Feeding habits of sturgeon fishes in shallow coastal waters of Guilan Province, southern Caspian Sea

We collected sturgeon specimens from seven fishing stations operating 30 to 35 Km away from each other in Guilan province over the years 1999 MD 2000. Trawl nets six meters long were drawn using motorboats at each station, repeated three times for each season. Among the studied premature sturgeons, 121 Acipenser persicus specimens with an average age of less than two years and a length of 10 to 49.9 ± 0.77 cm showed full stomachs (57.17 % fullness). Among the mature specimens with an average age of 11 years and a length range of 90 to 194 cm, only three showed full stomachs (11.54 % fullness). The highest gut index in this study belonged to premature A. persicus. A one-way analysis of variance showed no significant difference in condition factor and gastro-somatic index among the different length groups (P<0.05). We found that the food consumed by premature A. persicus was comprised of eight genera of benthic invertebrates Hypania sp., Hypaniola sp., Pterocuma sp., Stenocuma sp., Abra ovata, Paramysis sp., Gammarus sp. and Nereis sp. Adult sturgeons were found feeding mainly on fish species belonging to Gobidae, Atherinidae and Clupeidae families. The main preys of premature A. persicus were polychaet worms Hypania sp. and Hypaniola sp. belonging to the class Sedantaria. Crustaceans Stenocuma sp. and Pterocuma sp. of the class Cumacea were also seen in the diet of the premature sturgeons. The main preys of adult A. persicus were fishes belonging to the family Gobiidae and secondary prey were fishes of the family Atherinidae

The effects of temperature, salinity and photoperiod on sexual maturity and concomitant reproduction behavior in Nereis diversicolor

Nereis diversicolor worms were collected from the Anzali lagoon during the years 2004-2006 using Van Veen grab sampler with a surface area of 400cm ^(2). Water salinity, temperature and total organic matter (TOM) of sediments in the sampling region was determined. The worms were maintained in 0.5 tons (1x1m ^(2)) tanks until they reached a weight of 200-300mg. Sexual maturity in the samples was attained at 4-6C and spawning occurred at approximately 16°C. The first gametes were observed after the temperature increased from 6 to 16C. Sexual maturity was studied at various salinities (0.5, 5, 12, and 15 ppt). Results indicated that the worm attains sexual maturity at salinity 15ppt in a shorter period as compared to other salinities. No significant differences were observed between sexual maturity attained at salinities 12 and 15ppt (P>0.05). The effect of light and photoperiod in synchronizing reproduction in male and female N. diversicolor was also studied. We observed that reproduction behavior in adult worms increased for a period of one week at the end of each month after they were exposed to a prolonged photoperiod (L:D 16:8) followed by a period of dim light. Mature males crawled around outside the tubes in search of a female. In the presence of a mature female, the males released sperm directly in front of the female tube. Soon after, there was an increase in the activity of the females which showed intense ventilation movements. The female worms with their eggs already released began to carry the sperm into their tube. The ripe females nearby which had not yet laid eggs in their tubes released their gametes a few minutes after the male and began to carry sperm into their tubes. The fertilized eggs remained inside the tube protected by the female. The benthic larvae developed fast, feeding on the mucus and microbial film on the tube wall. After 10 to 14 days, larvae began to leave the tube. A few days later the females died

Prirodna hrana acipenser persicus gajenog u ribnjačkim jezerima

A study on live food in Acipenser persicus rearing ponds was carried out In four rearing ponds; two in the Shahid Beheshti hatchery and two ponds in the Yousefpour hatchery. Samples were collected from three points in each pond on a weekly basis. Samples were collected using plankton nets (mesh size 50 µm), Ruthner sampler and Ekman grab. Zooplankton and benthic samples were fixed in 4 % formalin solution for later analysis. Zooplankton species identified in water samples collected at all four ponds belonged mainly to two phyla; Arthropoda and Rotifera. Total abundance of zooplankton species was estimated 87576 individuals L-1 in the Yousefpour hatchery and 136626 individuals L-1 in the Shahid Beheshti hatchery. Insect larvae, oligochaeta worms and mollusks were found in the sediment samples collected from the Yousefpour hatchery while sediment samples collected from the Shahid Beheshti hatchery contained only insect larvae and oligochaeta worms. The total abundance of benthic organisms was 0.343 g m-2 in the Yousefpour hatchery and 1.28 g m-2 in the Shahid Beheshti hatchery. Condition factor in fishes ranged from 0.29-0.54 in the Yousefpour hatchery and from 0.30-0.47 in the Shahid Beheshti hatchery

Rearing Huso huso in earthen ponds and fiberglass tanks

Juvenile Huso huso with average weight of 28.76 plus or minus 0.35 were reared in fiberglass tanks and earthen ponds for 29 weeks in order to evaluate potential of rearing of the fish for meat production purposes. Fish in fiberglass tanks showed weight increase up to 584.17 grams in 200 days and produced 6 kg of biomass per metric square. Survival ratio, food conversion ratio and specific growth rate were measured as 98.4%, 2.21 and 1.41 (% per day) for the fish respectively. During the experiment period, H.huso reared in the earthen ponds reached a weight of 708 grams and produced 1.5 kg of biomass per metric square. The survival rate, food conversion ratio and specific growth rate for the fish cultured in the earthen ponds were 85.7%, and 1.32 and 1.69 (% per day). Based on the results, the fiberglass tanks provided better growth condition in the beginning of the experiment. However, in later stages of rearing the trend was reversed and fish reared in earthen ponds showed more suitable condition although no statistically significant differences between treatments were found (p>0.05)

Comparison of plankton and benthic organisms diversity and density in sturgeon hatcheries and assessing their effects on condition factor in sturgeon fingerlings

Phytoplankton and benthic organisms diversity and density were studied in six sturgeon rearing ponds in the Yousefpour and Shahid Beheshti hatcheries from 22 April to 1 July 2001. We used Ruttner sampler, plankton net with a mesh size of 50 microns and Ekman grab to sample the organisms on a weekly basis and fixed the samples in formalin solution 4% and then identified 22 genera of phytoplanktons for the three ponds in the Yousefpour hatchery and another 21 genera for the three ponds in the Shahid Beheshti hatchery. Planktons from the phyra Chlorophyta, Cyanophyta, Chrysophyta, Cryptophyta and Euglenophyta were present in the ponds. Schroederia sp. of the phyla Chlorophyta was the dominant species identified. We observed 2 x 106 and 1 x 106 cells of phytoplanktons per milliliter of pond water in the Yousefpour and Shahid Beheshti hatcheries respectively. The zooplankton phyla Arthropoda and Rotifera were represented with 9 genera in the two hatcheries showing a density of 36937 and 46603 zooplanktons per liter of water in the Yousefpour and Shahid Beheshti hatcheries respectively. Insect larvae and oligochaeta worms were the benthic organisms common to both hatcheries and mollusks were present only in the Yousefpour hatchery. The average benthic biomass was 1.58±0.19 and 2.16±0.75 g/m2 in the Yousefpour and Shahid Beheshti hatcheries respectively. The condition factor in sturgeon fingerlings of the Yousefpour hatchery varied from 0.294 to 0.554 while that of sturgeon fingerlings of the Shahid Beheshti hatchery were 0.297 to 0.6

Study of effect of nereis diversicolor in growth and survival of Acipenser persicus larvae

The present research aimed to study effect of Nereis worm in feeding, growth, survival and carcass biochimical compositions of persian sturgeon larvae. Five diets including zooplankton (100%) as the control (Z), Nereis diversicolor worm (100%), a mix of Nereis and zooplankton (50% for each), a mix of Nereis, zooplankton and concentrate food (33% for each) with 3 replicates were established. At first, Nereis worms were cultured up to the weight of 200 mg according to the protocol done in the International Sturgeon Research Institute. Required zooplanktons were obtained for Dr. Beheshti Sturgeon Rearing and propagation center. Concentrate food was also made in the ISRI. Persian sturgeon larvae with the average weight of 95.66 mg were put in 60-Liter tank (60 larvae in each tank) under the same physical and chemical parameters of water. 8 days after the beginning of active feeding, they were fed five times a day with experimental dites based on 20-30% of their weight for 15 days. Water quality parameters, such as dissolved oxygen, temperature, pH values were recorded daily. The average of temperature, pH and dissolved oxygen during the test were 22.8±1.3ºc, 7.5±0.1 and 6.58±0.9 mg/l respectively. At the end of this period, condition factor (k), specific growth rate (SGR), food conversion rate (FCR), weight gain (WG) and Body weight index (BWI) were calculated. Total fat and fatty acids profile were analyzed. The results showed that there was a significant difference between growth indexes and food consumption (p<0.05). BWI, GR and SGR indices showed no significant difference between N and NZ treatment, but the average of these indices were higher in NZ treatment. The most and the least average of SGR, BWI were observed in NZ and NZC treatments respectively. Condition factor showed no significant difference in all diets except NZ. FCR had no significant difference between N and NZ as well as after diets. The highest and the lowest survival rate was observed in N treatment (96.11±1.46%) and NZC (85.55±3.37%) respectively. The results of carcass analysis showed that there is a strong correlation between fatty acids of body and fat resources of diets. According to the significant difference in growth rate between treatments (p<0.05), the larvae fed with N diet presented a better performance compared with others. These results indicate that cultured sturgeon larvae need n-3 and n-6 series of fatty acids in their diet

The role of daphnia fed with purified and enriched phytoplankton with PUFA in enhancing growth and survival of Acipenser persicus larvae

In this study, Daphnia longispina were fed with two freshwater green algae species, Chlorella vulgaris and Scenedesmus dimorphus, enriched with Docosahexaenoic acid (DHA). Chlorella vulgaris and Scenedesmus dimorphus were isolated and cultured for mass production. Three treatments with three replicates and a control group were considered to conduct this study. In order to investigate feeding, a total of 30 Acipenser persicus larvae with the initial mean weight of 68±3.6 mg were distributed into 12 plastic tanks of 60 L. Experimental fish larvae were fed daphnia collected from earthen ponds (as control group), daphnia enriched with Scenedesmus dimorphus (treatment 1), daphnia enriched with Chlorella vulgaris (treatment 2) and daphnia enriched with Chlorella vulgaris and Scenedesmus dimorphus (at the rates of 50%) (treatment 3). The microalgae density to enrich daphnia is estimated at 5×107 cells mL^-1. Fish larvae were fed at an amount of 30% body weight per day for four times. During the experimental period, water temperature, dissolved oxygen concentration and pH ranged between 18-24°C, 5.8-7.2 mg l^-1 and 5.6-8.2, respectively. Monounsaturated fatty acids (MUFA) were the highest (32.3 %) in D. longispina enriched with Chlorella vulgaris and the highest concentration of polyunsaturated fatty acids (PUFA) (19.8%) was observed in D. longispina enriched with Scenedesmus dimorphus. The highest (21.6%) and lowest (13.2%) concentrations of PUFA in fish larvae were recorded in treatment 3 and the control group, respectively. The results obtained from the body weight increase (BWI %) revealed that there were significant differences (P≤0.05) between treatment 3 (daphnia enriched with chlorella and scenedesmus) and other treatments. The highest (5.5±1.24% day^-1) and the lowest (4.6±1.13% day^-1) mean specific growth rates (SGR) were recorded in fish fed treatment 3 and the control group, respectively. The lowest (68%) and the highest (85%) survival rates were obtained in the control group and treatment 3, respectively

Stock assessment of sturgeon fishes in the southern part of Caspian Sea (Iranian water)

The marine survey for sturgeon stock assessment was conducted in summer, winter and spring in the years 2006 and 2009 to estimate the relative and absolute abundance and percentage composition of each species in the Guilan, Mazandaran and Golestan Provinces. This survey was carried out in the Iranian waters of the Caspian Sea on board the Sisara2 and Guilan vessels using trawl nets at 2-100 m depths. Trawling was carried out in 85 stations that were selected using a stratified random design. The number of stations in each scope was based on the area of the scope in terms of the total area. Trawling and sampling in shallow water up to 10 m were carried out using 9 m trawl nets whereas 24.7 m trawl nets were used for depths more than 10 m. Trawl surveys were carried out in the daytime. Trawling velocity was kept at 2.5-3 kts and trawls lasted half an hour in order to calculate abundance, and biomass of sturgeons using the swept area method. Catch per unit area (CPUA) in the winter 2006 survey was 3853 specimens nm^2 , in the summer and winter 2007 survey was 1854 , 2912 specimens nm^2 at depths less than 10 m respectively . CPUA for sturgeons in spring 2008 survey was 2103 specimens nm2 at depths less than 10 m and 393 specimens nm2 at depths greater than 10 m (10-100 m depth). These values in the winter 2008 survey dropped to 44 specimens nm^2 at depths at depths above 10 m. CPUA for sturgeons in the spring 2009 survey was 300 specimens nm^2 at depths less than 10 m and 307 specimens nm^2 at depths greater than 10 m. In all the surveys conducted CPUA for A. persicus was higher than that for the other sturgeon species. Based on the calculations carried out in the marine survey in winter 2006 the estimated absolute abundance for sturgeons was about 2977.363 thousand. The total biomass of sturgeon was estimated as 131.713 tons. In the summer 2007 survey total abundance was estimated 1432.398 thousand, and total biomass of sturgeons was estimated at about 312.161 tons. In the winter 2007 survey total abundance for sturgeons was estimated at about 2250.105 thousand, and total biomass was estimated 578.08 tons. In the spring 2008 survey total abundance was estimated at about 3002.832 thousand. The total biomass was estimated at about 2533.318 tons .In the winter 2008 survey total abundance was estimated at about 152.722 thousand, and total biomass in winter 2008 was estimated 170.540 tons. Total abundance in spring 2009 survey was 1310.232 thousand and total biomass was estimated at 2019.tons. Investigation of stomach content of sturgeon Acipenser persicus caught under 10m depth in 2006 to 2007 surveys showed that there is significant difference in the consumed food. Polychaeta is the major food consumed and crustacean an the minor one(P>0.05).Also no new types of food( such as bony fishes or benthic) have been observed in food chain of Acipenser persicus only the food consumption rate has been related to the season of year and increases or decreases in warm or cold seasons, respectively For physiological study and determination of sexual maturation stages in sturgeon,119 gonad sampling prepared. The results showed that 63 % of fishes were females and 37 % of them were males. Gill microscopic study shows complications such as hyperplasia, curvature, adhesion, embowed, shorting and lengthen of secondary filaments and fraught bloody. Microscopic study on liver indicates signs of cloudy inflammation, fatty degeneration, dispersion of billed secretions and cell atrophy. The population genetic structure of Persian sturgeon (Acipenser persicus) in Sefidrood and Gorganrood rivers watershed analyzed based on microsatellite markers during sturgeons assessment in 2006-2008. Results showed that Acipenser persicus in two region of south part of Caspian Sea are two independent populations

The global burden of adolescent and young adult cancer in 2019: a systematic analysis for the Global Burden of Disease Study 2019

Background: In estimating the global burden of cancer, adolescents and young adults with cancer are often overlooked, despite being a distinct subgroup with unique epidemiology, clinical care needs, and societal impact. Comprehensive estimates of the global cancer burden in adolescents and young adults (aged 15–39 years) are lacking. To address this gap, we analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, with a focus on the outcome of disability-adjusted life-years (DALYs), to inform global cancer control measures in adolescents and young adults. Methods: Using the GBD 2019 methodology, international mortality data were collected from vital registration systems, verbal autopsies, and population-based cancer registry inputs modelled with mortality-to-incidence ratios (MIRs). Incidence was computed with mortality estimates and corresponding MIRs. Prevalence estimates were calculated using modelled survival and multiplied by disability weights to obtain years lived with disability (YLDs). Years of life lost (YLLs) were calculated as age-specific cancer deaths multiplied by the standard life expectancy at the age of death. The main outcome was DALYs (the sum of YLLs and YLDs). Estimates were presented globally and by Socio-demographic Index (SDI) quintiles (countries ranked and divided into five equal SDI groups), and all estimates were presented with corresponding 95% uncertainty intervals (UIs). For this analysis, we used the age range of 15–39 years to define adolescents and young adults. Findings: There were 1·19 million (95% UI 1·11–1·28) incident cancer cases and 396 000 (370 000–425 000) deaths due to cancer among people aged 15–39 years worldwide in 2019. The highest age-standardised incidence rates occurred in high SDI (59·6 [54·5–65·7] per 100 000 person-years) and high-middle SDI countries (53·2 [48·8–57·9] per 100 000 person-years), while the highest age-standardised mortality rates were in low-middle SDI (14·2 [12·9–15·6] per 100 000 person-years) and middle SDI (13·6 [12·6–14·8] per 100 000 person-years) countries. In 2019, adolescent and young adult cancers contributed 23·5 million (21·9–25·2) DALYs to the global burden of disease, of which 2·7% (1·9–3·6) came from YLDs and 97·3% (96·4–98·1) from YLLs. Cancer was the fourth leading cause of death and tenth leading cause of DALYs in adolescents and young adults globally. Interpretation: Adolescent and young adult cancers contributed substantially to the overall adolescent and young adult disease burden globally in 2019. These results provide new insights into the distribution and magnitude of the adolescent and young adult cancer burden around the world. With notable differences observed across SDI settings, these estimates can inform global and country-level cancer control efforts. Funding: Bill &amp; Melinda Gates Foundation, American Lebanese Syrian Associated Charities, St Baldrick's Foundation, and the National Cancer Institute

The global burden of adolescent and young adult cancer in 2019 : a systematic analysis for the Global Burden of Disease Study 2019

Background In estimating the global burden of cancer, adolescents and young adults with cancer are often overlooked, despite being a distinct subgroup with unique epidemiology, clinical care needs, and societal impact. Comprehensive estimates of the global cancer burden in adolescents and young adults (aged 15-39 years) are lacking. To address this gap, we analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, with a focus on the outcome of disability-adjusted life-years (DALYs), to inform global cancer control measures in adolescents and young adults. Methods Using the GBD 2019 methodology, international mortality data were collected from vital registration systems, verbal autopsies, and population-based cancer registry inputs modelled with mortality-to-incidence ratios (MIRs). Incidence was computed with mortality estimates and corresponding MIRs. Prevalence estimates were calculated using modelled survival and multiplied by disability weights to obtain years lived with disability (YLDs). Years of life lost (YLLs) were calculated as age-specific cancer deaths multiplied by the standard life expectancy at the age of death. The main outcome was DALYs (the sum of YLLs and YLDs). Estimates were presented globally and by Socio-demographic Index (SDI) quintiles (countries ranked and divided into five equal SDI groups), and all estimates were presented with corresponding 95% uncertainty intervals (UIs). For this analysis, we used the age range of 15-39 years to define adolescents and young adults. Findings There were 1.19 million (95% UI 1.11-1.28) incident cancer cases and 396 000 (370 000-425 000) deaths due to cancer among people aged 15-39 years worldwide in 2019. The highest age-standardised incidence rates occurred in high SDI (59.6 [54.5-65.7] per 100 000 person-years) and high-middle SDI countries (53.2 [48.8-57.9] per 100 000 person-years), while the highest age-standardised mortality rates were in low-middle SDI (14.2 [12.9-15.6] per 100 000 person-years) and middle SDI (13.6 [12.6-14.8] per 100 000 person-years) countries. In 2019, adolescent and young adult cancers contributed 23.5 million (21.9-25.2) DALYs to the global burden of disease, of which 2.7% (1.9-3.6) came from YLDs and 97.3% (96.4-98.1) from YLLs. Cancer was the fourth leading cause of death and tenth leading cause of DALYs in adolescents and young adults globally. Interpretation Adolescent and young adult cancers contributed substantially to the overall adolescent and young adult disease burden globally in 2019. These results provide new insights into the distribution and magnitude of the adolescent and young adult cancer burden around the world. With notable differences observed across SDI settings, these estimates can inform global and country-level cancer control efforts. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.Peer reviewe