Number Of Fish Caught Research Articles

AN ANALYSIS OF PAKISTAN’S CLIMATIC FACTORS AFFECTING MARINE FISH PRODUCTION

A lot of study has been done on how climate change impacts farming. But there aren't many studies in Pakistan that look at how climate change changes the number of fish that can be caught in the real world. This study's main goal is to look at the effects of climate change on fish in the sea around Pakistan from 1990 to 2020. It was given to us by the World Development Indicators. This study used the autoregressive distributed lag (ARDL) model to examine how the link between CO2 emissions, weather, rainfall, and sea fish production changes over time. Using the autoregressive distributed lag (ARDL) method to cointegration, a strong link was found between rains and the number of fish caught. To determine if rainfall has a statistically significant effect on sea fish production in the short term, we used the coefficient for rainfall (β = 5738.02) and found that it does. In the long run, it makes a difference at the 1% level of importance. Both changes in temperature and CO2 pollution hurt fish production a lot, according to the study. This is true in the short as well as in the long term. Researchers found that it would be helpful for lawmakers to make national policies that are better for adapting to climate change and supporting long-term control of marine fishing. Pakistan's fishing business should do a lot of research and development to find marine fish species that can live in places with a lot of CO2 and high temperatures.

The Nature of the Composition of the Fish Community in One of the Drains of Al-Alam District – Salah Al-Din – Iraq

The study was conducted in one of the drain in AL-Ahd Al-Jaded - Al-Alam - Salah Al-Din Governorate for the period from the beginning of October 2022 to the end of March of the year 2023, where the number of fish species caught in the two study stations reached 15 species, of which 12 belong to the Cyprinidae family, one to the Poeciliidae family, and one to the. Al-Mugilidae family and a type of family Mastacembelidae. The types of fish that he collected (Chondrostoma regium, Carassius auratus, Carasobarbus luteus, Alburnus mossulensis, Cyprinion kais Planiliza abu, Arabibarbus grypus Cyprinus carpio Gambusia holbrooki, Acanthobrama marmid, mastacembelus, Barbus belayewi, Mesopotamichthys sharpeyi, Garra rufa). The Cyprinidae family is considered the largest percentage of species in water bodies in Iraq, according to previous studies. It was found that there were three species in most of the fishing samples that were collected during the study period for a period of six months: Chondrostoma regium, Carassius auratus, Carasobarbus luteus. The number of fish caught was 566 fish with a total weight of 19844 grams. The Chondrostoma regium came first with 257, or 45.40% of the total number, the Carassius auratus, with 172, or 30.38% of the total number, and the Carasobarbus luteus, with 53, or 9.76% of the total number. The arassius auratus accounted for the largest percentage in terms of weight at 48.23%, Chondrostoma regium ranked second at 20.94%, and the third rank by Carasobarbus luteus at 18.61%, and the lowest percentage by weight was the share of the Garra rufa by 0.05%.

The effect of time and sea surface temperature on the total catches of beach seines in Gampong Jawa, Banda Aceh, Indonesia

Research of the influences of time and sea surface temperature toward catch of beach seines at Gampong Jawa, Banda Aceh conducted in December 2021 for 15 days. This research aims to analyze the composition of the number of beach catches, discover the effect of time on the number of catches of beach seines, to describe the sea surface temperature in the Gampong Jawa waters. The method used in this research uses a survey method through observing and collecting information directly at the research location; the data were analyzed descriptively and presented in the form of tables or charts. The results showed that the composition of dominant catches of beach seines in Gampong Jawa in the morning was dominated by petek fish (Leiognathus equulus) as much as 23% and in the afternoon dominated by moonfish (Megalops cyprinoides) with a percentage of 62%. The difference in catch time between morning and afternoon tends to have an impact on the catch where the best fishing time is in the afternoon. Based on statistics with paired t test obtained a significant value of 0.023 <α value of 0.05, morning and afternoon time has an effect on the number of fish caught. Then the sea surface temperature during the study was in the range of 27 ºC to 29 ºC.

FAIR TRADE DAN PERIKANAN TUNA DI INDONESIA (ANALISA PERAN YAYASAN MASYARAKAT DAN PERIKANAN INDONESIA)

Indonesia is one of the largest tuna producers in the world. In Indonesia tuna is produced by small-scale fishermen. This shows that small-scale tuna fisheries play an important role and as the mainstay of national food. However, the number of fish caught has not been followed by the welfare of small-scale fishermen. The exported tuna commodity also face difficulty in entering the market because it does not meet the requirements of the importing country, one of which is related to traceability. This is the concern of the Indonesian Fisheries and Community Foundation (MDPI). MDPI is a non-governmental organization that promotes fair trade-based fisheries in Indonesia. The evidence of fair trade fisheries implementation is through fair trade certification. The focus of this study is to analyze the role of the Indonesian Fisheries and Society (MDPI) in fair trade certification for tuna commodities in Indonesia. The research was conducted using descriptive qualitative research methods sourced from secondary data in the form of literature studies. In this study, the authors use the concept of the role of non-governmental organizations and fair trade. Researcher found that in fair trade certification for tuna commodities in Indonesia, the MDPI Foundation carries out three roles partner, implementer and catalyst. research is important to understand that non-governmental organizations play an important role in fair trade.

The The Effect of Using Led Lights (Light Emitting Diode) in the Operation of Bottom Gillnets on Catches In Pangandaran Waters, West Java

The objectives of the study were to analyse the response of dominant fish to different light colours that reflect the wavelength of light and to analyse the species composition of the gillnet catch to determine the fish that are positively phototaxis to LED light. Data collection was conducted using the experimental method. The experimental design used 1 unit of bottom gillnet gear with a mesh size of 4 inches, and used LED (Light Emitting Diode) lights. Trials using green LED lights and white LED lights were operated simultaneously between the control gillnet (without LED lights) and the experimental gillnet (with LED lights). The results of statistical analysis of gillnet catches with green LED light aids with white LED light aids and control nets have a significant effect on the number of gillnet catches. The results were: (1) The number of fish caught at a distance of &lt; 1 m and at a distance of 1-2 m, this proves that many fish are attracted to light (positive phototaxis); (2) Proven by gill net fishing gear using green LED light aids obtained fish weighing up to 77.7 kg. (3) It is proven that the distance of the lamp with the position of the fish caught on the net sheet can produce the highest weight of fish caught, on green LED lights at a distance of &lt;1 m the weight of the fish reached 30.89 kg.

STRATEGI PEMASARAN IKAN SALAI DI DESA KESUMA KECAMATAN PANGKALAN KURAS KABUPATEN PELALAWAN

Fresh fish from the catch that is processed into salai fish is a form of utilizing the potential of river natural resources in Kesuma Village. In its distribution, the salai fish business in Kesuma Village faces the problem of limited marketing reach. This study aims to analyze: (1) the current marketing mix strategy of the salmon business (2) Recommending the marketing strategy of the salai fish business in the future. This research was conducted for 6 months starting from November 2021 to April 2022. Sampling was carried out using the census method. The data analysis used consisted of the 7P, SWOT and QSPM approaches. The results showed that the condition of the salai fish business in Kesuma Village through the marketing mix produced a product with a distinctive taste and aroma, the price of the product was determined by the entrepreneur based on the type and number of fish caught, the business location was close to the river but far from crowds and markets, promotion still personal selling, always prioritizing polite and friendly service in the sales process, the process of getting the product can be through ordering or directly at the entrepreneur's house and the Sorek Satu Sunday market and the product has not been packaged. The results of the SWOT analysis show that the business is in quadrant I, namely the SO (Strength and Opportunities) strategy, namely increasing the quality and quantity of products offered, cooperation with restaurants and restaurants so that market share is wider, adding variants of product types and sizes. The priority strategy that has the highest level of attractiveness is the SO strategy, namely improving the quality and quantity of the products offered (STAS:5,39).

Rancangan Produk Rekreasi Wisata Memancing Sungai Bogowonto, Kabupaten Purworejo

The distribution of tourism potential in Purworejo Regency has been well mapped and must be supported by suitable approach, one of which is the development of river tourism. The actual river tourism activities that have been developed on the Bogowonto River are adventure tourism activities, namely white water rafting. However, the potential of river tourism on Bogowonto River is not only limited for rafting. The development of recreational fishing products on the Bogowonto River can be an opportunity for tourism development in Purworejo Regency. Recreational fishing regarded as a form of tourism activity in accordance with sustainable tourism (Hall, 2019; UNWTO, 2021). This can be seen from the pattern of recreational fishing that does not focus on the number of fish caught, the arrangement of the tools used, as well as the positive impact given to the community on the economic side. The study (Butler et al., 2020) shows that there is a positive contribution of fishing tourism to ecological preservation. From the business side, the Government of Indonesia has regulated fishing tourism businesses (Regulation of the Minister of Tourism of the Republic of Indonesia No. 19 of 2015 concerning Standards for Fishing Tourism Business, 2015), including business arrangements for providing places and facilities for fishing activities using special equipment and safety equipment including the provision of guide services. This study will identify and analyze recreational fishing tourism products based on packages, fishing equipment, fishing tour guides and supporting facilities in the Bogowonto River Area, Purworejo Regency. The long-term goal of this research is to contribute to the design of recreational fishing products for the development of tourist destinations in Purworejo Regency as a guide for stakeholders regarding the utilization of the Bogowonto River

Relationships between Fish Communities and Habitat before and after a Typhoon Season in Tropical Mountain Streams

The responses of habitat and fish communities to extreme hydrological and habitat disturbance in typhoon-prone mountain streams are not studied much. Such landscape–climate settings may provide a unique opportunity for fish to evolve without special habitat adaptation and involve different assembly rules compared to temperate regions. This study aimed to compare fish communities and habitat factors before and after the typhoon season and to test the influences of various aspects of habitat on fish assemblages between seasons. Fish and habitats were surveyed at 30 wadable stream sites in March and December 2010 in tropical southern Taiwan. Habitat variables differed between the pre-typhoon and post-typhoon seasons. Higher species richness and the total number of fish caught in the pre-typhoon season indicated fast recovery. Benthic fish were more vulnerable to typhoon disturbances than sub-benthic fish. Contrary to the original hypothesis, fish communities were more strongly related to physical habitats than water quality and riparian conditions. In addition, consistently high fish variance explained by habitat measures in the dry seasons indicated that environmental filtering predominated. Dominant fish species were related to main habitat gradients, characterized by low species richness but high beta-diversity. Our findings provide implications for fish conservation in typhoon-prone mountain streams.

Mapping the Distribution of Fish Caught in the Jatigede Reservoir, Indonesia

This research aims to map the structure of the fish community living in the floodplain of the Jatigede reservoir based on the catch. This research uses the field observation method, taking fish samples every 14 days and doing 6 times. The results of the survey show that the number of fish caught during the survey was 799 individuals, and the fish species identified at 6 stations of Jatigede Reservoir consisted of 9 families of 18 species. The fish species with the highest abundance was Parambassis siamensis at station 1. At stations 2, 3, 4, and 5, the fish with the highest abundance was Hampala macrolepidota and at station 6, the fish with the greatest abundance was Oxyeleotris marmorata. The distribution of native fish is more dominant than introduced fish with a comparison of 11 native fish species and 7 introduced fish species. The water quality at each station still meets the requirements of environmental quality standards according to Government Regulation (Indonesia) No. 22 of 2021 on Water Quality Standards and is suitable for fish life.

SEASON WISE FISH CATCH BY FISHERIES CO-OPERATIVE SOCIETY BERRIANWALA FROM GOBIND SAGAR RESERVOIR DURING THREE YEARS

Gobind Sagar Reservoir is one of the large reservoirs in Himachal Pradesh. This reservoir has been created by damming River Sutlej at Bhakra in 1963. Different fisheries co-operative societies are working in Gobind Sagar reservoir. Fisheries co-operative society Berrianwala is one of these co-operatives. Data about fish caught by co-operative society Berrianwala, during years 2014, 2015 and 2016, was obtained from the state fisheries department of Himachal Pradesh Govt. No fishing was done by fishermen during the June-July months for conservation reasons. As this reservoir is large reservoir, gill nets are suitable gears for operating, catching the fish. Size of the gill nets used was 80 meters X 5 meters. Catla catla, Labeo rohita, Cyprinus carpio, Hypophthalmichthys molitrix, Cirrhina mrigala, Ctenopharyngodon idella, Tor putitora, Labeo calbasu were some of the fish caught for commercial purpose. Due to flash floods, H. molitrix (silver carp) have got accidently introduced in this reservoir, in year 1971 from the tanks at Ghagus where it was kept. After the accidental introduction in this reservoir, it is flourishing very well. Different co-operatives working in this reservoir have been allotted specific beats for the administrative reasons. Co-operative society Berrianwala is one of the co-operatives working for fisheries in the Gobind Sagar reservoir. Fishing activities are being performed under the supervision of state fisheries department.&#x0D; During year 2014, number of fish caught by Berrianwala co-operative were 9014 weighing 20090 kg., during 2015 it remained 7807 (21174.5 kg) and in year 2016 it was 6227 (18092 kg). Different conservation measures were in practice. Season wise variation in fish, caught by Barrianwala co-operative, was recorded.

Restrictions on leader length in an in‐river sport fishery reduce catch of threatened wild chinook salmon Oncorhynchus tshawytscha and increase harvest of hatchery origin chinook

AbstractTo achieve conservation and harvest objectives associated with Chinook Salmon, fisheries managers have relied on mark‐selective and anti‐snagging rules in freshwater whereby anglers are required to release wild Chinook and fish hooked in anatomical locations other than the head and mouth. However, in some cases these regulations have resulted in increased mortalities due to the number of fish (hatchery and wild) that require release. Regulations effective at increasing the number of fish hooked in the mouth have the potential to decrease total encounters (number of fish caught) of both hatchery and wild fish while increasing the total number of fish harvested; however, this has not been tested. A roving creel survey and a test fishery were used to describe the effect leader length and bait under a bobber has on catch rate and hooking location and simulate how a variety of restrictions on gear type would affect catch and harvest on wild and hatchery origin Chinook salmon. Results indicate that a 6‐foot leader length restriction would result in the highest catch of hatchery fish harvested and reduce exploitation rate on wild fish by greater than 20%. Regulations limiting leader length to 3 feet are expected to result in the greatest reduction (75.7%) to total encounters on wild fish; however, this method was unpopular and resulted in few hatchery fish harvested. The use of bait suspended under a bobber resulted in intermediate results with a reduction of 60.0% to catch of wild Chinook and the smallest number hooked outside the mouth (0/30). These results provide the first evaluation of the effect of leader length in a mark‐selective hook and line fishery and suggest that a 6‐foot leader length restriction would be expected to reduce encounters on wild Chinook, increase harvest of hatchery fish and extend the fishing season.

Growth Pattern of Mystacoleucus marginatus (Valenciennes 1842) in Cimanuk and Cipeles River, West Java

Cimanuk River is the second longest river in West Java, flowing from Garut to Indramayu. One of the sub-watersheds of the Cimanuk River is the Cipeles River in Sumedang and Majalengka. Genggehek (Mystacoleucus marginatus) is a type of native fish (indigenous) found in these two rivers. The purpose of the study was to determine growth performance including size distribution, growth pattern and condition factors. The research was conducted by conducting a survey in the dry season in September 2020. The method used was the fisheries biology method. Measurement and data analysis were conducted at the Aquatic Resources Laboratory of Padjadjaran University. The number of fish caught was 231 with a length range of 45 mm - 116 mm and a weight range of 1,1 g – 37,4 g. The growth performance of fish living in Cimanuk River was different from that living in Cipeles River. In Cimanuk River had positive allometric with regression equation W = 4.10-6 L3.2171 and W = 6.10-6 L3.1449. Weight growth was faster than length, condition factor was between 1,27 and 1,33. The growth performance of fish growing in the Cipeles River had a negative allometric growth pattern. The length growth was faster than the weight with the regression equation W = 7.10-4 L2.1182 and W = 7.10-5 L 2.7434, R2 = 0.36 and 0.92, condition factor K = 1.01 and 1.35.

Hubungan Klorofil-a dan Suhu Permukaan Laut (SPL) Terhadap Hasil Tangkapan Ikan Lemuru Sardinella lemuru di Selat Bali Menggunakan Citra Aqua MODIS Tahun 2009-2018

Oceanographic parameters such as sea surface temperature (SST) and chlorophyll-a in the water can influence the productivity of pelagic fish such as Lemuru. Many studies have been conducted on the relationship between SST and chlorophyll-a and the fluctuations in the catch of Lemuru fish, especially using satellite databased sensing technology. Most of the research using satellite data is done in a short-term period (not climatology), so there are still a lot of unanswered questions. One of them is: how the correlation between the fluctuation in the number of Lemuru fish catches is related to SST and chlorophyll-a in the ENSO and IOD periods. The purpose of this study is to determine the distribution of SST and chlorophyll-a concentrations and their relationship with the yield of Lemuru fish catches in the Bali Strait from 2009 to 2018. Aqua Moderate Imaging Spectroradiometer (MODIS) satellite data level 2 from Oceancolor and data on the number of fish caught in the Bali Strait from the National Fisheries Port (PPN) Pengambengan and UPT PPP Muncar. The method is used with correlation analysis between SST and chlorophyll-a to the number of Lemuru fish caught. The monthly average SST in Bali Strait waters from 2009 to 2018 was approximately 24,76 0C-30, 11 0C, with an estimated monthly chlorophyll-a concentration of 0,10 mg/m3-3,68 mg/m3. The spatial distribution of SST tends to be low in the southern Bali Strait and tends to be high in the northern Bali Strait. The spatial distribution of chlorophyll-a appears to have a high value in the near land area. The cross-correlation test between chlorophyll-a and the number of Lemuru catches showed a positive correlation yield at the 4th month lag. While the correlation of SST to the number of Lemuru fish catches shows a positive correlation at lag (-1).

Information System for Predicting Fisheries Outcomes Using Regression Algorithm Multiple Linear

Bireuen is one of the regencies in Aceh province which has quite a lot of potential for marine and fishery resources, both capture fisheries and aquaculture, because some areas in this district are coastal areas supported by several fish landing bases (PPI), namely PPI Kuala Jangka, Kuala Jeumpa, Peudada, Jeunip, Pandrah, and Bate Iliek which are supporting sectors of the regional economy. The importance of this research is so that the Department of Food Security, Maritime Affairs and Fisheries can estimate the catch of fish in the coming year so that it can be used in terms of policies to increase the fishery production sector. The method used in information systems research to predict fishery results Multiple Linear Regression Algorithm using two independent variables (X), namely, the number of motorized boats (X1), the number of rainy days (X2) and one dependent variable, namely the number of fish caught (Y). ). The steps taken in this research are data collection, calculation of each variable, completion of the elimination method, substitution to get constant values, coefficients and inserting constants and coefficients into the Multiple Linear Regression equation. Based on data obtained from 2016, 1017, 2018, 2019 and 2020 using the Multiple Linear Regression algorithm, the prediction results of the Tangka fishery in Bireuen Regency in 2021 are 12,813.88 tons.

Fishers’ knowledge on historical changes and conservation of Allis shad -Alosa alosa (Linnaeus, 1758) in Minho River, Iberian Peninsula

Diadromous allis shad A. alosa is a fish species of high socio-economic and cultural value along the Minho River, and is also susceptible to multiple anthropogenic threats. This study aimed to assess fishers’ knowledge on artisanal fisheries of allis shad, and therefore assist and contribute to its conservation in northern Portugal. Results showed a negative relationship between the number of fish caught on the best day of allis shad fishing and the catch year (R2 = 0.29; p = 0.04) and between the largest individual ever caught and the catch year (R2 = 0.42; p = 0.01). There was a positive relationship between the largest individual ever caught and fishing experience (R2 = 0.13; p = 0.04). Our findings showed a significant differences (F = 5.40; p = 0.01) between fishers’ perceptions (Decrease, Increase, and Unchanged) of allis shad catches regarding fishing experience. Differences in perceptions of allis shad fisheries among fishers of different experience categories suggest the occurrence of the shifting baselines syndrome (SBS). The best fishing years were mainly around between 1950 and 1970, and the worst years of fishing in the most recent decades (1990 and 2010s.) Local management activities had low approval by fishers (I = 0.39). We suggest that fishers and managers must establish common conservation goals through participatory management. Also, a joint and synchronized approach between Portuguese and Spanish local authorities is essential for the management and conservation of A. alosa in the international section of the Minho River.

Morphology and weight-length relationship of tinfoil barb (Barbonymus schwanenfeldii) at Tasik River, South Labuhanbatu Regency, Sumatera Utara

Tinfoil barb is one of the fish caught in the Tasik river. The purpose of this study was to determine the morphology and weight-length relationship of tinfoil barb. This research was conducted in July-August 2020 in the Tasik river using a net with a mesh size of 1.25 inches. The number of fish caught was 96 fish with a total weight (TW) of 2-47 g and a total length (TL) of 60-125 mm. Meristic characteristics of tinfoil barb consecutively are as follows: 31-33 Linnea Literalis (LL), 24-26 Body Circular Scales (BCS), 12-14 Dorsal Front Scales (DFS), 12-14 Tail Scales (TS) a total of 12 pieces, the dorsal fin formula (DF) is DI. 8-9, the ventral fin formula (VF) is V8-10, the pectoral fin formula (PF) is P12-14, the anal fin formula (AF) is AI. 5-6 and the caudal fin formula is (CF) C14. The results of the length-weight relationship indicate that the growth pattern of fish is negative allometric (b =3.221) where the weight gain is faster than the length gain.

Aspek Biologi Ikan Duri (Piicofillis dussumieri Valenciennes, 1840)

This study aims to determine the biological aspects of blacktip sea catfish (Piicofillis dussumieri) in the Barumun River. Fish samples were taken for three months (September 2020-January 2121). The research station was determined by purposive sampling. The fish were caught using 3 gill nets with 1.5 inch mesh. The number of fish caught is counted and then the total length and weight are measured. The data were interpreted in graphical form using the Microsoft Excel 2010 application. The results showed that the growth pattern of blacktip sea catfish was negative allometric with a value of y = 26.3531e0.0796 and R2 = 0.9718. The sex ratio for male and female fish is 3:1. The population density is between 1.20 - 1.6 /100 m2. In conclusion, the growth pattern of P. dusumeiri was negative allometric. The sex ratio (sex ratio) between males and females is not balanced. The condition of blacktip sea catfish population in the Barumun River began to be disturbed.&#x0D; Keywords: Biological Aspects, Piicofillis dussumieri, Barumun River

Characteristics, preferences and perceptions of recreational fishers in northern Patagonia, Argentina

This study aims to compare the characteristics, preferences and perceptions of fishers in the recreational fisheries of San Blas (SB), El Cóndor (EC) and La Ensenada (LE), using the roving creel survey technique. No difference was detected in fishers’ characteristics (age, years of fishing experience, occupation), but the number of visits made per year was lowest in SB, which is located furthest away from large cities. The three fishing sites also showed significant differences in expenditure per trip. An inverse correlation between expenditure and number of visits per year in relation to distance travelled was observed only in SB. Micropogonias furnieri was the main target species In SB and EC fisheries, and Odontesthes sp. was the main one in LE. Most fishers in LE reported that fish size had not varied over time, while in SB and EC they considered that fish size had decreased in recent years. In all three sites, however, there was agreement on the decreasing trend observed in the number of fish caught per fishing trip. Between 70 and 90% of fishers agreed that there should be restrictions through daily quotas and minimum size, and recognized chondrichthyans as threatened species. It is concluded that the three fisheries presented fairly dissimilar profiles, suggesting that Patagonian recreational fisheries need to be assessed on a local scale instead of using a one-size-fits-all strategy, in order to recognize their differences and implement appropriate management measures. Understanding the preferences, motivations and demands of fishers is important if we are to update current regulations and improve the management of recreational Patagonian fisheries. This will contribute to their preservation as a valuable ecosystem service without compromising natural resources.

OCEANOGRAPHIC VARIABILITY ANALYSIS USING GIS AND GAM FOR POTENTIAL FISHING ZONE MAPPING OF BIG EYE TUNA (Thunnus obesus)

Southern Waters of Java Island are 573 fisheries management zones, the Big Eye Tuna ( Thunnus obesus ) commodity is one of fish that has high economic value. There are oceanographic factors affect fish distribution of Big Eye Tuna ( Thunnus obesus ) such as sea surface temperature, chlorophyll-a, and depth. The data research of Big Eye Tuna fishing zone was obtained from PPSC with data description were year, month, day, number of trips, and number of fish caught around 2018-2019. Oceanographic data used from citra satellite Aqua MODIS for sea surface temperature and chlorophyll-a, and citra satellite ETOPO-1 for depth, by using GAM statistical analysis by looking at the lowest AIC value and the largest CDE value of 7 combined models of oceanographic parameters. The results obtained from statistical analysis using the GAM which was very influential in determining the potential zone for the fishing of Big Eye Tuna ( Thunnus obesus ) showed that a combination of sea surface temperature + chlorophyll - a + depth with an AIC value of 28840.02 and CDE of 11.1%, with the results Oceanographic parameters optimum sea surface temperature was 25 ° C- 30 ° C, for chlorophyll - a 0.08 - 0.30 mg / m3, and for an average depth of 3500m. The depth parameter had a less positive influence because the Cilacap fishermen used FADs for the fishing area of Big Eye Tuna. The distribution area of Big Eye Tuna ( Thunnus obesus ) in the Southern of Java Island is at latitude (-7.3 °) - (-14.83 °) and longitude 102 ° - 115.25 °.

Bayesian modelling suggests that the sterlet (Acipenser ruthenus, Linnaeus 1758) population is ageing in the middle Danube River

Abstract In the past, sturgeons played an important role in commercial and recreational fisheries in the Danube River and its tributaries. Human impacts in the Danube River Basin coupled with exploitation of sturgeon stocks led to all species being either locally extinct, critically endangered or of unknown status. Sterlet (Acipenser ruthenus, Linnaeus 1758) is the last known sturgeon species occurring in the upper and middle Danube; however, the population of this species is considered unbalanced and decreasing since the beginning of the twenty‐first century. The decline of sturgeon stocks has been noted before owing to their economic importance. With commercial fisheries being forbidden in the Slovak section of the Danube River, there is generally no information available about the status of what is considered a local population. Databases containing recreational catch of sterlet (2003–2018) and historical records of commercial harvest (1961–1990) were used to describe the trend in the weight and number of sterlet caught over the following years. Modelling indicated that the number of fish caught each year appears to be lower, while the average weight of each individual is increasing. This might suggest that the population is ageing. Although older individuals can contribute a great deal more to spawning because they produce a greater number of eggs, several problems are apparent. The number of spawners might be decreasing as a result of bycatch or fishing, their ability to spawn might be obstructed, or annual recruitment may fail owing to unpredictable events. Although restocking programmes are in place to help maintain the sterlet population in the Danube River, their efficiency seems to be drastically low. In fact, restocking could be of little value unless studies on the availability of key habitats are conducted and their protection and restoration are ensured.