Boat Seine Research Articles

A study on the improvement of fishing system using miniaturized nets for anchovy boat seine to reduce the fleet size

A study on the improvement of fishing system using miniaturized nets for anchovy boat seine to reduce the fleet size

Energy efficiency and economics of small-scale fisheries (SSF) in India: A VIKOR based multicriteria decision-making model for sustainable fisheries management

The present study addresses the crucial sustainability concerns in small-scale fisheries (SSF) against the backdrop of escalating anthropogenic activities and climate change impacts on marine fishery and ecosystems. Our study focused on a traditional fishery exploitation area spanning 12,646.12 km2 along the Southwestern Coast of Kerala, India, and explored four widely used fishing gears. We established an integrated decision-making VIKOR framework, and preferential modelling by incorporating techno-economic and environmental aspects to draw the optimal solutions. Leveraging 10 sustainability indicators, the boat seine emerged as the most sustainable gear, showcasing significant profitability (US$ 16,126/year−1 net profit) and remarkable energy efficiency, surpassing gillnetters, longliners, and shore seiners by 8.4, 4.9, and 3.0 times, respectively. The Fuel Use Intensity (FUI) and CO2 emissions analysis (F value = 58.37, P < 0.0001) emphasizes the ecological implications. The developed VIKOR sustainability index, introduced in this study, effectively assesses gear efficiency and sustainability. Further, the study revealed that gear selectivity, technical specifications, and operational trajectories considerably influence the index dynamics. This research aligns with the global commitment to the Voluntary Guidelines for Securing Sustainable Small-Scale Fisheries (SSF Guidelines) and contributes scientifically to Sustainable Development Goals (SDGs). By bridging empirical rigor with international frameworks, the study could aid in sustainable fisheries management and environmental stewardship, deemed essential for the global pursuit of ecological, economic, and social sustainability in small-scale fisheries.

From Co-Operation to Coercion in Fisheries Management: The Effects of Military Intervention on the Nile Perch Fishery on Lake Victoria in Uganda

In 2017, Uganda’s small-scale inland fisheries underwent a significant transformation, shifting from local co-management to state military enforcement owing to ineffective enforcement of regulations and declining exports. Employing a mixed-methods approach and blending qualitative and quantitative data, we assessed the impact of military intervention on Lake Victoria’s Nile perch fishery, focusing on fishing effort, catch, and exports. Our findings indicate that military operations adhered to regulations, gaining primary support from key stakeholders, specifically motorized fishing operators. Consequently, between 2016 and 2020, legal fishing activities experienced substantial growth. By 2021, approximately 90% of Nile perch catches were made by motorized vessels using longlines and gillnets, despite a declining trend in catch-per-unit effort. Between 2015 and 2021, the Nile perch fishery saw changes: boat seines made up about 5% of motorized fleet catches in 2021, while catches in paddled vessels increased from 20% to over 50%, suggesting a potential role in the growing longline fishery. Therefore, the current management approach does not increase catches or exports compared with the co-management period. The observed decline in catch-per-unit effort among motorized gillnets suggests overcapacity. Further research is needed to comprehend the broader sociological and ecological impacts of the present enforcement strategy for sustainable fishery management.

Small-scale fishery catch composition in Rhodes (Eastern Mediterranean Sea)

Trammel net and boat-seine experimental fishing samplings were carried out seasonally, over a rocky-sandy and a Posidonia oceanica habitat respectively, in the coastal waters of Rhodes, south-eastern Aegean Sea, Greece, between 2019 and 2020. Fish catch composition, abundance and biomass were investigated as a contribution to the qualitative and quantitative monitoring of the fish assemblages in the artisanal fishery in this Greek marine region most affected by biological invasion. A total of 56 native and 11 alien fish species were captured. Five invasive species Fistularia commersonii, Pterois miles, Siganus rivulatus, Siganus luridus and Lagocephalus sceleratus were recorded using both fishing gear. In trammel nets, the alien to native fish species ratio was 1:2.87 with eight allochthonous species composing 43% of the total abundance and greatly exceeding native species biomass with the most dominant being F. commersonii, P. miles, S. rivulatus and S. luridus. Boat seine samples were dominated by Spicara smaris and Boops boops, which accounted for 84% and 56% of total abundance and biomass, respectively, while the alien to native fish species ratio was 1:5.1. The 10 Lessepsian fish, i.e., fish that have entered the Mediterranean Sea via the Suez Canal, identified on a Posidonia seabed represented a small proportion of the total abundance (3.4%), while their biomass reached 17% of the total catch, with a prevalence of F. commersonii. Among alien fish on P. oceanica, S. rivulatus exhibited the greatest abundance, followed by F. commersonii, Parupeneus forsskali and S. luridus, with small but not negligible densities of Pteragogus trispilus and Torquigener flavimaculosus. The abundance of Pterois miles over the rocky-sandy habitat was remarkable. Results indicate a transitional shift in fish catch composition with introduced species competing with natives for food and space (i.e. between introduced siganids and Sparisoma cretense, Sarpa salpa, between the recently introduced P. forsskali and mullids, and between introduced P. miles and scorpaenids), further influenced synergistically by environmental and anthropogenic factors. The Total-Standard length and Total weight-Total length relationships and their applications in fisheries data for the allochthonous fish are briefly discussed.

The Lobo-lobo fry fishery in the western Visayan Sea, Philippines: Abundance, catch composition, and potential fisheries impact

Lobo-lobo are small fishes that are caught using fine mesh nets in the western Visayan Sea whose market extends outside of the Visayan Sea, and perhaps even outside of the country. With high consumer demands, it is targeted year-round. Catches of fine-meshed boat seines operating in the waters off Concepcion, Iloilo which target large amounts of small and early juvenile fishes were monitored daily from June to December 2016 and June 2020 to October 2021. Results showed that catches were comprised of several species and clearly show the selection for early juveniles by the lobo-lobo fishery. At least 53 families comprise the lobo-lobo catches, dominated by Engraulidae (78.5%) and Clupeidae (13.1%), and are mostly comprised of post-larvae and early juveniles with sizes ranging from 0.2 to 3.6 cm standard length. The estimated total annual catch of the local boat seine fleet during the study period ranged from 313.8 mt to 869.0 mt. The fishing operations are concentrated between Tago and Igbon Islands and appear to be consistent throughout the year, but the composition and proportion of catches differed seasonally. This area appears to be a critical habitat, supporting the growth and survival of several species. Protecting this area and restricting the use of fine-meshed nets targeting fry will likely have an overall positive impact on the local fish stocks.

Analysis of profitability deterioration factors of anchovy boat seine fishery in South Korea

Analysis of profitability deterioration factors of anchovy boat seine fishery in South Korea

Round scad quality on mini purse seine boats, Rembang Regency, Central of Java

Mini purse seine boats in Rembang are divided into two sizes. The first one, namely mini purse seines measuring 10 - 20 Goss Tonnage (GT) (short trips) with a fishing operation duration of 3 - 7 days. The second one is mini purse seines measuring 21 - 30 GT (long trips) with a fishing operation duration of 7 - 10 days. The dominant catch on this boats is round scad, which used a cooling mechanism with ice blocks and bulking systems. This research evaluates the quality of round scad caught by mini purse seine boats (based on Indonesian National Standard/SNI 2729: 2013) and the quality of ice used in handling the fish (based on SNI 4872: 2015). The sampling technique was purposive sampling. Fish samples were carried out in the first and last hold on the short trips and long trips boats, where each handle of the fish was sampled in the upper, middle, and lower layers. Data analysis for sensory evaluation were analyzed by Kruskal Wallis statistics, while the TPC value of round scad was tested by ANOVA test. The laboratory test results obtained the sensory assessment of round scad. The value of the TPC round scad and the E. coli ice blocks are still within the limits of the Indonesian national standards, but the TPC scale of the ice block exceeds the standard limit of SNI. The Kruskal Wallis statistics results showed tha the difference in fish hold, the difference in the trip, and differences in fish hold layers had a significant effect on the sensory of scad. ANOVA test showed that differences in the fish hold and trip differences had a significant impact on the TPC of scad. In contrast, the difference in fish hold layers gave a non-significant effect on the TPC of round scad.Keywords:Quality organolepticTPcRound scadMini purse seineRembang

Growth and utilization rate of yellowstripe scad (Selaroides leptolepis, Cuvier 1833) landed at Pekalongan Archipelago Fishing Port

Abstract Yellowstripe scad (Selaroides leptolepis) is a small pelagic fish. Yellowstripe scad is one of the catches of mini purse seine fishing gear which has important economic value. Continuous fishing activities for yellowstripe scad can disrupt the sustainability of yellowstripe scad. The purposes of this study were to determine size structure, growth parameters, length-weight relationship, size of the first caught (Lc50%), mortality rate, and utilization rate of yellowstripe scad. This research was conducted in June, July, and August 2022 at Pekalongan Archipelago Fishing Port. The data was collected by using a simple random sampling method, taking a 10% random sample of fish from one of the baskets caught by the mini purse seine boat landed at Pekalongan Archipelago Fishing Port. The data collected included total length (mmTL) and weight (gr). Data analysis used FiSAT II program with analysis ELEFAN I. The results obtained a sample of 1081 individuals with a length range of 94-152 mmTL and a weight of 9-54 grams. The size of the first caught (Lc50%) was 113.88 mmTL. The length-weight relationship of the yellowstripe scad was W = 0.0000054L3,1614 and the growth pattern was positive allometric. Von Bertalanffy growth parameters of yellowstripe scad were Lt = 158.03[1 - e(-0.56(t+0.184))] with L∞ was 158.03 mm; K was 0.56 and t0 was -0.184 years. The total mortality (Z) of yellowstripe scad was 1.86/year; natural mortality (M) was 0.77/year and fishing mortality (F) was 1.09/year. The exploitation (E) of yellowstripe scad was 0.58 which is included in the over-exploited category.Keywords: Exploitation; Growth; Mortality; Yellowstripe scad

Improved size selection and estimated at-vessel mortalities for an Australian whiting (Sillago spp.) boat seine

In response towards more species in New South Wales (NSW), Australia being managed via quotas, efforts have recently focused on developing more efficient fishing methods with concomitantly low unaccounted fishing mortality and/or other environmental impacts. The present study contributes information towards this initiative by investigating the relative selectivity of a boat seine with a traditional vs modified codend when targeting eastern school whiting, Sillago flindersi and stout whiting, S. robusta—species historically caught in NSW using otter trawls. The traditional boat seine represented those used in other Australian jurisdictions, tapering from an 85-mm stretched mesh opening in the body to a codend comprising 38.5-mm diamond-shaped mesh ('T0') throughout, and was alternately fished with a modified codend made entirely from 40.9-mm mesh to match the grith of mature individuals of both whiting species and orientated 90° ('T90') with shortened lastridge ropes. Regardless of codend, the boat seine was very efficient at quickly harvesting large quantities of whiting (i.e. often >3 tonnes 60 min deployment–1), with a total discarded-to-retained catch weight ratio (0.44:1) much less than for conventional otter trawls used across similar areas (e.g. >2:1). At-vessel mortalities were high (>95%) for both whiting species, but all were retained. Mortalities were lower for two key discards, bluespotted, Platycephalus caeruleopunctatus (61%) and longspine flathead, P. grandispinis (82%) and both were negatively affected by the total catch weight. The mortality of bluespotted flathead was also negatively correlated to their total length. The T90 codend allowed many immature eastern school whiting to escape, however there were issues with fish being entangled in meshes. We conclude boat seining could represent an effective and relatively selective method for harvesting whiting in NSW, but future work is required to progress an appropriate codend configuration (possibly with fewer T90 meshes) and also address any impacts of rapid, regional depletions on the overall stock structures of both whiting species.

ANALISIS STUDI KASUS KELAYAKAN USAHA PENANGKAPAN IKAN: MENGGUNAKAN PUKAT CINCIN DI LAMPULO BANDA ACEH

Analysis to the Fishing Business Feasibility Using Purse Seine in Lampulo Banda Aceh has been done from March to June 2020. The objective of this analysis is to know the fishing business feasibility using purse seine in Lampulo. Survey methods were used on 8 active purse seine boats and the data were collected by interviewing techniques. Data were analyzed by means investment criteria Net Present Value (NPV), Internal Rate Return (IRR), Net Benefit-Cost Ratio (B/C Ratio), Break Even Point (BEP),and Payback Period (PP). The results show that the value of Net Present Value (NPV) ranges between Rp 1.055.432.152 to Rp 1.857.087.678, Internal Rate Return (IRR) ranges between 20,20% to 20,30%, Net Benefit-Cost (B/C Ratio) ranges between 1,96to 2,42, Break Even Point (BEP) ranges betweenRp 474.737.261 to Rp 604.509.983 by the results fish sell 52.137 Kg to 73.077 Kg and Payback Period (PP) ranges between 1 year and 8 mounth to 2 year and 3 mounth. In other word, fishing business by using purse seine in Lampulo is deserve and reasonable and it has a good prospect to be developed.Keywords: Feasibility Analysis, Investment Criteria, Purse Seine

Production, Fishing Season and Fishing Ground of the Dominant Fish (Euthynnus affinis, Mene maculata, Leiognathus equulus) Caught by Boat Seine in Palabuhanratu Indonesia

Boat Seine net is a very productive fishing gear in Nusantara Fisheries Port (NFP) Palabuhanratu. Boat Seine was a fishing unit that has the third largest contribution to the provision of fish stocks in 2019, which is 9% of the total production volume of NFP Palabuhanratu after lift net (40%) and longline (35%). The purpose of this study was to analyze the composition of the main catch, productivity, fishing season and to analyse the fishing ground in Palabuhanratu Bay. The type of data collected in this study was quantitative data. Primary data from interviews and field observations of fish landing activities at Palabuhanratu in October 2020 were used to compile this study's data, which included the type of fishing gear used, the composition of the types, and the production of the catch. Secondary data collected were monthly catches and trips made by Boat Seine fishing units. By analyzing the data of Boat Seine net fishing from 2015 to 2019, descriptive analysis method was used to investigate the composition of Boat Seine net catch. The results of the research showed that mackerel (Euthynnus affinis), moonfish (Mene maculata), and ponyfish (Leiognathus equulus) are the dominant fishes caught at the Palabuhanratu waters. The productivity level of Boat Seine net was 348 Kg/Trip in 2015, which increased to 603 Kg/Trip in 2019. The mackerel season occurs around May to September and November. Moonfish fishing season occurs in March, September and October. Ponyfish fishing season occurs in January, March, May, October, November, and December. Boat Seine net fishing grounds in the waters of Palabuhanratu Bay are relatively stationary around the waters of Palabuhanratu Bay.Keywords: CPUE, Fishing Area, Fishing Season Index, Productivity

Handler Proficiency (Nahkoda) Dnature Operationalize Purse Saine Fishing Gear

This study aims to: (1) find out the skills of handlers in operating purse seine fishing gear (2) Knowing the fishing ground of purse seine fishing gear (3) Knowing the factors that affect fishing operations with purse seine fishing gear. The research methods used are survey methods, interviews and questionnaires. The data were analyzed descriptively. A total of 30 purse seine handlers at PPP Lampulo have been respondents in this study. The results showed that the purse seine ship handlers in Lampulo PPP are mostly 41-50 years old, the average handler education level is junior high school, the majority of handlers in Lampulo PPP have more than 5 years of experience, handlers at Lampulo PPP only have a Certificate of Proficiency (SKK) in operating ships. Generally, purse seine boat handlers at PPP Lampulo have satisfactory skills when viewed from how to determine fishing grounds, search for fish swarms, collect schools of fish and operating techniques for fishing gear.

Fishers and whales in Iceland

In Iceland, as in many places globally, the detrimental impacts of whale interactions with fishing gear on both fisheries and whales are not well understood and managed. This study conducted anonymous questionnaires of Icelandic fishers and interviews of capelin purse seine boat captains to gather first-hand knowledge of the issues fishers face due to whale interaction with their fishing gear. Results suggest that the humpback whale is the large whale species that is most often entangled or encircled in fishing gear and causing damage, however on occasion other large whale species are interacting with gear as well. Interactions between humpback whales and fishing gear appears to be primarily concentrated in the north/northeast and southwest of the country where there is high fishing effort and known humpback whale feeding habitat. Humpback whale interactions with gear occurred most often with capelin purse seines, which are targeting humpback whale prey, and data suggests that bycatch of whales in this fishery may be underreported. Damage and losses due to whale collisions with gear were reported to cost fishers up to 55.000.000ISK, suggesting this can be a costly issue for which mitigation measures should be explored. The use of acoustic “pingers” is one mitigation measure that has been previously tested by capelin purse-seiners and is something that captains indicated they would be interested in continuing to try. The creation of a whale entanglement/whale-gear interaction reporting system in Iceland would aid in gathering more data and quantifying how often these events are witnessed and what the consequences of these events are to both the fishers and the whales. This study provides new information about the consequences of large whale interactions with Icelandic fisheries and suggests that future collaboration with fishers can provide insight contributing to best management practices for sustainable fishing and whale conservation.

ANALYSIS OF PRINCIPLE DIMENSION AND SHAPE OF PURSE SEINERS IN AMBON ISLAND

Abstrak Purse seiners as a ship's main small pelagic fish Catcher is increasingly growing in number and size. In the last 5 years has been an increase in purse seine boats in Maluku by 20% and 15% of the overall operating in waters around the island of Ambon. Purse seiners tend to be made traditionally based on experience and not in accordance with the criteria of size comparison of a fish boat. It is very technical and operational feasibility of affect in this speed, stability and longitudinal strength . This research aims to calculate speed, tonnage (GT), the size of the principal as well as set the geometric shapes of purse seiners on the island of Ambon. The methods used in this research is a survey method by gathering primary and secondary data by making observations and measurements directly against the 32 purse seiners in Ambon island. Analysis and discussion is done through estimation the ship's speed by using the formula of Nomura, estimated tonnage (GT) using the Standard Fish Vessel Regulations by the Director-General of Fisheries Catch of Indonesia in 2004, the determination of the optimal size of the principal ship in the empirical formula by numerical – Traung and geometric forms of purse seiner . Estimation against speed (V) and the tonnage (GT) shows that the speed average (Vaverage) = 7.1 knots and tonnage average(GTaverage) = 22.4 tons. The calculation of the size of the principal ship by using empirical methods-numerical based on Traung equation with input of Vaverage and GTaverageindicates that the principal dimension is as follows: LBP = 15.8 meters; B = 4.8 meters; D = 2.2 meters and d = 1.9 meters and form coefficient as follows : CB = 0,6 ; CW = 0,7 ; CM = 0,97 ; CP = 0,62

Status of the fishery of Jaffna lagoon, Sri Lanka

Jaffna lagoon (9° 50' N and 79° 50' E to 9°20' N and 80° 30' E) is the largest lagoon in Sri Lanka and it provides many services including fishing opportunities to the people in northern Sri Lanka. However, the status of the Jaffna lagoon fishery is not fully known at present due to the lack of detailed studies over the last 40 years. Therefore, this study was designed to fulfil this research gap. Both primary data and secondary data were used in this study. Primary data, including catch and fishing effort were collected at three major landing sites, Gurunagar, Paasaiyoor, and Kachchai by making fortnight field visits from March to December 2019. Secondary data of the monthly total catch and fishing effort were obtained from the district fisheries offices in Jaffna and Kilinochchi districts in order to estimate MSY and FMSY. This study revealed that ~5340 fishers confined to 39 landing sites were actively engaged in lagoon fishing during the study period using 12 different fishing methods. Fyke nets (71%) followed by stake nets (10%), lagoon seines, and lagoon boat seines (6%) are the widely used fishing methods in lagoon fisheries. Catch rates of major fishing gear were calculated and recorded as kg fisherman-1, day-1. Stake net (37kg ± 7) reported a significantly higher catch rate than fyke net (18kg ± 3), seine net (17kg ± 6), and crab net (16kg ± 3) (p&lt;0.05; ANOVA). Both mechanized (59%) and non-mechanized (41%) crafts are used in the lagoon fishing practices. Forty-six commercially important finfish and shellfish species belonging to 25 families were identified in the lagoon catches of which Penaeidae made the highest percentage contribution (27%), followed by Siganidae (13%), Mugilidae (11%), Lethrinidae (10%), and Gerreidae (9%). Analysis of secondary data confirmed the increasing trend of fishing effort since 2009 but the total landings declined gradually after reporting its maximum value of 6958 Mt. in 2012. A rough estimate of maximum sustainable yield of the fishery of Jaffna lagoon was 6,694 Mt with the annual fishing effort (FMSY) of 1007 crafts. As the current fishing effort is higher than the FMSY, input control measures are recommended to utilize the lagoon fishery resources in a sustainable manner.

Identification of fishing ground hotspot of traditional purse seine fisher at northern waters of Aceh – A community-based data collection approach

Fishing grounds are among the most important key of information kept by the fishermen. Understanding the fishing ground locations are considered important as an evaluation of the fishing effort being reached by the fishermen as well as understanding the pressure being received to the fish stock at the surrounding water. The recent study has shown that a community-based data collection approach was found successful in recording and analyzing the fishing ground locations and its properties. One of the few projects implementing this concept is the Community-Based Bathymetric Survey (CBBS), which was realized by the Body of Rehabilitation and Reconstruction (BRR) Nanggroe Aceh Darussalam (NAD) – Nias with funding from the Asian Development Bank (ADB). As many as 151 GPS-transducer recording devices were installed to the fishermen boats along the coast of Aceh, with 45 devices were installed to the traditional purse seine fisher at the northern water of Aceh. These devices were configured to automatically record locations each time the boat moved 30 m. Other important information, such as water depth, time, speed, and sea surface temperature (SST) were recorded as well. This study aims to examine the fishing ground and its fishing hotspot of the traditional purse seine fisher in the northern waters of Aceh. The data collection was performed between June 2007 and May 2009 and gathered as many as 922 data sets consist of 6,170,648 data points, from the 45 purse seine boats. Trough the data, we are able to identify the typical fishing activities of purse seiner and as many as 1,619 data points were being detected. The results indicate that there are five main regions of the fishing ground hotspot in the northern waters of Aceh, i.e. 1. Western offshore of Lhok Nga, 2. Northern offshore of Ulee Lheue, 3. Western offshore of Aceh Islands, 4. Eastern offshore of Aceh Island, and 5. Northern offshore of Krueng Raya. Among the fishing ground hotspot analyzed, the Western offshore of Lhok Nga is the highest density of fishing ground, while the lowest is at the northern offshore of Krueng Raya. These findings suggest that the western offshore of northern waters of Aceh are likely more fertile than its north- northeastern offshore.

NVESTIGATION ON TUNA FISHERIES ASSOCIATED WITH FISH AGGREGATING DEVICES (FADs) IN INDONESIA FMA 572 AND 573

The use of anchored fish aggregating devices (a-FADs) in the Indonesia-Indian Ocean has increased rapidly. Since 2004, the Government of Indonesia has issued various FAD related fisheries regulations; however, its implementation was difficult, largely due to the lack of such information. As an endeavor to improve the management of tuna fisheries associated with FADs in this area, an Indonesia–Australia research collaboration project conducted a port sampling program from November 2013 to December 2015 in three key fishing ports in the western Indonesia, i.e., Pelabuhanratu (West Jawa), Muara Padang (West Sumatera), and Bungus (West Sumatera). Data were collected through daily enumeration and interviews with skippers, which consisted of catch, trip duration, biological data, and number of FADs visited. These data were analyzed to estimate catch rate, success rate, and length frequency distribution. The success rate of hand line/trolling line (HL/TR) at Muara Padang showed much lower than that at Pelabuhanratu. This may be due to more a-FADs or higher density in the Padang region, competing with purse seine (PS) boats operating in the same area, than those in the Pelabuhanratu region. The species composition caught by HL/TR and PS associated a-FADs in Indonesian FMA 572 and 573 include skipjack (SKJ, Katsuwonus pelamis), yellowfin (YFT, Thunnus albacares) and bigeye tuna (BET, T. obesus). A large proportion of the SKJ, YFT and BET caught at both Indonesian FMA 572 and 573 were juvenile fish, below the reported length at maturity (Lm) for those species.

Application of a multi-annual generalized depletion model to the Mediterranean sandeel fishery in Catalonia

A multi-annual generalized depletion (MAGD) model was applied to the data-limited Mediterranean sandeel boat seine fishery in Catalonia. The results show that catch and effort data at high temporal frequency (month), complemented with biological information on mean body weight and initial estimates of natural mortality and time of recruitment to the fishery, can be used to produce assessment results of interest to fisheries management. The estimates of fishing mortality obtained for the Mediterranean sandeel in this fishery are very low compared to natural mortality estimates (less than 10 %) and the important fluctuations in recruitment strength suggest that the dynamics of this fishery are mainly driven by density-dependent effects on the population dynamics of the species. Given the high rate of natural mortality estimated (∼ M = 2 y−1), its short life-span (1–2 y) and that exploitation is based on age 0 individuals, it is recommended to keep exploitation rates at current levels (<4%), which can be adapted on a short time basis, subject to the perceived availability of the stock. This low exploitation rate is compatible with a precautionary escapement biomass of 40 %. A parallel stock assessment was carried out with a surplus production model (SPiCT), which led to similar trends in biomass and fishing mortality as the MAGD model application. The parameter estimates obtained with both models have wide confidence intervals, particularly for the quantities related to population size, suggesting that these data-limited models are likely to suffer from low precision. Precision was lower for SPiCT than for MAGD, and the performance diagnostics for SPiCT were poor. The MAGD model can be used for small-scale fisheries that are unlikely to meet the requirements of standard stock assessments based on catch-at-age methods and can provide indicators (fishing mortality, vulnerable biomass) of interest to fisheries managers.

Fishing Vessel Characteristics with Multipurpose Gear to Support Fishing Operations in the Northern Sea of Java, Indonesia (Case Study in Indramayu)

This study aims to analyze the ratio of the main dimensions of the vessel to see the performance of vessels with multipurpose gear. The research was conducted in February-March 2018 at the Karangsong Fish Landing Base (Ind: PPI), Indramayu. The object of research is the vessel used for fishing operations with multipurpose gear. The research method uses survey methods through the measurement of the main dimensions of fishing vessels, interviews and literature studies. The data obtained were then analyzed by comparative descriptive to compare the value of the ratio of the main dimensions of the vessel between Length and Breadth (L/B), the ratio between Length and Depth (L/D) and the ratio between Breadth and Depth (B/D). The calculation results of the ratio of the main dimensions of the vessel are then compared with the standard ratio values in Indonesia. Fishing vessels with multipurpose gear in Indramayu have good vessel motion characteristics but have an impact on slow speed, strong elongation strength of the vessel, and stability and ability to drive a good vessel. The dimension ratio of multipurpose gear vessels generally meets the criteria of the ratio of the main dimensions of vessels based on the method of operation in Indonesia. It should be noted that the L / B ratio tends to exceed the minimum standard criteria for the Indonesian dimension ratio, this results in slow speeds and will interfere with the setting and hauling fishing gear on seine boat and mini trawl fishing gear.

Numerical Estimation of Glass Fiber Reinforced Plastic Propeller Performance Using Rigid and Flexible Model

Composite materials have offered some improvements on the performance of hydrodynamic and structures of marine constructions. The high strength to weight and stiffness to weight ratio might be tailored through the exploitation of the fiber orientation in order to reduce the load and the stress distribution of the structure. In order to fully explore the performance of the developed glass fiber reinforce plastics (GFRP) B-series propeller for traditional purse seine boat in the North Coast of Central Java, the aim of the research is focused on the comparison of the rigid and the flexible model adopted for the simulation analysis of the propeller performance. The thrust force, the torque moment and the efficiency of the two propeller models are discussed.