Use of RAPD fingerprinting for delineating populations of hilsa shad Tenualosa ilisha (Hamilton, 1822)

RAPD was used to delineate the hilsa populations sampled from the Ganga, Yamuna, Hooghly, and Narmada Rivers at six different locations. Six degenerate primers were used to generate the fragment patterns from the samples collected. All primers were highly polymorphic and generated high numbers of amplification products. Nei's genetic distances were calculated between locations. The overall average genetic distance among all the six locations was 0.295. The Fst value within the Ganga was 0.469 and within the Hooghly it was 0.546. The overall Fst value for the six populations analyzed was 0.590. The UPGMA dendrogram clustered the hilsa into two distinct clusters: Ganga and Yamuna populations and the Hooghly and Narmada populations.     

Ectopic expression of olfactory receptors and associated G-protein subunits in the head integument of the amphihaline migratory fish hilsa Tenualosa ilisha

The chemosensory nature of the tissue from the dorsal surface of the head (also termed sensory pad; SP) of the amphihaline diadromous fish hilsa Tenualosa ilisha was investigated for odorant receptor (OR), olfactory marker protein (OMP) and G-protein subunits (Gαs-olf, Gαq, Gαo, Gαi3) through immunolocalization and immunoblotting techniques. The immunolocalization of OR, OMP and G-protein subunits showed clear expression of these proteins in the tissues of the SP. Robust expressions of these proteins in the SP were detected with immunoblot analysis. The strong expression of these proteins in the SP indicates that the tissues from this area in riverine T. ilisha may play significant role in chemosensing and signalling through ectopic expression of olfactory receptor proteins which are otherwise reported in olfactory organs in vertebrates. Being migratory in nature, ectopic expression of these receptors in T. ilisha probably helps them to prevent damage to epidermal tissues of the SP, or they may also utilize them as a chemo and mechanosensory tool to optimize chemo-communications during migration.     

Hormonal signatures of gonad maturity and seasonality of spawning in migrating hilsa,Tenualosa ilisha

Environmental Biology of Fishes - Identifying the hormonal signature of gonad maturity and spawning seasonality is essential for upgrading the forecast of recruitment, environmental impacts, and...     

High levels of genetic variability and differentiation in hilsa shad, Tenualosa ilisha (Clupeidae, Clupeiformes) populations revealed by PCR-RFLP analysis of the mitochondrial DNA D-loop region

The hilsa shad, Tenualosa ilisha (Clupeidae, Clupeiformes) is an important anadromous clupeid species from the Western division of the Indo-Pacific region. It constitutes the largest single fishable species in Bangladesh. Information on genetic variability and population structure is very important for both management and conservation purposes. Past reports on the population structure of T. ilisha involving morphometric, allozyme and RAPD analyses are contradictory. We examined genetic variability and divergence in two riverine (the Jamuna and the Meghna), two estuarine (Kuakata and Sundarbans) and one marine (Cox's Bazar) populations of T. ilisha by applying PCR-RFLP analysis of the mtDNA D-loop region. The amplified PCR products were restricted with four restriction enzymes namely, XbaI, EcoRI, EcoRV, and HaeIII. High levels of haplotype and gene diversity within and significant differentiations among, populations of T. ilisha were observed in this study. Significant F(ST) values indicated differentiation among the river, estuary and marine populations. The UPGMA dendrogram based on genetic distance resulted in two major clusters, although, these were subsequently divided into three, corresponding to the riverine, estuarine and marine populations. The study underlines the usefulness of RFLP of mtDNA D-loop region as molecular markers, and detected at least two differentiated populations of T. ilisha in Bangladesh waters.     

Anadromy and heterogenous population of a tropical shad Tenualosa ilisha in Malaysia,as revealed by otolith microchemistry and molecular evidence

Tenualosa ilisha was found recently in the Perak River in western Peninsular Malaysia. Molecular phylogenetic and haplotype network analyses suggest that T. ilisha has two genetically distinct populations/groups: (i) Peninsular Malaysia (Malaysia population), and (ii) Peninsular Malaysia, Thailand, India and Bangladesh (Indian Ocean population). The results also suggest that the T ilisha population in Peninsular Malaysia is genetically heterogeneous with a typical anadromous migration pattern.     

Use of RAPD fingerprinting for discriminating two populations of Hilsa shad (Tenualosa ilisha Ham.) from inland rivers of Bangladesh

The Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) was applied to analyze the genetic variation of the Hilsa shad, Tenualosa ilisha Ham., from the two major inland rivers (Padma and Meghna) in Bangladesh. Twenty-eight random 10-mer primers were primarily scored in 8 individuals from each of the two locations. Fifteen primers, which gave polymorphism, were selected and used in the final analysis of 34 individuals from the two sites. Using these primers, 480 scorable DNA fragments were found, of which 98 (20.41%) were polymorphic. By comparing the RAPD banding patterns, variations were found between and within the populations. A dendrogram was constructed with the polymorphic fragments to analyze the genetic distances between the Hilsa shad populations. The results show two major clusters of Padma and Meghna, assuming different spawning populations with different stocks or races of Hilsa shad in the major Bangladesh rivers.     

Some aspects of the Upper Palaeolithic period in Sindh,Pakistan

The study of the Upper Palaeolithic of Sindh is still in its infancy. Although it has slightly improved during the last twenty years, and a few more sites have been discovered in different parts of the province, we are still far from achieving a good knowledge of the sequence of the events that took place during the final stages of the Pleistocene in this region of the Indian Subcontinent. Despite the archaeological importance of the southern part of the country, the Arabian Sea coast in particular, which represents the suggested route followed by Modern Humans to move to India and farther east, most of this territory has not yielded any tangible trace of their passage. The scope of this paper is to update the evidence available for the Upper Palaeolithic of Sindh, and to discuss it within the general framework of the Upper Palaeolithic period of the Indian Subcontinent.     

Diet Composition and Intensity of Feeding of Tenualosa ilisha (Hamilton, 1822) Occurring in the Northern Bay of Bengal,India

Feeding intensity and diet composition of Hilsa Shad (Tenualosa ilisha) from Northern Bay of Bengal were studied between June 2010 and March 2011. The stomach contents of 320 fishes were analyzed from the northern part of the Bay of Bengal to understand the food items of this species. The major constituents of food are organic debris (26.06 ± 5.19 % SD), diatoms (31.22 ± 11.97 % SD), other algae (12.41 ± 2.62 % SD), and crustaceans (3.50 ± 1.28 % SD). The most abundant species of diatoms were Coscinodiscus, Pleurosigma, Bacillaria, Nitzschia, Biddulphia, Diatoma and Asterionella. The stomach of Hilsa was found to be almost empty during June to October while it was almost full during November to March. Significant positive correlation among feeding intensity, chlorophyll-A concentration and salinity of the ambient water indicated that feeding in T. ilisha is influenced by a number of factors. Strong positive correlation between percentage occurrence of diatoms and intensity of feeding indicated their preference for diatom–food.     

Habitat modelling of juvenile Hilsa Tenualosa ilisha (Clupeiformes) in the coastal ecosystem of the northern Bay of Bengal,Bangladesh

Hilsa shad Tenualosa ilisha comprises the largest and most valuable single fishery of Bangladesh. This study was conducted to identify suitable habitats for Hilsa juvenile in the northern Bay of Bengal along the coast of Bangladesh using Geographical Information Systems (GIS) based Multi-Criteria Evaluation (MCE) of water temperature, dissolved oxygen, pH, salinity, turbidity, current, depth and rainfall. Landsat imagery and 8 thematic layers were analyzed with ENVI and GIS capabilities, and developed as a series of GIS models to identify and prioritize the appropriate habitats for Hilsa juvenile. The study covered 29.484 km² water body and revealed that 56% (16.388 km²) is the most suitable, 21% (6.054 km²) is moderately suitable and 24% (7.042 km²) is not suitable which was consistent with field verification. The assemblage of marinebrackish-freshwater ecosystems with favourable ecological parameters and rainfall patterns are very much important for supporting juvenile Hilsa in the study area. The results are useful for habitat-specific sanctuary development as the efficient conservation may lead to higher production of adult Hilsa and increase the economic benefit to the fishers.     

Distribution of molluscs in Layari River (Sindh), Pakistan

Between January 1982 and December 1985, 65 species of Mollusca were collected from the Layari River, an ephemeral stream that bisects Karachi. Gastropods were dominant followed by bivalves. The upstream region is hypersaline and devoid of molluscs; the stretch within Karachi is heavily polluted and almost no living molluscs occur here.     

Evidence of putative sensory receptors from snout and tongue in an upstream amphihaline migratory fish hilsa <Emphasis Type="Italic">Tenualosa ilisha</Emphasis>

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.     

Gestational Anemia and its effects on neonatal outcome,in the population of Hyderabad,Sindh, Pakistan

BackgroundAnemia in pregnancy is a globally health-related issue, that affects both mothers and their newborn. Anemia during pregnancy across the world involves approximately 38% of the world population. To evaluate the effect of gestational anemia on perinatal outcome in the population. The aim of present study is to evaluate the effect of gestational anemia on perinatal outcome in the population of Hyderabad, Sindh, Pakistan.MethodsA cross-sectional comparative analysis was conducted among pregnant mothers who were listed to give birth at Liaquat University of medical and health sciences Jamshoro/Hyderabad during the period of September 2018 to September 2019. The study population 400 were selected by convenient random sampling, and grouped into 2 on the basis of their Hb levels, with Hb < 11 gm% they were classified as anemic mothers, Hb ≥ 11 gm% were termed as non-anemic mothers, data was collected on the preformed questionnaire, and was analyzed on SPSS 21.ResultsThe prevalence of anemia was 51.5% in in total population out of which, the incidence of normocytic normochromic anemia was highest 52.4 %microcytic hypochromic anemia was found in 19.4%, Overall, extremely low Apgar was found in 53 anemics, and 8 non. anemic mother’s infants, LBW incidence was 47.5 %; in anemic mothers, and 15.4 % in non-anemic group, the term, small for gestational age infants were 14.5% in anemic mothers, and 3.6% in non-anemic mothers, there were 36 preterm births to anemic mothers and 10 in non-anemic mothers. The incidence of caesarian section is 53.3% in anemic mothers compared to 30.9% in non-anemic mothers.ConclusionsAnemia in pregnancy significantly increases risks of low Apgar, LBW, term SGA, preterm birth, and an increase incidence of caesarian section.     

Population dynamics in migratory networks

Migratory animals are comprised of a complex series of interconnected breeding and nonbreeding populations. Because individuals in any given population can arrive from a variety of sites the previous season, predicting how different populations will respond to environmental change can be challenging. In this study, we develop a population model composed of a network of breeding and wintering sites to show how habitat loss affects patterns of connectivity and species abundance. When the costs of migration are evenly distributed, habitat loss at a single site can increase the degree of connectivity (mixing) within the entire network, which then acts to buffer global populations from declines. However, the degree to which populations are buffered depends on where habitat loss occurs within the network: a site that has the potential to receive individuals from multiple populations in the opposite season will lead to smaller declines than a site that is more isolated. In other cases when there are equal costs of migration to two or more sites in the opposite season, habitat loss can result in some populations becoming segregated (disconnected) from the rest of the network. The geographic structure of the network can have a significant influence on relative population sizes of sites in the same season and can also affect the overall degree of mixing in the network, even when sites are of equal intrinsic quality. When a migratory network is widely spaced and migration costs are high, an equivalent habitat loss will lead to a larger decline in global population size than will occur in a network where the overall costs of migration are low. Our model provides an important foundation to test predictions related to habitat loss in real-world migratory networks and demonstrates that migratory networks will likely produce different dynamics from traditional metapopulations. Our results provide strong evidence that estimating population connectivity is a prerequisite for successfully predicting changes in migratory populations.