Number Of Caught Research Articles

Penerapan Metode Single Exponential Smoothing (SES) dalam Peramalan Jumlah Ikan

The fisheries sector is a sector that is one of the factors that can support activities and the Indonesian economy. Fishery resources, especially those in the sea, are natural resources that are freely used by anyone. In carrying out fishing business in Asahan Regency, there has been a cycle of ups and downs from the last ten years, so that the fish supply is not in accordance with its needs. Besides that, it takes a long time to find out the number of fish according to the origin of the catch if there is no technique used. Because this cycle occurs in fish production, it is not yet known how much fish production in the coming year will meet their needs, whether it will increase or decrease, the Government and fishermen in Asahan must be able to take policies to get solutions to these problems. So we need a method to predict the number of fish catches in order to know the predictive value in the next period by using calculations to find the error value for each value using the Single Exponetial Smoothing (SES) method. The results of the study obtained a prediction of the number of fish, namely in the July 2022 period 676836.19 (Kg) with a MAPE value of 3.38%, which value was greater in May 2022 and smaller than June 2022, the Asahan District Fisheries Service must meet the number of fish. in stock of their needs

Factors contributing to anglers’ satisfaction and their requests concerning recreational salmonid fisheries management: Insights from a questionnaire survey in strictly regulated, catch-and-release stream fishing areas

Regional fisheries managers need to consider anglers’ satisfaction and requests and balance them with resource conservation when making decisions to promote the sustainability of recreational fisheries. However, there is a marked paucity of information on inland recreational fisheries, particularly in non-Western countries. This study was designed to gain insight on the factors contributing to the anglers' satisfaction and their requests concerning salmonid recreational fisheries management. The approach used was a questionnaire survey of salmonid anglers in two strictly regulated, reservation-only, catch-and-release stream fishing areas in Japan. We evaluated the relationships among anglers’ characteristics and the fishing experience with their satisfaction degree. We also investigated the anglers’ requests concerning the use of fishing license proceeds. The catch numbers of the larger masu salmon available in the area (e.g., 20–40 cm standard length) were positively related to the satisfaction degree of anglers. This study confirms the findings on the determinants of anglers’ satisfaction in Western countries, especially concerning avid anglers. The highest priority for using the fishing license proceeds was for enhancing the number of fish and conserving the fish habitats. Surprisingly, enhancing the number of large fish received the lowest priority among the requests. These results suggest that anglers’ requests for recreational fisheries management do not necessarily reflect their preference to catch more and larger fish. Thus, reflecting only the anglers’ requests and discontinuing stocking the special areas with large fish could paradoxically reduce the anglers’ satisfaction. These results strongly point out that understanding the factors contributing to anglers' satisfaction is crucial to avoid misunderstandings and make sounder and more sustainable recreational fisheries management decisions.

Development of a high-efficiency sex pheromone formula to control Euproctis pseudoconspersa

The tea tussock moth (Euproctis pseudoconspersa) is one of the most destructive chewing pests in tea plantations and causes a serious allergic reaction on the skin of tea plantation workers. The sex pheromone components of its Japanese population were first identified as 10,14-dimethylpentadecyl isobutyrate (10Me14Me-15:iBu) and 14-methylpentadecyl isobutyrate (14Me-15:iBu), with a stereogenic center. Only 10Me14Me-15:iBu has been identified in the Chinese E. pseudoconspersa population. However, field tests have shown that 10Me14Me-15:iBu cannot meet the demand of effective pest control in China. To develop a high-efficiency E. pseudoconspersa sex pheromone formula, electroantennogram (EAG) recordings of (S)- and (R)-enantiomers of 10Me14Me-15:iBu and 14Me-15:iBu were obtained in the present study. The results demonstrated that the EAG responses of male antennae to (R)-enantiomers were significantly higher than responses to the (S)-enantiomers, and 14Me-15:iBu also elicited EAG activity. Field tests showed that the catch numbers of male moths by (R)-enantiomers were significantly higher (P<0.05) than those of (S)-enantiomers. Addition of 14Me-15:iBu significantly increased the catch numbers of both the (S)- and (R)-enantiomers. The efficient pheromone formula containing 0.75 mg (R)-10Me14Me-15:iBu and 0.1 mg 14Me-15:iBu showed significantly higher attractiveness than commercial pheromone products. Our study demonstrated that (R)-10Me14Me-15:iBu was the major sex pheromone component of E. pseudoconspersa, and 14Me-15:iBu might be the minor sex pheromone component. Furthermore, a high-efficiency sex pheromone formula for E. pseudoconspersa control was defined in this study.

Seasonal migratory activity of SPODOPTERA FRUGIPERDA (J.E. Smith) (Lepidoptera: Noctuidae) across China and Myanmar.

The fall armyworm (FAW) Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) invaded Myanmar and China in 2018 and greatly impacted agricultural production and ecosystem balance in these areas. FAW is a migratory insect, but its seasonal migration pattern between the two countries has been largely unknown. From 2019 to 2021, we monitored the seasonal migration of FAW in the China-Myanmar border area using a searchlight trap, assessed the reproductive development status of female migrants and traced the migratory routes by trajectory simulation. FAW moths were trapped by the searchlight trap in Lancang County (Yunnan, China) all year, with obvious seasonal differences in the number caught. There were small-scale persistent trapping peaks in spring and summer, and obvious peaks in autumn; only a small number of moths were trapped in winter. Examination of the ovaries of female moths collected in different seasons showed that most females had matured, indicating that the moths were migrating and did not take off from the local area. In the migration trajectory simulation, FAW mainly migrated from Myanmar to Southwest China in spring and summer and back to Myanmar in autumn. Our findings indicate that FAW migrates between China and Myanmar according to the monsoon circulation, which will help guide cross-border regional monitoring and management strategies against this pest. © 2022 Society of Chemical Industry.

Exploring the vulnerability of a commonly exploited fish stock, Galeoides decadactylus in the artisanal mixed capture fisheries of Sierra Leone

Galeoides decadactylus is a commonly exploited fish stock in Sierra Leone, and the study of its vulnerability to capture in the artisanal mixed fisheries of Sierra Leone has not gained the needed attention of researchers, for which the present study has come in handy particularly when such information is critical for sustainable management of the stock. The study utilized length-frequency data obtained from 865 specimens as input datasets of analytical models inscribed for the FAO Fish Stock Assessment Tool (FiSAT II) software. Vulnerability indices for this study were the Length Structured Virtual Population Analysis (LVPA) and the Probability of Capture (PC). Results revealed minimum and maximum total length of 11cm and 36cm respectively for the study species, and LVPA showed highest catch (in numbers) for the length range, 20 cm (n = 94, 0000) - 21 cm (n = 100, 000). Also, the probability of capture evinced greater selection probability (p = 0.9) of the larger sizes (17cm - 22 cm (mean, 19.5 cm TL) at a maximum mesh size of 8cm of bottom drift net utilised by the fishers. The results of LVPA implied that the smaller length groups of the assessed stock (TL are less vulnerable to fishing mortality, but most susceptible to natural mortality, and the probability of capture indicated that the gill nets used by the artisanal fishers for this study were highly selective to allow greater number (n = 4.8 x 106) of the smaller length group escape capture. In conclusion, G. decadactylus was efficiently exploited in the artisanal mixed fisheries. However, stringent measures on capture input and output controls are advised for the assessed stock.

MANAGMENT STRATEGY OF 2nd and 3rd CLASS FISH AUCTION LOCATIONS IN PATI REGENCY, INDONESIA

Fisheries management policies are needed to achieve the prosperity of society in Indonesia. The auction process at fisheries in Indonesia does not run optimally; therfore, the impact of the role and function of fish auctions is not yet the best it could be in some areas. This study aimed to formulate a strategy for managing 2nd and 3rd class fish auction places in Pati Regency. The research locations were the Puncel, Banyutowo, Alasdowo, Sambiroto, Margomulyo, and Pecangaan fish auctions in the Pati Regency. The research was conducted from January 2021 to November 2021. The research respondents, namely a sample of critical figures (key persons), were determined by purposive sampling of as many as 15 people. Data was analyszed using the Analytical Hierarchy Process and Expert Choice 11.0 software. The study results prioritize the most critical management strategies, namely fish production with a weight of 0.309 (30.9%), infrastructure with a weight of 0.295 (29.5%), institutions with a weight of 0.206 (20.6%), and human resources with a weight 0.190 (19.0%). The priority of alternative management strategies is as follows: (1) maintaining the existence of businesses run by fishermen, with a weight of 0.172 (17.2%), (2) improving facilities and infrastructure to support fish auction place operations, with a weight of 0.164 (16.4%), and (3) increasing the number of catches landed, with a weight 0.145 (14.5%).

Estimation of CPUE and CPUA of pufferfish (Tetraodontidae) caught by the Bottom Trawl Fishery in the eastern Mediterranean Coasts

Two indicators of pufferfish communities, catch per unit effort (CPUE) and catch per unit area (CPUA), were used with surveys of bottom trawl fishery to elucidate the level of the catch of each pufferfish species in the Mediterranean coasts of Turkey, comprising the Iskenderun Bay, Mersin Bay, and Antalya Bay. The surveys were conducted seasonally in 2019. The average rate of CPUE for Lagocephalus sceleratus, L. suezensis, L. spadiceus, and Torquigener flavimaculosus were 2.2, 0.8, 0.5, and 0.2 kg km-2, respectively that the highest CPUE values were in winter (8.0 kg km-2) for L. sceleratus and also lowest was in winter (0.08 kg km-2) for L. spadiceus. The highest and lowest CPUE values were at the depth of 20-50 m (2.7 kg km-2) for L. sceleratus and 50-80 m (0.08 kg km-2) for T. flavimaculosus, respectively. The highest CPUE values (3.5 kg km-2) were found at the sandy bottom for L. sceleratus, and the lowest one (0.01 kg km-2) was at the hardy-ground for T. flavimaculosus. The average annual CPUA of pufferfish species at the Iskenderun, Mersin, and Antalya bays was estimated as 15.6, 28.4, and 6.81 kg, respectively, with a mean value of 17.3 kg/day/boat. In multiple correspondence analysis, L. sceleratus showed a great contribution to CPUE and CPUA data. However, T. flavimaculosus revealed contribution, especially in catch numbers which were positively affected by precipitation. L. spadiceus, L. suezensis, and T. flavimaculosus were positively affected by depth, temperature, month, season, and bottom structure.

How do El Niño Southern Oscillation (ENSO) Events Impact Fish Catch in Sarawak Water?

The response of chlorophyll to climate variability plays an important role in regulating the regional marine ecological environment and carbon cycle. This study focuses on the impact of changes in chlorophyll on the catches of deep-water fish and offshore fish. The chlorophyll factors from satellite image MODIS were analysed during La Niña in 2008/2011 and El Niño in 2015/2016. Remote sensing reflectance’s 443 nanometres and 555 nanometres were utilized to examine the bias of the chlorophyll concentration, Thus the higher phytoplankton absorption coefficient at 443, and backscattering coefficient for dissolved and detrital material stated the more phytoplankton biomass and higher suspended sediment concentration. The results found that the fish catch during El Niño is higher at 295572 metric tons compared to during La Niña which is 255783 metric tons. The El Niño event was found to have experienced an increase in catch of 29789 metric tons. This is due to the influence of the change in the mean value of the concentration in the study area of 0.31 mg-3 during La Niña compared to during El Niño 0.4 m mg-3. A decrease in the average value concentration of -0.09 mg-3 resulted in a decrease in the number of catches. In addition, the maximum value of chlorophyll concentration was also found to be high during El Niño which is 22 m mg-3 compared to during La Niña which is 18 m mg-3. The high distribution of chlorophyll-a is in the coastal areas of Sarawak, which explains why the coastal fish catches are higher than in the deep sea. It is concluded that the distribution of chlorophyll concentration is different during the occurrence of ENSO. This may result in different fishing rates in the study area. Remote sensing technology successfully explains why fish catches during El Niño are higher than during La Niña based on different chlorophyll dispersions. The provision of information in this space is very important to fishermen to reduce operating costs.

THE EFFECT OF THE DISTRIBUTION OF SEA SURFACE TEMPERATURE IN THE INDIAN OCEAN SOUTH OF JAVA ON THE CATCH OF YELLOWFIN TUNA (Thunnus albacares) USING AQUA MODIS SATELLITE IMAGERY

Tuna (Thunnus sp.) is the second largest foreign exchange earner after shrimp. One type of tuna which is an export commodity is yellowfin tuna (Thunnus albacares). Research on the effect of the distribution of sea surface temperature in the Indian Ocean south of Java on the catch of yellowfin tuna (Thunnus albacares) has been carried out at the Nizam Zachman Ocean Fishery Port (PPS) from April 8 to April 30, 2021. This study aims to determine the effect of sea surface temperature (SST) on the catch of yellowfin tuna. The research method used was the method of observation and analysis of satellite imagery. Coordinate data and the number of catches were obtained from the Ocean Fishery Port Logbook (PPS) Nizam Zachman. SPL data obtained from satellite imagery Modis Aqua Level 3. The data was obtained and then analyzed using a simple regression test and the F test results of regression analysis showed that the correlation coefficient (R) of 12.7% and the coefficient of determination (R2) of 1,6% means that 1.6% of yellowfin tuna catches are influenced by SST and 98.4% is influenced by other factors. The F test results show that the SPL significance value is 0.332. The conclusion is that changes in SST have no significant effect on the catch of yellowfin tuna

Composition and Catch Rate of Purse Seine Fishery Unit at the Tegal Fish Landing, Central Java

Purse seine fishing gear is one of the fishing gear used by the fisherman at the Tegal Fish Landing to catch pelagic fish. This study aims to analyze the composition of purse seine catches and catch rates based on the number of catches and trips to sea, determine the selectivity of purse seine fishing gear base on the number and species. The research method used survey methods and data in quantitative analysis, the analysis of the composition of the catch is secondary to the volume of purse seine catches at Tegal Fish Landing throughout September to November 2019. The capture rate was calculated using secondary data on the number of trips and the total production of purse seine at the Tegal Fish Landing from 2014 to 2018. Selectivity of puse seine fishing gear using primary data includes the number and weight of catches, identification of fishing gear, work equpment, safety equipment, supplies, navigation tools, accident history. The dominant variety of catch species was small pelagic fish, namely Decapterus macrosoma, Sardinella lemuru, and Rastrelliger kanagurta. The largest percentage of catches in September was 52% Decapterus macrosoma, 13% Sardinella lemuru, and Rastrelliger kanagurta. The location of the fishing grounds is in the WPP area 712 and 713 the average CPUE purse seine per year at Tegal Fish Landing was 26.710 kg or 26,7 tons per trip for each vessel. This shows that purse seine capture productivity was still quite low when compared to the size of Gross Tonnage. Purse seine gear for five fishing vessels that landed at Tegal Fish Landing selectively. During the study the proportion of the amount and weight of the five vessels was more thant 60%.

Differences in catching time and baits on the catch results of Krendet in Coastal Fishing Port (CFP) Sadeng, Gunungkidul, Yogyakarta

Krendet is one of the fishing gears used to catch Lobster in the South Coast of Java. Krendet is a passive fishing gear. Lobster is a fishery commodity that has high economic value. This research was conducted to determine the difference in lobster catches based on differences in fishing time and bait types on Krendet fishing gear. The method used in this research is experimental fishing with 4 treatment combinations and 6 repetitions. The difference in fishing time used was morning – afternoon and afternoon – morning, while the bait used was trash fish and no bait as a control. This research was carried out in February 2021 in the waters around the Sadeng area, Gunung Kidul. The analysis carried out in this study used the Two Way Anova Test method. The results showed that the time difference had an effect on the number of catches. The effective time to catch Lobster is at night. This can be caused by Lobster's behavior or habits which tend to be active at night. Giving bait to Krendet is also able to increase the number of catches. The trash fish bait is able to lure the Lobster to come closer to Krendet. Giving bait to Krendet is also able to increase the number of catches. The trash fish bait is able to lure the Lobster to come closer to Krendet so that the Lobster can be trapped.Keywords:KrendetLobsterCoastal Fishing PortSadeng

Exploitation of striped snakehead (Channa striata) in Sempor Reservoir, Central Java, Indonesia: A proposed conservation strategy

Abstract. Setyaningrum N, Lestari W, Krismono, Nuryanto A. 2022. Exploitation of striped snakehead (Channa striata) in Sempor Reservoir, Central Java, Indonesia: A proposed conservation strategy. Biodiversitas 23: 3584-3592. Striped snakehead (Channa striata) has important economic value in freshwater systems, including Sempor Reservoir in Indonesia, where increases in catch sizes have resulted in a declining population. In this study, we determined its population size based on abundance and distribution of length and assessed the rate of exploitation based on estimated growth and mortality rates to determine a conservation strategy in Sempor Reservoir. The study was undertaken from March to October 2020. The method used was a purposive random sampling survey. Fish samples were taken from five stations with different land uses. The estimated growth, mortality, and exploitation rates were analyzed by Pauly's model using FISAT II. Channa striata abundance data were analyzed using a Kruskal-Wallis test. The results showed that the highest abundance of C. striata at the KW station was almost three times higher than at the BK station. The average size of the gonads at first maturity was 277.4 mm in females and 284 mm in males. The estimated growth parameters indicated an asymptotic length (L?) of 409.5 mm. An exploitation rate of 0.74 was classified as overfishing. The proposed conservation strategy is to limit the number of catches by as much as 44% and prohibit the catching of individuals with a length of 230-349 mm. Kedungwringin Station was defined as a reference area with the largest abundance and complete size distribution, namely, the pre-reproduction, reproduction, and post-reproduction stages. Bangkong Station was defined as a spawning ground because there were many fish in the reproductive stage and Sempor River Station was the nursery ground with mostly juvenile fish. These two sites must be protected for sustainable striped snakehead populations in the river and reservoir.

Species diversity of gillnet catches along the Egyptian Mediterranean coast of Alexandria

The present work deals for the first time with the species diversity of gillnets operated on the fisheries coasts of Alexandria City from El-Montazah to Sidi Kirayr. A total of 6161 specimens of about 427 kg were collected during periods from Feb 2018 to Jun 2018 and from Dec 2019 to Nov 2020 using two types of gillnets: the demersal and the pelagic gillnets. All samples were identified and photographed. A total of 108 species were identified in the catch of gillnets (99 fish species; 1 molluscan species and 8 crustacean species). From that, 28 lessepsian species were recognized. The catch was dominated by Family Sparidae (25 species) and Family Scombridae (8 species). The results showed that the species and size composition of gillnets catch were depending on the type of the gillnet and its mesh size. The catch of the demersal gillnets represented 63.27% of the total production by number and 84.72% by weight of the total catch of gillnets, while the catch of pelagic gillnets represented 36.73% and 15.28% by number and weight of the total catch, respectively. Eighty nine fish species were caught by the demersal gillnets and 36 fish species were caught by pelagic gillnets. Diplodus vulgaris was the main species caught by the demersal gillnets and Boops boops and Sardinella aurita were the main species caught by the pelagic gillnets. On the other hand, according to mesh number, which is defined as numbers of meshes in half-meter length of net, the gillnets with mesh number 17–18 followed by gillnets with mesh number 20 were the main meshes for the demersal gillnets. As for the pelagic gillnets, they were restricted to mesh number 33–34. In addition, only mesh numbers 11, 14, 17–18, 20 and 25–26 (demersal gillnets) and mesh numbers 33–34 (pelagic gillnets) were operated all over the year. Only 7 fish species from the target production were represented in all seasons namely: D. vulgaris, B. boops, Diplodus levantinus, Diplodus sargus, Umbrina cirrosa, Lithognathus mormyrus, and Trachurus mediterraneus. The seasonal diversity index of fish species was H' = 1. 3652 and the large numbers of fish species recorded were in spring (61 species) followed by autumn (58 species), summer (47 species), and winter (27 species). Further biological studies are needed to identify the most dominant species caught by the gillnets operated in Alexandria.

Ichthyofauna assemblage and their spatiotemporal distribution: a case study in Asura beel of Dinajpur, Bangladesh

Ichthyofauna diversity acts as a bio-indicator and is playing a significant role in the sustainability of an aquatic environment. The present study explores the ichthyofauna assemblage in one of the largest wetlands of Bangladesh known as Asura beel located in Dinajpur district. Fortnightly fish samplings were done from November 2017 to October 2018 considering three seasons as winter,summer, and rainy. Fish biodiversity was assessed with their threatened status and analyzed seasonal abundance with the diversity indices. Findings revealed a total of 35 identified species of fish belonging to 7 orders, 17 families, and 26 genera. According to IUCN- Bangladesh 2015, the current research recorded 6 fish species as vulnerable (17%). While only 1 species is data deficient (3%), 6 species are endangered (17%), and the other 22 species are not threatened (63%). Among the fish species, Amblypharyngodon mola of Cypriniformes order contributed the highest abundance (12%). On the contrary, Ostreobrama cotio and Macrognathus armatus both represented the lowest abundance by contributing 0.35%. The survey also reported that the seasonal diversity indices and richness values did not vary significantly according to seasons although the number of catches was found higher in the winter season followedby summer and rainy seasons.

Analysis of the Welfare Level of Gillnet Fisherman in the Nusantara Fishery Port Palabuhanratu, Sukabumi

The condition of natural resources, especially in the field of fisheries, which is very abundant, does not guarantee the economic life of the community is prosperous. This is supported by previous research that discusses the problems of the economic life of the fishing community in Palabuhanratu which is still below the poverty line, especially traditional fishermen and laborers. This study aims to analyze the welfare level of gillnets Fisherman in the Nusantara Fisheries Port, Palabuhanratu, Sukabumi. This research was conducted from Februari 2022 to June 2022. The method used is a descriptive method with a case study approach. Welfare level is analyzed using qualititative data and primary data that is scored on welfare indicators according to the modified Central Statistics Agency (2015). Data collection using questionnaires and documentation techniques. The sampling technique used in this research is the census. Technique census sampling is using the entire population to be used with total of 24 respondents. The results showed that the average score of the welfare level of drift gillnet fishermen in Palabuhanratu, Sukabumi was 2.27, which means that it belongs to the moderate level of welfare. The most influential factor in the level of fishermen's welfare is income. The income of fishermen is not stable due to the uncertain number of catches, extreme weather, irrelevant fishing gear and fishermen still relying on ship owners. Fishermen must have a side income in order to increase income to fulfill their daily needs. Besides that, there needs to be a government institution that is able to fight for fishermen in obtaining capital and reactivate existing cooperatives.

KOMPOSISI HASIL TANGKAPAN DAN DAERAH PENANGKAPAN IKAN SIDAT (Anguilla spp) DI SUNGAI LUAS DAN SUNGAI KINAL, KABUPATEN KAUR, PROVINSI BENGKULU

Eel (Anguilla spp) is a fish from the order Anguilliformes belonging to the catadromous fish, fish that migrate between freshwater and marine waters. The activity of catching eel for daily consumption has been carried out by the people of Kaur Regency, but the data related to the type of eel, catch structure, and the eel fishing area in Kaur Regency is still limited, especially in the Luas River and Kinal River. Data and information on eel fisheries in Kaur Regency are expected to be used as basic information in the utilization of eel commodities. This study aims to analyze the structure of eel catches and determine eel fishing areas in the Luas River and Kinal River. Research using eel fishing was carried out in June - August 2021 in Luas river and Kinal river, Kaur regency, Bengkulu. The results of identification of morphological characteristics and comparison of ano-dorsal values ​​found one species of eel, namely Anguilla marmorata with an ano-dorsal ratio of 14.05-18.23%. The Anguilla marmorata eel was caught at every station in the Luas river and Kinal river. Overall, each station in Luas river and Kinal river gets the same H' value, which is relatively moderate. The eel fishing areas in the Luas river and Kinal river are divided into 3 locations, estuary, mid-river, and upstream. The number of catches with the heaviest weights were found at station 3 in Luas river and Kinal river.

The complex relationship between weight and length of Atlantic cod off the south coast of Newfoundland

The relationship between the length and weight of fish is used to assess their growth and condition. This relationship is often assumed to be the same spatially and temporally. However, variability in the weight–length relationship can occur, which provides important information about stock productivity. We developed a spatiotemporal model for the weight–length relationship that is useful for predictions in un-sampled areas. We applied the model to survey data for Atlantic cod off the southern coast of Newfoundland, Canada. We found that weight-at-length was higher inshore, oscillated over time, was below average in recent years, declined during late-January to early-June especially for intermediate sized cod, and that the temporal oscillations were correlated with several local environmental time series. Finally, the model estimated a decrease in the allometric coefficient for intermediate sized cod (40–80 cm), indicating that those cod may be experiencing additional feeding deficiencies. Spatiotemporal variation in the weight-at-length relationship should be accounted for in the stock assessment process when fishery catch numbers are derived from tonnes landed and when estimating stock and fishery weights-at-age.

Catching trial around portable Fish Aggregating Devices (FADs) at Belitung Waters

Belitung Regency is an administrative area in the Bangka Belitung Islands Province. Handline is one of the most popular fishing gear in Belitung Island. However, the production value of handline fishing gear has decreased recently. This decrease was caused by the lack of fishing technology in handline fishing which potentially threatened the sustainability of small-scale fishing industry in the region. The use of portable Fish Aggregating Devices (FADs) technology was expected to increase the productivity of handline fishing gear. This study aims to compare the composition of handline catch, productivity, and fishers total income using portable FADs and without FADs. Sixteen experimental fishing trips were conducted to collect data. The results showed that the dominant catch of handline using portable FADs was threadfin breams (Nemipterus hexodon) (50.7%), greater lizardfish (Saurida tumbil) (27.4%), yellow stripe threadfin bream (Pentapodus aureofasciatus) (10.7%), grouper (Epinephelus bleeker) (4.6%), monocle bream (Scolopsis sp.) (4.2%), yellow jack (Caranx bartholomei) (2.1%), and mackerel (Acanthocybium solandri) (0.2%). The number of catches using portable FADs was 521 of fish (37%), while the one without FADs was 888 of fish (63%). However, based on its weight, the operation using portable FADs resulted in 84.4 kg (58%) and those without FADs was 61.6 kg (41%). The productivity of handline fishing with portable FADs was higher, 1.32 kg / trip, compared to its counterpart which was 0.91 kg / trip. Based on the Kruskal-Wallis test, it showed that the use of portable FADs has a significant effect on handline fishing. Additionally, the total income of fishermen with portable FADs was higher than those without portable FADs.

Effects of the different distributed practice regimes on the learning of three-ball cascade juggling task

BACKGROUND: In its majority, the literature supports the superiority of distributed practice compared to massed practice on motor learning outcomes. However, inconsistencies in some findings claim for more efforts on this topic. AIM: We aimed to elucidate potential mechanisms that would support the distinct results between the different distributed practice regimes (among days and within-one-day). METHOD: Ninety participants, aged 18-25 years (45 men, 45 women) were randomly divided into 3 groups: Massed practice group (MASSED) - 30 minutes of practice without rest/ one day; Within-one-day distributed practice group (WITHIN) – 6 blocks of 5 minutes of practice interspersed by 3 minutes of rest/ one day; and, Among days distributed practice group (AMONG) – 3 blocks of 10 minutes of practice divided into 3 consecutive days. They practiced the three-ball cascade juggling task. The number of catches was the dependent variable. There was a retention test (absolute retention and savings analyses) after 24 hours from the acquisition phase. RESULTS: We identified that AMONG demonstrated higher absolute retention than WITHIN and MASSED. Both distributed practice regimes demonstrated better savings than MASSED. CONCLUSION: Our results showed that distributed practice regimes enhance consolidation processes and information processing that benefit motor learning.

Artificial enhancement of sturgeon stock in freshwater reservoirs: A case study on sterlet Acipenser ruthenus of the Kama reservoir

The paper presents the results of the sterlet sturgeon Acipenser ruthenus reintroduction into the Kama Reservoir (Perm Krai, Russia) by sterlet fry from hatcheries into the reservoir since 2001. The effectiveness of hatchery releases was evaluated by monitoring gillnet sampling 2014–2020. The results showed that the species was reported throughout entire Kama Reservoir, which contrasts with 1988–1994 data, when the species was registered only at the upper part of the reservoir near the Kama River mouth. The highest number and biomass values of catch per unit effort (CPUE) of the sterlet were found in submerged river channels – the deepest habitats with flow conditions which are close to the ecological requirements of the species. The distribution of the sterlet within the channel biotopes of the reservoir is defined by reduced variability. The biggest individuals and the widest size range of the sterlet were typical for the upper area of the reservoir and Chusovskoy Bay, which have the greatest flow. The smallest sizes were typical for fish from catches near the dam of the reservoir, which is consistent with the published data on the distribution of sterlet in reservoir conditions. The presented results may indicate the artificial formation of the sterlet stock in the Kama Reservoir maintained by hatchery releases. The revealed distribution of the sterlet in the reservoir determines the direction of further research on natural reproduction and thus formation of an artificially formed population. Also, future studies are required to assess the possibility of hybridization of the sterlet of artificial origin with natural populations of the species, since the low genetic diversity of the sterlet released into the Kama Reservoir which can lead to irreversible loss of genetic individuality of the natural stocks of the species in the catchment of upper course of the Kama River.