Monitoring teških metala (Cu, Pb, Cd, Zn) u vodama Shahid Beheshti mrestilišta jesetri, Rasht, Iran

The presence of heavy metals; copper (Cu), lead (Pb), cadmium (Cd) and zinc (Zn) in water was monitored during different stages of breeding and rearing of Acipenser persicus at the Shahid Beheshti Sturgeon Hatchery. Water samples were collected (3 samples from each point) from the main pond, Kurenski pond, incubators, vniro tanks, earthen ponds and at the river estuary where fingerlings are released into the sea. Water parameters such as pH and water and air temperature were measured and recorded at the time of sampling. Heavy metal concentrations in water samples were determined using Atomic Absorption Spectrophotometer FAAS-Varian AA-220. In the present study the distribution pattern for heavy metal concentrations in different stages of breeding and rearing was as follows: Zn>Cu>Pb>Cd. Highest concentrations of heavy metals belonged to the element Zn (36.0±3.6 ppb) which was determined in the water sample collected from the inlet of master pond. Lowest concentration for Zn recorded was 0.98±0.26 ppb. Highest concentration for Cu was 10.5±1.18 ppb and the lowest concentration for this element was 0.65±0.26 ppb. The highest and lowest concentrations recorded for lead were 9.33±1.19 and 0.15 ±0.01 ppb, respectively, while those for cadmium were 0.116±0.019 and 0.016±0.003 ppb, respectively. The results obtained indicate the presence heavy metals studied in the water samples although they were lower than the maximum permissible concentration for these pollutants for the breeding and rearing of Acipenser persicus in sturgeon hatcheries

Poređenje gustine nasda nereis diversicolor u prirodnim i uzgojnim (anzali lagona) uslovima

Nereis diversicolor is regarded as a live food and is significantly effective in increasing stocks, enhancing tolerance in sturgeons and also increasing survival of sturgeon fry. Research conducted indicates that N. diversicolor is more abundant in May as compared to other months of the year. In February, only breeders of this species are found in the environment. N. diversicolor was found in four different weight classes from March 2009 to February 2010. They showed decrease in density with increase in temperature and reached the lowest numbers in February. In years 2009 and 2010, 200 sampling conducted monthly at the point where Caspian Sea mixes with the Anzali lagoon. Sampling was performed by Van Veen sampler with 400 cm2 cross section. Sediments were washed through a sieve with 0.5 mm mesh size. The residue along with Nereis was transferred to a dish, worms separated and transferred to lab. The density of worms per m2 was calculated according to the density formula. Two experiments were conducted to determine the best stocking density for the culture of N. diversicolor. Stocking density of 381-6350 worms m-2 were used in 6 trials initially and best growth was recorded in trial with density of 381 worms m-2. In the second experiment using 381-3175 worms m-2 in 7 trials, trial with 381 worms m-2 again showed better growth as compared to other trials. These results obtained were almost similar to those obtained for N. diversicolor is in its natural environment (447 worms m-2)

Mitogenic effects of phytohemagglutinin (PHA-P) and lipopolysacharide extracted from E.coli on cultured lymphocyte of the Caspian Sea ship sturgeon (Acipenser nudiventris)

The present study was designed to obtain the most effective dose for phtytohemagglutinin (PHA-P) and lipopolysaccharide (LPS) extracted from E. coli to optimize the lymphocyte culture method, the highest mitotic index (MI) and metaphase plates number of ship sturgeon, Acipenser nudiventris. Twenty specimens of two-year old A. nudiventris weighing on average 137g and with an average length of 32cm were used in this study. Different doses (0, 40, 60 and 80kgml ^(-1)) of PHA-P, LPS and a combination of the most effective dose of both mitogenic factors {(40 kgml super(-1)) PHA-P+ (80kgml super(-1)) LPS} were added to the culture media and mitotic indices were calculated for each treatment. Results indicated that a dose of 40kgml^(-1) PHA-P and 80kgml ^(-1) LPS produced the highest MI (6.26 and 3.02 respectively). Using higher concentrations of PHA-P and LPS resulted in decreased MI, whereas at lower doses of these mitogenic factors, mitotic arrest of cultured lymphocytes was observed. Using a combination of the most effective dose of the two mentioned mitogens {(40kgml ^(-1)) PHA-P + (80kgml super(-1)) LPS} yielded a MI of about 3.84. A dose of 40kgml ^(-1) PHA-P produced the highest MI (6.26), the highest number of lymphocytes was cultured and the largest number of metaphase plate was counted

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

Efekat tri različite hrane na rast i preživljavanje larvi persijske jesetre (acipenser persicus)

A feeding experiment was conducted to evaluate growth and survival of Persian sturgeon larvae fed with live food (Nereis diversicolor and Daphnia spp.) and artificial diet. Diets were included: Diet 1: Dafnia (Dafnia magna), Diet 2: Nereis diversicolor worm; Diet 3: Mix of Daphnia (Daphnia spp.) (50%) and Nereis diversicolor (50%), Diet 4: Mix of Nereis diversicolor (50%) and concentrate food (50%) and Nereis diversicolor (50%); Diet 5: Mix of Daphnia spp. (33.33%) and Nereis diversicolor (33.33%) and concentrate food (33.33%). Persian sturgeon larvae were distinctly transferred to 15 tanks and fed for 15 days. For each treatment, 60 larvae were stocked into tanks. The total length and body weight of the fish were determined once before initiation of the experiment and at the end of the experimental period to assess their growth performance. Water quality parameters were recorded two times a day. There was significant difference (P0.05) were not found between diets 2 and 3 and also between diets 4 and 5. The value for BWI, PBWI, GR, DGI, SGR was higher in larvae fed mix of Nereis diversicolor and Daphnia spp. (diet 3) (p<0.05) and there was significant difference between all of groups. Except diet 3 there was no significant difference in the CF of fish fed the survey diets

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

Effects of enriched daphnia with microscopic algae on some growth indices and survival rate of Persian sturgeon (Acipenser persicus) larvae

Microalgae as a source of valuable compounds such as fatty acids are isolated from the natural environments and their mass production with high nutritional value is one the necessities of many hatcheries. The present study aimed to determine the effects of enriched daphnia with microscopic algae on some growth indices and survival rate of Persian sturgeon (Acipenser persicus) larvae. Chlorella vulgaris and Scenedesmus dimorphus were purified and cultured. Then, Daphnia longispina was fed microalgae including Chlorella vulgaris and Scenedesmus dimorphus enriched with Docosahexaenoic acid (DHA). The microalgae density to enrich daphnia was estimated at 5× 107 cells mL-1. Three treatments with three replicates and a control group were considered in this study. A total of 30 Acipenser persicus larvae were allocated to each sixty liters tank. Experimental fish were fed daphnia enriched with Chlorella vulgaris (treatment 1), daphnia enriched with Scenedesmus dimorphus (treatment 2) and daphnia enriched with Chlorella vulgaris and Scenedesmus dimorphus (at the rates of 50%) (treatment 3). Persian sturgeon larvae in the control group were fed like VNIRO stage from daphnia caught in pond. Larvae were fed 30% of 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. The minimum (219 ± 98.4 mg) and maximum (315.16 ± 140.8 mg) mean (±SD) weights were observed in the control group and treatment 3, respectively. The results obtained from the body weight increase (BWI %) revealed that there were significant differences between treatment 3 and other treatments. Highest (4.6±1.13% day-1) and lowest (5.5±1.24% day-1) mean (±SD) specific growth rates (SGR) were recorded in fish fed the control group and treatment 3, respectively. Lowest (68%) and highest (85%) survival rates were recorded in the control group and treatment 3, respectively

Summer and winter feeding behavior in Acipenser persicus and Acipenser stellatus in the south Caspian Sea

Feeding behavior in Acipenser persicus and Acipenser stellatus in summer and winter was studied from 2004 to 2006 simultaneously with the marine survey for sturgeon stock assessment. Bottom trawls (9m) on board the research vessel Sisara 2 (50 hsp) were used to collect specimens at depth below 10m, while specimens at depths more than 10m were collected using bottom trawls (24.7m) on board the Guilan Research Vessel (1000 hsp). Examination of stomach contents of 135 A. persicus and 80 A. stellatus specimens revealed that the food spectrum was composed of bony fishes (Neogobius sp., Atherina sp., Clupeonella cultriventris), invertebrates belonging to the family Ampharitidae (polychaeta worms including Hypanai sp. and Nereis diversicolor), various crustaceans (Gammarus sp. and Paramysis sp.) and the bivalved mollusc, (Abra ovate). Significant differences were detected in the frequency of prey items in the different seasons studied. Also significant differences (P<0.05)

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