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Tenualosa ilisha is an anadromous fish from the Clupidae family that is distributed in several Asian countries. The relationship between T. ilisha from Indonesian waters and other waters in Asia is unknown, therefore this study was conducted to provide an overview of the relationship between T. ilisha from Indonesia and other waters in Asia based on the Cytochrome b gene (Cyt b) of mitochondrial DNA (mtDNA). The base sequence of T. ilisha from Labuhanbatu with a length of 568-572 base pairs (bp) was analyzed, then compared with Genbank data. All sequences compared showed that the composition of A+T (52.5%) was greater than G+C (47.5%). Genetic distance was calculated using Kimura two parameter (K2P); the lowest genetic distance of 0.000 was obtained between T. ilisha Labuhanbatu and Iraq with accession numbers LC619671.1; LC619673.1; LC619674.1. Meanwhile, the highest genetic distance is known to be 0.021 between T. ilisha Labuhanbatu and Bangladesh with the accession numbers MN748964.1, and MN748966.1. Neighbor-joining and maximum likelihood with 1000x repetition were the phylogenetic methods used to analyze the evolutionary relationships of T. ilisha. In general, both methods showed the same result that T. ilisha from Indonesia and other Asian waters are the same population. [ABSTRACT FROM AUTHOR]

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The studied area is the single largest fishery in Bangladesh. The present work was conducted at two points of the Padma River (Sureshwar and Tarabunia) from July 2019 to June 2021 to monitor the efficiency of the 5th Hilsa sanctuary. Proportion of spent rate, length frequency, larvae and Jatka abundance, CPUE of larvae, the length-weight relationship of Jatka, plankton composition, and physico-chemical parameters of water were assessed and found adequate in the Hilsa sanctuary. [ABSTRACT FROM AUTHOR]

With priority given to various-sized samples of market-available Hilsa (Tenualosa ilisha), human health consequences of trace metals along with total essential acids, including the fatty acid (FA) and amino acid (AA) profile were measured and compared to different size groups (G I, G II, and G III) using chemometric approaches. Essential amino acids were lower than nonessential amino acids. The G III contained the highest (97.55%) saturated and unsaturated fatty acids. The highest concentrated metal was found in G1 among the groups and the order of metal (mg/kg) was Zn (205.01) > Mn (37.37) > Fe (69.39) > Cu (1.47) > Cr (1.31) > Ni (0.42) > Pb (0.017) > Cd (0.005). Even though the adult group showed no health hazards for Hilsa consumption, non-carcinogenic risks have been identified for G1 fish consumption by children. Continued monitoring is recommended to overcome the health consequences caused by fish consumption. [Display omitted] • The fat content of fish increases proportionally with their size. • Zn content displayed higher than the suggested concentration by FSG. • HI values for both adult and child groups followed a declining order: G I > G II > G III. • The health risk index displayed a higher risk for children consuming Hilsa fish than adults. • Most metals in the fish were of anthropogenic origin. [ABSTRACT FROM AUTHOR]

Introduction. Fish can sometimes be contaminated with several highly toxic substances at once, e.g. heavy metals, pesticides, and preservatives. In this regard, it is essential to determine the presence of these harmful chemicals in fish products. The research objective was to analyze the level of organochlorine pesticide residues and other toxic substances in Tenualosa ilisha L. Study objects and methods. The study featured organochlorine pesticide residues and other toxic substances in raw and cooked samples of fresh and salted T. ilisha, which is a popular dish in Northeast India, especially in the state of Tripura. The analysis involved tests for formaldehyde, pesticides, and heavy metals. Formaldehyde content was estimated using high-performance liquid chromatography, pesticides content – by low-pressure gas chromatography/tandem mass spectrometry, and heavy metals – by inductively coupled plasma/mass spectrometry. Results and discussion. The salted samples had a high content of formaldehyde, though it remained within the normal range. Both fresh and salted samples demonstrated high concentrations of heavy metals such as zinc, copper, and selenium. The salted sample appeared to have a high content of toxic organochlorine pesticide residues. Frying and boiling of fresh and salted fish decreased formaldehyde and organochlorine pesticide residue contents but did not reduce heavy metal content. Conclusion. T. ilisha was found to be quite safe for human health.

Sanctuaries are widely regarded as a protected area where fishing has been placed under some restrictions by local, state, regional and national authorities for the conservation and management of fisheries resources. These sanctuaries have a broad array of positive and negative social, economic, cultural and political impacts on fishers. This study aims to analyze the socio-economic and ecological benefits and costs of hilsa sanctuaries to protect single most important hilsa species using Sustainable Livelihood Approach (SLA). Under the Protection and Conservation of Fish Act of 1950, six sites along the Padma, Meghna, Tetulia, and Andharmanik rivers have been designated as hilsa sanctuaries. Findings of the current study revealed that most fishers perceived production of hilsa and other species were increased as a direct consequences of sanctuaries establishment. However, a considerable proportion of hilsa fishermen was found to have low socioeconomic capital, as measured by monthly income, housing circumstances and asset ownership. During the restricted fishing season in the sanctuaries, these households are particularly vulnerable to food insecurity. The government's compensation scheme is a good example of payment of ecosystem services in an open water fishery; however, this scheme does not include all the affected fishers. It is found that hilsa sanctuaries lead to income loss of the poor fishers which is insufficiently compensated by government support program. To compensate income loss, fishers resort illegal fishing which undermine the success of sanctuary. If the sanctuaries are to function effectively, affecting fishers must be addressed by offering enough compensation schemes so that fishers are able to support their families. Moreover, some fishers believed that a co-management approach involving fishers and government is the possible best management option for operating sanctuaries in a sustainable way. [ABSTRACT FROM AUTHOR]

Morphological characteristics, length-weight relationships (LWRs) and length-length relationships (LLRs) using multi-linear dimensions of Tenualosa ilisha (Hamilton, 1822) from the Ganges River, north-western Bangladesh, are examined. Samples (257 specimens) were occasionally collected during July 2018 – June 2019. Fin rays and scales were counted by a magnifying glass. A total of 9 morphometric lengths and total body weight (BW) were measured to the nearest 0.1 cm and 0.01 g for each specimen. Fin formula was: Dorsal, D. 15-19 (2-4/13-17); Pectoral, P. 14-16 (1/13-15); Pelvic, PV. 6-10 (1-2/5-8); Anal, A. 18-21 (1-2/16-20); and Caudal, C. 20-22 (2/18-20). Each LWRs were greatly significant (p< 0.001) with r² ≥0.963. Based on r² value, BW = 0.0215×SL3.01 was the fittest. Additionally, LLRs by TL vs. SL was the best fitted model among 8 equations depending on r² values. The provided biological information will support further studies and management of T. ilisha in the Ganges River and elsewhere using any liner-dimensions. [ABSTRACT FROM AUTHOR]

Hilsa species are broadly described as largely anadromous fish with a large valuable population size. It is well-known as one of the most critical commercial and occurs in marine, estuarine and riverine environments Hilsa shad, Tenualosa ilisha locally known as Sbour, migrates to the freshwater environment of the Shatt Al-Arab River systems for breeding. It was determined the genetic variation in 70 specimens of T. ilisha from four sites at the Shatt Al-Arab River, the mtDNA cytochrome-b gene was selected as a molecular marker for detecting genetic diversity, origin, and divergence of the population through comparing them with 6 samples from different locations at Indo- Pacific. The AMOVA analysis showed that the variation between groups is 60.97% and 39.02% within population indicating statistically significant P value (P<0.05). Furthermore, the maximum likelihood phylogenetic tree showed two main clusters of all T. ilisha groups representing two stocks of separated breeding grounds have a common ancestor. [ABSTRACT FROM AUTHOR]

Food and feeding habits of Tenualosa ilisha collected from two sampling locations in Brahmaputra River, Assam, India for a period of 12 months from May 2018 to April 2019 were studied. Index of preponderance revealed semi-digested animal matter (25.92 %) as the most dominant food item followed by Bacillariophyta (23.32 %). 31 genera of phytoplankton and 15 genera of Zooplankton were observed in the gut of the species. Major groups of Zooplankton include cladocerans, copepods, followed by rotifers, while diatoms, green algae and blue green algae were dominant phytoplankton groups. The anadromous tropical shad is planktivorous by nature and has a preference for Zooplankton in smaller size groups (< 250 mm) and phytoplankton in larger size groups (> 250 mm). GaSI values (mean±SE) ranged from 1.50±0.14 to 6.93±0.89 and HSI values from 0.58±0.06 to 1.54±0.15. Index of fullness was found to range from 7.08±0.42 to 1.81±0.40. Feeding intensity, GaSI, HSI values showed seasonal variation, found to be low during October to December and high during February to June. Size group-wise analysis of feeding intensity showed high feeding intensity in lower size groups (< 250 mm) and comparatively low feeding intensity and high percentage of empty stomachs in higher size groups (> 250 mm). RLG values ranged from 1.181±0.028 to 1.450±0.052. Monthly average RLG values were found to be highest during November and in the size group of 351 - 400 mm. Changes in food composition were noticed in both months and as well as size groups. [ABSTRACT FROM AUTHOR]

Fresh and salted Tenualosa ilisha is very popular among the common people of Tripura, North-eastern part of India. In the present study, nutritional value of fresh and salted T. ilisha and the effects of different cooking methods such as boiling and frying on them were evaluated. Significant differences were detected in proximate composition as well as in mineral, amino acid and fatty acid content. The increased amount of protein, ash, dry matter and mineral content was observed in salted T. ilisha but reverse was observed in case of amino acid and fatty acid content. Fried sample of both fresh and salted T. ilisha contained more amount of protein, fat, dry matter, ash, minerals and fatty acids than the boiled fish which play an important role in human health. In conclusion, frying process for preparation of fish is found to be good for cooking.

Hilsa species are broadly described as largely anadromous fish with a large valuable population size. It is well-known as one of the most critical commercial and occurs in marine, estuarine and riverine environments Hilsa shad, Tenualosa ilisha locally known as Sbour, migrates to the freshwater environment of the Shatt Al-Arab River systems for breeding. It was determined the genetic variation in 70 specimens of T. ilisha from four sites at the Shatt Al-Arab River, the mtDNA cytochrome-b gene was selected as a molecular marker for detecting genetic diversity, origin, and divergence of the population through comparing them with 6 samples from different locations at Indo-Pacific. The AMOVA analysis showed that the variation between groups is 60.97% and 39.02% within population indicating statistically significant P value (P

Despite different approaches used to assign the risk scores for missing information in productivity susceptibility analysis (PSA)--a widely used semi-quantitative risk assessment tool for target and non-target fisheries stocks--for the selected attributes of a given species, no formal comparison has been made between scoring approaches in terms of how well they can predict species vulnerability. The present study evaluated the PSA findings of 21 bycatch stocks of the Hilsa (Tenualosa ilisha) gillnet fishery of Bangladesh using two different scoring approaches (the conservative scoring approach, CSA; and the alternative scoring approach, ASA) to determine the most reliable approach to minimize false estimates of species vulnerability. Our analysis revealed that the V scores increased by 0.0-0.20 with a mean value of 0.09 for 21 selected bycatches when CSA was applied. The inconsistency between the vulnerability (V)-score-suggested fishing status (V ≥ 1.8 = underfishing, V > 1.8 = overfishing) and the fishing status defined by exploitation rate (E > 0.5 = overfishing, E < 0.5 = underfishing) were 38.1% and 19.0% under CSA and ASA, respectively. Likewise, the consistency between the V-score-suggested fishing status and fishers' perceived catch trends was found to be higher when using ASA than when using CSA. Our analysis suggests that CSA could overestimate species vulnerability. Therefore, ASA is more reliable than CSA in PSA, which may increase the confidence of fisheries stakeholders in PSA. [ABSTRACT FROM AUTHOR]

Tenualosa ilisha is a popular anadromous and significant trans-boundary fish. For sustainable management and conservation of this fish, drawing an appropriate picture reflecting population status of this species is very essential based on their all-strategic habitats in Bangladesh. In this study, 139 samples from 18 sites were collected and cross-species gene enrichment method was applied. Like most of the Clupeiforms, nucleotide diversity of this shad was very low (0.001245–0.006612). Population differences between most of the locations were low and not significant (P > 0.05). However, P values of a few locations were significant (P < 0.05) but their pairwise FST values were very poor (0.0042–0.0993), which is inadequate to recognize any local populations. Our study revealed that the presence of a single population in the Bangladesh waters with some admixtured individuals, which may contain partial genes from other populations. Most of the individuals were admixed without showing any precise grouping in the ML IQtree and Network, which might due to their highly migratory nature. Fishes from haors and small coastal rivers were not unique and no genetic differences between migratory cohorts. The hilsa shad fishery should be managed considering it as a single panmictic population in Bangladesh with low genetic diversity. [ABSTRACT FROM AUTHOR]

The current study was conducted on the temporal variation of the growth pattern and the physiological status of Tenualosa ilisha (Hamilton, 1822) from the Meghna River, Bangladesh for the period of July 2018 to June 2019. A sum of 1433 individuals were collected, where its body weight (BW), total length (TL), standard length (SL) and fork length (FL) were measured with 0.01 g and 0.01 cm accuracy. The growth pattern was estimated through length-weight relationship by the equation: BW = a×TLb, where BW was in g and TL in cm. The parameters a and b were estimated with linear regression analyses. Physiological status was determined using equation provided as follows: ā = W/Lb. If ā was close to the a value (a, LWR parameter) then the fish was in an ideal condition, where ā > a pointed to fatty fish and ā < a to lean fish. The TL ranged from 15.3cm to 57.8 cm while the BW was from 37.17-2250 g. The overall growth pattern for T. ilisha was positive allometric (b = 3.135) in the Meghna River. The maximum fatty fish was found in the month of December (44%) while the minimum was in October. The highest percentage of lean fish was found in the monthof February (41%) and the lowest was in September (22%). The present findings would add some beneficial data for consumer preference, meanwhile further studies are recommended to achieve a sustainable management of hilsa fishery and other water bodies in the Meghna River. [ABSTRACT FROM AUTHOR]

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.

The migratory tropical shad, Tenualosa ilisha has a wide range of habitat preferences like rivers, reservoirs, estuaries, backwaters, and coastal waters during different phases of its life cycle. The present study investigates morphological variations among three populations of Hilsa from distinct ecosystems such as the River Brahmaputra, Narmada estuary and Ukai reservoir. Thirteen morphometric and nine meristic measurements were considered for the present study. Among the meristic traits, significant variation was observed in counts of lateral line scales and post ventral scutes. The MANOVA results depict a significant difference in the morphometric traits among the three populations. The factor analysis indicated a very significant loading of head-related traits on the first factor and traits related to the middle and caudal region on the second factor. The study portrayed a significant morphological variation among the different stocks of T. ilisha and the results were confirmed in discriminant function analysis. [ABSTRACT FROM AUTHOR]

Tenualosa ilisha, T. toli and Hilsa kelee are three Indian shad species of the family Clupeidae. In past, relationships among these shads have been explored in few morphological studies but still remain poorly understood. In this study, 120 specimens of three shad species were collected from the wild and a truss network system of 13 landmarks was interconnected to yield 77 size‐adjusted characters. Discriminant function analysis (DFA) produced 13 discriminating variables in delineating the three species. The landmark based morphometric distance between origin of dorsal fin and posterior end of eye was the most important character in discriminating the three species. Three prominent characters extracted from DFA (distance between posterior end of operculum and posterior end of eye, distance between origin of dorsal fin and posterior end of eye and distance between insertion of pelvic fin and end of operculum) were used as traditional morphometric characters and their ratio to standard length were found significant in differentiating the three shad species. The present study strongly supports the efficiency of landmark‐based morphological characters generated from digital images in discriminating the species and can be used as a rapid diagnostic tool in recognizing them. [ABSTRACT FROM AUTHOR]

Tropical hilsa shad (Tenualosa ilisha) contributes significantly to the society and economy of Bangladesh, India and Myanmar, but little is known about their habitats across the life cycle and their relationship with environmental drivers. This study describes spatial and temporal variability of productivity in the Bay of Bengal (BoB) relating to hilsa fishery. Decadal data on net primary productivity, nutrients (i.e. nitrate, phosphate and silicate) and zooplankton were collected from Aqua MODIS, world ocean database and COPEPOD respectively with spatial resolution 1°×1°. Moreover, monthly abundance of phytoplankton, hilsa catch and long-term catch dynamics were analyzed to determine the associations between variables. The present study was extended over 3.568 million km2 area, of which 0.131–0.213 million km2 area characterized as the most productive with net primary production of >2,000 mg C/m2/day, 0.373–0.861 million km2 area as moderately productive with 500–2,000 mg C/m2/day, and 2.517–3.040 million km2 area as the least productive with <500 mg C/m2/day which were consistent with field verification data. In case of nutrients, the Ganges-Brahmaputra-Meghna (GBM) delta was rich in nitrate and phosphate than that of the Ayeyarwady delta, while silicate concentration persisted high all over the northern BoB including the deltas. A peak abundance of phytoplankton was observed in GBM delta during the months of August-November, when ~80% of total hilsa are harvested in Bangladesh annually. Variations in seasonal productivity linked with nutrients and phytoplankton abundance are important factors for predicting hilsa habitat and their migration patterns in the deltaic regions and shelf waters of BoB. These results can be useful in forecasting potential responses of the hilsa in BoB ecosystem to changing global ocean productivity. [ABSTRACT FROM AUTHOR]

Hilsa shad (Tenulosa ilisha) is Bangladesh’s most important single-species fishery that contributes to 11% of total catch and employment for millions of people. However, heavy metals (HMs) toxicity in the edible organs of T. ilisha and their plausible public health threats have received weak attention. To provide insights on this issue, we determined, using ICP-MS, the concentration of Zn, Cu, Cr (VI), Pb, and Cd in the edible organs of five different sizes of T. ilisha and the surface water collected from the Padma–Meghna River confluence, Chandpur (Bangladesh). Multivariate analysis indicated that T. ilisha gills and liver contained higher HMs than muscle, and the surface water was below the safety limits. The study revealed that only Cr crossed the safety limits and bioaccumulated in the smaller-sized gills and liver. To assess the public health risks, target hazard quotient (THQ), total THQ (TTHQ) and carcinogenic (CR) risks were calculated. Only Cr imposed non-carcinogenic risks to consumers, while TTHQ showed higher chronic health risks. There was no CR risk measured for consumers, except for the largest-sized gills for children. Randomly positive relations between HMs and sizes were found; whereas, consistently positive relations were found among the tissue types. The outcomes of our study may aid policymakers in managing pollutants, especially the Cr sources in the greater Chandpur regions.

Despite different approaches used to assign the risk scores for missing information in productivity susceptibility analysis (PSA)—a widely used semi-quantitative risk assessment tool for target and non-target fisheries stocks—for the selected attributes of a given species, no formal comparison has been made between scoring approaches in terms of how well they can predict species vulnerability. The present study evaluated the PSA findings of 21 bycatch stocks of the Hilsa (Tenualosa ilisha) gillnet fishery of Bangladesh using two different scoring approaches (the conservative scoring approach, CSA; and the alternative scoring approach, ASA) to determine the most reliable approach to minimize false estimates of species vulnerability. Our analysis revealed that the V scores increased by 0.0−0.20 with a mean value of 0.09 for 21 selected bycatches when CSA was applied. The inconsistency between the vulnerability (V)-score-suggested fishing status (V ≤ 1.8 = underfishing, V > 1.8 = overfishing) and the fishing status defined by exploitation rate (E > 0.5 = overfishing, E < 0.5 = underfishing) were 38.1% and 19.0% under CSA and ASA, respectively. Likewise, the consistency between the V-score-suggested fishing status and fishers’ perceived catch trends was found to be higher when using ASA than when using CSA. Our analysis suggests that CSA could overestimate species vulnerability. Therefore, ASA is more reliable than CSA in PSA, which may increase the confidence of fisheries stakeholders in PSA.

Abstract Objective Hilsa shad (Tenualosa ilisha), is a popular fish of Bangladesh belonging to the Clupeidae family. An anadromous species, like the salmon and many other migratory fish, it is a unique species that lives in the sea and travels to freshwater rivers for spawning. During its entire life, Tenualosa ilisha migrates both from sea to freshwater and vice versa. Data description The genome of Tenualosa ilisha collected from the river Padma of Rajshahi, Bangladesh has been sequenced and its de novo hybrid assembly and structural annotations are being reported here. Illumina and PacBio sequencing platforms were used for high depth sequencing and the draft genome assembly was found to be 816 MB with N50 size of 188 kb. MAKER gene annotation tool predicted 31,254 gene models. Benchmarking Universal Single-Copy Orthologs refer 95% completeness of the assembled genome.

Nutritional composition of hilsa, Tenualosa ilisha, of different size groups was analyzed to study variations in their composition with the progression of growth, and to correlate it with the flavor of adult hilsa (>800 g size) collected from different riverine systems (Hooghly and Padma). The amino acid analysis revealed significantly higher arginine (P < 0.01), methionine (P < 0.01) and glycine (P < 0.05) contents in samples below 5 g, whereas samples above 800 g had higher (P < 0.01) leucine and isoleucine contents. Total saturated and monounsaturated fatty acids were lower (P < 0.01) in fish below 5 g as compared to larger size groups (>5 g), whereas docosahexaenoic acid was higher (P < 0.01) in fish below 5 g size. Nutritional composition of adult hilsa (>800 g) from Hooghly and Padma river revealed higher (P < 0.01) aspartic acid, glutamic acid, alanine, palmitoleic and oleic acid in samples from the Padma, whereas leucine and isoleucine contents were higher (P < 0.01) in hilsa from Hooghly. Sensory evaluation test revealed superior (P < 0.05) taste, aroma, and muscle texture of hilsa from the Padma as compared to those from Hooghly. Higher alanine, aspartic acid, glutamic acid, oleic acid, and palmitoleic acid along with higher n3:n6 fatty acid are attributed to the superior taste of hilsa from the Padma. [ABSTRACT FROM AUTHOR]

The population structure of Hilsa Shad (Tenualosa ilisha), a choicest table fish, in the estuaries of India, Bangladesh and Myanmar of Bay of Bengal has been studied by different methods and each provided complementary data on population structure. Considering the present scenario of climate change, increasing pollutant load in Indo--Bangladesh estuarine region and its effect on reproduction and maturation of anadromous Hilsa Shad, a thorough and detailed understanding of the life history of Hilsa is a pre requisite criterion. Results of such studies would be important for sustainable management of this highly economic biological resource. The present paper deals with the aspects of life history and population dynamics of Hilsa Shad in Sundarban estuaries. The data collection was done during the period of June 2011 to March 2012 at Frasergunje Fishing Harbour and offshore of northern Bay of Bengal. The length and weight of total 617 Hilsa fish were measured under this study. Monthly variations of length and weight, length frequency distribution, monthly variation of the allometry coefficient, movement pattern, and catch per unit effort were estimated. The exploitation rate of Hilsa species was found to be 0.78 and the maximum sustainable yield was 11700.18 tonnes whereas the annual catch was 18126.00 tonnes. Highest weight of adult Hilsa was recorded during the monsoon i.e. the months of June, July and August. The result of relative yield per recruitment indicated that the mortality due to current fishing period and pressure were high. Widespread fishing of juvenile and growing Hilsa (< 500 g) declined the Hilsa population considerably losing the economic advantage. The present paper dealt with life history parameters like, growth, exploitation, mortality, stock assessment for sustainable management of Hilsa population. In our study we have observed that Hilsa fish, especially Jatka (<500 gms and <230 mm) is over harvest, from West Bengal coastal areas. [ABSTRACT FROM AUTHOR]

In order to study the effects of contaminants on human health, fish is considered as a powerful model among all available species for risk-benefit assessments. Tenualosa ilisha and Dorosoma cepedianum are two fish species of great economic importance as they are found in undeveloped, developing and developed countries. Concentrations of heavy metals lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As) and mercury (Hg) were determined using validated and accredited test methods in order to assess the potential human health risk from the dietary intake of these two selected fish species. The estimated daily intake (EDI) of all the five heavy metals was measured from the consumption of the two species considering the mean fish consumption of 61 g person−1 day−1 defined for European population. The EDI indicates that no risk to people's health with respect to the EDI of Pb, Cd, Cr, As and Hg through the consumption of the two fish species. The estimation of target hazard quotient (THQ) demonstrating the non-carcinogenic risk indicates that intake of Pb, Cd, Cr and Hg through the consumption of two fish species is safe for human health, whereas, consumption of As suggests potential risk to consumers. The estimation of carcinogenic risk of Cd, Cr and As due to the consumption of two selected fish species indicates that consumers remain at risk of cancer. Thus, these fish species should not be considered safe for human consumption. [ABSTRACT FROM AUTHOR]

Faustula gangetica (Srivastava, 1935) Yamaguti, 1958 (Plagiorchiida: Faustulidae) from the Hilsa shad, Tenualosa ilisha (Hamilton) (Clupeiformes: Clupeidae), collected in the Arabian Gulf off Iraq between June and October 2014 is redescribed. We include details of the structures within the cirrus sac and provide further basic morphology for this species not previously available. Faustula ilishii (Srivastava, 1935) Yamaguti, 1958 is synonymized with F. gangetica. This is the first report of F. gangetica from the Hilsa shad in the Arabian Gulf. [ABSTRACT FROM AUTHOR]

Aims: This study conducted bacterial community, virulence and antibiogram profiling inside the hindgut and skin of freshly caught hilsa fish and those sold at markets. Methods and Results: The results of 16S rRNA‐based high‐throughput sequencing showed a higher number of bacterial genera in marketed fish samples than in fresh fish samples. The total operational taxonomic units, genus counts and diversity index were significantly higher (P > 0·05) in marketed fish, which also had abundant pathogenic bacterial groups. Skin samples had a lower profusion of pathogenic bacteria than gut samples. A total of 52 bacterial isolates from nine species were identified in this study, of which 25 were from a Chittagong market and 22 were from a Dhaka market, whereas only five were from fresh hilsa. The polymerase chain reaction amplification of 12 species‐specific virulence genes in the 52 isolates, namely, aer, hly, chxA, toxB, rtxC, sfa, uge, norB, trx, toxA, ipaH, sigA and coa, indicated a high number of positive samples containing Vibrio cholerae, Aeromonas spp., Klebsiella pneumoniae, Escherichia coli and Staphylococcus aureus. Antibiogram profiling of these bacteria against 10 commercial antibiotics showed high‐resistance patterns of the isolates against sulfamethoxazole, kanamycin, neomycin, ampicillin and tetracycline. Conclusion: The results reveal the spread of multidrug‐resistant bacteria in hilsa fish marketed for human consumption in Bangladesh. Significance and Impact of the Study: This study highlights the risk of spreading environmentally and clinically pathogenic bacteria in fish sold for human consumption in Bangladesh. Such bacteria come from aquatic pollution and poor handling, storage and transportation practices that may predispose fish to major outbreaks of infectious and waterborne diseases. [ABSTRACT FROM AUTHOR]

Length-weight relationship and relative condition factor of T. ilisha was conducted for one year (2014-15) at Narmada estuary, Gujarat, India. Fish samples were collected from Bharuch, Bhadbhut, Mehgam and Ambetha landing sites covering 72 km of estuarine stretch. Two distinct fishing seasons were observed at Narmada estuary, viz., June-October and January-March, though the bulk of the harvest comes from monsoon season. A total of 312 fish samples were collected, 270 during monsoon and 42 during the winter season. The mean length and weight were recorded 35.37±11.36 cm and 625.83±39.81 g during monsoon and 36.84±3.82 cm and 537.44 ± 17.45 g during the winter season. The ‘b’ value was found to be 3.07 and 2.76 and relative condition factor was 1.02 and 1.01 during monsoon and winter seasons, respectively. [ABSTRACT FROM AUTHOR]

The predators of hilsa shad (Tenualosa ilisha) in the marine and riverine ecosystems of Bangladesh were identified. Data on the availability of hilsa shad in the stomach contents of top carnivore fishes were collected from 324 individuals with diversified occupations and hilsa-dominated geographical locations. Data analysis revealed that 15 predatory fishes preyed on hilsa, of which tuna, mackerel, shark, Indian threadfin, red snapper and fourfinger threadfin are dominant predators of adult hilsa in the Bay of Bengal, while freshwater shark, giant catfish, river catfish, humped featherback, stripped snakehead and giant snakehead are the main predators of juvenile hilsa in the Padma-Meghna river systems of Bangladesh. Further research leading to predation observations in controlled experiments can provide novel and robust information on predator-prey interactions in the context of ecosystem-based fisheries management and conservation initiatives. [ABSTRACT FROM AUTHOR]

Hilsa, Tenualosa ilisha has received much attention for culture due to decline of the natural population. Lack of knowledge on larval rearing is the bottleneck for its culture. This study was aimed at developing larval rearing protocols for hilsa shad. Hilsa larvae (4 days old, 4.76 ± 0.06 mm/0.49 ± 0.01 mg) were stocked in fibreglass‐reinforced plastic tanks (1.7 m3 water volume) at 300, 600 and 1,200 nos/m3 in triplicates in three experimental systems viz., E‐I (circular, 0.567 m water depth), E‐II (circular, 0.962 m water depth) and E‐III (rectangular, 0.567 m water depth) and reared for 46 days. The larvae were supplied with Chlorella vulgaris, Brachionus calyciflorus, mixed phytoplankton and mixed zooplankton during 4–50, 6–25, 8–50 and 26–50 days of their age respectively. In each system, higher (p < 0.05) fry survival at 300 nos/m3 than in higher densities indicates density dependent stress. Circular tanks showed higher survival (13.3%–61.31%) than in rectangular tanks (6.88%–27.26%) in each stocking density, indicating the importance of tank shape for rearing. Water depth affected fry survival in circular tanks (E‐I and E‐II) at 300 nos/m3; at 0.962 m depth, survival was higher (61.31%, p < 0.05) than that of 0.567 m depth (49.93%). Good fry survival was achieved through feeding the larvae initially with Chlorella followed by co‐feeding with Brachionus, mixed phytoplankton and zooplankton and rearing in circular tanks at 300 nos/m3 densities at 1 m depth. This first‐ever larval rearing protocol is useful for mass production of fry to support hilsa aquaculture in future. [ABSTRACT FROM AUTHOR]

Tropical 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. [ABSTRACT FROM AUTHOR]

Hilsa, Tenualosa ilisha, Ham. 1822 , is the prime table fish and important commercial fish in the Indo-Pacific region. However, the species has recently declined drastically due to various factors. Our earlier studies recorded a significant association between the breeding season and its migration. Studies on milt and its biochemical properties are essential to ensure its successful conservation and artificial breeding. Here, milt samples of the hilsa of varied sizes were evaluated for their antioxidant property, fatty acid and amino acid content, and the histology of the testis. Analysis of milt antioxidants was done using free radicals DPPH, FRAPS & ABTS methods and compared with the free-radical quenching properties of the synthetic antioxidants. High performance liquid chromatography (HPLC) and gas chromatography and mass spectrometry (GC/MS) determined the composition of amino acids and fatty acids, respectively. The highest and lowest antioxidant activity was exhibited by hilsa milt samples M3 (b.wt 358.6 ± 0.75 g) i.e. 84.59 ± 0.48% and M12 (b.wt 168.35 ± 0.12 g) i.e. 27.53 ± 3.59%. Most notably, the antioxidant activity was found to follow a body weight gradient. Omega (ꙍ)-3 polyunsaturated fatty acids (PUFAs), docosahexaenoic acid (C22:6, DHA) and eicosapentaenoic acid (C20:5, EPA) were the predominant PUFAs and among the amino acids, arginine (0.70 g/100 g) was present in the highest quantity followed by glutamic acid (0.14 g/100 g) and proline (0.14 g/100 g). The histology study of the testis reveals the changes in the cells during the process of spermatogenesis. Histological images demonstrated the different stages of testis maturation of males sampled at the spawning sites. This baseline information generated is of its first kind in hilsa, a transboundary migratory fish in South Asian countries supporting conservation and artificial breeding for commercial production. • Semen of Tenualosa ilisha has significant antioxidant activity. • Antioxidants increase linearly with body weight. • Higher PUFA and specific amino acids indicate their importance in sperm performance. [ABSTRACT FROM AUTHOR]

In this study, for the first time, we profile the actual protein sequences of known and potential allergens of premature hilsa shad (Tenualosa ilisha), an economically important fish of South Asian countries. Proteomics was employed to dissect the muscle tissue proteome collected from the riverine habitat hilsa samples. We successfully identified and quantified >600 proteins wherein many known allergens such as parvalbumins, beta-enolase, and creatine kinases were identified as abundant proteins in muscle tissue. Label-free quantitative proteomics revealed significant differences in the abundance of myosin, dynein, gamma-enolase, creatine kinase B-type, and collagens between the two hilsa samples. In silico analysis determined the allergen potential of these proteins. Notably, our findings indicate that many well-characterized allergen proteins are developmentally regulated in the muscle tissue. Thus, the profiling of a muscle tissue proteome map would further facilitate fundamental and applied research on hilsa fish and greatly improve our understanding of the crucial issue of hilsa customers' nutritional safety. [Display omitted] • First muscle tissue proteome map of Hilsa shad, an economically important fish. • Comparative allergome of immature Hilsa shad. • Actual peptide sequences of Hilsa allergen proteins were identified. • Some allergen proteins are developmentally regulated. [ABSTRACT FROM AUTHOR]

In this research, histological changes of gill and kidney, as a basic and important organ in osmoregulation, during migration from Musa creek to Karun and Bahmanshir rivers was studied. Ten fish from each station of Persian gulf, Karun and Bahmanshir with similarity in biometric of size and weight were collected. After fixation in Bouin's solutions, routine procedure of tissue preparation was done and 6μm sections stained with Hematoxylin and Eosin, studied by optical microscope equipped with a daynolit lenses. The greatest number and area of chloride cells were seen in sea samples but they decreased during migration to Karun and Bahmanshir rivers (p0.05). In kidney, during migration from the sea to the river, the diameter of proximal and distal lumen increased. But in Karun samples, diameter of lumen of distal tubules were higher than others station. Also, there was no significant difference in other tubule between in Karun and Bahmanshir samples. Therefore according to this study, gill and kidney have active participation in osmoregulation. This fish can be a good model for study of osmoregulation in different salinities because of adaptation and response to different environmental salinities in gill that associated with histologic changes.

The gut and flesh microbiome of the national fish of Bangladesh, Tenualosa ilisha , were analyzed using 16S rRNA gene sequencing. Our findings revealed a significant microbial disparity between sample categories and the habitat of hilsa fish, which will serve as a valuable foundation for further comprehensive studies on the hilsa microbiome., Competing Interests: The authors declare no conflict of interest.

The Indian river shad, Gudusia chapra (Hamilton, 1822), is a commercially important freshwater clupeid that contribute to the livelihood of subsistence and marginal fisheries in inland open waters of India and its adjacent countries. The present study was carried out on the growth and mortality of Indian River shad, Gudusia chapra (Hamilton, 1822) based on the commercial length-frequency data collected monthly during October 2014 to September 2015 of a large reservoir located in the border of Jharkhand and West Bengal. The ELEFAN-I (Electronic Length Frequency Analysis) module in FiSAT (FAO-ICLARM Stock Assessment Tools) was used for estimation of growth parameters (L∞, K). The total mortality was estimated following Pauly (ICLARM Fishbyte 2(1):9-13, Pauly 1983) whereas exploitation ratio and maximum sustainable yield were calculated following Gulland (1979). The asymptotic length (L∞) and growth coefficient (K) were estimated as 194 mm and 1.23 year−1, respectively. The species grows to 141.56 and 182.91 mm at the end of the 1st and 2nd years of life. The total natural and fishing mortalities were 6.63, 2.45 and 4.18 year−1 respectively. The value of growth performance index was 2.69. The exploitation ratio (E) was estimated as 0.63. As the exploitation ratio (E) is slightly beyond the optimum, there is likelihood of some threat of overexploitation. Though recruitment was continuous, major pulse was observed during April-May. The present investigation is a first report from Indian reservoir. The maximum sustainable yield of this species was estimated as 485.6 t against the present annual yield of 612.3 t. Avoiding overfishing and wise use of available resources are of prime importance for sustainable fishery management of the reservoir. [ABSTRACT FROM AUTHOR]

A comparative study between pre-juvenile hilsa shad (Tenualosa ilisha) and Indian river shad (Gudusia chapra) using systematics study (morphometric measurements, meristic counts and external morphology) was conducted and significant differences were found between them. The findings of the present study will act as a catalogue to distinguish pre-juvenile hilsa shad and Indian river shad, which ultimately will help to sustain the hilsa population in Indian sub-continent waters. [ABSTRACT FROM AUTHOR]

In the present study, data on total fishing of Tenualosa ilisha have been collected from the Iraqi marine waters and the southern part of Shatt Al-Arab which were landed at Basrah city. The study was conducted during the period from January 2013 to December 2013, from 41 Sampling sites (stations). The total number of landed T. ilisha was 1141671 individuals; the highest numbers of landed T. ilisha were obtained during April and May which were 301598 and 339748 individuals with a percentage of 26.4 % and 29.8 % of the total number of landed fishes, respectively. The total weight of the landed T. ilisha was 560.053 tons and its highest level was obtained during March 81.805 tons, April 151.500 tons, May 169.700 tons, and June 117.900 tons with a percentage of 27.05, 14.6, 30.30, and 21.05 % of the total weight of landed T. ilisha then start to decrease to lowest level in January 300 kg, 0.053 % of the total weight of the landed fish. The numbers of the large sized T. ilisha landed (larger than 24 cm) were 1089896 individuals with a total weight of 545,283. The highest number and weight of the landed fishes at Al-FAO station 185520 individuals, 185.520 tons, and the lowest number and weight was at Al-Behar station was 23686 individuals, 23.686 tons. The total number of fishing trips which were catching T. ilisha during 2013 was 11042 sampling trips. The highest fishing trips were recorded during March (1580), April (1512), May (1670), June (1277), July (1177), and the lowest fishing trips were during December (221 trips). [ABSTRACT FROM AUTHOR]

Conservation payments are increasingly advocated as a way to meet both social and ecological objectives, particularly in developing countries, but these payments often fail to reach the ‘right’ individuals. The Government of Bangladesh runs a food compensation scheme that aims to contribute to hilsa (Tenualosa ilisha) conservation by improving the socioeconomic situation of households affected by hilsa sanctuary fishing bans. Analysing data from a household survey of compensation recipients and non-recipients, we identify the current correlates of compensation distribution and explore perceptions of fairness in this distribution. We find that distribution is largely spatial rather than based on the household characteristics that are supposed to determine eligibility for compensation, indicating political influence in the distribution process. We also find the compensation scheme is widely perceived to be unfair, which could be undermining its potential to compensate vulnerable fishers while improving compliance with fishing bans. The spatial distribution of compensation would shift substantially under alternative targeting scenarios that are likely to improve the cost-effectiveness of the scheme, such as targeting those who are most dependent on fishing for their livelihood. This study highlights a challenge for conservation payment schemes that aim to achieve the dual objectives of poverty reduction and ecological sustainability, particularly large-scale public schemes, and suggests that more effective targeting and transparency about the basis of payment distribution are prerequisites for schemes to be both cost-effective and socially acceptable. [ABSTRACT FROM AUTHOR]

Abstract: The Hilsa shad, Tenualosa ilisha popularly known as ‘Hilsa’, is one of the most commercially important fish species in South Asian countries. The species is widely distributed from the Persian Gulf to Bay of Bengal and ascends into estuaries, rivers and brackish‐water lagoons of the Indo‐Pacific region. Recently, the availability of hilsa has drastically dwindled in aquatic systems across this region, due to anthropogenic pressures, mainly intensive fishing and river obstruction by dams and barrages. Climate change may also be contributing to the declining populations. Hence, there is an urgent need for conservation of the species. In addition, hilsa is of great cultural and economic importance among the peoples of Ganga‐Brahmaputra‐Meghna basin, with very high market demand and increasingly high prices, presently an average of around US$ 12 per kg for consumers both in India and Bangladesh. Many attempts at hilsa breeding and culture have been made across South Asia, particularly in India and Bangladesh, since the 1900s. To date, no breakthrough has been achieved in completing the life cycle in captivity. This review provides an insight into the status of artificial breeding, larval rearing and culture of this species, and identifies research gaps that need to be addressed by future aquaculture development programmes for hilsa in South Asia. [ABSTRACT FROM AUTHOR]

Epidermal sensory structures of adults and juveniles of amphihaline migratory fish hilsa Tenualosa ilisha were studied from two habitats, i.e., freshwater (FW) and marine water (MW). Every year, adults and sexually mature hilsa migrate upstream from marine habitat to riverine freshwater habitat for breeding. This report provides evidences of chemoreception on their upstream migration through several characteristic features on their body, especially on the head and oral cavity. Scanning electron microscopy (SEM) reveals that freshwater adult hilsa (FH) has abundant solitary chemosensory cells (SCCs) on the snout epidermis (around the openings of the epidermal pit) and upper lip, whereas marine water adult hilsa (MH) moderately possesses such sensory structures. The juveniles returning to marine water completely lack SCCs. Immunohistochemical studies revealed the expression of PLC β2 on the snout of FH and tongue of both FH and MH. Further analysis (immunofluorescence, immunoblot and densitometry) of the epidermis confirms the presence of chemosensory structures through strong expression and localization of G-proteins (Gαq and Gα s/olf) from the snout as well as tongue in freshwater hilsa. The SEM also confirms the presence of two types of taste buds in FH, viz. type I (TB I) and type III (TB III). Whereas TB I and TB III are observed on the upper palatine and lips, most of the TB III are located on the tongue region of freshwater and marine hilsa. The juvenile hilsa are devoid of such structures. The presence of dense and rich SCCs and taste sensory cells in adults could be a characteristic feature for strong sensory reception to recognize odour and food-related environmental cues from habitats where they often migrate. [ABSTRACT FROM AUTHOR]

Tenualosa ilisha (Hilsa) is a commercially important food fish in countries around the Bay of Bengal and enjoys high consumer preference for its unique flavor and culinary properties. Fish flavors, an important factor for consumer acceptance are largely characterized by the volatile compounds. Static headspace gas chromatography mass spectrometry was used to investigate the volatiles in hilsa. A total of 41 compounds were identified: 12 alcohols, 1 ketone, 2 aldehydes, 4 furans, 3 acids, 7 esters, 5 alkadienes, 3 alkynes, 3 aromatic compounds, and 1 epoxide derivative. Principal component analysis showed gradual changes in the volatile composition with increasing storage time. The volatile substances present in hilsa which could be contributing to its flavor were identified. 2,4-Pentadiene-1-ol, 3-ethyl-(2Z), and 2,4-hexadienal were identified as possible freshness indicators and 7-Heptadecyne-17-chloro and 2-methyl-1, 5 hexadiene as possible spoilage indicators which could be useful in assessing the quality of the fish. Practical applications Hilsa is a commercially important food fish and is known for its unique flavor and culinary properties; the flavor is perhaps attributed to the volatile compounds present. Hilsa is transported for import/export purpose in large scale in ice packaging, especially in South East Asian countries; therefore, there is a need to access the quality of frozen fish during ice storage, both freshness and spoilage. In this context, the volatile compounds in hilsa could be useful in characterizing its unique flavor as well as freshness and spoilage status during transport/storage. Static headspace GC-MS combined with a statistical multivariate approach could be a useful method to identify volatile compounds and characterize fish freshness and spoilage. As the consumers are now more conscious about food safety and quality issues; freshness and spoilage markers would be useful in quality management in fish trade. [ABSTRACT FROM AUTHOR]

It is envisaged that the influence of river hydrology on the commercial catch of anadromous species in river–estuary systems is very pronounced. We delineate a general framework to quantify the effect of changing river hydrology on the catch of a very unique anadromous species, the HilsaTenualosa ilisha, a shad species that is distributed across the Indo-Pacific region. The Narmada River–estuary system was studied as a representative for the region. Two synthesized factors—migratory habitat availability (factor 1) and migratory habitat quality potential (factor 2)—were derived from five hydrological variables to explain 96% of the variability in the hydrological regime of the Narmada River–estuary system. Based on the proposed autoregressive integrated moving average with explanatory variables (ARIMAX) modeling framework, we found that both factors had significant positive effects. Model-based forecasts of Hilsa catch revealed a decreasing trend in the future if a similar hydrological regime prevails. In a simulated future scenario, a 15% increase in Hilsa catch was predicted to occur in response to a 2% increase in factor 1, considering the last 5 years’ average catch as a benchmark. Some management strategies focused on controlling the hydrological regime are suggested to enhance Hilsa fisheries. Received February 15, 2017; accepted July 1, 2017 Published online October 11, 2017 [ABSTRACT FROM PUBLISHER]

Commitments for sustainable growth often look good on paper but are messy in the practice. The Government of Bangladesh shows huge initiative towards SDG 14 (conservation and sustainable use of marine resources) by establishing measures to improve the stock of hilsa fish in the country, thus ensuring the supply of a valuable and charismatic fish species. Initial reports of the measures are optimistic, suggesting larger sizes of fish caught across the seasons. Bigger hilsa fetches better prices – as high as US$25 per kilo in niche markets. It is conservation business with profits. Yet the costs of these regulations are falling squarely on the shoulders of small fishermen who are poor, uneducated and in permanent debt. The government offers a small in-kind payment for ecosystem service (PES) in the form of rice, which is good but does not compensate for the loss of revenues and household protein during bans. These small fishers have no bargaining power and no voice in the design of policies that affect them. A common problem in policy design is the lack of clarity of the markets they affect, especially if they are informal. This study uses value chain models to unpick the hilsa value chain. It study provides hard data and evidence on processes, power, and profit creation. This consultation can help policy makers design better strategies to re-govern markets in more inclusive ways and help to achieve Sustainable Development Goals commitments. [ABSTRACT FROM AUTHOR]

Knowing the trophic level of marine organisms is essential to understanding their ecological role in the ecosystem and for quantifying the ecosystem effects of fishing to establish effective management of fishing resources. In comparison to other systems, information about the trophic level of marine organisms in the Persian Gulf and Oman Sea is very scarce. Here, the main aim was to estimate trophic level in these areas using all available diet information from different marine species using TrophLab software. The trophic level of 32 fish species was estimated with the available diet data. The trophic level ranged from 2.28 to 4.50. High trophic levels were found for Chorocentrus nudus ( TL = 4.7), Saurida tumbil ( TL = 4.6), Rhizoprionodon acutus ( TL = 4.5), Torpedo sinuspersici ( TL=4.5), Gymnura poecilura ( TL = 4.5), Sphyraena putnamae ( TL = 4.5) and Euthynnus affinis ( TL = 4.5). In contrast, lower trophic levels were estimated for Tenualosa ilisha ( TL = 2.28) and Sardinella sindensis ( TL = 2.92). As expected, a positive correlation was found between the trophic level and body size, indicating changes in the diet due to variations in predatory capacities. The results of this study may be useful in the formulation of trophic indicators and modelling of the ecosystems. [ABSTRACT FROM AUTHOR]

The anadromous fish species Hilsa ( Tenualosa ilisha) constitutes the largest single fishery in Bangladesh and West Bengal, India. River Meghna is the important habitat for Hilsa as the major breeding and nursing grounds are situated along this portion of the river. In this paper, we investigate fishers' perceptions on effect of climate change and anthropogenic impact on Hilsa fishery at lower Meghna. Fishers' ecological knowledge indicates that the stock of Hilsa is declining due to several adverse climatic conditions such as increased water temperature, salinity intrusion and low freshwater discharge from upstream. Fishers believe that dams and polders have immense effect on river sedimentation which already blockade several upward migratory route of Hilsa. Fishers' experience shows that intensity of coastal cyclone is gradually increasing, which causes severe physical and economical damage. The study also indicates that the major constraints to adopt with the change situation are low level of human capital and restricted access to the formal credit system. Therefore, incorporation of local knowledge in governmental policy formulation and public support to improve human skill are essential for the adaptive management. [ABSTRACT FROM AUTHOR]

Tenualosa ilisha, the Indian Shad, is one of the most important commercial fish of the Indo-Pacific region and the Hilsa fishery in India is dependent on this species. Presently, the fishery resource of the species lies largely within the Bhagirathi–Hooghly component of the Ganga River system. The annual fish catch of Hilsa from the Bhagirathi–Hooghly River has fluctuated over the years ranging between 12,733 and 20,000 t between 2000–2001 and 2010–2012. The monsoon migration of Hilsa commences in July and gradually picks up in August. From September onwards, the magnitude of migration to the freshwater system showed a declining trend. Stretches between Nischintapur and Diamond Harbour downstream, Hooghly Ghat and Kalna in the freshwater tidal zone, and Lalbagh to Farakka in the Bhagirathi River have been delineated as potential breeding grounds for Hilsa. The intense fishing pressure in the coastal estuarine zone almost year round, especially in breeding season, adversely affects the breeding migration, spawning, and recruitment success vis a vis overall fishery of Hilsa in the system. There is an immediate need to implement effective conservation measures to protect breeders, potential breeding grounds, and juveniles for the cause of sustainable Hilsa fishery. [ABSTRACT FROM AUTHOR]