Hilsa Research Articles

On the population characteristics of anadromous Tenualosa ilisha (Hamilton, 1822) occurring from River Brahmaputra, India

Abstract Tenualosa ilisha, commonly called Hilsa, is a highly prized species, which has declined in River Brahmaputra, India. The study was carried out for one year and a total of 1,026 individuals were sampled at monthly intervals. In the study, the following growth parameters were observed: asymptotic length (L∞) = 445 mm, growth coefficient (K) = 0.5 year-1, and age at length zero (t0) = −0.5 year-1. Growth performance index (φ) was estimated to be 2.996. Natural mortality rate, total mortality, and fishing mortality was found to be 0.51 year-1, 1.57 year-1, and 1.06 year-1,respectively. Exploitation ratio (E) was found to be 0.675, which indicates that the species is slightly over-exploited. It was seen that length groups that represented the catch in the Indian part of River Brahmaputra comprised fishes of 0–4+ years age. The present study was carried out to assess the population characteristics of this commercially important species from the Indian part of Brahmaputra River, which will contribute towards sustainable fisheries management.

Bioaccumulation of heavy metals in fish and shellfish from Rupsa River, Bangladesh, and risk assessment for human

Spatial variation of Pb, Hg, Cr, Cd and As concentrations between up- and downstream fish (river shad Tenualosa ilisha, silver jewfish Otolithoides pama) and shellfish (black tiger shrimp Penaeus monodon) collected from Rupsa River of the south-west coast of Bangladesh was studied in order to assess the potential health risks in human. Samples (n=18) were collected representing 3 species from two locations of the river system and muscle analyzed for heavy metal concentration. Mean concentration of the elements was significantly higher (p<0.05) in the downstream samples compared to those of the upstream with a high concentration in benthic fauna and interspecific variation at a trend: black tiger shrimp > Hilsa shad > silver jewfish and distribution As>Cr>Hg>Cd>Pb. Bioaccumulation of As and Hg was correlated well with fish size although their concentrations were well below the international legislation limits set by WHO and FAO. For potential human health risk, the estimated daily intake (EDI), target hazard quotient (THQ) and total target hazard quotient (TTHQ) for non-carcinogenic risk suggest that most of the values were within the acceptable limits for all species expect As. Besides, the carcinogenic risk (CR) values indicate less prone to cancer risk yet CR values of Cd and As in both black tiger shrimp and Hilsa shad were close to the unacceptable range.

Reproductive potential and histological profiling of the wild female anadromous shad (Tenualosa ilisha) in lower Meghna Estuary, Bangladesh

Hilsha shad (Tenualosa ilisha, Hamilton 1822) is the most commercially important and national fish of Bangladesh, belongs to the family of Clupeidae of the Clupeiformes. The study was conducted to identify the seasonal gonadal cycles through histological study and the peak breeding season combining histological and Gonado Somatic Index (GSI). One hundred and twenty fish samples with an average weight of 756.75±6.25 g was collected from the Tentulia river for the study throughout the year. Monthly mean GSI values of females ranged from 6.36±0.69 to 15.02±1.33. The lowest mean GSI value was found in December and the highest GSI value was in October. From the histological observation of the ovary, early perinucleolar stage, late perinucleolar stage, yolk vesicle stage, yolk granule stage, pre-mature and mature stages were identified. The highest percentage (75%) of mature oocytes and peak breeding season were observed in October and the breeding season continues from October to November. These results will be helpful for fishery managers to impose adequate regulations for sustainable fishery management in Bangladesh.

Assessing growth performance and survival of wild shad Tenualosa ilisha fry in two earthen ponds with different feeding regime: A new insight for conservation

The present study describes the rearing and growth performance of Hilsa (Tenualosa ilisha) fry in experimental trial performed in earthen pond ecosystem located adjacent to river Rupnarayan for developing in-situ rearing protocol of fry collected from the wild sources. The seed was collected during May, 2020 from the river and stocked in two different rearing ponds. One of the ponds was provided with artificial feed and another fed with chicken offal to raise the production of zooplankton. Routine monitoring of water and soil quality parameters as well as other biotic communities like plankton was performed to understand the dynamics of ecological conditions in relation to changes in length and weight. The results of PCA between sediment quality and specific growth of fish indicated the strong positive loading of available nitrogen, available phosphate and free calcium carbonate, while moderate positive loading was observed with percentage of silt. Interestingly, it is observed that survivability rate of fish was approximately 80% in both the ponds. The results indicated natural growth fish was considerably well in both the experimental ponds. However, higher growth of juveniles were observed in the pond 2 with higher phytoplankton density (9120cells/L) than pond 1 having lower phytoplankton density (920cells/L) at the end of the experiments. The water quality parameters were comparable in both the experimental ponds. Based on this study it is evident that plankton (especially zooplankton) has induced better growth in pond 2 and possible incorporation of live feed along with formulated feed might trigger better growth of the stocked Hilsa. The present study provides new insight in developing field based approaches for successful rearing and conservation of threatened Hilsa in Indian waters.

Praniza (Isopoda: Gnathia) Parasitic on Gills of Arabian carpetshark Chiloscyllium arabicum with Notes of its Occurrence on some Marine Fishes of Iraq

Praniza larvae of Gnathia sp. were reported on the gills of 18 Iraqi sea fish species. Hosts were eight elasmobranchs and 10 teleosts. Cartilaginous hosts belong to four families, with highest mean prevalence was 100% in Pastinachus sephen, while the lowest prevalence was 25% in Gymnura poecilura. Teleost hosts belong to seven families, the highest prevalence was 50% in Rabdosargus haffara and the lowest was 1.6% in Tenualosa ilisha. The higher mean intensity of infection was 12.3 in Chiloscyllium arabicum, and only one in all teleost fish species. Praniza parasite of C. arabicum has long body, concave cephalon, narrowing anteriorly with truncate frontal margin, the compound eyes large, pleotelson triangular, uropods have endopods not extending beyond the end of the pleotelson.

Review of the validity of scales to estimate age, growth, life history and maturity schedule of Hilsa shad Tenualosa ilisha(Hamilton, 1822)

This study reviewed the validity of using the scales of Hilsa Shad (Tenualosa ilisha) and other migratory species as a tool to estimate age, growth, maturity schedule and migration. Hilsa Shad scales were used long ago, and proved in several studies. Most of these studies showed that scales could give valuable information, which could be used as benchmarks in the study of fisheries and plans for future successful management policies. Bt it needs Patience and precision for the extraction of these information, because of difficulties in reading these scales. The work need to study the sufficient number of scales and practice, to be easily. As a result, this study will open doors that were closed for decades to set new migration study tools for Hilsa Shad in Iraq.

Genetic Indications for Anadromous Hilsa Shad (Tenualosa ilisha) in Shatt Al-Arab River Using mtDNA Cytochrome B Gene

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.

Review of the validity of scales to estimate age, growth, life history and maturity schedule of Hilsa shad Tenualosa ilisha(Hamilton, 1822)

This study reviewed the validity of using the scales of Hilsa Shad (Tenualosa ilisha) and other migratory species as a tool to estimate age, growth, maturity schedule and migration. Hilsa Shad scales were used long ago, and proved in several studies. most of these studies showed that scales could give valuable information, which could be used as benchmarks in the study of fisheries and plans for future successful management policies. Bt it needs Patience and precision for the extraction of these information, because of difficulties in reading these scales. The work need to study the sufficient number of scales and practice, to be easily. As a result, this study will open doors that were closed for decades to set new migration study tools for Hilsa Shad in Iraq.

Comprehensive Overview of Nutritional Values of Tenualosa ilisha with Emphasis on Vitamin, Amino Acid, Fatty Acid and Mineral Composition

Tenualosa ilisha (T. ilisha) is one of the most important tropical fishes in the Indo-Pacific region. It ranks first among edible fishes because of its exquisite taste, delicate culinary talents, and remarkable taste. Available literature of T. ilisha was collected from Google Scholar, PubMed/Medline, Science Direct, Scopus, Wiley Online Library, and Web of Science search engine. T. ilisha is a large tropical fish comprising amino acids, minerals, and lipids, especially polyunsaturated fatty acids (PUFA). The fatty acid, i.e., ɷ-3 and ɷ-6 fatty acid acquired from T. ilisha, plays a crucial role in curbing cardiovascular disease, rheumatoid arthritis, dementia, and other neurological disorders. T. ilisha is enriched in essential minerals such as Na, K, Ca, and Mg and vitamins like A, D, E, and K, which are fat-soluble. This review highlights the proximate compositions, minerals, vitamins, fatty acids, and amino acids of T. ilisha (fresh). The outcome of the present studies signifies that T. ilisha benefit human health for their high nutritional value.

Role of tide and lunar phases on the migration pattern of juvenile Hilsa shad (Tenualosa ilisha) within a meso-macrotidal estuary.

Tide and lunar phases often influence the behaviour and life cycle of different fishes, especially migratory species. In the Hooghly River estuary, Hilsa shad is an anadromous fish species that migrates from the adjacent sea to the estuary and rivers for spawning. After spawning, the juveniles remain in the rivers and estuary for few months then start their downstream migration towards the adjacent sea. However, the pattern of their downstream migration has not been studied in detail so far. This study investigates the role of tide and lunar phases on the juvenile Hilsa shad migration pattern. In this study, we have estimated the rate of juveniles migrating through the river channel (no. m-2 h-1 ) during high tide and low tide in all of the lunar phases. The number of juvenile Hilsa shad fishes is found to be much higher during low tides in most of the observations and there is a significant difference (t=11.904, P < 0.001) between the high tide and low tide catches in the entire study region. Among the eight lunar phases, the number of juveniles is also observed to be higher during the new moon and full moon, and there is also a significant difference in juvenile catch among the lunar phases (F=64.372, P < 0.001) in the entire stretch of the study area. These observations enabled us to develop a plausible mechanism of the downstream migration of Hilsa shad juveniles.

Status and potential of ecosystem approach to fisheries management (EAFM) in Bangladesh

The vulnerability of coastal and marine ecosystems provides strong arguments for the adoption of the ecosystem approach to fisheries management (EAFM) which incorporates both human and ecosystem well-being with good governance practice. The objective of this study is to investigate the present status, future potentials for the development of a framework of the EAFM for the sustainable coastal and marine resource development of Bangladesh. Using both primary and secondary sources of information, this study has found that some levels of EAFM are already in practice to some extent in some specific coastal river ecosystems along the hilsa (Tenualosa ilisha) sanctuaries for the protection of juvenile and brood hilsa, but often not implemented and managed in an appropriate planned and objective way. There are some signs of ecosystem well-being for a few fisheries but some levels of deterioration of the ecosystem have been noticed as well. It is unclear how this ecosystem well-being in one hand and its continued interruption and deterioration in another hand interact and affect human well-being for making a resilient society in the fishing communities. The EAFM has great potential to improve both the ecosystem and human well-being in the coming years as well as to contribute to the blue economy and achieve some SDG targets. However, how the ecosystem's well-being will be translated into social well-being will depend on the efficiency of governance, particularly maintaining inclusiveness and equitable benefit sharing among resource users.

Stable isotope on hilsa shad (Tenualosa ilisha) otoliths revealed migratory behavior of a population found in Hooghly River, West Bengal, India

Stable isotope on hilsa shad (Tenualosa ilisha) otoliths revealed migratory behavior of a population found in Hooghly River, West Bengal, India

Conservation of genetic resources for sustainable aquaculture

Conservation of genetic resources for sustainable aquaculture

Assessment of Arsenic (As), Lead (Pb) and Chromium (Cr) Accumulation in Different Organs of Commercially Important Fish Species Collected from Chattogram Coastal Region of Bangladesh.

Aims: The purpose of this study was to evaluate whether there are any significant toxic effects of the widely exposed metals on different organs (gill, liver, kidney, and muscle) of some commercially important marine fish species (Herpodon nehereus, Pampus chinensis and Hilsa ilisha).&#x0D; Study Design: The collection of the samples was done from January to March 2018 from Bay of Bengal near Chattogram city of Bangladesh. The study is based on randomly collected samples from the intended sampling sites (Randomized Block Design) to ensure the evenness and unbiases of the collected samples.&#x0D; Methodology: Analyses were performed for metals such as arsenic (As), lead (Pb) and chromium (Cr) using Atomic Absorption Spectrophotometer (AAS). During each month, five individuals each with three replications from the three targeted species were collected, with a total of 135 (45*3) fishes in the study period.&#x0D; Results: The concentrations of the metals found in the fishes varied in the following ranges: As: 0.029-0.071 ppm, Pb: 0.008-0.083 ppm and Cr: 0.0001-0.03 ppm. The obtained result revealed the highest concentrations of all three metals were recorded in H.nehereus fish. The organ wise lead concentration was recorded highest in kidneys and gills of examined fishes with significant variation in muscles and liver. The scenario depicted quite differently in case of chromium where concentration in gills was found to be the highest with insignificant variation in accumulation in other three organs. In case of Arsenic, kidneys and livers were the most exposed two organs in comparison to significant exposure to muscles and gills. The obtained values of arsenic accumulation were considered critical for human consumption as it was higher than the recommended values stated by WHO and FAO; but the concentration of lead and chromium were found to be safe for human consumption. The values recorded for lead were increasingly approached to the safety values.&#x0D; Conclusion: So, crucial steps should be taken regarding safety and environmentally friendly discharge of arsenic and lead; high levels of pollution will not only affect aquatic life but will also invite socio-economic disasters.

Organ-specific accumulation of toxic elements in Hilsa shad (Tenualosa ilisha) from Bangladesh and human health risk assessment

Purpose: We aimed to determine the amount of some toxic elements in three organs of Hilsa shad, focusing on the possible exposure to human health through Hilsa consumption. This study was designed to determine the concentration of seven toxic trace elements (As, Cd, Cr, Cu, Ni, Pb, and Zn) in three distinct organs (n = 21) (muscle, liver, and gills) of Hilsa shad (Tenualosa ilisha) fish collected from the Bangladeshi coastal area. The samples were digested following a microwave digestion. Inductively coupled plasma mass spectrometer was used as analytical instrument. Estimated daily intakes (EDI) and target cancer risk (TR) were used to evaluate carcinogenic and non-carcinogenic risk. Results: The mean concentrations (mg/kg-wet weight) of toxic elements in different organs of T. ilisha were determined as follows: in muscle, As (4.05), Cd (0.09), Cr (0.12), Cu (0.77), Ni (0.26), Pb (0.20), and Zn (10.64); in liver, As (2.83), Cd (0.84), Cr (0.18), Cu (6.17), Ni (0.55), Pb (0.23), and Zn (30.16) and in gills, As (3.45), Cd (0.05), Cr (0.08), Cu (1.06), Ni (0.51), Pb (0.78), and Zn (35.21). The liver showed higher concentrations of most elements than that of muscle except for As. Concentration of As, Cd, and Pb in the fish were found above the food safety guidelines, while other trace element concentrations were below the permissible range for human consumption. According to EDI and TR values, there were carcinogenic and non-carcinogenic risks from exposure to total As concentration from Hilsa fish consumption. Conclusion: This study suggests that the toxic trace elements contamination levels in Hilsa fish from Bangladesh’s coastal area need to be monitored on a systematic and regular basis to ensure the safety of this food item for human consumption.

Food spectrum dynamics of anadromous Hilsa, Tenualosa ilisha (Hamilton, 1822) inhabiting River Brahmaputra, India curtailing apprehension of food selectivity: An insight into its domestication

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.

Modeling of Hilsa (Tenualosa ilisha) landings in the lower stretch of Brahmaputra River (Assam, India) under time-series framework

Modeling of Hilsa (Tenualosa ilisha) landings in the lower stretch of Brahmaputra River (Assam, India) under time-series framework

Nature, extent, and causes of post-harvest losses at fisher and farmer level: An in-depth study

Post-harvest loss (PHL) in fisheries and aquaculture is critical because of its impact on welfare and economic growth. However, precise estimations of PHL are more challenging in developing countries, mainly due to poor data as well as unorganized landing points and markets. This study estimated PHL at the fisher and farmer level, applying the questionnaire loss assessment method (QLAM) and drawing from random interviews with 2582 fisherfolk, covering 446 markets and 202 inland capture and aquaculture fish species in Bangladesh. The estimated post-harvest loss in quantity and monetary value was 20.83 kg/ton (i.e., 2.08%) and $82.45 per ton in inland capture and 6.84 kg/ton (i.e., 0.68%) and $20.90 per ton in inland aquaculture. Thus, the country is losing about $102 million (25,740 tons) from inland capture at the fisher level and $52 million (17,022 tons) from aquaculture at the farmer level. Market loss was higher than physical loss for both inland capture and aquaculture. River fish and pond fish experienced higher losses as inland capture and aquaculture species respectively. However, estimated post-harvest losses were higher for hilsha (Tenualosa ilisha) and puti (Puntius chola) in inland capture and for rui (Labeo rohita) and mrigel (Cirrhinus cirrhosus) in inland aquaculture. Delayed selling, high temperature, and excess supply were critical causes of physical and market losses for both inland capture and aquaculture. Adoption of modern harvesting technologies and the improvement of storage capacity at landing and selling points are recommended for reducing post-harvest loss of inland capture and aquaculture species.

Juveniles and larvae of eleven fish species collected from three countries of the Arabian Gulf and the Arabian Sea

The finding of larval and juvenile specimens from the Omani coast of the Arabian Sea and the Arabian Gulf waters of Saudi Arabia and Iraq is reported for the first time. Based on available information, one larva was a leptocephalus, Conger sp. (family Congridae) and one larva of an acronurus stage belonging to the genus Acanthurus (family Acanthuridae). Also juveniles of the following families are included in the present study: Clupeidae – Tenualosa ilisha (Hamilton, 1822) and Nematalosa sp.; Dactylopteridae – Dactyloptena orientalis (Cuvier, 1829); Gobiidae – Acentrogobius sp.; Bothidae – Arnoglossus aspilos (Bleeker, 1851); Scatophagidae – Scatophagus argus (Linnaeus, 1766); Sparidae – Acanthopagrus arabicus Iwatsuki, 2013 and Sparidentex hasta (Valenciennes, 1830); Tetraodontidae – Lagocephalus sp. The discovery of the barred rather than spotted juveniles of S. argus collected from pure freshwater environment of the Shatt al-Arab River, Basrah, Iraq was remarkable; it raises questions whether there is more than one species within the nominal S. argus. For both larvae and juveniles of bothid flounders, the olfactory organ is a useful character for the examination of the developmental stage of the metamorphosing specimens. The occurrence of the different early life history stages of fishes from the three Arabian countries shows the needs them to be studied further so that inferences about the areas and periods of spawning and development of these fishes can be made more accurately.

The Low Flow Assessment of Padma River in Bangladesh

Low flow or Environmental Flow (EF) assessment is vital to ensure the river and ecosystem remain healthy. Both natural and human interventions might alter a river. Therefore, this study presents EF requirements of the famous Hilsa breeding center in the Padma River, Bangladesh, by applying the Hydrologic Engineering Centers River Analysis System (HEC-RAS) for discharge and water surface levels simulations at different stations. The frequency analysis of 20 years of historical data, spanning 2000-2019, used the Log-Pearson Type III (LP-III) distribution method, while the one-dimensional unsteady flow simulation was performed for the last 10 years (i.e., 2012-2019). Subsequently, the HEC-RAS simulated water level values reasonably correlated with the field observations at four stations, namely Baruria Transit, Mawa, Tarpasha, Sureswar, with Coefficient of determination R2=0.86, 0.83, 0.92, and 0.74, alongside simulated minimum water surface levels of 1.57 m, 0.37 m, 0.30 m, and 0.27 m, respectively. Also, the Baruria Transit and Mawa had simulated flows that reasonably correlated with the field observations at R2=0.70 and 0.61, with a simulated minimum flow of 3849.51 m3/s and 3789.14 m3/s, respectively. The minimum flow according to the frequency analysis was 4017 m3/s, 3685 m3/s, 3449 m3/s, 3229 m3/s, and 3113 m3/s at Baruria Transit and 3304 m3/s, 2781 m3/s, 2438 m3/s, 2141 m3/s, 1992 m3/s at Mawa station in 5, 10, 20, 50 and 100 years return periods, respectively. This study overlooked to report the ongoing investigations into the water quality issues. Thus, this study is expected to guide the required EF quantity towards a healthy Hilsha fish habitat and surface water source for drinking purposes in this studied river. The stated method is also applicable to other similar rivers around the world.