Makassar Strait obtained for 2017-2019. The generalized additive model (GAM) and empirical cumulative distribution function (ECDF) analyses were used to investigate the skipjack’s tuna habitat. A pelagic habitat index (PHI), with PHI > 75%, was applied to determine suitable FAD positions. The gravity center of the skipjack tuna habitat for ten months (January-October 2020) was calculated to validate the model’s results. The results showed that the optimum SST range was from 28.78°C to 31.25°C, while the SSC from 0.18 to 0.28 mg m-3. The best skipjack habitats in the southern Makassar Strait are criterion 4 (PHI > 90%) and criterion 3 (PHI = 85-90%), having a relatively high consistency of the average PHI values. These results can help determine the optimal positions for setting FADs to benefit the global management and sustainable development of skipjack tuna fisheries.

The Sustainability of Skipjack in Sikka Regency: An Analysis of Economic Dimension

Skipjack has an essential economic value and it is spread in almost Indonesia’s territorial waters. Skipjack resource utilization activities have contributed greatly to the fisheries sector in Indonesia. The need and high market demand for skipjack causes the fishing intensity is increase. The increasing of skipjack fishing intensity by fishermen in pemana village is concerned that it will threaten the preservation and sustainability of the utilization skipjack resources. The Pemana village is the biggest skipjack producer in Sikka regency. The increasing of the skipjack fishing intensity in this area also occurs every year. Therefore, it is need a skipjack fisheries management in order to ensure the sustainability of skipjack fisheries. A management is development such as ecologically, socially and economically sustainable. This study was aimed to find out the status of sustainable skipjack fisheries that investigated from the economic dimension. The analysis which used was Rapfish (Rapid Apparaisal for Fisheries). The result of Multi-Dimensional Scaling (MDS) revealed that sustainability status of the economic dimension of the skipjack fisheries in Sikka regency was 53,108 or it was in a fair sustainable status. The result of sensitivity Analysis/Leverage of Attributes revealed that there were two key factors of the sustainability of skipjack fisheries such as other income and market oriented. The result of Monte Carlo analysis (eror effect/error) revealed that this analysis had a high confidence level and could be used as an instrument in economic dimension evaluation of skipjack fisheries resources.

Spatial and temporal distribution of anchovy density in Inner Ambon Bay on dry season (December-February)

Inner Ambon Bay is a small pelagic fish fishing ground, especially anchovy. Anchovy plays important role in the skipjack fishery as live bait in Ambon city. Nevertheless, research for its resource management is rarely done. The aims of the research are to obtain information of density, vertical distribution and horizontal distribution of anchovy on Dry Season. Densities data of anchovy were collected using hydro-acoustic device at six parallel transect lines and one cross- parallel transect line. Geo-statistical analysis technique was used to describe horizontal distribution of anchovy meanwhile, to observe vertical distribution pattern, vertical anchovy data was plotted on the graph. Result shows that lower average density of anchovy was found in January while higher density was in February. On vertical distribution, anchovy was distributed from near surface to 35 m depth layer, but higher densities were found at 25 m depth layer in December and February respectively and in January at 30 m of depth layer. On horizontal distribution, lower density of anchovy occupies a large space, in contrast, higher density was in small fish schools occupy a small space and are scattered in given parts of Inner Ambon Bay but at differ locations between months.

Size, spatial distribution and potential of anchovy in Inner Ambon Bay

Inner Ambon Bay is a small pelagic fish fishing ground, especially anchovy. Anchovy plays important role in the skipjack fishery as live bait in Ambon city. Nevertheless, research for its resource management is rarely done. The aim of the research is to obtain information of population size, spatial distribution of densities and Maximum Sustainable Yield of anchovy. Densities data of fish were obtained using hydro acoustics device at six parallel transect lines and one cross parallel transect line in October 2015. Three fish species caught by beach seine, comprise Encrasicholina heteroloba (96.3%), Sardinella spp.(2.8%) and Rastrelliger spp.(0.9%). Mean value of total length of E. heteroloba was 5.30 cm shorter than the length of same fish noted in October 2005 was 5.48cm. Spatial distribution of anchovy densities shows that low density (0-2 fish/m2) occupy wider space, evenly distributed in north, east, and south of the bay. The fish density of 2-4 fish/m2 were in small groups occupy smaller space distributed in the middle to west of the bay. The density 4–6 fish/m2 to high density 28–30 fish/m2 occupy only very small space in the west near bay mouth. Maximum sustainable yield of anchovy in inner Ambon Bay was estimated 6.9±4.3 tons.

Dynamics of Thermal Fronts Distribution in the Flores Sea, Indonesia: An implication for locating potential skipjack tuna fishing ground

Flores Sea is one of the most productive fishing grounds within the Indonesian Fisheries Management Area 713 which has the unique physical structures such as topographic feature, the seasonal wind driven upwelling, and also the dynamics of frontal patterns. The purposes of this study were to map the dynamic spatial of the thermal fronts in the east and the second transition seasons, and to describe their implications to the skipjack fishery. We applied the satellite data of sea surface temperature (SST) for the period of June-October 2018 with spatial and temporal resolutions of 0.04 degree latitude and longitude and monthly, respectively. For fishery data, we used sampling data of skipjack tuna fishing ground distributions during this period. The thermal fronts were estimated using a Single Image Edge Detection (SIED) algorithm and the available fishing ground data were superimposed on the SST frontal maps. The results showed that the spatial distribution patterns of thermal fronts along Flores Sea tended to be different every month. However, the thermal fronts were consistently detected throughout the study period. Skipjack tuna fishing grounds started to develop in the eastern area of Selayar Island in June (before upwelling event) and reached a peak in October (after upwelling). During these months, the skipjack fishing grounds well formed around the thermal fronts with the distance of 0-40 km. It implies that the formation of the thermal fronts especially after upwelling gives a significant contribution on the development of skipjack fishery in the Flores Sea.

Pengelolaan Sumber Daya Ikan Cakalang didaratkan di Pelabuhan Perikanan Nusantara (PPN) Prigi, Trenggalek: Aplikasi Feedback Harvest Control Rule

Cakalang (Katsuwonus pelamis) is one of the leading export commodities landed at the Prigi Fishing Port (PPN Prigi). Skipjack tuna fisheries management conducted the conventional single-species Schaefer model which is often applied although it is not technically suitable for multispecies fishery. The application of feedback harvest control rule (HCR) is an alternative harvest strategy that has been successfully implemented and validated for multispecies fishery. This study estimated allowable biological catch by applying two harvest strategies, HCR feedback and Schaefer surplus production model using catch-effort data of skipjack tuna landed at PPN Prigi in the period 2010 - 2019. Model Schaefer pointed out that catches have exceeded the maximum sustainable yield () even employed low the fishing effort which was under the fishing mortality consistent with achieving MSY (). The application of feedback HCR that has been previously validated can be an alternative of harvest strategy for use in fisheries where only mixed species data is available. 
 Key words: multispecies fishery, harvest strategy, Schaefer model, maximum sustainable yield, single-species approach

PRODUKSI CAKALANG DI WILAYAH PENGELOLAAN PERIKANAN 713

The vast Indonesian sea holds a lot of marine fishery potential that can be utilized by the Indonesian people. In the sea there is the potential for marine resources in the form of fisheries. The Indonesian sea has a large number of sustainable potential, namely 6.4 million tons per year. Skipjack tuna is one of the main targets in fishing activities. One of the Cakalang producing areas in Indonesia is the Fishery Management Area (WPP) 713. WPP-713 is a potential water area in Eastern Indonesia. This study aims to provide a basic overview of Skipjack fishery production in Indonesia and WPP-713. The results of this study indicate that the production value and price of Skipjack tuna in Indonesia has increased from 2005 – 2015. In 2015, the Cakalang price reached IDR 18,164 and a production value of ± IDR 7.54 trillion. Meanwhile, in WPP-713 the average catch production of skipjack tuna shows an increase of 11.4%.

Coasean Approaches to Address Overfishing: Bigeye Tuna Conservation in the Western and Central Pacific Ocean

Bigeye tuna in the Western and Central Pacific Ocean were perceived as overfished for nearly 20 years, in large part because of incidental catch in the much larger skipjack tuna fishery. Efforts to halt the overfishing of bigeye stalled because of disagreements over the distribution of costs and benefits from reform. An alternative Coasean-style approach to setting both harvesting levels and the allocation of costs and benefits might offer a path forward. We calculate the costs and benefits of achieving bigeye conservation goals and describe an exchange through which benefits could be realized via removal of fish-aggregating devices (FADs). Through trade, aggregate benefits and costs are more apt to be in balance relative to mandated protection controls. The realities of bargaining costs in a multilateral setting are not underappreciated, but in light of existing stalemates in this and other fisheries, consideration of Coasean-style approaches is warranted.

Coasean Approaches to Ending Overfishing: Bigeye Tuna Conservation in the Western and Central Pacific Ocean

AbstractBigeye tuna in the Western and Central Pacific Ocean were perceived as overfished for nearly 20 years, in large part because of incidental catch in the much larger skipjack tuna fishery. Ef...

PENGUKURAN KAPASITAS PERIKANAN CAKALANG ANTAR WAKTU DI MALUKU

Skipjack tuna resources in Maluku waters are quite potential, so its management and utilization need to be a concern for sustainability of the skipjack resources and fishing industry. However, the nature of open access resources tends to lead to overcapacity in fishing. At this condition, how is the condition of the skipjack fishing industry in Maluku in terms of using fishing inputs? This study aims to measure the capacity of skipjack tuna fisheries over time. Using the Data Envelopment Analysis (DEA) approach, which is CRS in nature. Time series data were obtained form the government institutions, i.e the KKP and the DKP Maluku, and the fishery’s NGOs. The results show that during observations from 1996 to 2015, the eficient of inputs was found in DMU-1996 and DMU-2014. Thus, in the DMU-1998 and DMU-2014, there were indicative of an increase in fishing equipment followed by an increase in production, but the number of fishing efforts actually decreased. Conclude, that fishing input, effort and fishing gear were efficient in the DMU-1998 and DMU-2014. In both DMUs were indicative of an increase in fishing equipment followed by an increase in production, but the number of fishing efforts actually decreased.

Typology of Skipjack (Katsuwonus pelamis) Fisheries at Nizam Zachman Oceanic Fishing Port, Jakarta, Indonesia

This study aims to analyze the aspects of technical, social, and economic typologies of skipjack fisheries at Nizam Zachman oceanic fishing port, Jakarta. This research expected to provide information for decision-making in formulating policies in skipjack fisheries activities, thus they remain sustainable—this research conducted at Nizam Zachman oceanic fishing port, Jakarta from August 2019 to February 2020. The method used in this research is the survey method by interviewing the respondent through questionnaires for 100 respondents. The sampling method was done randomly, and the data were analyzed by descriptive qualitative. The social typology shows the orientation of Nizam Zachman as an industrial ocean fishing port is for commercial purposes. The main productive age level of fishers ranges from 35-39 years (33%) and the last education is a primary school (46%). Regarding the work experience, 38% had been fisher between 16-20 years. The technical typology shows the fishing gear that operated to catch skipjack at Nizam Zachman are purse seine, longline, also carrier vessel. In general, 74% of the size fleets were in 100-200 GT and the length of trips in 1-2 months (48%). The fishing ground area is in 572, 711 and 712 FMA. The economic typology shows skipjack production/trip by purse seine was 54%, longline (1%) and carrier vessel (57%).

ANALISIS DAYA SAING PERIKANAN CAKALANG (KATSUWONUS PELAMIS) PADA ALAT TANGKAP PURSE SEINE

Skipjack fishery business is one of businesses in catch fisheries sector whichis potential to be developed since it has the ability to increase fishermen’sincome and macro economy. This research was aimed to analyze: a) Competitiveness of skipjack fisheries bussines the Purse Seine Fishermen Capture Device Kendari at WPP 714 on comparative and competitive advantages, b) the impact of policy on the competitiveness of skipjack fishery business in Kendari. The research was carried out for seven months from December 2013 to July 2014 in Kendari, the center of catch fisheries in Southeast Sulawesi. The sampling is done by simple random sampling. The data was analyzed by using Policy Matrix Analysis (PAM) model. The result showed that; Skipjack fishery business using in Kendari has a good competitiveness in both domestic and international market. This result implied that the skipjack fishery business in Kendari is economically and financially feasible, and will become more competitive if supported by government’s policy on input and output prices of the skipjack fishery business.

Tingkat Pemanfaatan Sumberdaya Perikanan Pelagis Besar dan Kesejahteraan Rumah Tangga Nelayan di Perairan Kota Jayapura, Provinsi Papua

The territorial waters of Jayapura City, especially the waters of North Jayapura and South Jayapura are the centers of capture fisheries activities of big pelagic species, namely tuna and skipjack tuna, which need to be utilized to provide welfare for the community, especially fishermen in a sustainable manner. For this reason, this study was conducted to analyze the level of utilization of big pelagic fisheries resources and analyze the welfare level of big pelagic fishermen households in Jayapura city waters. Primary data collection is done through interviews with respondents who are randomly selected. Utilization level analysis was carried out using multispecies bioeconomic analysis and analysis of fisherman welfare levels was carried out using the criteria of the poverty line set by the Central Bureau of Statistics. The results showed the actual utilization rates of tuna and skipjack fisheries resources in the waters of Jayapura City are still in the continuous production of MSY and MEY. Nevertheless, the utilization of these big pelagic fisheries resources needs to be supported by economic institutions that can better distribute their benefits, especially to fishermen. This is because based on the survey conducted; most of the household welfare of the big pelagic fishermen tuna and cakalang in the waters of Jayapura City are still classified as not prosperous.

Effect of oceanographic conditions on skipjack tuna catches from FAD versus free-swimming school fishing in the Makassar Strait

Fish Aggregating Devices (FADs) have become the preferred choice in skipjack tuna fisheries rather than looking for free-swimming schools (FSS) which is considered less effective. This study aimed to identify the effect of oceanographic conditions on skipjack tuna catches in the FADs versus free-swimming schools in the Makassar Strait. We collected fishing data from vessels using purse seine fishing gear and satellite-based oceanographic data (Sea Surface Temperature (SST) and chlorophyll-a (chl-a)) from May to July 2017. The satellite and catch data were analysed using a Generalized Additive Model implemented in R and mapped using Spatial Analyst in ArcGIS 10.6. The results showed that SST ranges in the FAD areas were relatively wider (29 – 31°C) than those in free-swimming school areas (29.5 – 30.5°C). The chl-a concentrations in free-swimming school areas were relatively higher (0.25 – 0.80 mg m-3) than those in the FAD areas (0.15 – 0.50 mg m-3). It was also found that mean skipjack tuna catches in the FAD areas (337 fish/setting) were relatively higher than in the free-swimming school areas (145 fish/setting). These findings suggest that the high skipjack tuna catches in Makassar Strait were significantly affected by specific SST ranges and relatively low chl-a.