40 research outputs found
The life cycle of green tiger prawn in the northern part of the Iranian water, Persian Gulf Phase 1: the identification of migration route and determination of the spawning areas and nursery grounds
Shrimp fisheries in the Persian Gulf have a long history. Since 1960 trawl fishery for Penaeid shrimp developed in the middle part of the northern coasts of the Persian Gulf (Bushehr waters). From 1998 to 2004 landing of shrimp have fluctuated between 480t and 2700t per year. The major species of penaeid shrimp (more than 80 percent) in the Persian Gulf and Bushehr waters is Penaeus semisulcatus. More than 2000 vessels and 33000 fishermen in Bushehr area were involving of shrimp catch (August and September) in study area in the recent decade. This species has an economical important role in the region. The present study was carried out in Bushehr coastal waters from 2003-2005. This study are described the bio-dynamic and life history of Penaeus semisulcatus in Bushehr area. Monthly samples of shrimp were collected by R/V LavarII from January 2003 to March 2004 for 15 months in 50 fixed stations. The carapace length frequency data were used to estimate the growth, mortality and exploitation rates by FiSAT program for males and females. The Von Bertalanffy growth parameters were estimated as K = 1.6 Year-1 and 2.2 Year-1 and L = 38mm and 50.4mm for male and female respectively. The results of mortality rates for males are Z = 6.4 per year F=4.3 per year and M = 2.11 per year. These results for female are Z = 8.2 per year, F=5.8 per year and M 2.41 per year. The exploitation rates for male and female are E=0.67 and E = 0.70 respectively. Relatively high values of total mortalities and exploitation rates were obtained which indicate that this species is overexploited. The maximum age was calculated 15 months for females and 18 months for males. Gonad maturity results were shown, the major spawning periods of green tiger prawn in the study area is in winter and early of spring and also there is a minor peak in autumn. Therefore two peaks of spawning were happened during this study. These periods are the main rainy seasons in the Bushehr area. The size at 50 percent mature (L50%) is 40.6mm and less than 5% of females were smaller than 24mm CL. Mature shrimps were aggregated in 20-30m depth of middle and southern part of study area. Imam Hassan, Genaveh and Helleh areas were the most important spawning grounds in Bushehr waters. The sex ration (male/female) of 0.84 was found during study period. This ratio was calculated in different months and the number of females were increased in spawning months. The number of 2571 shrimp were tagged and released by a green color polyethylene steamer tag during 15 months of survey and also before shrimping season (June and July) in 2005. The recaptures were done in two shrimp seasons in August and September 2004 and 2005 and 68 tagged shrimp recaptured that 4 recaptures were omitted due to inconsistencies information. Maximum recapture depths were 16-20m and 26-30m for males and females respectively. The majority of shrimp had a speeds of less than 2 Km/day, but maximum speed was recorded 3-4 Km/day in males and 2 Km/day in females. Only 10 percent of shrimp moved more than 50Km in study area and majority of shrimps, about 70 percent, were recaptured within 20Km of released area. The maximum recorded distance was 127Km after 95 days liberty in a female shrimp, but another female shrimp had only 20Km movement after 381 days and it was the maximum time between release and recaptured date. Tagged shrimp mostly moved to the northern part (Bahrekan area) of study area and recaptured shrimps pattern described stronger movement to the deeper waters. In the shallow waters of study area, sampling of juveniles of P. semisulcatus was carried out from July 2003 to March 2005. The survey was done after spawning months of this species and sampling were carried out in July, November and December 2003 and January, February, April, June, July 2004 and February and March 2005. Some stations in less than 10m depths were trawled by a small boat, equipped with a small beam trawl and the prawns (P. semisulcatus) less than 15mm carapace length were collected as juvenile. In this study 748 individuals shrimp were collected during study period. These juveniles were observed in July and November 2003 and April and June 2004. The carapace length of juveniles ranged from 3mm to 15mm and minimum of mean of carapace length were 4.5mm in November and maximum 9.6mm in July. The juveniles were observed around southern part (Mottaf) and middle part (Helaileh) of vegetated sites. A few juveniles were observed in non-vegetated areas. In the nursery grounds 47% of marine organisms were included other species that Sparidae, Platycephalidae, crabs, shells and other penaeid shrimp species such as Metapenaeus af inis and M. stebbingi were observed in nursery ground of green tiger prawn. Very few juveniles were caught during the colder months and seasonal abundance of juveniles was observed in the warmer months. Present study was shown that mature shrimp are dominant from December till March and juvenile stages were mostly observed in April to July. Spawning was occurred through the year, with two peaks minor in autumn and major in winter and spring. Fishing activity should be controlled in spawning and nursery ground of shrimp
Monitoring green tiger prawn stock in Bushehr Province waters
The results of 30 months of trawl sampling on P. semisulcatus, De Hann 1848, obtained through operational phase of MONITORING GREEN TIGER PRAWN RESOURCES project, along with results of another available 28 months of the data of the same structure prior to this, has formed an invaluable time series of data as a proper basis for the further analysis. The survey area is located at North-west of the Persian Gulf from Bahrekan to Dayer waters. The ultimate goal of this study is to come to a better understanding of behavioral pattern of Green Tiger Prawn in its exploited phase after recruitment to the fishery. In this study, the confirmation of the life cycle of P. semisulcatus, to the general life pattern of Penaeidae shrimps was observed. Of the peculiarities of this pattern are the yearly bi-modal spawning and two corresponding peaks of recruitment. There exist two spring and autumn generations, which the major spawning in autumn produces the main recruitment in summer and the autumn generations stem from spring spawning. The spatial and temporal distribution of shrimp is highly variable by month and year. Depending on the year, higher shrimp densities are often found in early summer between Lavar and Rostami and/or Rostami to Bushehr and extend north and south in August. This result can be used in better design of sampling scheme for nursery studies. The main recruitment, which the fishery is depended upon, is in July to August and a second one occurs December-February. The timing and strength of both recruitments vary inter-annually. The proportion of prerecruits in southern area is always higher and the modes more prolonged than in northern area. The period of major recruitment starts earlier and lasts longer in the south than the north. A consistent pattern is not seen for the secondary recruitment, which, usually occurs in December-January. It is hypothesized that 1- the secondary recruitment might occur in Kuwait and/or Saudi Arabia waters, 2- insufficient number of spawners in spring or 3- high mortality in summer could cause the weakness of secondary recruitment. The spatial distribution of the mature female shrimps in spawning months indicates that the northern part of study area is an aggregation ground. It is also found that this aggregation grounds are close to two main fresh water sources (Helleh and Mond rivers), and these phenomena can be somehow related. The average length at 50% maturity varies inter- annually and is estimated to be 15.3 Cm. Length-frequency distribution of shrimps by sex reveals 1 to 3 modes depending on the month and year. In southern part a more complicated and less consistent pattern of recruitment and growth between years was observed. There is multiple or/and continuous recruitment especially during summer months. The von Bertalanffy growth parameters were estimated. The Findings are used to design new sampling schemes to cover the whole life cycle of this species enabling one to explain the variations in their response to the environment and fishery. The results of this study, lead us in building appropriate assessment and management models
Physico-chemical parameters and aquatic investigation in Tajan River and identification of effects on destroytion its
This project was carried out for one year in 1994-1995. Tajan River originated from Alborz Mountain and passes from sari city, and then entered into Caspian Sea. In this study 14 physical and chemical factors surveyed. This survey demonstrated that water quality in milk factory and kilka factory was more than standard. With utilization of water in agriculture period and dry of river, caused to increasing of chloride, total hardness, Ca^++, Mg^++ in estuary. This issue obtained to mixture of fresh water and saline water in estuary. In the survey of the river phytoplankton, 92 species identified that belong to 41 genus and five phyla. The Chrysophyta has more variation and density. Zoo plankton of river included in Protozoa, Rotaria, Cladocera and Copepoda, also the meroplankton such as Lamellibanchiate and Cirripedia observed. The high species variation is relative to protozoa but copepoda has high density and biomass. The five classes of zoobenthos observed in Tajan river such as Bivalvia, Crustacea, Arachnoids, Oligochaeta and insecta. The insecta class has six order and 22 families that Diptera order from insecta class has high variation. The river fishes are belonging to 23 species, 18 genus and eight families. The highest variation observed in station 4 in estuary that 17 species identified in this area. Ths seasonal stations situated in tributary river, station 5 (Zarem rood) has high variation and station 7 (Khormabad river) has important for salmo truta fario habitat
Study on environmental of Litopenaeus vannamei (Boone, 1931) ponds culture with brackish water of Caspian Sea
Different studies on Litopenaeus vannamei (Boone, 1931) has performed in Iran, but less noted in water quality conditions. Water quality, in addition to creating optimal environment for the growth of vannamei shrimp, as well as cause the live food production and improve economic performance are produced. This study was conducted to evaluate the water quality environment vannamei shrimp in the south of Caspian Sea (Mazandaran province) and in the Caspian Ecology Research Center. The results showed that the enrichment of water out of the ponds, can provide favorable conditions for water quality in the culture of vannamei shrimp with different densities. As a result, Mazandaran province environmental conditions (particularly temperature and salinity of the Caspian Sea) has perfectly suited for optimal growth vannamei shrimp. Therefore, vannamei shrimp (PL12) achieved a final individual weight of 21.1gr in a period culture of 85-day with a density of 35 ind/m^2. Also, The nutrients and water quality parameters (Temperature: 27.4±1.79 ° C, Transparency: 10.7±1.2 cm, Salinity: 10.57±0.78 psu, pH: 8.42±0.38, Dissolved Oxygen 8.04±1.35 mg per liter) were within normal limits during the culture period
Evaluation of stocking density vannamei shrimp Litopenaeus vannamei (Boone, 1931) in culturing with brackish water of Caspian Sea
Recently, the development of aquaculture has focused on the use of seawater, because of freshwater crisis in the world. Whiteleg shrimp (Litopenaeus vannamei) is one of the most important species for aquaculture development, because of tolerance and adaptation to different ecological conditions. One of the advantages of species in aquaculture, compatibility status is dense in the rearing period. In this study, the effect of different densities (45/m^2 , 50/m^2 , 55/m^2 and 60/m^2 ), of primary stock whiteleg shrimp postlarvae (PL12) on the growth and survival rate were evaluated. Brackish water (10.52±0.43 ppt) was providing from Caspian Sea. The experiments were performed in 12 circular concrete pond with a sandy bed (area: 78m^2 ) in four treatments and three replications for each treatment. The experiments performed in a 75-day period. In this study, the water temperature was 27.4±1.79°C. The results showed statistically difference in growth parameters and survival rate among experimental treatments (Duncan test, P<0.05). Therefore, with high levels of density, has decreased the amount of weight gain and survival rate (SR), specific growth rate (SGR) and average daily growth (ADG). In addition, the treatments were different variations of FCR (P<0.05) and not depend on the primary stock density of postlarvae. In low density (45/m^2 ) were observed the highest growth (SGR=11±0.04 and ADG=0.25±0.01 gr/day/ind.), survival rate and calculate the amount of production per 78m2 equal 43.6±3.3kg (5596±433kg/ha). Therefore, It is possibility that there is commonly increasing primary stocking of density about L. vannamei postlarvae culture in Iran
A comparative study of plankton and pelagic fishes in the southeast Caspian Sea (Mazanderan-Goharbaran)
Region South East of the Caspian Sea (area Goharbaran) having valuable resources biological flora and fauna, the diversity of commercial fishes, especially reserves the exclusive sturgeon as well as reserves abiotic such as oil and gas resources and transit of goods through Bandar Amirabad to Central Asia , the ecological conditions for the implementation of the project is very necessary. The aim of this study was to determine species composition, spatial and temporal distribution of plankton and fish of this region. Plankton sampled from different depths (5, 10 and 15 m) were carried out. Sampling of phytoplankton did by Ruttner and sampling of zooplankton did by net with mesh size 100 microns. The fish were sampled monthly from December 2013 to July 2014 and within months was carried out. From livestock gill Monofilament.. In this study, a total of 130 species of phytoplankton of 7 filums Bacillariophyta (60 species), Pyrrophyta (23 species), Cyanophyta (22 species), Chlorophyta (14 species), Euglnophyta (9 species), Haptophyta (1 species) and Chrysophyta (1 species )and 24 species of zooplankton branch of Copepoda (5 species), Rotatoria (7 species), porotozoa (3 species), Cladocera (9 species), and Meroplankton (2 species) of larvae of Cypris Balanus and bivalves Lamellibranchiate larvae and 256 fish Acipenser persicus at 5, Alosa braschnikowi 71 number, Alosa caspia 40 number, Benthophilius lipidus 1 number, Cluponella cultriventris 72 number, Cyprinus carpio 1 number, Liza saliens 15 number, Neogobius bathybius 1 number, Neogobius caspia 5 pcs, Neogobius flauviatilis 19 number, Neogobius gorlab 6 number, Rutilus kutum 14 number, Rutilus rutilus 2 pcs, vimba vimba 4 number was observed.Different ecological conditions appointment dietary needs and relationships of organisms and their adaptations to the environment, the density and distribution of different species of phytoplankton, zooplankton and fish specifies.Also the Caspian Sea due to the type of biological species and number of endemic species (42%) in addition to comb jelly invasion, were force of the effects some species like Gloeotrichia Echinulata and as a result, now or in the future, more species will be observed and recognized will be of most interest. Also Psedonitzschia seriata ability to produce Domick acid that can be hazardous to aquatic animals and even human, was in Goharbaran area. This was considered for fishes of the southern Caspian Sea and ecological distribution of most species depends on the region. The abundance of two species of whitefish and pelagic fish in Ghahrebaran region is more than the whole Caspian Sea. On the other hand, the dominant phytoplankton of this region is Bacillariophyta and dominant zooplankton is Copepoda, which shows the goodness of these plankton branches, and by changing the various factors as the different terms of receiving solar energy and resulting in temperature and water currents can cause seasonal differences in the density of the Bacillariophyta branch and also the Copepoda, therefore one of the most important factors is season, and in the winter, when the aquatic rotation of this ecosystem increases, it increases the nutrients and moves it from the floor to the water column, and as a result, increasing the amount of silica in various levels of water can affect the nutrition of fish
The survey on growth and survival larvae of different generation of Litopenaeus vannameiu
In the present Shrimp industry Has become a huge industry . The shrimp culture in Bushehr province began with Penaeus semisulcatus and Fenneropenaeus indicus and with introducing Litopenaeus vannamei in Iran Was known as a culture species. The shrimp production rate in IRAN is about 23000 metric ton. Outbreak of Various diseases and Biosecurity are most important things to produce Specific Patogen Free (SPF) shrimp. In this regard, production of SPF shrimp is The main requirements of shrimp industry. The survey on growth and srvival larve of different generation of Litopenaeus vannamei project was carried out in 2013 and 2014. Broodstock selecting, propagation, culture and shrimp generation Was performed in 2012 until 2014.In 2014 we produced 4300 pieces of prebroodstock with 22.38 gram and 86 percent survival rate after 120 days of culture
Supply and protected different population of Litopenaeus vannamei subadult zero foster (F0) from difference provinces Iran
Nowadays, Litopenaeus vannamei are the most important species of farmed penaeidae shrimp in the world that is rapidly replacing native species in areas aquaculture. Due to demand increase for this species culture, shrimp displacement to different areas may be associated with some potential pathogens transferred to new areas farmed. Therefore, in this study were prepared bi-osecurity conditions for specific disease-free production of L. vannamei. Thereafter, three populations (Molokaei, High health and mix of Molokaei and High health) of the shrimp various reserves were detected base on origin and genetic indexes such as: observed heterozygosity, expected heterozygosity, allele frequency, coefficient inbreeding, genetic differentiation, genetic distance and genetic identity. On the other hand, epidemiological studies indicate non pathogens (viral, bacterial, fungal and parasitic) recognition of different populations selected in the quarantine salon. The bioassay results showed that the average weight and length of the populations of High health and Mix significantly greater than was a population of Molokaei. The shrimp populations were stocked in fiberglass tank (five ton) and were kept separated in the quarantine salon. During maintenance shrimp of populations in the quarantine salon were evaluated living and non-living pathogens with PCR, microbiology and biochemical methods. There is not any pathogens detection from shrimp populations stocking in the quarantine salon, so the shrimps were carried over to pond for broodstock culture of specific pathogenic free
Global age-sex-specific fertility, mortality, healthy life expectancy (HALE), and population estimates in 204 countries and territories, 1950-2019 : a comprehensive demographic analysis for the Global Burden of Disease Study 2019
Background Accurate and up-to-date assessment of demographic metrics is crucial for understanding a wide range of social, economic, and public health issues that affect populations worldwide. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 produced updated and comprehensive demographic assessments of the key indicators of fertility, mortality, migration, and population for 204 countries and territories and selected subnational locations from 1950 to 2019. Methods 8078 country-years of vital registration and sample registration data, 938 surveys, 349 censuses, and 238 other sources were identified and used to estimate age-specific fertility. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate age-specific fertility rates for 5-year age groups between ages 15 and 49 years. With extensions to age groups 10-14 and 50-54 years, the total fertility rate (TFR) was then aggregated using the estimated age-specific fertility between ages 10 and 54 years. 7417 sources were used for under-5 mortality estimation and 7355 for adult mortality. ST-GPR was used to synthesise data sources after correction for known biases. Adult mortality was measured as the probability of death between ages 15 and 60 years based on vital registration, sample registration, and sibling histories, and was also estimated using ST-GPR. HIV-free life tables were then estimated using estimates of under-5 and adult mortality rates using a relational model life table system created for GBD, which closely tracks observed age-specific mortality rates from complete vital registration when available. Independent estimates of HIV-specific mortality generated by an epidemiological analysis of HIV prevalence surveys and antenatal clinic serosurveillance and other sources were incorporated into the estimates in countries with large epidemics. Annual and single-year age estimates of net migration and population for each country and territory were generated using a Bayesian hierarchical cohort component model that analysed estimated age-specific fertility and mortality rates along with 1250 censuses and 747 population registry years. We classified location-years into seven categories on the basis of the natural rate of increase in population (calculated by subtracting the crude death rate from the crude birth rate) and the net migration rate. We computed healthy life expectancy (HALE) using years lived with disability (YLDs) per capita, life tables, and standard demographic methods. Uncertainty was propagated throughout the demographic estimation process, including fertility, mortality, and population, with 1000 draw-level estimates produced for each metric. Findings The global TFR decreased from 2.72 (95% uncertainty interval [UI] 2.66-2.79) in 2000 to 2.31 (2.17-2.46) in 2019. Global annual livebirths increased from 134.5 million (131.5-137.8) in 2000 to a peak of 139.6 million (133.0-146.9) in 2016. Global livebirths then declined to 135.3 million (127.2-144.1) in 2019. Of the 204 countries and territories included in this study, in 2019, 102 had a TFR lower than 2.1, which is considered a good approximation of replacement-level fertility. All countries in sub-Saharan Africa had TFRs above replacement level in 2019 and accounted for 27.1% (95% UI 26.4-27.8) of global livebirths. Global life expectancy at birth increased from 67.2 years (95% UI 66.8-67.6) in 2000 to 73.5 years (72.8-74.3) in 2019. The total number of deaths increased from 50.7 million (49.5-51.9) in 2000 to 56.5 million (53.7-59.2) in 2019. Under-5 deaths declined from 9.6 million (9.1-10.3) in 2000 to 5.0 million (4.3-6.0) in 2019. Global population increased by 25.7%, from 6.2 billion (6.0-6.3) in 2000 to 7.7 billion (7.5-8.0) in 2019. In 2019, 34 countries had negative natural rates of increase; in 17 of these, the population declined because immigration was not sufficient to counteract the negative rate of decline. Globally, HALE increased from 58.6 years (56.1-60.8) in 2000 to 63.5 years (60.8-66.1) in 2019. HALE increased in 202 of 204 countries and territories between 2000 and 2019. Interpretation Over the past 20 years, fertility rates have been dropping steadily and life expectancy has been increasing, with few exceptions. Much of this change follows historical patterns linking social and economic determinants, such as those captured by the GBD Socio-demographic Index, with demographic outcomes. More recently, several countries have experienced a combination of low fertility and stagnating improvement in mortality rates, pushing more populations into the late stages of the demographic transition. Tracking demographic change and the emergence of new patterns will be essential for global health monitoring. Copyright (C) 2020 The Author(s). Published by Elsevier Ltd.Peer reviewe
Twelve-month observational study of children with cancer in 41 countries during the COVID-19 pandemic
Introduction Childhood cancer is a leading cause of death. It is unclear whether the COVID-19 pandemic has impacted childhood cancer mortality. In this study, we aimed to establish all-cause mortality rates for childhood cancers during the COVID-19 pandemic and determine the factors associated with mortality. Methods Prospective cohort study in 109 institutions in 41 countries. Inclusion criteria: children <18 years who were newly diagnosed with or undergoing active treatment for acute lymphoblastic leukaemia, non-Hodgkin's lymphoma, Hodgkin lymphoma, retinoblastoma, Wilms tumour, glioma, osteosarcoma, Ewing sarcoma, rhabdomyosarcoma, medulloblastoma and neuroblastoma. Of 2327 cases, 2118 patients were included in the study. The primary outcome measure was all-cause mortality at 30 days, 90 days and 12 months. Results All-cause mortality was 3.4% (n=71/2084) at 30-day follow-up, 5.7% (n=113/1969) at 90-day follow-up and 13.0% (n=206/1581) at 12-month follow-up. The median time from diagnosis to multidisciplinary team (MDT) plan was longest in low-income countries (7 days, IQR 3-11). Multivariable analysis revealed several factors associated with 12-month mortality, including low-income (OR 6.99 (95% CI 2.49 to 19.68); p<0.001), lower middle income (OR 3.32 (95% CI 1.96 to 5.61); p<0.001) and upper middle income (OR 3.49 (95% CI 2.02 to 6.03); p<0.001) country status and chemotherapy (OR 0.55 (95% CI 0.36 to 0.86); p=0.008) and immunotherapy (OR 0.27 (95% CI 0.08 to 0.91); p=0.035) within 30 days from MDT plan. Multivariable analysis revealed laboratory-confirmed SARS-CoV-2 infection (OR 5.33 (95% CI 1.19 to 23.84); p=0.029) was associated with 30-day mortality. Conclusions Children with cancer are more likely to die within 30 days if infected with SARS-CoV-2. However, timely treatment reduced odds of death. This report provides crucial information to balance the benefits of providing anticancer therapy against the risks of SARS-CoV-2 infection in children with cancer