By-catch of sturgeon juveniles in beach seine fishing method in Mazandaran Province, northeast Iran

In an attempt to recognize the harmful fishing times and locations for sturgeons, we used catch statistic to evaluate by-catch of sturgeon juveniles during beach seine fishing over the years 2001-2002 in Mazandaran Province. We found that over the fishing period, 23760 hauls were conducted during which 103000 sturgeons were caught. The highest by-catch occurred in October (37% of the catch) and the lowest occurred in January (5% of the catch). The maximum sturgeon catch per haul was 14.2 in autumn decreasing through the year with 1.26 sturgeon fish caught in each haul in spring. The species composition of the by-catch sturgeon juveniles was determined to be Persian sturgeon (54%), Stellatus sturgeon (37%), Beluga (6%), Russian sturgeon (2%) and Spiny sturgeon (1%)

A comparative analysis of feeding habits of sturgeon fish in shallow coastal waters of Mazandaran and Golestan Provinces, south Caspian Sea

Feeding habits of different genera of 354 sturgeon specimens (Acipenser persicus, Acipenser nudiventris, Acipenser stellatus) were compared over the years 1999-2000 caught in the coastal waters less than 20 meters deep of Mazandaran and Golestan provinces, southern Caspian Sea. The caught specimens ranged 30-18cm in length. Overall, 16 families of food items were identified in the digestive system of the sturgeon specimens, of which 11 belonged to macro-benthos. The sturgeon fishes preyed on food items composed of Annelids 50.8%, Amphipoda 41.5%, small fish 4.8%, Decapoda 2% and Bivalvia 0.9%. Fish specimens shorter than 40 cm were mostly found feeding on shrimps, polychaets and gamarids. The 41-80cm length class mostly fed on shrimps, gamarids, polychaets, bivalves and smaller fish. Sturgeons longer than 80cm fed mostly on shrimps and smaller fish. Average fat coefficient for Acipenser stellatus was 0.43. A. persicus showed a fat coefficient 0.63 while that of the A. nudiventris was 0.97. Average stomach fullness was 8.3, for Acipenser stellatus, 100 for A. nudiventris and 165 for A. persicus. We found a similar diet between group one fish less than 40 cm long and group two with fish in the length class 41 to 80cm (r=0.7)

The effects of creosote on mortality rate and blood biochemical factors of stellate sturgeon (Acipenser stellatus)

The effects of creosote on stellate sturgeon (Acipenser stellatus) juveniles each weighing 3.6 ±1 grams was evaluated. Acute toxicity test was undertaken in static water quality at 22 degree C plus or minus 1 according to the OECD method at the Caspian Sea Ecology Institute in 2005. The effect was assessed based on the results of the acute toxicity test. For the test, the hematological and biochemical properties of one control and five experimental groups of the fish juveniles what were exposed to creosote were compared. The acute toxicity test lasting 96 h was performed in fully static water condition with aeration

Physicochemical characteristic of Penaeus indicus ponds in coastal area of Gorgan Bay (Mazandaran province)

A series of studies were conducted to evaluate the possibility to culture Penaeus indicus in coastal area of Gorgan bay concerning the proper climate potential of Behshahr zone during summer till autumn 2000. Thirty two water samples were collected from four shrimp ponds for further laboratory studies to measure some physicochemical parameters such as: temperature, pH, salinity, transparency, nitrogen, phosphorus, D.O. according to the Russian Standard (1988). As a result, the range of water temperature, pH, salinity and trasparency were 24.5-29.0°C, 8.02-8.18, 31.5-43.5 ppt and 21-50cm, respectively and the fluctuation concentration of D.O, NH^+4, NO^-2, PO4^-3 were 3.8-9.5 ml/l, 0.0022-0.015, 0.0021-0.1210 and 0.0145-0.3710 mg/l, respectively. As a conclusion, this shrimp species can be easily adopted with different climate, so this region is suitable for shrimp culture as view point of temperature and salinity. For demonstration of this issue, the semi-intensive shrimp culture has been successful. Also the toxic material such as ammonia and nitrite did not show any restriction for shrimp culture

Some hematological and biochemical changes in blood serum of Grass carp (Ctenopharyngodon idella) vaccinated with Aeromonas hydrophila following exposure to sublethal concentration of diazinon

.Diazinon is commonly used for pest control in the agricultural fields in north of Iran. This study was conducted to determine the chronic toxicity of organophosphorous pesticide (Diazinon) in vaccinated fish and its effects on some hematological parameters and biochemical blood plasma profiles of Grass Carp (Ctenopharyngodon idella).This experiment was carried out in three groups. The first group was vaccinated and exposed to diazinon (group A) while the second group was vaccinated and bathed with PBS bath (group B). The remaining fish were used as unvaccinated fish and were kept in clean water separately (group C). Diazinon was applied at concentrations of 2 mg/L for 12 hours since the experiments were initiated. The experimental groups(A and B) showed significantly lower values (p < 0.05) of erythrocyte count, haemoglobin content, haematocrit, leucocytes, Lymphocyte, myelocyte and monocyte, as well as in alkaline phosphatases, alanine aminotransferase, aspartate aminotransferase and, lactate dehydrogenase compared to the control group(C). Values of MCV, MCH and MCHC of experimental species (A and B) were compared to the control group(C). The results of examinations of the biochemical blood plasma profile indicate a marked neurotoxic effect of diazinon in fishes. Changes in values of both erythrocyte and leukocyte profile after exposure to diazinon-based preparation may be referred to disruption of haematopoiesis as well as to a decrease on non-specific immunity of the fis

Study on ecological capacity of the release sites of the fingerlings of sturgeon and bony fishes in order to regulate the restocking program at the Gorganrud River

This review is started from April 2002 in Gorgan River and continued for one year. Three sampling stations along the river to the mouth of the estuary were 4000 meters away from the bridge to the village Charqly all samples were collected in this area. Four million sturgeon larvae with average weight of 3/2 grams were obtained from martyr Marjani and Vushmgir Dam farms. Over 40 days released at release stations, and 316 million bony fish fingerlings are being release that 282 million were whitefish, 25 million carp and 9 million bream from Vushmgir Dam and Syjval Bream Center within two months at the release stations in Gorgan River. At sampling stations, especially estuaries to determine the shelf life of fry in the river and to determining migration into the river as well as physical - chemical and assess the frequency and biomass of feeding materials (phytoplankton, zooplankton, and benthos) at the sampling stations in Gorgan River were studied. The entire estuary to the sea makes itself. Maximum migration happened at sunset. Average Debbi for 20-year was at the rate of 14.95 cubic meters per second. In 2002, the annual average was 20.8 cubic meters per second, respectively. Evaluation of abundance and biomass of feeding materials (phytoplankton, zooplankton, and benthos) indicates the status of the average biomass of phytoplankton in the river at the release station was 23/75 mg per liter that was highest in September and was lowest in December. Mean primary production based on a 145 mg chlorophyll cubic meters. 6 orders of benthic invertebrates were observed. Benthic including 9 families and 11 genera have been identified including groups of insects, worms, low-tar and Polychaetes, crustaceans, bivalve and gastropod. But at the release station (S2) the highest levels of benthic biomass (18/18 grams per square meter) degree of diversity of benthic organisms (12) species have largely been seen as a maximum in April and minimum in December. Also zooplankton condition, zooplankton total of 27 genera belonging to five categories, Rotatoria, Kladvsra, Coupe Pvda, Balanvs, and protozoa were identified. In general, in September zooplankton has the greatest diversity and abundance and in September and March, the lowest number is observed

Study on rearing movine carps in the ponds of brackish water and freshwater

In this study, mono culture of Cyprinus carpio in fresh water and brackish water with 3500 specimens per hectare with 3 replication each carriedout from midel April to end the October 2010 and mide april to end the October 2011 recptively. Juline fish with 40 gr weight takeup from the sade voshmgir and after prepara tion of rearing ponds were introduced to pond according to appropriate and caluclate stocking density. Juline were fed by concentracted food(GFC). Feeding calculation based on percentage of body weight varied from 5 to 10 % of body weight. In fresh water Average weight and lenghth were in the stage time stocking 40 gr 14.68 cm and at the end of cultuivation period were 704.26 gr and 37.04 cm respectively. Inorder to comparecultivation of Cyprinus carpio in freshwater with breackish water another stocking 350 specimens per hactar with 3 replications also tookplace in this study. Junlin fish with average weight of 40gr and average length of 14.12cm were introduced to the ponds. At the end of rearing period average final weight was 700.26 with average length of 38.86cm.mean daily growth in fresh water treatment was 3.39. in brackish water replication the average daily . average condition factor in fresh water was 2.41. The average value CF in breackishwater was 1.39. in this research was survival rate in the fresh water and breackish water were more 77%

Study of penculture of the common carp (Cyprinus carpio L.) fingerlings at the Gorgan Bay to the maturity stage (broodstock management)

The aim of present project is study on the possibilities of brood stock production from fingerlings in the penculture condition and the effect of density on it .this project was done during three years with two different treatment and three repetitions in the Gorgan Bay. First treatment with two fingerlings per square meter and the 2nd with four fingerlings per square meter in each pen.To carry out the project at first fingerlings were brought from breeding and recruitment centre –Sijeval (Kolmeh) and the stocked at the earthen pound with concentrated food .After that they were adaptated with brakish water between 7-10 days and transferred to Gorgan Bay for cultivation with average weight of 93.78±32.66 grams and 20.53±2.37 cm in length. It should be noted that 6 pens (which surrounded by nets in the water) were fixed using mast with 15-20 cm in diameter and 5.5 meter in length , Net mesh size was 16 mm with string number 33 of kapron.Feeding was done according to the program two times by giving concentrated food at the period of cultivation Physic -o -chemical factors were measured. biometery was done monthly at each pen and other fishes (unwanted) were observed at the same time. results indicate that in the 1st and 2nd treatments average survival rate was 52.3 and 41 percent respectively with average weight of 410±64.98 grams and 390±52.8 and 28.3±1.79 cm and 27.66±1.57in length. SPSS used to analysethe data such as average length and weight of fish in the treatments and in different months with ANOVA method (p≤ 0.05) . results show that there is no significant difference between treatments. Autopsy observation also showed that fishes (female and male) are mature and histological studies showed that most of observed eggs are entirely mature with 800-1200 micron diameter gonad ( male) were mature at the pen in the Gorgan Bay condition .The male and female hormones were evaluated. 17-B- Estradiol and 11-keto testosterone hormones for adult fish (female and male) parents respectively are similar in dense with those adult fish before injection to use at the artificial breeding. Maturation were verified by autopsy, histology and hormone studies

Investigation on the possibility of artificial propagation, cultivation and brood stock management of Vannamei shrimp

Project was carried out at the Gomishan Centre for training and education which is located 15 km far from Gomishan City in the Golestan Province. Prebroodstocks were chosen from ponds (stocking density: 3/m^2). 860 male and 890 female broodstocks were separated and transferred into greenhouse (400 m^2). The average growth rate per day was 0.3 g and survival rate was 90%. After reaching 42 g in males and 52 g in females they were ready for Eyes stalk Brood stocks were transferred into propagation hall in June and after a week females gone under Eyes stalk. 10,890,000 eggs were yielded from 50 females and consequently 7, 187, 0.50 nauplius were produced. Each broodstock spawned 1.34 Times. The maximum hatching was 75% that in was average 64.2%. Mass of Cetocerous Algae was mass produced to be fed for post larvae. Finally 35,000 PL15 were yielded. PL15 were transferred into two half hectare and one 1 ha ponds in July. The stocking density was 18 PL/m^2. Biometric parameters together with air and water temperatures, and pH were recorded daily. Results indicate that the maximum survival rate was 58% (pond No. 5) and minimum was 52% (pond No. 17). The average weight after 101 days cultivating was 23 g which is appropriate. Also the average daily growth rate was 0.2g and the FCR was 1