Seasonal dynamics in the occurrence and abundance of Pseudo-nitzschia species in the Maheshkhali channel of the Bay of Bengal, Bangladesh

Occurrence and abundance of Pseudo-nitzschia spp. at the mouth of the Maheshkhali channel of the Bay of Bengal, Bangladesh were studied. Plankton and water samples were collected monthly from the sub-surface water during high tide at daytime from June 2000 to May 2001. Four species of Pseudo-nitzschia, namely P. pungens, P. pseudodelicatissima, P. delicatissima and P. australis were identified and among them the first three were most commonly encountered and they varied seasonally. Pseudo-nitzschia delicatissima was the dominant species during the autumn and winter months, whereas P. pungens was dominant during the summer and spring months. Pseudo-nitzschia pseudodelicatissima exhibited its highest abundance level during the summer. Surface water temperature, salinity, nitrate-nitrogen (N03-N) and phosphate-phosphorus (P04-P) were recorded and their relationship with the occurrence and abundance of Pseudo-nitzschia species were studied. At the mouth of the Maheshkhali channel, Pseudo-nitzschia cell density was highest in late autumn (November) when highest salinity (35 o/oo) and P04-P (3.2 mg/l) concentrations and low temperature (23 °C) were recorded.

Seasonal dynamics of phytoplankton in relation to environmental factors in the Maheshkhali channel, Cox's Bazar, Bangladesh

In total 68 phytoplankton species were identified at the mouth of the Maheshkhali channel with the Bay of Bengal, among them 41 belong to Bacillariophyceae, 17 Dinophyceae, 7 Cyanophyceae and 3 to Chlorophyceae. The highest phytoplankton production was observed in November (578.0 x 105 cells/L) and the lowest in June (37.5 x 105 cells/L). Some hydrographic parameters e.g., surface water temperature, salinity and nutrients (N03-N and P04-P) were recorded and their relationship with the occurrence and abundance of phytoplankton population were also studied. Nutrient concentration was higher during the autumn months, when rain water provided the maximum outflow of rivers discharging into the channel. During the nutrient peak period, the total phytoplankton production was maximum. Bacillariophyceae was the dominant group of phytoplankton throughout the study period except in June and September, when Dinophyceae was dominant. Cyanophyceae was abundant in spring months when temperature began to rise.

Ecological risk assessment of pollution in sediment on benthic fauna in coast of Bandar Abbas

Ecological risk assessment is determination of the probability of an adverse effect occurring to an ecological system. This investigation was carried out to assess the ecological risk of sediment in coast of Bandar Abbass in 9 stations including Shilat Jetty, Hotel Amin, Poshte-Shahr, Souro, Bahonar Jetty, Powerhouse, Refinery and Rajaee Jetty from autumn 2013 to summer 2014. Results showed that Polychaete with 1177 , 1109 , 414 , 573 , ind.m2 in autumn 91 , winter 91 , spring 92 and summer 92 were the most abundant in frequency respectively. Among ecological indices, the Margalof that ranged from 4 to 7 was in a good situation while Shanoon and Berger – Parker with 1.2 (at most) and 0.32 (at least) respectively indicated an environment with probable stress. Heavy metal distribution obtained as Cd>Pb>Cu>Zn in sediment. In tissue, the distribution of heavy metals were as Crab>polychaete>Bivalve>gastropod for Pb, Gastropod>Bivalve>Polychaete>Crab for Cd, Gastropod>Crab>Polychaete>Bivalve for Cu and Gastropod>Bivalve>Crab>Polychaete for Zn. Maximum and Minimum of TOM obtained 10.16 and 1.96 percent in Posht-e-Shahr and shilat Jetty respectively and clay was the dominant grain in most area. Bioaccumulation coefficient of Zn and Cu was high in all stations. Igeo as a single index was high for Cd indicating a high risk in all stations. Potential Ecological Risk was high for Cu and Zn and goes increasingly from shilat Jetty to Rajee Jetty but goes down for Pb. Pollution index for Cu and Pb was nearly the same as Potential Ecological Risk but for Zn goes constantly. Among PAH, 5-ring and 6-ring PAhs were more concentrate comparison to other compounds in sediment. 2-ring and 3-ring, 3-ring, 4-ring and 5-ring and 5-ring PAHs were more concentrate in Gastropod, Bivalve, Crab and Polychaete respectively. HI as an index of PAH obtained 1. Ecological Risk Indices showed that the heavy metals are a serious risk for invertebrate in sediment but PAHs are not a risk for benthic community.

The zooplankton population structure and their trend of variations in the southern of Caspian Sea (Iranian waters)

Caspian Sea has gone under a lot of changes due to human influences and the unwanted presence of a ctenophora Menomiopsis leidyi which has greatly changed the structure of planktons in the last recent years. Therefore, this study was carried out in order to determine these changes in the zooplankton community. the Sampling was done in 8 transacts in Astara, Anzali, Sefidrood, Tonekaboun, Noushahr, Babolsar, Amirabad and Bandar Torkaman coastal waters at 5 different depths including 5, 10, 20, 50 and 100 m. Sampling was carried out in four seasons of spring, summer, autumn and winter during 2008, 2009 and 2010 on board of R/V Gilan. Altogether, 12 species of zooplankton were identified in 2008, 22 species in 2009 and 14 species in 2010. The zooplankton included four groups: copepoda (4 species), cladocera (8species), rotatoria (10 species) and protozoa (2 species).The increase of diversity in 2009 was due to cladocera and rotatoria groups. The abundance of zooplankton in the spring was 5074 + 7807 ind/m3 more than other season in 2008. The abundance of copepoda in the summer reached the highest value of 3332 ind/m3 and since autumn the abundance gradually decreases and in the winter reached to the lowest value. The most abundance of cladocera was 797 ind/m3 in winter and decreased in summer and autumn. The abundance of rotatoria was 2189 ind/m3 in winter. rotifera and copepoda consisted the main population of Zooplanktons in the winter. The results of 2009 and 2010 showed that the abundance of zooplankton in winter was 2.6 fold of autumn, 1.6 fold of summer and 1.1 fold (1/9 fold in 2010)of spring. After increasing increased of temperature, phytoplankton, and zooplankton in summer, M.leidyi increased too. In the autumn M. leidyi reached to the highest rate and decreased zooplankton. The maximum population of zooplankton was in the layer 0-20 m and in the layer more than 20 meters, the abundance of zooplankton decreased very much. In 216 2008, 2009 and 2010, the abundance of zooplankton was 87, 77 and 77 percent in the layer 0-20 m respectively. In this study, the thermocline was observed in the layer 10 – 20 meters in the spring, that formed a thin layer but in the summer it was in the layer 20 to 50 meters. Temperature decreased between 11 to 15 oC in this layer. The variation of temperature between surfaces to bottom was 10 to 13 oC in spring, 19 to 21 in summer, about 9 oC in autumn and maximum 3 oC in winter. The most biomass of zooplankton was in the west. The biomass of zooplankton in central west and east of Southern of Caspian Sea was 54 %, 22 % and 24 % respectively in 2008, in 2009 was 48%, 33% and 20% respectively and in 2010 was 54 %, 29 % and 16 % respectively .The biomass decreased from west to east. The model of zooplankton designed by principal component analysis (PCA)and linear regression for Southern of Caspian Sea.

Effect of two green algae species (Chlorella sp. & Scenedesmus obliquus) enriched with B group vitamins on food chain of Rutilus frisii kutum (Kamensky, 1901) fry

The Effect of two freshwater green algae species Chlorella sp. & Scenedesmus obliquus enriched (from the beginning of culture and after 96 hours) with different dosages of B group vitamins (0, 0.5, 1, and 2 ml of enriching solution per each liter of algae medium) on fecundity of Daphnia magna and growth of Rutilus frisii kutum fry were investigated in a research from spring, 2008 to autumn, 2009. First, each of the green algae species were cultured purely and massively in the Zander (Z-8+N) medium and then the nutritional value (the amount of protein, lipid, and carbohydrate) of enriched algae were meausered. In this study, enriching of Chlorella sp. & S. obliquus with a suitable mix of B group vitamins significantly improved their nutritive value. So the highest amount of nutritional value of Chlorella sp. was obtained because of enriching with dosage 0.5 ml.l-1 (366.654Kcal) and for Scenedesmus obliquus with dosage of 1 ml.l-1 (376.95Kcal). The acquired amount from control group showed an increase of respectively 42% and 11%. According to the results, increased dosages of enriching solution caused Daphnia fecundity to increase (at both stages : enrichment from the beginning of culture and after 96 hours). So the highest average of D. magna reproduction rate was obtained through being fed with Chlorella sp. and S. obliquus enriched with dosage of 2 ml enriching solution per liter of algae medium. The average fecundity of D. magna fed with Chlorella sp. enriched with dosage of 2 ml.l-1 enriching solution from the beginning of culture and after 96 hours was obtained respectively 2.128 ± 0.375 and 2.1 ± 0.69 and the average fecundity of D. magna fed with S. obliquus enriched with dosage of 2 ml enriching solution from the beginning of culture and after 96 hours was obtained respectively 2.128 ± 0.375 and 2.1 ± 0.69 which showed respectively an increase of 61 ٪, 91٪, 77 ٪, and 83٪ in proportion to the acquired amount from control group. When enriching solution was added to either algae culture medium from the beginning of culture, showed statistically significant differences (P<0.05) between dosages of 0 and 2 ml.l-1, 1 and 2 ml.l-1, and 0.5 and 2 ml enriching solution per each liter of Chlorella sp. culture medium and between dosages of 0 and 1 ml.l-1, and 0 and 2 ml enriching solution per each liter of S. obliquus culture medium. The highest average of body weight gain percentage and specific growth rate of kutum fry was obtained respectively 21.19%, 26.63%, 1.92, and 2.34 from the beginning of culture and after 96 hours with dosage of 1 ml B group vitamins per each liter of Chlorella sp. culture medium, which showed respectively an increase of 50%, 70%, 46%, and 62% in proportion to the acquired amount from control group. In the cases which Chlorella sp. were grown in the medium containing vitamin, from point of view of the average percentage of weight and specific growth rate of kutum fry significant differences were observed on the basis of the result of One-way ANOVA between dosages of 0 and 1, 1 and 2 , 0.5 and 1 ml B group vitamins per each liter. The highest average of body weight gain percentage and specific growth rate of kutum fry was obtained respectively 32.02%, 29.42%, 2.78, and 2.34 from the beginning of culture and after 96 hours with dosage of 2 ml B group vitamins per each liter of S. obliquus culture medium, which showed respectively an increase of 32%, 19%, 28%, and 17% in proportion to the acquired amount from control group. In the cases which S. obliquus were grown in the medium containing vitamin, from point of view of the average percentage of weight and specific growth rate of kutum fry significant differences were observed on the basis of the result of One-way ANOVA between dosages of 0 and 1, 0 and 2. According to the results of the present research we can say that considerable enhancement in the quality of the food of D. magna can be made by manipulation of the nutritional value of fresh water unicellular green algae with suitable mixture of B group vitamins, so that both the fecundity of D. magna will increase and the nutritional requirements of the kutum fry will be filled in this way.

Study on macroscopic, microscopic and hormonal changes in gonads of the crayfish Astacus leptodactylus in Aras Dam

This study was carried out to seasonal determination of some morphological characteristics, Seasonal fecundity, Seasonal fluctuations of vertebrate-type steroids and seasonal analysis of gonadal histology in both female and male sexes of freshwater crayfish (Astacus leptodactylus Eschscholtz 1823) in the area of Aras dam Lake. Crayfish were collected respectively in June, August, November (2011) and January (2012). The average length and weight of male crayfish was higher than that of females. %GSI of females fluctuated within an extended range (between 0.6 and 13.5% from June to January). Both of synchronous and asynchronous ovaries were seen in August sampled ovaries; however asynchronous form was higher than another. The annual reproductive cycle of male A. leptodactylus was surveyed by study on the seasonal changes of the external appearance of the testes and vasa deferentia, fluctuations in the gonadosomatic index (GSI%) and the histological analysis of the male reproductive system. Based on the histological differentiation of testis, spermatogenisis devided to 5 separated stages. The findings suggested asynchronous testis in the species A.leptodactylus. The presence of primary spermatophore layer may help keeping spermatozoa alive while the secondary spermatophore layer may produces spermatophore or synthesize of acellular material which forms spermatophre. Pleopodal fecundity was 37.3%lower than ovarian fecundity observed. The significantly higher number of eggs attached to 3rd and 4th pairs of pleopods. The egg number and gonadosomatic index increased with female size while egg weight and egg diameter didn’t increase with female size. Hemolymph levels of 17β-estradiol and progesterone followed a similar fluctuation pattern with % GSI in females, while testosterone didn’t follow the mentioned pattern. The testis of November sampled crayfish presented significantly higher gonadosomatic (%GSI) index (P < 0.05).The most observed gonadosomaticindices were 13.5%(forfemales) and 1.21% (for males, in autumn. Althogh the lowest GSI was (0.50%) formales in spring and (0.26%0 for spent females in January. Testosterone which followed a similar pattern with %GSI in males increased remarkably in November. 17β-estradiol increased strictly in January. The strictly enhancement of the three estroid hormones in January in both male and female sexes could bedue totheir stimulating role in in spermatophre and egg lying in the mating season (In January). Most of the ovaries followed the asynchoronous growth pattern. Also the testes presented asynchoronous growth pattern in autumn.

Population genetic structure of Rutilus frisii kutum in Caspian Sea using biometry and microsatellite molecular technique

In order to carry out Biometric studies, 75 samples were caught from 3 locations ( Tajan river, Sefidrud and Shirud) using Salic and the length (±1 mm) and weights (± 5 gr) of samples were determined. Using One-way ANOVA by SPPSS software, there wasn’t significant difference between locations in length and fecondity (P ≥0.01(, but there was significant difference between Shirud and tajan samples with sefidrud in weight ) P≤0.01(. In order to carry out genetic variation studies, 210 fish were caught from 3 different regions of the Iranian coastline (Khoshkrud, Tonekabon, Gorganrud) and 1 region in Azerbaijan (Waters of the Caspian Sea close to Kura River mouth) during 2008-2009 . Genomic DNA was extracted of fin using the phenol-chloroform. The quantity and quality of DNA from samples were assessed by spectrophptometer and 1% agarose gel electro-phoresis. PCR was carried out using 15 paired microsatellite primers. PCR products were separated on 8% polyacrylamide gels that were stained using silver nitrate. Molecular weight calculate using UVTech software. The recorded microsatellite genotypes were used as input data for the GENALEX software version 6 package in order to calculate allele and genotype frequencies, observed (Ho) and (He) expected heterozygosities and to test for deviations from Hardy-Weinberg equilibrium. Genetic distance between two populations was estimated from Nei standard genetic distance and genetic similarity index (Nei, 1972). Genetic differentiation between populations was also evaluated by the calculation of pairwise estimates of Fst and Rst values. From 15 SSR markers were used in this investigation, 9 of them were polymorph. Average of expected and observed heterozygosity was 0.54 and 0.49 respectively. Significant deviations from Hardy-Weinberg expectations were observed in all of location except Anzali lagoon- autumn in AF277576 and EF144125, Khoshkrud in EF144125 and Gorganrud and Kura in AF277576. Using Fst and Rst there was significant difference between locations ) P≤0.01(. According to Fst , the highest population differentiation (Fst= 0.217) was between Gorganrud and Khoshkrud that have the lowest Nm and the lowest (Fst= 0.086) was between Gorganrud and Tonekabon that have the highest Nm. Using Rst the highest population differentiation (Rst= 0.271) was between Tonekabon and spring Anzali lagoon and the lowest (Rst= 0.026) was between Tonekabon and Autumn Anzali 159 lagoon. Also the difference between Spring Anzali lagoon and Autumn Anzali lagoon was noticeable (Fst=0.15). AMOVA analysis with consideration of 2 sampling regions (Iran and Azerbaijan) and 7 sampling locations (Iran: Khoshkrud, Tonekabon, Gorganrud, Spring Anzali lagoon and Autumn Anzali lagoon ; Azerbaijan: the Kura mouth) revealed that almost all of the variance in data namely 83% )P≤0.01( was within locations, Genetic variances among locations was 14% )P≤0.01( and among regions was 3% )P≤0.01(. The genetic distance was the highest (0.646) between Gorganrud and Autumn Anzali lagoon populations, whereas the lowest distance (0.237) was between Gorganrud and Tonekabon River. Result obtained from the present study show that at least 2 different population of Rutilus frissi kutum are found in the Caspian sea,which are including the kura river population and the southern Caspian sea samples and it appears that there is more than one population in southern Caspian sea that should be attantioned in artifical reproduction Center and stoke rebilding.

The study of biological characteristics and heavy metal determination of Cd, Pb, Fe, V, Ni in the muscle, liver and gonad tissues of kingfish Scomberomorus commerson in the coastal waters of the Hormozagan Province (Persian Gulf)

Biological studies and heavy metal (Ni, v, Fe, Pb,Cd) determination in liver, gonad and muscle of Scomberomorus commerson were carried out from Oct 2006 to Sept 2007 in Hormozgan coastal waters. 599 Samples were gutted for reproduction and nutrition studies, fork length and weight were measured to nearest cm and g respectively. Meanwhile 40 samples were also investigated for heavy metal studies. All specimens were collected from two major landing sites (Bandar Lengeh & Bandar Abbas). Minimums & maximum fork length & weight were 29, 128 cm & 235 and 15350 g respectively.Isometric growth was shown according to our study and b was estimated 2.9 (overall), 2.91(male) & 2.89 (female). The average relative gut length was 0.52± 0.007 and it was determined that S. commerson is a carnivorous. More than 99 percent of gut content was different teleost fishes. Gastro somatic index had two peaks in Nov & Jan (before spawning) and with a decreased trend in July, the spawning period. Occurrence of empty stomach was estimated % 65.77. Maximum amount of condition factor was in Dec. Spawning season was started from June. The average of Absolute & relative fecundity (to weight unit) was 1217149±179315 and 178.2±15.58 respectively. Lm50% was estimated 75 cm for females. Sex ratio was 0.97: 1 (male: female). Chi- Square test showed no significant difference (p>0.05). Maximum amount of hepatosomatic index was estimated in March.Metal concentrations were determined using either Flame Atomic Absorption Spectroscopy (for Fe) or Graphite Furnace Atomic Absorption Spectroscopy (for Pb,Cd,Ni and V). The mean concentration (μg/g dry weight)of Pb,Cd,Ni,V and Fe in the liver were 0.0309, 0.0268, 0.0672, 0.0077, 2.5159 in the gonad 0.0440 ,0.0295, 0.1096, 0.0000, 1.4449 and in the muscle 0.0244, 0.0324, 0.0656, 0.0128, 1.6138 respectively. The maximum metal concentrations were below the maximum permissible limits for human consumption recommended by the USEPA, WHO and the UK. The results of Kendall's Tau-b correlation coefficient were as follows: The Liver tissue: There were significant positive linear relationships between accumulation of V, Fe, and Pb with Fork length, Pb and Fe with weight, GSI with Pb, Cd, V and 109 Fe, and a negative linear relationships between HSI with accumulation of V and Fe, Fork length, weight and GSI. The Gonad tissue: There were significant positive linear relationships between GSI with accumulation of Pb, Cd, Fe, Fork length and weight, a negative linear relationship between HSI with Fork length, weight and GSI. The Muscle tissue: There were significant positive linear relationships between accumulations of V, Fe with Fork length and weight factors and as well as GSI with Cd, V, Fe, Pb, Fork length and weight,a negative linear relationship between HSI with Fork length, weight, Cd, Fe and GSI. The results of Mann-Whitney U tests (P≤0.05) show that there were significant differences between summer and autumn from heavy metal contents in the studied tissues point of view. The only exceptions were for Ni in the liver, gonads and muscle and as well as there were significant differences between male and female from heavy metal contents in the studied tissues. The only exceptions were for Pb in muscle, Ni in liver, gonad and muscle, V in muscle, and Cd and Fe in gonads.

The seasonal variations of sea level due to density variations in the Arabian Gulf and Gulf of Oman

From the distribution of oceanographic data (temperature and salinity) in both Arabian Gulf and Gulf of Oman, the steric components (thermal, haline and steric heights) are calculated for the upper 50m layer during different seasons. The analysis reveals relevant evidence, that temperature variations (thermal component) play a role in the fluctuations of sea level within the investigated area. The salinity variations (haline component) is only significant near the entrance. The sea level variations due to density (steric component) is low during winter and spring and high during summer and autumn. The steric height is always lower in the northern and central regions of Arabian Gulf and higher in eastern region of Arabian Gulf and in the Gulf of Oman, i.e. the surface water must flow from the Gulf of Oman to the Arabian Gulf. The steric sea level gradient around the Strait of Hormuz are 0.04 cm/km in winter, 0.04 cm/km in spring, and 0.025 cm/km in summer and 0.014 cm/km in autumn.

Water quality assessment of Sonbolrood River by using hylsenhof index

This research investigates the quality of sonbolrood river by using Hylsenhof HFBI indicators and identified Macroinvertebrates invertebrates community in the family level. This study took place during 1388-1389 with four sampling season in four stations respectively in the forests of Kalyj kheyl village in Savadkuh (first station), industrial area of Islamabad (second Station), earth dam of Sonbolrood (third station) and the Place crosses Sonbolrood with Babolrood river (fourth Station). Macroinvertebrates invertebrates collected by quantitative sampler of Sorbr and they were isolated in laboratory by loop and they were identified in the family level. Generally, Macroinvertebrates of Sonbolrood river were formed three branches: Arthropods and flat worms and mollusks, including 3 tiers, 6 orders and 14 families that showed the maximum diversity and density in autumn and the least diversity and density in summer at all stations, also the third and fourth stations respectively were highest and lowest diversity and density. The water quality of Sonbolrood river based on the water quality Guide(Hylsenhof) is evaluated with excellent condition for all stations except third station. Sonbolrood river with having high slope, rocky and sandy bed, with self-refining act, completely is a proper ecosystem for aquatic organisms, but it is done due to increased organic matter and sewage factory located in industrial zone in the third station and then the increased water pollution caused by nurturing the water warm fish in the earth dam of Sonbolrood. (because of this, the water quality at third station based on the water quality Guide(Hylsenhof) are evaluated in a fairly good condition) and adding domestic sewages of adjacent villages like Seyedkola village and Shirdarkola caused increased pollution and increased trophy of Macroinvertebrates that are resistant to pollution and affect upon Macroinvertebrates community.

Comparative study of seasonal changes in some blood parameters and genetic polymorphisms of serum antibodies and antigens on red blood cells surface in immature Caspian salmon

Seasonal sampling from 40 immature Caspian salmon were performed in summer, autumn, winter and spring. The maximum ranges of RBC counts, Hct, Hb, WBC count and clotting times were observed in spring, summer, spring, spring and winter, respectively. The minimum amounts of these factors were counted in summer, winter, winter, winter and winter, respectively. Blood Samples were taken from healthy smolt, immature and adult Caspian salmon in spawning time. Hematological determinations and biochemical serum analysis were performed in 101 fish in the three samples. The ranges of hematological values for sample mean were counted. Red blood cell counts were 866600 mm3 and 1259400 mm3 in smolt and adult respectively. Hematocrit was 48.39% in smolt and 44.29% in adult. Hemoglobin was 8.85 gr/dl in smolt and 10.91 gr/dl in adult. White blood cell count was 8781.58 mm3 in smolt and 5217.55 mm3 in adult and mean were differential of WBC, Lymphocyte 90.57%in smolt and73.22% in adult. Neutrophil was 5.12% in smolt and 16.92% in adult, Monocyte were 1.27% in smolt and 4.24% in adult, Clotting time was 282.34 Seconds in smolt and 291.47 seconds in adult MCV, MCH and MCHC also meagered in smolt and adult. Biochemical parameter in immature and mature Caspian salmon meagered .Glucose concentration was 2.97 mmol.l- in immature and 1.99 mmol.l- in mature .Cholesterol concentration was 4.26 mmol.l- in immature and 7.06 mmol.l- in mature. Triglyceride amount was 2.35 mmol.l- in immature and 2.47 mmol.l- in mature and Calcium was 2.47 in immature and 2.61 mmol.l- in mature. An in situ study was made on erythrocytic isoantigens and hetero-antigen and their corresponding iso-and hetero-antibodies of sera by means of hemoagglutination tests on the blood sample, of 450 immature and 50 mature Caspian salmon. The absence of erythrocyte iso-antigens and hetero-antigen and their corresponding iso-and hetero-antibodies were shown by the experimental. It could be indicated an intra-specific variation and differences in species for kelardasht hatchery.

The genetic diversity of Acipenser stellatus populations in the Caspian Sea was studied using microsatellite technique

A total of 361 caudal fin samples were collected from adult A. stellatus specimens caught in the north Caspian Sea, including specimens from Kazakhstan (Ural River), Russia (Volga River), Azerbaijan (Kura River), specimens caught in the south Caspian Sea including specimens from Fishery Zone 1 (from Astara to Anzali), Fishery Zone 2 (from Anzali to Ramsar), Fishery Zone 3 (from Nowshahr to Babolsar), Fishery Zone 4 (from Miyankaleh to Gomishan) as well as from specimens caught in Turkmenistan (all specimens were collected during the sturgeon stock assessment survey). About 2 g of fin tissue was removed from each caudal fin sample, stored in 96% ethyl alcohol and transferred to the genetic laboratory of the International Sturgeon Research Institute. Genomic DNA was extracted using phenol-chloroform method. The quality and quantity of DNA was assessed using 1% Agarose gel electrophoresis and Polymerase Chain Reaction (PCR) was conducted on the target DNA using 15 paired microsatellite primer. PCR products were electrophoresed on polyacrylamide gels (6%) that were stained using silver nitrate. Electrophoretic patterns and DNA bands were analyzed with BioCapt software. Allele count and frequency, genetic diversity, expected heterozygosity and observed heterozygosity allele number, and the effective allele number, genetic similarity and genetic distance, FST and RST were calculated. The Hardy Wienberg Equilibrium based on X2 and Analysis of Molecular Variance (AMOVA) at 10% confidence level was calculated using the Gene Alex software. Dendrogram for genetic distances and identities were calculated using TFPGA program for any level of the hierarchy. It is evident from the results obtained that the 15 paired primers studied, polymorphism was observed in 10 pairs in 12 loci, while one locus did not produce DNA bands. Mean allele number was 13.6. Mean observed and expected heterozygosity was 0.86 and 0.642, respectively. It was also seen that specimens from all regions were not in Hardy Wienberg Equilibrium in most of the loci (P≤0.001). Highest Fst (0.063) was observed when comparing specimens from Fishery Zone 2 and Fishery Zone 4 (Nm=3.7) and lowest FST (0.028) was observed when comparing specimens from the Volga River and those from the Ural River (8.7). Significant differences (P<0.01) were observed between RST recorded in the specimens studied. Highest genetic distance (0.604) and lowest genetic resemblance (0.547) were observed between specimens from Fishery zones 2 and 4. Lowest genetic distance (0.311) and highest genetic resemblance (0.733) was observed between specimens from Turkmenistan and specimens from Fishery zone 1. Based on the genetic dendrogeram tree derived by applying UPGMA algorithm, A. stellatus specimens from Fishery zone 2 or in other words specimens from the Sepidrud River belong to one cluster which divides into two clusters, one of which includes specimens from Fishery zones 1, 3 and 4 and specimens from Turkmenistan while the other cluster includes specimens from Ural, Volga and Kura Rivers. It is thus evident that the main population of this species belongs to the Sepidrud River. Results obtained from the present study show that at least eight different populations of A. stellatus are found in the north and south Caspian Sea, four of which are known populations including the Ural River population, the Volga River population, the Kura River population and the Sepidrud River populations. The four other populations identified belonging to Fishery zones 1, 3, and 4 and to Turkmenistan are most probably late or early spawners of the spring run and autumn run of each of the major rivers mentioned. Specific markers were also identified for each of the populations identified. The Ural River population can be identified using primers Spl-68, 54b and Spl-104, 163 170, 173, the Volga River population can be identified using primers LS-54b and Spl-104, 170, 173 113a and similarly the population from the Kura River can be identified using primers LS-34, 54b and Spl-163, 173 and that from the Sepidrud River can be identified using primers LS-19, 34, 54b and Spl-105, 113b. This study gives evidence of the presence of different populations of this species and calls for serious measures to be taken to protect the genetic stocks of these populations. Considering that the population of A. stellatus in Fishery zone 2 is an independent population of the Sepidrud River in the Gilan Province, the catch of these fishes in the region needs to be controlled and regulated in order to restore the declining stocks of this species.

Investigation on reproduction process in two species of crab, Eriphia sebana and Ocypode saratan in the intertidal zone of Chabahar area

The present study with headline investigation on reproduction in two species of crab Eriphia sebana and Ocypode saratan was carried out in the intertidal zone of Chabahar in thirteen month from December 2004 to December 2005. Checked samplings have been taken, 45 number Crab monthly from any four stations by manual or use trap. During this study the following subjects were measured: temperature range and salinity, measurable coast granule, determination of sex ratio, relations carapace width with carapace length, Carapace width with total body weight, Gonad weight, gonadosomatic index, condition factor, gastrosomatic index, investigation content in stomach, LM50, growth parameters, plenty distribution length and width and gonad weight and total body weight. Studied on measurable coast granule were expressed that Ocypode saratan in Desalination station, were nest in soils equable sand and this quantity were confirmed in Pozm station. Sex ratio were assign in desalination area and Pozm M: F 0/44:0/56 and in Tiss and Chabahar M:F 0/45:0/55. Carapace length and carapace width (cm) and body weight (g) Furthest were designated in Ocypode saratan within carapace width sequential: In female: 5/42-6/15-105/13 and in male: 5/53-6/25-108/91 and in Eriphia sebana within Tiss area sequential: in female: 5/12-5/94-110/21 and in male 5/14-60/01-114/37. Have been linear relationship between carapace length and carapace width and equaled CW=aCL+b. Weight growth in two species were be modal and equaled BW=aCLb And increased crab weight by built up carapace width. Maximum gonad weight in Ocypode saratan within Desalination area in female have been outcome 3/39 and in male 0/84g and in Eriphia sebana extreme within Tiss during may in female were be 4/18 and in male 1/1g. Stomach content in Eriphia sebana were involved a black until half-purplish liquid and yellowish in Ocypode saratan. Stomach contents identifiable were being in four groups: Molluscoid, Crustacean, Plankton and Fish. Carapace width during the first year of maturation have been LM50:3/77 in Desalination area and LM50:3/92 in Pozm for Ocypode saratan and LM50:4/26 in Tiss and LM50:4/62 in Chabahar. Ability spawning in Eriphia sebana within Tiss has been CW=4/17cm and in Ocypode saratan within Desalination area CW=4/23cm. Maximun value of Loo for Eriphia sebana was equal 59/67 and growth factor K=0/68 within Tiss and Loo =61/64, K=0/65 for Ocypode saratan within Desalination area. Maximun GSI and GI have been within Desalination area and Tiss and minimum within Pozm and Chabahar. The maturity stages of two species were classifed into six stages. Review on GSI, CF have been showed that relation with temperature and salinity and definer in two species have been spawned in two period that Maximun in spring premier than autumn.

Distribution and growth biology of rock oyster Saccostrea cucullata in the Oman Sea

Distribution and growth biology of rock oyster (Saccostrea cucullata) in the northern shores of Oman sea have been struied. During this one-year study, samples have been taken monthly from ten different stations. quantity of vertical distribution of this species was obseredl in the mid - intertidal zone. After determining the spread pattern, the following subjects were studied: - Growth parameters - Distionction of the "cohorts" - Determination of "spawning Season" - Condition of the "Gonado Somatic Index" - Sex ratio - Length of the species during the first year of maturation. - Identification and determination of percentage of "Biofouler Organisms." Results obtained from the above - mentioned studies show that considering a growth factor (k) of 0.52, the value of "Loo " for this species is equal to 114 (mm).Five to six different age groups were observed among the samples taken. In the areas where this study was conducted, this species grows 24 to 30 (mm) in the first year of its life this growth rate is lower in the higher - aged grpups relative to the lewer - aged groups, so that the longest size classes grow between 4 to 6 (mm) per year. • The maxinum Value of the "Condition Index" is in the pozm area and the minimum value of it belongs to Darak and Tang areas. Along with the increase in the growth of gonads the above mentioned condition index increases gradually simultaneous with the onset of spawning. Also, study of the influence of environmental factors on the maturation process suggests that the most important factors affecting maturation and spawing are temperature and salinity. The study of GSI shows that this species has a coordinated bimodal spawing trend, with its spring peak in june and its autumn peak, being still higher than the spring peak, in september. The recruitment curve confirms the above spawning peaks with its peaks occuring after a delay of one month or maximum two months in comparison to the spawning peaks. The results of calcuation of "Sex Ratio" of this species in each area show that sex ratio is 1:1. Among the first size classes that reach maturity, nearly 67% of the samples are male and the remaining 33% are female. with the increase in the shell size, the percentage of males decreases and the percentage of females increases. , The above facts prove the protandrous nature of this species the diagram showing the sizes of the first samples which reach maturity suggests that more than 50% of the samples mature after their length exceeds 36 (mm). The shortest mature sample was found to have a length of 22(mm). After studying "Biofouler Organism" nine different invertebrate groups were indentified. Barnacles and Tunicates have the highest and lowest percentages respectively. According to zonal observations, Barnacles and polychacta do the greatest damage to this species.

Study biological characteristics related with development and reproduction in Barbus capito on the southern coast of the Caspian Sea, Gilan Province

In the present research, a total of 207 pieces of fish from 25 sampling stations in Gilan Province coasts in the years 2001-2002 were biologically studied in terms of their growth and development, reproduction and feeding. The average length and weight of the fishes are increased, as they get older. The highest index of length and weight growth is observed in the years 1 to 2. As the age increases, gradient of length and weight growth diagrams decrease. In studying the relation between length and weight, it was observed that proportionate to the total length, the weight is increased progressively. The fatness coefficient index in the initial years of life and prior to maturity is higher than the post maturity period. As the age increases, the decrease of this index is observable. The fatness coefficient index rate is directly related to index of fullness. The highest Gonadosomatic Index is seen in the months of June and July, i.e. at the times of spawning; and the lowest index rate is observed in the months of November and December. The appropriate temperature for reproduction of these species is from 18 to 22 degree centigrade. The Gonadosomatic Index is higher in spring and summer seasons as compared with autumn and winter. Besides, as the fishes become aged, the amount of the said index increases in a manner that the gradient of it in the years to maturity is less than the maturity time and thereafter. Sexual maturity stages in different months are directly related to Gonadosomatic index, and increase as the age increases. The sexual ratio of male fishes to the female fishes in terms of number is plus one prior to maturity; about one at the time of maturity and minus after maturity. In general the frequency of male fishes as compared with female fishes in all group ages is approximately two times. The fecundity mean, and the diameter and the rate of eggs will substantially increase, as the Gonadosomatic index rises. The maturity age in the male fishes is 3 to 4 years and in female fishes is 4 to 5 years. The spawning of this species in rivers occurs repeatedly and in different time intervals, and do not take place once (Asyncronous). The Gastrosomatic index is directly related to index of fullness and will decrease, as the age increases. The index of fullness is relatively the months of April and May. The underlying reason is the need of the fishes to energy for reproduction. As the spawning time commences, the index of fullness moves down and the downward direction continues. After spa g mg and reduction of the volume of energy in the body, the index of fullness rises, and it will be substantially high until the beginning of fall. In fall and winter as it gets cold, the index of fullness moves downward and the body fat deposits are used. A correlation is shown between the changes in vacuity index and fullness indices. This means that as the fullness index rises, the vacuity index decreases, and vice versa. The Hepatosomatic index prior to the reproduction is at the highest amount and after spawning is at the lowest. No correlation is observed between the fullness and Hepatosomatic indices. In other words reproduction is an inherent and instinct originated matter; and its cycle goes on, alternately and in an orderly manner, upon completion of germinal cells, even when it coincides with reduction or stoppage of somatic cell growth. The rising trend of Hepatosomatic starts in August and will continue until the next July. The volume of fat around digestive tract is severely reduced in early spring and this trend will reach its apex in summer season. In the cold seasons, i.e. the fall and winter, the accumulation of fat around digestive tract increases. Consequently, a meaningful and inverse relation is observed between index of fullness, also the progress of sexual maturity stages and the volume of fat.