Decline In Catch Research Articles

Effects of black soldier fly (Hermetia illucens L.) larvae meal on growth performance, organs-somatic indices, body composition, and hemato-biochemical variables of European sea bass, Dicentrarchus labrax

Fishmeal (FM) is one of the major protein sources used in fish diets, which was obtained from wild fish catches. Due to the steady decline in fish catches accompanied with the increased demands for aquafeeds, a rapid decrease in the FM availability is much more expected. Alternative protein sources of animal origins, such as dried black soldier fly (Hermetia illucens L.) larvae meal (DBSFLM), may be used as an alternative protein source instead of FM in aquafeeds. Therefore, a feeding trial was carried out to evaluate the effects of partial replacement of FM with DBSFLM on growth performance and body composition of European sea bass, Dicentrarchus labrax. A basal diet (45% crude protein) was formulated, where DBSFLM protein replaced 25, 35, or 50% of FM protein. Fish (12.1 ± 0.21 g) were fed one of the tested diets up to apparent satiation thrice a day for 8 weeks. No significant differences were observed in fish growth, feed utilization, and survival (P > .05). The DBSFLM inclusion in diets of European sea bass did not affect its body constituents. Additionally, values of red blood cells, hemoglobin, hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration were not significantly influenced by DBSFLM inclusion in fish diets as compared to the FM-control fish. Likewise, no significant changes were observed in counts of white blood cells, lymphocytes, monocytes, and neutrophils in DBSFLM-fed fish as compared to the FM-control fish. The DBSFLM inclusion in diets for European sea bass did not affect levels of serum total protein, albumin, globulin, serum alanine aminotransferase, and aspartate aminotransferase. The simple economic analysis evoked that feed cost decreased with increasing DBSFLM levels in fish diets. The findings of the present study elucidated that the growth performance was not significantly changed by partial replacement of FM protein up to 50% by DBSFLM protein, which reduced the feeding cost by 15.6% as compared with the FM-control diet.

The current state of fish market in Ukraine

The fishing industry is an important component of the economy of Ukraine at the present stage of development. The development and implementation of the innovative technologies in fish farming and fish processing require mandatory and ongoing analysis of a fish market infrastructure. The demand for food protein, which is characterized by a balanced amino acid content is provided by fish and seafood at 20–30 %. The aim of this work was to understand a current state of a fish products market in Ukraine, its pricing and consumption. Based on the specialized literature the evaluation of a current state of fish and fish products consumption in Ukraine and own studies of the price category of fish products in Ukraine in recent years were conducted. We studied fish and fish products consumption per year per capita in Ukraine over the last 20 years, assortment of fish in Ukraine, the import of fish and fishery products by species, the product prices in UAH per kg both in previous years and today. According to international medical standards the annual consumption of fish and seafood should be 20 kg per person. At the same time in Ukraine according to the State Statistics Committee on the 01.01.2019 14.5 kg of fish and seafood came out per capita. In 2018–2019 herring traditionally remained a leader of consumption in Ukraine. Ukraine also imported such species of fish: mackerel, hake, herring, salmon, pilchards, pollack, capelin, sardines, notating. In addition pangasius, shrimp, blue whiting, mussels, squid, saury, Jack mackerel, sea bass, tuna, flounder, anchovies, smelt, cod, salmon and other species of fish, caviar and seafood are imported in Ukraine. The investigated assortment of fish in Ukraine is represented both domestic and imported products. The domestic production are: carp, pike, capelin, herring, mackerel, sprat, the imported products are: flounder, perch, pangasius, salmon, butter, hake, Pollock, capelin, nototenia, herring, mackerel, cod, tuna, tilapia (sole), sea trout, whiting and so forth. It is established that the condition of a fish market in Ukraine is affected by an unstable economic and political situation in the country, low solvency of the population, corruption and the high payables of the enterprises. In Ukraine a tendency towards a decrease in the volume of fish and fish products consumption by the population of Ukraine is observed annually, which is a consequence of the decline in fish catch and fish production, depreciation of fixed assets and a lack of financial support to the fishing industry.

Tracking interactions: Shifting baseline and fisheries networks in the largest Southwestern Atlantic reef system

Abstract Increasing evidence has revealed that different fisheries have collapsed around the world. This is generally more evident in countries that can maintain long‐term research and fisheries monitoring. When monitoring data are not available, alternative approaches to assess fisheries trends can be used, such as the local ecological knowledge of fishers. To investigate decadal changes in fisheries the local ecological knowledge of small‐scale fishers' was evaluated at four sites in Brazil: Porto Seguro, Prado, Alcobaça, and Caravelas. A fisher–fish network weighted by interaction strength was built to indicate the most relevant resources among fishers. The results suggest the occurrence of the shifting baseline syndrome among generations of fishers regarding commercially important fishes such as groupers and snappers. Handline fishers indicated a decline in catch per unit effort over 5 decades. Fisher–fish networks from Caravelas showed greater stability with stronger interaction strength, while Porto Seguro and Alcobaça networks were more fragile, and Prado network showed intermediate characteristics. Overfishing has affected high trophic level species that act as module hubs across the majority of sites. The fisher–fish network approach can be applied in data limited cases, improving the assessments of fisheries' dynamics (in space and time) and declining species.

Exploitation level of shortfin scads fish (Decapterus macrosoma) caught with purse seine in Bulukumba waters, South Sulawesi

Shortfin scads fish is a pelagic fish that has an important role in the economic sector of fishermen in South Sulawesi waters. In the last five years, there has been a decline in catch resulting from uncontrolled exploitation. However, there is no control instrument for the exploitation of shortfin scads fish to date, hence, there is a concern that the sustainability of shortfin scads fish resources will be threatened. This study aimed to determine the exploitation level of shortfin scads fish (Decapterus macrosoma) caught with a purse seine. The research was carried out in the waters of Bulukumba Regency, South Sulawesi, from April to August 2018. The method used was direct observation. Data on catches were recorded based on the fish species caught at the time of hauling. Data time series of shortfin scads fish and effort data tabulated from fisheries statistical data. Maximum sustainable yield (MSY) of shortfin scads fish in Bulukumba waters in 2016-2017 exceeded the maximum sustainable production (MSY) of 10,739 tons/year (overfishing). The regression analysis between effort and CPUE Schafer model, showed the estimation parameter intercept value (a) 42.38620491, slope (b) -0.041823411. The equality relationship interpreted as the fishing effort for f units per year will reduce the production value (CPUE) of shortfin scads fish by 42,386 tons/year. The estimation of sustainable potential value (MSY) of shortfin scads fish in Bulukumba waters was 10,739 tons/year, while the optimum fishing effort (fopt) was 507 units/year and the total allowable catch (TAC) 8,591 tons/year.

Determination of water quality condition from water samples around location of ship to ship transfer of coal in Balikpapan, East Kalimantan, Indonesia

A collection of water samples from area of Ship To Ship (STS) transfer of coal in Balikpapan was carried out in June November 2018 to provide data for a study related to issues on fish catch decline in the area that was claimed by mini trawlers. The study aimed to determine and assess water quality parameters which play an important role on the current issues. All samples were taken in six sampling sites between the shore and the STS, and the nearest sampling site was 0.18 km and the farthest was 5.5 km from the STS. Each sample consisted of 27 analysed parameters including eight heavy metals. Results of laboratory analysis showed that the concentration of water transparency, DO (dissolved oxygen), turbidity, TSS (total suspended solid), temperature, NH3, PO4-P and NO3-N in the sampling sites far from the STS were found higher than those ones near the STS. In contrary, the concentration of pH, salinity, BOD5 and Phenol were noticed to be high near the STS. Others such as odour (smell), debris, oil layer and H2S were observed nil, while CN, oil and fat and MBAS (methylene blue active substances) showed the same concentration at all sampling sites. Hence, all of the concentration was in the range of allowable limit according to KepMen LH No.51 Year 2004 except for PO4-P and NO3- N. From eight heavy metals, Hg, As, Cd, Cu, Zn and Ni were discovered to comply with the regulation while two metals Cr (IV) and Pb reached the limit. The study concluded that the water quality around the STS transfer was generally in favourable condition. However, harmful algal blooms could be occurred since the study area was detected to have high concentration of nutrients.

Changes in the strategy of a small-scale jigging fishery for Japanese flying squid Todarodes pacificus off northeastern Japan

Long-term fluctuations in the strategy of a small-scale squid jigging fishery for Japanese flying squid Todarodes pacificus off northeastern Japan were evaluated based on time series data for nine variables derived from the catch obtained by Iwate’s fishing boats, the total catch and the income from the waters off Iwate, the number of licenses issued by Iwate Prefecture, and crude oil prices from 1970 to 2008. Upon applying principal component and change-point analyses, the first three principal components were found to explain 80.4% of the total variance, and eight temporal change points were detected. A multiple sequential t-test analysis of regime shifts detected significant shifts in the time series for each variable. A decrease in the total catch obtained by Iwate’s fishing boats was delayed with respect to the decline in catch from off Iwate in the 1970s, which can be explained by adaptive migration, as the fishers shifted grounds to exploit more abundant resources. In the 1980s, the number of licenses for fishing boats from Iwate remained high as the fishers again adapted to better exploit the reduced resources available without migrating to different fishing grounds. In the 1990–2000s, the number of licenses for fishing boats from Iwate declined for economic reasons (high running costs and low squid prices), but the remaining fishers adapted yet again in the mid-2000s to increase the catch off Iwate by operating in daylight.

Livelihood Strategy of Lake Fishing Community in Guguk Malalo Village, West Sumatra Province, Indonesia

Lake Singkarak is a livelihood source for people who live on the banks, especially for fishing activities. Unfortunately, this fishing sector shows a decline in fish catches since 1996 and significantly in 2007-2016. This paper presents the results of a study that specifically reveals the current state of the biophysical and environmental conditions of Lake Singkarak and explores the types of fishermen's livelihood strategies in relation to access to their livelihood assets at the current biophysical and environmental conditions of Lake Singkarak. This research framework adopts the Sustainable Livelihood Framework by applying a calculation of the index value/ratio of each livelihood asset. The results of this study indicate that changes in the biophysical conditions and the environment of the lake have played a role in influencing access to fishermen's livelihood assets at the study site and have implications for decreasing sources of livelihood from the lake. It was found that presently there are 6 types of livelihood strategies that are carried out by fishermen to be able to fulfill their living needs, namely Type B: Fishermen who carry out fisheries intensification and extensification (6.12%), Type C: Fishermen who have diversified their economic activities either in agriculture or non-agriculture (34.69%) , Type E: Fishermen who carry out fisheries intensification and extensification and also diversification (44.9%), Type F: Fishermen who carry out intensification and extensification of fishing and also temporary migration (2.04%), Type G: Fishermen who diversified their economic activities also temporary migration (4, 08%) and Type H: Fishermen who carry out fishing intensification/extensification, diversification and also temporary migration (8.16%). In relation to access to livelihood assets, it turns out that human resource assets are the main assets that influence the alternative choices of fishermen's livelihood strategies. The alternative type of strategy for diversifying economic enterprises, both in agriculture and non-agriculture, is the most widely chosen option besides alternative intensification and extensification of fishing in lakes.

Interannual decrease in condition factor of the western sand lance Ammodytes japonicus in Japan in the last decade: Evidence for food‐limited decline of the catch

AbstractAnnual catch of the western sand lance Ammodytes japonicus in the eastern Seto Inland Sea, Japan, has shown a decreasing trend since the 1990s. To examine whether food shortage was the main cause for the catch decrease, we investigated the condition factor of the age‐0 fish at the beginning of the estivation period (late July) in Harima‐Nada, eastern Seto Inland Sea, for 10 years from 2008 to 2017. The mean abundance of copepods as food for the age‐0 fish during the fish growth period (from February to June) around the estivation area was also determined. The condition factor showed a significant decrease, and values for 2011 and later years were mostly lower than the known minimum threshold (4.2) for maturation. In the recent 4 years from 2013 to 2016, the mean copepod abundance was much lower than values for the other years. The condition factor showed a significant positive correlation with the copepod abundance. These results indicate that decline of western sand lance catch after 1990 was caused mainly by food shortage.

Adapting to change in inland fisheries: analysis from Lake Tanganyika, East Africa

Fisheries around the world are declining due to growing anthropogenic pressures including climate change and overexploitation. Understanding how small-scale fishers respond to this unprecedented challenge is critical for developing more effective management strategies in vulnerable socio-ecological systems. While considerable research is focused on adaptation to change in marine contexts, greater attention is urgently needed on regionally important but often neglected inland fisheries. This study analyzes the adaptation intentions of littoral fishers on Lake Tanganyika, a biodiversity hotspot and one of the largest inland fisheries in Africa. Data were collected through in-person surveys of 154 littoral fishers across 11 major landing sites in Tanzania. Based on the Theory of Planned Behavior, we identified and tested 15 individual and site-level factors as potential indicators of adaptation intentions to a hypothetical 50% decline in catch. Our results show that fishers with other (non-fishing) primary livelihoods are more likely to adapt in ways that decrease fishing pressure, increase income, and are supported by family and friends. Homeowners were also more likely to adapt in ways that lessen fishing pressure. Our findings highlight the importance of fostering regional adaptation strategies that increase primary livelihood alternatives and capital outside the fishery, while discouraging investment in adaptations focused on increasing catch amount or fishing income.

The hidden value of artisanal fisheries in Honduras

AbstractDeclining fisheries catches are a global trend, with management failing to keep pace with growth in fishing effort and technological advances. The economic value of Honduras’ catches was estimated within the industrial and artisanal sectors. Catches were found to be 2.9 times greater than the official statistics between 1950 and 2015. The merging of industrial and artisanal catch data masked the decline in industrial catches and hid the strong growth of artisanal fisheries. In 1996, annual artisanal fisheries landed catches surpassed the industrial fishery sector, and in 2000, the annual net value of artisanal fisheries eclipsed the value of the industrial fisheries. These data highlight the importance of artisanal fisheries in Honduras and challenge the long‐held belief that the industrial sector contributes more to the national economy. The global paucity of fisheries data highlights the need for comprehensive strategies to collect more detailed and accurate fisheries data.

Development of Catfish Cultivation Business as Off Fishing Activities in Glondonggede, Tuban Regency

The pressure on the utilization of marine resources has decreased the results of fishermen's fishing both in quality and quantity. The use of fishing equipment that is not environmentally friendly also contributes to the decline in fishermen's catches. Catfish cultivation is one of an off fishing activity in Glondonggede Village, to reduce the pressure on the utilization of marine resources. The purpose of research: (1) Describe the technical aspects and market opportunities for catfish farming. (2) Analyzing the value of profitability. (3) Arrange the development of catfish farming. Purposive sampling was used in this descriptive research. The catfish cultivation business can be carried out by fishermen on the yard house using pond with a size of 3x4 m2, 60cm high, with a stocking density of 200 tails / m2. The results of catfish cultivation are marketed around Tambakboyo Subdistrict. Catfish cultivation is profitable and feasible to develop. The catfish consumption and financial analysis, the catfish cultivation business can be developed as an off fishing activity. The strategy for developing catfish business includes optimal land use; development of intensive cultivation technology; strengthening fishermen groups for aquaculture and marketing networks as well as preventing environmental pollution.

The European pilchard Sardina pilchardus (Walbaum, 1792) stock off the western Algerian coast is fully exploited

The European pilchard Sardina pilchardus is one of the main target species of the commercial fishery along the Algerian coasts. To better understand the observed decline in catches we studied the state of exploitation and simulated the effect of changing fishing effort on the population of sardines. The Beverton-Holt yield-per-recruit model and the Thompson-Bell model showed that the stock is presently fully exploited. In order to estimate the required model parameters, a sample of 1234 specimens was obtained from commercial catches on the western Algerian coast. Analysis of otoliths and gonads allowed the estimation of age-length model parameters, length-weight relationship, length at first maturity, and length at 50% selectivity. In light of the high vulnerability of small pelagic species to environmental fluctuations one might consider to reduce the current level of exploitation to allow for the annual renewal of the exploitable stock of sardine in the western region of the Algerian coast, and hence for a sustainable yield on the long-term.

Biological Aspects of Shortfin Scad (Decapterus macrosoma) in Makassar Waters, South Sulawesi, Indonesia

The shortfin scad is a pelagic fisheries resource that plays an important role in the economy of the South Sulawesi marine fisheries sector. Besides its use for consumption by local communities, shortfin scad are also used as bait in the tuna fishery and exported frozen. Over the past five years there has been a decline in catches caused by uncontrolled exploitation. To date, there is still no control over the exploitation of shortfin scad, and it is feared the sustainability of shortfin scad as a fisheries resource is threatened. This research aimed to analyse specific aspects of shortfin scad biology for this population, including sex ratio, size at first maturity, and growth pattern. The study was conducted in the waters off Makassar, in South Sulawesi, Indonesia, using direct observation with a survey method. Fish samples were obtained from catches landed by fishermen at the Paotere fishing harbour in Makassar City. Sampling was conducted from early April to early August 2017. The shortfin scad sample obtained comprised 201 male fishes and 169 female fishes. The results showed that the sex ratio of the shortfin scad (male:female) was 1.1:1.0. The shortfin scad reached first maturity at a fork length of 18.24 − 19.54 cm for males and 16.45 − 17.24 cm for females. The Gonad Maturity Index (GMI) of male fish was dominated by immature gonad classes (GMI I and GMI II), while for females GMI III and GMI IV dominated the sample, indicating that females mature earlier than males. Male and female growth patterns were allometric positive with b>3, indicating that the gain in weight was faster than the increase in length.

Late arrival: The development of resource rent in Icelandic fisheries

The development of resource rent in Icelandic fisheries has been charted since the introduction of the individual transferable quota system in 1990. An estimation of the rent capture of the fishing fee, which is a form of resource rent taxation, is also presented. Two methods were applied to calculate the resource rent. One method is based on the weighted average cost of capital of the Icelandic fishing industry, and the other method involves comparing the return of the capital of fisheries to the general aggregate Icelandic economy. The findings indicate no presence of the resource rent in Icelandic fishing and processing until 2008. Since that time, the rent has been, on average, 16–19% of the export value of the fishing industry, depending on the methods that were applied. The most obvious reason for the long delay before the rent appeared is the almost continual decline of fish catches from 1990–2008. The industry was rationalized during that time, but the rationalization kept up only with the reductions in landings; thus, no resource rent was produced. The rent appeared when the catches started to increase in 2009. In addition, the exchange rate and the weakening of the Icelandic krona were major contributors to the emergence of rent after 2008. The fishing fee captured approximately 13–15% of the calculated rent from 2009. The fee has been relatively modest but was significant in 2016, when it was increased and set at approximately 26–29% of the estimated resource rent of Icelandic fisheries.

Spatiotemporal distribution and growth pattern of Venus nux (Gmelin, 1791) in the Gulf of Cádiz (Southern Spain)

Spatiotemporal distribution and growth pattern of Venus nux (Gmelin, 1791) in the Gulf of Cádiz (Southern Spain)

Tropical hilsa shad (Tenualosa ilisha): Biology, fishery and management

AbstractTropical hilsa shad, which is an anadromous fish migrating from the sea to spawn in freshwater river, constitutes an important fishery in some Asian and Middle East countries, particularly in Bangladesh. But, historical information on hilsa biology and ecology has confronted the scientists and policymakers with research and management challenges. We have reviewed both the old and recent findings on hilsa fishery to document the status of knowledge and potential gaps, necessary to comprehend for formulating a more effective fishery management plan. Thus, there has been a decline in hilsa catches in the riverine system associated with shift in fish migration routes, indiscriminate harvesting of brood and juvenile fish, and degradation of habitat. Specifically, the riverine hilsa catches peaked in the 1960s, declining thereafter, and became relatively abundant in marine waters since 1990s. Biological data indicated that hilsa goes through multiple reproductive cycles; therefore, a comprehensive understanding of reproductive biology, recruitment by various cohorts, stock abundance and habitats across the life cycle are necessary to accurately impose fishery regulatory measures, such as fishing ban in spawning season in Bangladesh. Moreover, domestication initiative is important for artificial seed production and mariculture development of hilsa that can not only offer economic return to small‐scale farmers but also reduce the growing pressure on capture fishery. Importantly, the arrangement of co‐management is found ideal as fishermen, scientists and managers can work jointly to improve the regulatory processes and to sustain the hilsa fishery over time.

Historical and recent reductions in genetic variation of the Sarotherodon galilaeus population in the Sea of Galilee

The Sea of Galilee has great significance as a natural habitat and a freshwater source for Israel. Anthropogenic impacts have been placing significant pressure on the species inhabiting this lake, among which is Sarotherodon galilaeus, an omnivorous fish with a relatively large population and significance for commercial fishing. An alarming decline in annual catch towards 2008 suggested that this unique population might be at risk. With that in mind, we characterized the current genetic variation of this species in Israel with reference to fish from Ghana, based on D-loop and microsatellite markers. Genetic variation and differentiation were found mostly among fish from Ghanaian localities and between fish from Israel and Ghana, whereas fish from all Israeli localities had uniform and limited variation, a signature compatible with historical founder effect followed by local adaptations. Such historical processes could leave a population vulnerable as reflected in the sudden and recent population decline. Comparing genetic variation between archived 30 year-old scales and modern lake fish revealed further reduction in genetic variation coincident with the recent population decline. Thus, a recently occurring genetic bottleneck had placed this unique and isolated population at an even higher risk. We carefully discuss the events leading to the current risk status for S. galilaeus in Israel and highlight the need for vigilant monitoring and active management to support a more sustainable future for this and other fish communities in this important habitat.

The role of the Liwonde National Park in conserving fish species diversity in the upper Shire River, Malawi

Tremendous decline of fish catches in Lake Malawi, mainly due to uncontrolled fishing, is a clear evidence of challenges of managing a common/open resource. East of the Shire River lies the protected area known as Liwonde National Park about 538 km2. Species diversity around the National Park including the southeast arm of Lake Malawi, Lake Malombe, and the upper Shire River were studied to determine if the moratorium in the park has any impact to the fishery in these areas. Fish samples were collected using a variety of fishing gears including mosquito nets, gill nets, scoop nets, cast nets, and hand lines from southeast arm of Lake Malawi, Upper Shire River, Lake Malombe, and the area near the Liwonde Barrage. Over 40 species belonging to 27 genera and 6 families were sampled compared to 50 species recorded in earlier studies suggesting that, despite the general decline in the fish species diversity, this area still maintains its resilience. The family Cichlidae was the most diverse with 19 genera followed by the Cyprinidae with 4 genera. These results showed that Cichlidae and Cyprinidae fish species that have nearly disappeared in Lake Malawi are still found in considerable abundance in the Shire River especially in areas around the National Park. Most of the determined fish species originated from surrounding areas to the park suggesting that it is a breeding area for fishes that are caught upstream and downstream. Findings underpin the importance of managing and protecting the National Park or even establishing other moratoriums for the same.

Impacts of water regulation on Tenualosa ilisha in the Narmada Estuary, Gujarat, India

Hilsa, Tenualosa ilisha is a highly prestigious fish for esteemed delicious taste, high market demand and price. It forms an important fishery of funnel-shaped 72 km long Narmada Estuary. Rapid decline in hilsa catch has been recorded in the Narmada Estuary over last few decades. Hilsa catch was recorded 5180 ton in 2006–07 that reduced to only 419 ton in 2014–15. Pre-impoundment of dam showed that T. ilisha contributed to the tune of 977.1 to 3727 ton from 1974–75 to 1982–83 and the highest catch of hilsa was 15319 ton during 1993–94. Sardar Sarovar Dam started functional in the year 1994 which has impacted natural water flow of the river and resulted in a reduction of freshwater availability in the estuary; the development of sand bars at the mouth of the estuary also reduced the tidal ingress into the system; low depth, loss of breeding, nursery and feeding grounds, over fishing may be the most important factors affecting hilsa fishery in Narmada estuary. Catching of juvenile hilsa during winter by ‘Golava’ net (small meshed bag net) also led to a rapid decline in hilsa catch. To maintain the sustainable yield of hilsa, selective fishing and control of juvenile catch are the prerequisites along with maintaining regular flow from the dam.

Impacts of water regulation on Tenualosa ilisha in the Narmada Estuary, Gujarat, India

Hilsa is a highly prestigious fish for esteemed delicious taste, high market demand and price. It forms an important fishery of funnel-shaped 72 km long Narmada Estuary. Rapid decline in hilsa catch has been recorded in the Narmada Estuary over last few decades. Hilsa catch was recorded 5180 ton in 2006–07 that reduced to only 419 ton in 2014–15. Pre-impoundment of dam showed that T. ilisha contributed to the tune of 977.1 to 3727 ton from 1974–75 to 1982–83 and the highest catch of hilsa was 15319 ton during 1993–94. Sardar Sarovar Dam started functional in the year 1994 which has impacted natural water flow of the river and resulted in a reduction of freshwater availability in the estuary; the development of sand bars at the mouth of the estuary also reduced the tidal ingress into the system; low depth, loss of breeding, nursery and feeding grounds, over fishing may be the most important factors affecting hilsa fishery in Narmada estuary. Catching of juvenile hilsa during winter by ‘Golava’ net (small meshed bag net) also led to a rapid decline in hilsa catch.