Lift Nets Research Articles

Ichthyofauna Diversity in Danau Teluk: Analysis Using Gill Nets and Lift Nets

This study aims to explore and document the ichthyofauna diversity in the waters of Teluk Lake, Jambi City, using gill nets and lift nets. Sampling was conducted at three research stations from April to June 2024. Environmental physical and chemical factors such as temperature, pH, and water clarity were measured to understand their impact on the fish community. The results showed that the water temperature at stations I and II was 29°C, while at station III, it was 28°C. The pH values ranged from 6.41 to 6.95, and water clarity ranged from 7 to 21 cm. A total of 218 individual fish from 17 species and 8 families were found, with the Cyprinidae family being the dominant group. The Shannon-Wiener diversity index (H') ranged from 0.94 to 2.01, indicating moderate to high diversity. The evenness index (E) ranged from 0.58 to 0.91, indicating relatively even distribution of individuals. The dominance index (C) ranged from 0.14 to 0.53, indicating no species significantly dominated the community.

A passive fish sampling method is representative for size but selective for parasite load

Fish capture in industrial aquaculture is both necessary (i.e., for transfer, monitoring and harvesting) and difficult. The most logistically feasible methods rely heavily on crowding, a process that is detrimental to fish welfare and production outcomes. Jump nets, which rely on passive capture via jumping behaviour, present a welfare-friendly alternative. But reliance on behaviour means capture is not guaranteed, and limited knowledge of their capture rate and sampling biases means they are not yet used to their full potential. Here, in sea-cages stocked with Atlantic salmon Salmo salar, we investigated how capture rate varied with net size, position, and time of day, and if salmon caught via jump net were representative of the sea-cage population. A comparison of jumping rates into surface rings (without nets) indicated that larger jump nets will catch more fish. Capture rate was highest in rings positioned in the centre of cages, and during the morning and evening. Jump nets sampled representatively for fish size but caught salmon with marginally lower condition (<2% difference) and with three times higher parasitic salmon louse (Lepeophtheirus salmonis) loads than fish caught using lift nets. Our results indicate that jump nets can be used as a size-representative sampling tool and to target lice infected salmon for treatment.

The reproduction performance of catching Planiliza subviridis (Teleostei: Mugilidae) in different moon periods from Jepara Coast, Central Java, Indonesia

Abstract. Yudiati E, Yuniarti T, Trianto A, Arifin Z, Ruliaty L, Soleh M, Naryaningsih A, Suryati. 2024. The reproduction performance of catching Planiliza subviridis (Teleostei: Mugilidae) in different moon periods from Jepara Coast, Central Java, Indonesia. Biodiversitas 25: 1823-1830. Mullets (Planiliza subviridis Valenciennes 1836) are highly promising species for aquaculture development. Information on the reproductive performance of wild-caught fish is crucial for enhancing mullet production. This study aimed to assess the gonadal maturity level of female mullets captured during full and new moon phases. Sampling using lift nets was conducted from June to July 2023, comprising 104 individuals, 51 during the new moon and 53 during a full moon. Fish caught during different moon phases were measured for gonad maturation level (GML) and morphometric parameters (body weight, total length, head length, body width, and head width), assessed for gonad somatic index (GSI), fecundity, and egg diameter. Over 50% of individuals were at GML III during dark moon phases, while during bright moon phases, only 10-15% were at GML III; GSI ranged from 0.6-15%. The fecundity of GML I and II females was higher during the full moon (220,212-395,000 eggs per individual) compared to the new moon, while GML III females during dark moon phases ranged from 225,000-250,000 eggs. Mullets exhibit increased reproductive output during the new moon phase and engage in synchronous spawning during moonlight cycles. Therefore, prospects for mullet culture appear promising, with cultivation and domestication suggested during new moon periods.

Catch composition, catch per unit effort (CPUE) and species selectivity of fishing gears on multi-species Kaptai Lake in Bangladesh

Kaptai Lake, the largest artificial reservoir in Southeast Asia, is home to a diverse fish fauna that supports thousands of livelihoods and is distinguished by multi-species and multi-gear fisheries. In Kaptai Lake, the gear-based catch composition, catch rate and distribution pattern are little known. From August 2020 to April 2021, a nine-month study was conducted in five upazilas using direct catch assessment surveys and fishing effort surveys from four fishing gears, namely seine nets, gill nets, lift nets, and push nets. A total of 49 morpho-species from 22 families were found, with three species from the Clupeidae accounting for 93.63 % of the catch in all gear combined. The total catch composition and CPUE were higher in seine nets (75.07 %, 13.86 ± 1.8 kg/gear/trip respectively) and lower in lift nets (4.97 %, 1.01 ± 0.21 kg/gear/trip) and showed significant differences among gears, except sampling sites whereas CPUE was higher in Naniarchar for seine nets (17.29 ± 8.89 kg/gear/trip) and lower in Langadu for lift nets (0.62 ± 0.25 kg/gear/trip). Seine nets captured more species, and the number of species increased significantly as CPUE increased. Our study assessed four gears that targeted different fish species with little overlap in leading species; seine nets and gill nets primarily targeted Clupeidae (96.53 % and 41.69 %, respectively), whereas lift nets and push nets primarily targeted Cyprinidae and Palaemonidae (38.93 % and 99.37 % respectively). The observed abundance and variety of fish species captured in gill nets suggest a significant overlap in the selectivity of this fishing method with that of lift nets. Due to the varying contributions of sites and gears, the nMDS ordination pattern reveals a weak spatial variation in catch composition. According to the SIMPER results, Bagridae, Gobiidae, and Ambassidae were the most significant contributors to site grouping patterns across all gears. Furthermore, the findings indicate that the catch composition does not follow the typical pattern of spatial variation. By implementing measures to eliminate or decrease the usage of small mesh nets, there is expected to be a corresponding decrease in the capture of small fish. Additionally, this action will help mitigate the issue of overlapping selectivity among the current fishing gears. Our findings provide baseline data on the potential efficacy of gear limitation and suggest a gear-based management strategy.

Technical and Financial Analysis of Floating Lift Net Business in Tulehu Village, Central Maluku Regency

Uncertainty of sustainability is a common problem in the fisheries business due to the nature of the fishes, which are seasonal and highly perishable. Therefore, financial analysis of this kind of business is essential to maintain its sustainability. Many small-scale fishing businesses requires an organized financial record keeping. This research is aimed at (1). Analyze the technical conditions of the floating lift net business in Tulehu Village, Central Maluku Regency, and (2) Analyze the financial aspects of the floating lift net business in Tulehu Village, Central Maluku Regency. The results show that the floating lift net in Tulehu Village measured 18m x 20m, with the construction parts consisting of a balancer, lift net house, support poles, net rollers, and anchor rollers, while the parts of the additional equipment which consist of nets, lighting devices, boats, and transport machines as well as scoops. The average number of fishing activities for floating lift nets in non-fishing seasons is 55 trips, while in the fishing season, it is 138 trips, with different fishing areas depending on the season. Based on the investment assessment criteria, the average R/C calculation value is 3.4, the average PP value is 3.26, and the average ROI value is 34.87%. The floating lift net business at the research location is financially feasible to develop.

Analysis of Occupational Safety of Boat Lift Net’s Fishermen at the Bungus Ocean Fishing Port (PPS) Bungus West Sumatra

Boat lift nets are one of the fishing gears in PPS Bungus, data from December 2021; 142 Bagan boat boats departed to carry out fishing operations with the number of fishermen boats 6 - 21 people and the weight of the ship 8-30 GT. In recent years, there have been several work accidents experienced by Bagan boat fishermen, such as falling while walking on the boat deck, fatigue, stepping on rotten wood, and broken hands. This study aims to determine the cases of work accidents that occurred in boat-bagan fishermen in the period January 2022 - January 2023, describe the activities carried out by boat-bagan fishermen, and determine the level of risk experienced by boat-bagan fishermen. This study uses a descriptive observational method with data analysis of probability concepts, JSA, and HIRA using the 2004 Australia and New Zealand standard risk control matrix. The results showed that the activities carried out in the operation preparation stage at PPS Bungus were mainly carried out by laborers (non-fishermen), work accidents in 7 operation activities were classified into five low-risk accidents and two moderate-risk and work accidents in the post-operation stage occurred 4 out of 7 activities which were classified into three common risk accidents and one medium risk.

FISHING PRACTICES OF BLUE SWIMMING CRAB IN NORTHERN CATANDUANES, PHILIPPINES: IMPLICATIONS TOWARDS SUSTAINABLE MANAGEMENT

Fishermen in Northern Catanduanes rely heavily on Blue Swimming Crab (BSC) as a source of income. The goal of this study was to characterize the BSC fishery in the maritime environments of Viga, Panganiban, Pandan, and Bagamanoc. A survey was conducted to gather data on the BSC fishery in Northern Catanduanes from February to May 2023. The results revealed that the income of crabbers and their families was well below the poverty threshold. This was worsened by the lack of formal education among crabbers, which restricted their options for finding alternative sources of income. The primary fishing gears utilized by fishers were bottom set gill nets, crab pots, and crab lift nets with 55.77%, 14.90% and 15.38%, respectively. The peak fishing season for most municipalities occurred between May and July while the lean season varied from October to February. About 95.19% of the crab fishers violated regulation on the implementation of the minimum carapace width of 10.2 cm for blue swimming crabs allowed for catching, collecting and trading. The sustainability of the BSC fishery in Northern Catanduanes is under threat. It is critical to put in place efficient management strategies to deal with the issues causing the BSC stocks to decrease. In order to ensure sustainable fishing methods, these actions should prioritize lowering fishing pressure, keeping an eye on and informing crab fishermen, offering substitute revenue streams, and launching education and awareness initiatives.

CPUE TREND AND DOMINANT FISHING GEAR OF MACKEREL (Rastrelliger sp.) LANDED IN KARANGANTU

PPN Karangantu is one of the fish landing sites in Serang City, Banten Province. One of the most commonly landed fish species at PPN Karangantu is mackerel. Several fishing gears are used by Karangantu fishermen to catch mackerel, including single monofilament gillnets, boat lift nets, lift nets, and lines. While mackerel fishing efforts in the 2017-2021 timeframe are likely to increase, specific management measures for mackerel fishery at Karangantu PPN have not been implemented. The purpose of this study was to determine the CPUE trend for mackerel fisheries in the 2017-2021 timeframe and to identify the dominant types of fishing gear used in mackerel fishery activities. The data used in this study were obtained from the PPN Karangantu statistical report and field observations. The collected data was processed and analyzed using CPUE and descriptive analysis. The results showed that the CPUE trend for mackerel from 2017 to 2021 tends to increase sustainably, with the single monofilament gillnet being the dominant fishing gear used in mackerel fishing.

Technical-economic prospect for photovoltaic on fixed lift net in Indonesia

The limited fossil energy and uncertain prices have an indirect effect on fishing activities using a fixed lift net. Therefore, energy diversification is carried out by utilizing solar energy with photovoltaics on the fixed lift net. This energy is very abundant and available throughout the year, except during the rainy season. This study uses observation, interviews, and questionnaires given to fishermen and tries to compare the utilization of photovoltaic (PV) systems with generators using different types of lamps, such as LED, CFL, incandescent lamps, and halogen lamps. The use of PV systems in fixed lift nets from a technical and economic perspective allows it to be utilized in the long term. Based on the technical aspects, the PV system can produce 471.59 Wh per day. This technical result will be more profitable if the lamp used is a light emitting diode (LED) lamp. Meanwhile, from economic aspect, the use of electrical energy from a PV system is more profitable because it provides a lower operational value than a generator, and provides good net present value (NPV) and internal rate of return (IRR) values. This utilization is also supported by the good response from fishermen towards the energy produced and the ease of operation and maintenance of the PV system.

Distribution of artisanal fishing gears with impacts on sedimentation and benthic macroinvertebrate assemblages in Songkhla Lake, the largest lagoon in Thailand

The present study investigated the distribution and diversity of stationary fishing gears in Songkhla Lake and assessed the effects of the most abundant gear in the lake, the standing trap, on sedimentation and the abundance of benthic macroinvertebrates. Our survey revealed that six types of fishing gear were used: standing traps, fyke nets, fish aggregating devices, seabass net cages, small traps and stationary lift nets. The type of fishing gear used depended on the depth of water. The density of installed standing traps reached a maximum of 357 traps/km2, which was the highest density of any fishing gear installed on the lake. They were mainly set in the middle part of the lake, where the water was less than 2 m deep. Sedimentation was examined inside and outside the areas influenced by standing traps. Sediment samples were collected with sediment traps in the northeast and southwest monsoon seasons. Sedimentation rates inside and outside the areas influenced by standing traps differed at some sites but the pattern was not consistent across seasons. Sedimentation rates were higher in the northeast monsoon season with the average rate 1132.32 ± 43.73 (mean ± SE) g m−2day−1 when precipitation and run-off were higher and 323.98 ± 10.68 g m−2day−1 in the southwest monsoon or dry season. Moreover, the proportion of finer clay particles was greater in the sediment from the areas influenced by traps. Benthic macroinvertebrate communities between the two areas were different. A bivalve, Potamocorbula sp., which dominated benthic macroinvertebrate assemblages, had a higher abundance in areas influenced by traps. The effects of stationary fishing gears on sedimentation and benthic macroinvertebrates highlighted in this study suggest that the long-term deployment of these gears may affect food chain dynamics in this lagoon system. Ultimately, a proper regulation of the use of these gears may be needed.

Zoo-holoplankton assemblages in the surrounding waters of Kamal Western Part of Seram Island Maluku Indonesia

Zoo-holoplankton dynamic between the sites are useful to knowledge with the regard to the characteristic of the areas and in relative to the community structure of zoo-holoplankton.The research conducted in the surrounding waters of Kamal village, the western part of Seram Island, Maluku Province. Zoo-holoplankton organisms collected from six-fixed Research stations consisted of different characteristics, namely stations 1 and 2 are Fish Aggregation Device placement areas, station 3 is the area for setting the lift nets, stations 4 and 6 are in front of the river mouth and station 5 is in the coral reef area. Sampling done every two weeks by using zooplankton net (diameter of 45 cm) sled with a 200 µm meshed. The result showed that the composition of zoo-holoplankton consisted of 37 genera from 8 phylum, 9 classes, and 28 families. There were about 9 genera (Calanus sp, Calocalanus sp, Acartia sp, Centropages sp, Oithona sp, Onceae sp, Corycaeus sp and Copilia sp), which found in all stations and periods. While some genera are only present at certain stations or periods (Eucalanus sp, Labidocera sp, Sapphirina sp, and Evadne sp). The abundance of zoo-holoplankton peaked at station 5 (16,332 ind/m−3) in the third period, while the lowest was at station 1 (809 ind/m−3) in the second period. Similarities indices was high between station 1 and 2 during the whole period (91%, 82% and 78%) and was low between station 1 and 6 (In the first period) and station 3 and 5. We noticed that differences characteristic of sampling areas leading to the abundance and the genera numbers of zoo-holoplankton. .

Sustainability Status Of Squid Fishery Business Using Boat Lift Nets Based On Bioeconomics In Ekor Village, East Halmahera Regency

Squid fishing business is an activity to exploit squid resources with the aim of obtaining a continuous profit. The aim of the research was to analyze the biological aspects which include the structure of the length of the mantle and the size suitable for catching as well as the percentage of the size of the squid that is suitable for catching; analyze economic aspects; and analyze the status of a sustainable squid fishery business. The research was conducted in Ekor Village, South Wasile District, East Halmahera Regency for 7 days, from 7 to 13 December 2022. The research method used was a survey method. The structure of the length of the mantle of the squid caught in the boat net was dominated by the size suitable for catching, namely 57.17% and the size not suitable for catching, by 42.83%. Financially and investment, the squid fishing business with a boat chart is feasible to be cultivated throughout the year, with a profit value of IDR. 53,303,000.00, B/C ratio 1.12, IRR 33%, BEP IDR. 152,576,999, and PP 3.78 years. The squid fishing business with a boat chart based on biological and economic aspects (financial and investment criteria) in Ekor Village, South Wasile District, East Halmahera Regency has high sustainability.

Effect of hauling and soaking time of stationary lift nets on fish aggregation using a hydroacoustic monitoring approach

This study aimed to determine the effect of hauling and soaking time of stationary lift nets on the pattern of fish aggregation in the Banyuasin waters, South Sumatra, Indonesia using a hydroacoustic monitoring approach. The fish aggregations were monitored using the SIMRAD EK-15 single beam (200 kHz) during hauling, and the transducer was mounted on the side of the fishing gear. Furthermore, data were collected before (17:00–23:59) and after midnight (24:00–05:00) at four different soaking times (S1, S2, S3, and S4). The data obtained were then analyzed using pairwise comparisons (nonparametric tests). The pairwise test (p = 0.25 > 0.05) showed that there was no significant difference between the acoustic mean densities obtained before and after midnight (292.2 and 178.9 g/m3), but the total values for both periods varied widely (6,797 and 3,507 g/m3). Dunn’s post hoc tests (p = 0.001 < 0.05) revealed that there were significant differences in the acoustic mean densities between S1 (1–16 min) and S2 (17–32 min). Based on the results, the optimum soaking time was 17–32 min, which was recommended for improving the effectiveness of the stationary lift nets. Furthermore, fish aggregation began to spread out of the catchable area when the soaking time was over 32 min.

Produktivitas dan Pola Musim Tangkap Ikan Peperek (Leiognathus spp.) di Teluk Banten

Ponyfish (Leiognathus spp.) is one of the dominant types of fish landed at the Nusantara Fishing Port (PPN) Karangantu. Its high-intensity fishing activities are feared to cause future problems with the sustainability of ponyfish resources. This study aims to calculate fishing productivity, sustainable optimal fishing effort, maximum sustainable catch, and determine the pattern of fishing season in Banten Bay. The research was conducted from April to June 2021 at PPN Karangantu. The fishing gear analyzed were fixed lift nets, floating lift nets, and seine nets. Fishing productivity was calculated from catch per unit effort; the maximum sustainable catch was analyzed using the Schaefer, Fox, and Walter-Hilborn regression models. The seasonal pattern of the ponies was determined from the Fishing Season Index. The results showed that pony fishing productivity in PPN Karangantu decreased from 2016 to 2020. The optimum fishing effort value and the optimum catch through the Schaefer model were 2088 trips/year and 276.12 tons/year, respectively; the highest fishing season occurred in November (145.5%) and the lowest in May (70.2%). Based on the analysis of the Schaefer, Fox and Walter-Hilborn models, the exploitation of Ponyfish (Leiognathus spp.) in Banten Bay can be said to be over-exploited.&#x0D; &#x0D; Keywords: catching season, Banten bay, Leiognathus spp., productivity

Implementasi Strategi Pengembangan Usaha Bagan Apung Rakit Skala Kecil Untuk Meningkatkan Pendapatan Nelayan Kecil di Ohoi Namar, Kabupaten Maluku Tenggara

Catching efforts in the small-scale lift net raft floating business in Ohoi Namar, Southeast Maluku Regency, continues to increase in quantity, information obtained in the field shows that there was an additional 5 units of small-scale lift nets raft floating fleets from 2012 to 2022, but the increase in fishing effort has not been able to increase the income of small fishermen, these problems are generally influenced by internal and external factors. Therefore, the right step that needs to be taken to increase income is to provide counseling and implement a strategy for developing a small-scale floating raft business using lecture and discussion methods followed by evaluation and monitoring of these small fishing businesses. The strategy for developing the lift net raft floating business can be conveyed well and based on the evaluation results of the participants it shows that the material presented can be well understood, this is evidenced by the number of participants included in the sufficient category of 20 people with a value range of 76-100, the sufficient category is 5 people with the value range is 60-75 and no one is in the less category with a value range &lt;60. Monitoring of the fishing business is not carried out because the fishing business is not operating and it is the west season. however, to further increase income, additional capital is needed and assistance from academics, bureaucracy and private/BUMN.

A Resident Fish Guild as a Higher Trophic Level Indicator of Oyster Reef Restoration Success

Eastern oysters (Crassostrea virginica) are critical foundation species in estuarine waters, but due to a combination of natural and anthropogenic pressures, oyster abundance has declined. Restoring oyster reefs and monitoring restoration success often focuses on oyster metrics, but relatively infrequently, responses of higher trophic level species and the production of related ecosystem services are accounted for. To address this, we compare the response of a resident reef fish guild (gobies, blennies, toadfish) to standard metrics of oyster restoration success. Using lift nets and seines, natural and restored reefs were monitored over a two-year period within Mosquito Lagoon, Florida, USA. Standard metrics are indicative of restoration success; live oyster density and reef thickness increased in restored reefs after 12 and 24 months. Combined, live oyster density and reef thickness were the best predictors of annual resident reef fish abundance compared to water quality metrics. These results suggest that the benefits of restoring oyster reef habitat are conferred to broader components of the food web, with benefits accruing to reef resident fishes that are a key trophic linkage between lower trophic level foundation species and higher trophic level predators inhabiting coastal ecosystems.

Life-history traits of ten commercially important small indigenous fish species (SIFS) in the Oxbow lake (Southwestern Bangladesh): key for sound management

For the first time, we revealed the life-history traits including growth pattern (length-weight relationships, LWRs), condition factors, form factor (a3.0), first sexual maturity (Lm), age at first sexual maturity (tm), life span (tmax), natural mortality (Mw), asymptotic length (L∞), and optimum catchable length (Lopt) of ten commercially important small indigenous fish species (SIFS) in the Oxbow lake (Baor), southwestern regions of Bangladesh. A total of 1651 specimens were sampled during January to December 2020 with traditional fishing gears including seine nets, gill nets, and lift nets. Individual total length (TL) and body weight (BW) were measured by digital slide calipers and digital balance, respectively. To calculate the Lm, empirical maximum length-based model was considered, and Lopt was calculated based on L∞. The TL vs. BW relationship indicated positive allometric growth for Chanda nama (Hamilton 1822), Channa punctata (Bloch 1793), Channa striata (Bloch 1793), Lepidocephalichthys guntea (Hamilton 1822), Macrognathus pancalus (Hamilton 1822), and Puntius sophore (Hamilton 1822), but negative allometric growth for Badis badis (Hamilton 1822), Gudusia chapra (Hamilton 1822), Glossogobius giuris (Hamilton 1822), and Hyporhamphus limbatus (Valenciennes, 1847). All r2 values exceed 0.910 that indicated all LWRs were highly significant (P < 0.001). According to Spearman correlation test, Fulton's condition factor (KF) vs. BW was highly correlated (P < 0.001), indicating better well-being for these species. Moreover, a3.0 indicates B. badis, C. punctata, C. striata, G. giuris, H. limbatus, L. guntea were elongated; C. nama, P. sophore, were short and deep; G. chapra was fusiform, and M. pancalus was eel-like body shape respectively. The minimum tm and tmax were obtained as 0.74year and 2.66year for C. striata and maximum were 0.93year and 3.31year for B. badis, respectively. This study provided information on tm and tmax for ten SIFS that is globally absent. From empirical models, the smallest mean value of Lm was found for B. badis (3.98cm), and the greatest was found for C. striata (16.96cm). The minimum Lopt was obtained as 3.78cm TL for B. badis and maximum was 14.09cm TL for C. punctata. The minimum Mw was documented as 1.39 for B. badis and maximum was 1.73 for C. striata. The output of this research will be helpful for developing sustainable management policies and protection of SIFS through the application of mesh size based on Lm and Lopt in the Oxbow lakes, Bangladesh and neighboring countries.

Life‐history traits of Guntea loach, Lepidocephalichthys guntea (Hamilton, 1822) in the Payra River, southern Bangladesh

AbstractThe present study provides the first wide‐ranging elucidation of life‐history traits, including length–frequency distribution (LFD), length–weight and length–length relationship (LWR and LLR), form factor (a3.0), best condition factor (allometric, KA; Fulton, KF; relative, KR; and relative weight, WR), length at first maturity (Lm), natural mortality (Mw) and optimum catchable length (Lopt) of Lepidocephalichthyes guntea from the Payra River in southern Bangladesh. A total of 470 fishes were randomly collected seasonally from February 2019 to January 2020, using several traditional fishing gears (cast nets; drag nets; lift nets; and gill nets). The total length (TL), standard length (SL) and total body weight (BW) of each individual fish were measured with a 0.01 cm and 0.01 g precision, respectively. The TL size classes of 6.00–6.99 cm and 7.00–7.99 cm TL were the numerically dominant groups among the total fish population. Exponential b values of LWR (TL vs. BW) indicate a positive allometric growth (b = 3.20) pattern in the Payra River. The b value of LLR also indicates the same growth pattern. The estimated a3.0 value was 0.007, indicating the fish has an elongated body profile. Among the four types of condition factors, KF is the best‐suited tool for evaluating the well‐being of L. guntea in the Payra River. Additionally, WR exhibited very significant divergence from 100 (p &lt; .0001), designating an imbalanced habitat for L. guntea. The calculated Lm, Mw and Lopt values were 6.54 (~6.5 cm) in TL, 1.16/year and 7.46 cm TL for L. guntea in the Payra River, respectively. Thus, the results of the present study could be used in the future for improved management of this species in Payra River, as well as for linking ecosystems.

Life‐history traits of three Ambassid fishes (Chanda nama, Parambassis lala and Parambassis ranga) from the Mathabhanga River, southwestern Bangladesh

ABSTRACTThe present study provides the first indication of the life‐history traits, including, population structure, growth pattern, condition factor, form factor (a3.0), size at first sexual maturity (Lm), natural mortality (MW) and optimum catchable length (Lopt), of three Ambassid (Chanda nama, Parambassis lala and Parambassis ranga) fishes from the Mathabhanga River in southwest Bangladesh. A total of 370 individuals were occasionally collected from August 2017 to July 2018 with cast nets, gill nets, square lift nets, and conical‐ and box‐traps. The total length (TL) ranged from 2.4 to 7.5 cm for C. nama, 1.9–3.8 cm for P. lala and 1.8–6.5 cm for P. ranga. The length‐frequency distributions (LFDs) showed the 4.0–5.0 cm TL size group for C. nama and the 3.0–4.0 cm TL size group were numerically dominant for P. lala and P. ranga. The length–weight relationships (LWRs) indicated isometric growth for C. nama, and positive allometric growth for P. lala and P. ranga. All the LWR values were very significant (p &lt; .001), with all r2 values &gt; .950. Based on the Spearman rank correlation test, body weight (BW) versus Fulton's‐condition factor (KF) was extremely correlated (p &lt; .001), indicating a better wellbeing for these species. The a3.0 value was 0.0082, 0.0138 and 0.0104 for C. nama, P. lala and P. ranga, respectively. Based on the maximum length (Lmax), the Lm was 4.4 cm TL for C. nama, 2.5 cm TL for P. lala, and 4.0 cm TL for P. ranga. Based on the asymptotic length (L∞), the Lm was 4.88 cm TL for C. nama, 2.63 cm TL for P. lala, and 4.28 cm TL for P. ranga. The MW value was 2.2, 3.3 and 2.7/year for C. nama, P. lala and P. ranga, respectively. The optimum catchable length (Lopt) was 5.36 cm TL for C. nama, 2.75 cm TL for P. lala and 4.65 cm TL for P. ranga. The findings of the present study should be very useful for effective and sustainable management of these fishes in the Mathabhanga River and the connecting ecosystems.

ANALISIS PENDAPATAN NELAYAN TRADISIONAL DENGAN MENGGUNAKAN ALAT TANGKAP UDANG LIFT NETS (Ali) DI KECAMATAN ARONGAN LAMBALEK KABUPATEN ACEH BARAT

Capture fisheries is a source of livelihood for fishermen. Fishers in Arongan Lambalek are still classified as traditional fishermen and still use simple fishing gear in their operations. One of the fishing gear used is Lift Nets (Ali) fishing gear to catch shrimp. This study aims to determine the income of traditional fishermen using Lift Nets (Ali) fishing gear in Arongan Lambalek District, West Aceh Regency. This research was conducted from June to July 2020. The data collection method was purposive sampling method with 20 respondents. The analyzes used total cost, total beneficiary, profit and RCR. The results showed that, the amount of catch of fishermen using Lift Nets (Ali) fishing gear in Arongan Lambalek District was 2.872 kg / month with an average of 144 kg / month / fisherman, the total cost of 20 fishermen was Rp. 24.540,278 with an average total cost of Rp.1.227,013 months / fisherman, the amount of revenue from 20 fishermen is Rp.73.235,000 / month with an average income of Rp. 3.661,750 months / fisherman and income from 20 fishermen is Rp.48.694.722 / month and the average income of fishermen is Rp.2.434.736 / month and the average RCR of Rp.2.98 months / fisherman, which means RCR&gt; 1, then traditional fishing business using Lift Nets (Ali) fishing gear is feasible.