Iranian Scientific Fisheries Journal
Year:2007 | Volume:15 | Issue:4 |Papers Count:21

Morphologic and meristic analyses were performed aided by regression charts on 96 specimens of the genus Parastromateus, 67 specimens of Caranx, 70 specimens of Alepes, 69 specimens of Scomberoides, 62 specimens of Atropus, 104 specimens of Carangoides, and 67 specimens of Trachionotus from March 2004 to February 2005. The samples were collected by using bottom trawling in the Persian Gulf. The analyses showed the complete separability of the genus while keeping their close connection with the Family. We found that Parastrometeus was specially unique in terms of keeping its relationship with the family Carangidae.

A feeding experiment was conducted in a flow through water system to investigate effects of different dietary protein levels (isocaloric diets) on growth performance and survival of juvenile crayfish (Astacus leptodactylus). Four purified experimental diets with various levels of protein (25,30, and 40%) were formulated and fed to 120 crayfish for 90 days in the individual compartment. The diets which contained 35-40% dietary protein produced the highest values in weight gain (WG), specific growth rate (SGR), and feed utilization (ANPU). Survival of crayfish was not effected by dietary protein levels. The crayfish that were fed on the diet containing 35% protein had significantly higher PER than those which were fed with a diet containing 40% protein. Carcase composition was found to be influenced by food type. The higher protein content resulted in an increase in carcase protein and ash contents while a decrease in carcase in lipid and moisture levels was detected as influenced by the protein content. The results indicate the optimum dietary protein level for crayfish to be in the range35 to 40%.

We investigated the effects of Vibrionaceae family of bacteria as probiotics in the process of growth and survival rate of shrimp during propagation stages. Bacterial flora were extracted from seawater, culture farms, shrimp culture farms and sludge of private propagation farms. Different bacteria such as Vibrio alginolyticus (serotype 1-4), Vibrio splendidus I, Vibrio fluvialis II, Vibrio anguillarum I, Vibrio costicul, Vibrio vulnificus, Vibrio nereis, Vibrio camplbelli, Vibrio natriegens, Vibrio proteolyticus, Vibrio plegius II , Vibrio jischeri, Aeromonas hydrophila, Aeromonas schuberti, Aeromonas salmonisida, Aeromonas veronii were isolated, identified and lyophilized. These bacteria were used in different experiments on shrimp life cycle stages while the shrimps were being fed on live food such as Chaetoceros, Skeletonema and Tetraselmis algae. Vibrio alginolyticus (serotype 1) with 107 cells/ml increased proliferation of Tetraselmis sp to 71 % in 6 days compared to the control experiment. Also Vibrio alginolyticus (serotype 4) with 105 cells/ml increased Tetraselmis sp. production to 389% in 6 days compared to control. Vibrio splendidus I was also found to be able to increase shrimp fork length in postlarvae stage 3 up to 23% as compared to control. Vibrio alginolyticus and Vibriojischeri increased survival, fork length and body weight of green tiger shrimp in postlarvae stage significantly (P<0.05).

Morphometric and meristic specifications of Abramis brama orientalis of the Caspian Sea and Aras Dam Reservoir was studied in the year 2002. For this purpose, 40 morphometric attributes, 16 meristic attributes and 37 specifications in relation to the proportions of especiality of morphometric attributes of the Abramis brama orientalis were evaluated from the two habitats. Anova, factor and discriminant function analyses were conducted on the data. According to results the average coefficient of variation in morphometric, meristic and proportion of speciality of morphometric attributes for Abramis brama orientalis of Caspian Sea was 22.85, 3.24 and 7.68 and for Abramis brama orientalis of Aras Dam Reservoir was 17.45, 3.53 and 15.27. The Abramis brama orienta/is of the two areas showed meaningful differences in 35 morphometric factors, 6 meristic factors and 25 factor of proportion of the especiality of the age had signific and differences (P£0.05).Factor analysis showed that the Abramis brama orientalis of the two habitats had 80.62% of changes in 7 factors of first morphometric attributes, 73.65% of changes in the 9 factors of the first proportion of morphometeric especialities and 46.52% of changes in the 4 factors of the first meristic attribute. We showed that, fork length, standard length, proportion of head length to the standard length, number of scales of the lateral line, number of scales under the lateral line, number of scales above the lateral line, radius of dorsal fin and number of dorsal fins can be used to separate population of the fish from the two habitats. The first two factors of proportion of speciality of morphometric and meristic attributes causes total separation of the two populations. We found different in morphometeric specialities between the two specialities of morphometric and meristic attributes. It is suggested that different environmental conditions have led to the differences in the populations of the fish in the Caspian Sea and Aras Dam Reservoir.

Cyprinids are the main and most significant bony fishes found in the Caspian Sea. In this study, 15 specimens of Rutilus frisii kutum (Kamensky, 1901), 10 specimens of Barbus capita (Gueldenstaedtii, 1772), 10 specimens of Bream Abramis brama (Linnaeus, 1785), 10 specimens of Redlip, Aspius aspius, and 15 specimens of Kora volba, Rutilus ruti/us caspius, were collected from commercial catch stations. DNA from all specimens was extracted using the phenol-chloroform method in 500lll tubes and amplified using PCR method with a pair of primers with cytochrom b gene sequence of Kora volba. For RFLP analysis, PCR products of cytochorome gene b (1117 bp) from each species were digested with five restriction enzymes under suitable conditions of incubation. DNA bands were visualized by gel electrophoresis (polyacrylamide) and staining with silver nitrate. Five enzyme Rsa 1, Hinf I, Hhal, Hinc II, and Mbo I showed polymorphism. Genotypes obtained from digestion of enzymes Rsa I, Hinf I, Hha I showed haplotypes AAAAA for Barbus capita, BBBB for R. rutilus caspius, CCCC for Bream Abramis brama, DDDD for Aspius aspius and EEEE for R. frisii kutum. Each of these haplotypes serves as a genetic marker for the species and is of significant importance in distinguishing them.

Distribution and biomass of seaweeds in the Persian Gulf and its islands were assessed monthly during low tide from July 2001 to August 2003. Ten stations were defined in the study area and random spots along a transect vertical to the coastline were selected to carry out the sampling. Six stations were located in the coastal waters and four others were close to the islands. Samples were taken in quadrats 0.25 square meter in size (0.5mx0.5m). As a result, 77 species belonging to 4 division of seaweeds were identified. Rhodophyta was represented by 38 species, Chlorophyta had 21 species followed by 17 species of Phaeophyta and only 1 species of Cyanophyta. The highest and lowest seaweed diversity was seen around Larak Island and Michael station with 74 and 31 species respectively. Although some species such as Gracilaria corticata, Gelidiella acerosa, Laurencia snyderia, Colpomenia sinousa, Padina australis and Dictyosphaeria covernosa were abundant in all stations during the study, some species were absent from some stations. Thrbinaria conoiedes was only seen in Larak island, Spatoglassum variable and Steochospermum marginatum were present only in Larak and Qeshem islands, Codium papilatum and Ulva spp. were spotted only in Larak and Hormoz islands, and Sargassum ilicifolium was detected only in Bandar Lengeh, Shiyo, Larak and Qeshem islands. The maximum and minimum algal biomass (wet weight) was recorded in Bandar Lengeh with 1058gr.m-2 and Qeshem island with 391gr.m-2 and there was significant difference between the two stations (P<0.05). Also, the maximum algal biomass was recorded in summer (l466 gr.m-2) in Tahoneh Gorzeh and the minimum biomass (130 gr.m-2) in Qeshem islands. The highest biomass was recorded for the brown algae division (824 gr.m-2) in Bandar Lengeh and the minimum biomass was seen for the green algae division (26 gr.m-2) in Hormoz and Qeshm islands. The maximum biomass was 755gr.m- in summer for red algae, 1160gr.m-2 in Spring for brown algae and 5l9gr.m-2 in Summer for green algae.

The acute toxicity and effects of diazinon on some hematological indices of Beluga (Huso huso) juveniles weighting 4.3±0.12 grams was assessed following the O.E.C.D. direction in a static temperature in the range 20.27 ±2.05oCT.he 96h LC50 value of diazinon for beluga juveniles was 5.821. Also, the maximum allowable concentration of diazinon in natural waters for beluga was determined to be 0.5821 mg.l-1. Based on the toxicity table of insecticides, diazinon was listed as toxic for beluga .The clinical symptoms that were observed in this study consisted of lordosis and neural paralytic syndrome in fish exposed to the pesticide. Some abnormal reactions such as losing the balance when swimming and swimming in a half circle; expressive pigmentation mainly on the dorsal part were seen in the juveniles. Examination of hematological indices was performed on control and experimental specimens of beluga weighting 16.08 grams on average that were treated with 96h exposure to diazinon in a concentration lower than LC50 96h. The experimental group of beluga showed significantly lower value (P<0.05) of ,erythrocyte (RBC) and leukocyte count, hemoglobin content (Hb), and haematocrite (PCV), MCV, MCH and relative lymphocyte and eosinophil counts compared to the control group .In comparison, the relative heterophil count in the juveniles of the experimental group was significantly higher than the control group. By observing a decrease in the amount of leukocyte profile specially lymphocytes which are important in non-specific immunity of the fish, it can be said that diazinon may cause a decrease in the non-specific immunity of beluga.

Heavy metal tlocculation process was studied in the year 2002 in order to determine the interaction of water in Pirbazar River with Caspian Sea water. The effects of various salinity concentrations of Caspian Sea water were studied on determined heavy metals including Fe, Zn, Pb, Cu, Cd and Cr level of Pirbazar River using APHA method of extraction and measurement. The results illustrated that the level of heavy metal concentration in Pirbazar River were above standard limits and the extent of flocculation depended on both the salinity level and the heavy metal itself. The maximum flocculation for Cd and Cr were recorded at 7.65 ppt, for Zn and Fe at 9.35ppt while for Pb and Cd were at 2.55ppt salinity. The order of tlocculation with respect to percentage of original concentrations was found to be Zn > Fe > Cr> Cu > Cd> Pb.

In this study, the digestive systems of 10 adult Otolithes ruber specimens from Bushehr I province water, south-west Iran were removed and the livers and pancreases were fixed in formalin 10%. The routine procedures of preparation of tissues were followed and the paraffin blocks were cut at 6 microns, stained with H&E and studied under light microscope. The results of microscopic studies showed that liver as the largest accessory organ surrounds the pancreatic tissue in the fish. Liver was found to be a lobulated organ encircling the pancreas among its lobules. Hepatic tissue of the fish was found to be similar to many other bony fishes. Hepatocytes included glycogen and fat vacuoles that located around the hepatic sinusoids. Pancreas as a mixed gland microscopically, was composed of lobules consisting of serous acini (exocrine portion) and langerhans islets (endocrine portion). Pancreatic lobules are usually found as two rows of acini which a large blood vessel located in between.

We used Mercury Analyzer to assess possible correlation between length and weight of the KutumRoach (Rutilus frisii kutum) and mercury accumulation in different tissues of the fish. Wecollected fish specimens from central south Caspian Sea from October to December 2005. After biometrical measurement of samples and sex determination, mercury concentration was assessed in muscle, liver and skin tissues of the specimens. The mean concentration of mercury in muscle, liver and skin tissues was 849.9, 670.9 and 493.7ng/g respectively. Statistical analysis of the results showed a significant difference between mercury amounts in different tissues (P<0.05). No significant difference was found between male and female fishes in terms of mercury concentration (P>0.05). The mercury amount in muscle of Kutum Roach was lower than permissible limits proposed by FDA (1000 ng/g).

We determined the LC50 of copper (as CUS04) and it's Maximum Allowable Concentration(MAC) for Litopenaeus vannamei. The study was performed in 2003 for which bioassays were used for acute toxicity tests in a period of 96 hours during which water parameters such as water temperature, pH, dissolved oxygen, hardness, alkalinity were also measured. Ten treatments and three replicates for each treatment were used. A LC50 of 86.71, 27.28, 7.98 and 3.90 mg/l and also Maximum Allowable Concentration of 8.671, 2.728, 0.798 and 0.390 mg/l were determined at 24, 48, 72 and 96 hours post exposure. Results showed that L. vannamei is relatively resistant to copper. Hence, short period applicationof copper to white shrimp farms for controlling algal bloom is judged harmless to thefish.

Assessment of length frequency, length-weight relationship, distribution and biomass of the shrimp P. adspersus was done four times in the summer of the year 2002 in the Gorgan, Bay and south east of the Caspian Sea. Results indicated that the mean carapace length (CL) was 13.55±1.79 mm, and minimum and maximum CL was 8.7 and 18.7mm respectively. We determined the length weight relationship as W=0.0035CL2.3123. In the south east region of the sampling area the mean carapacelength was 12.67±2.23mm and minimum and maximum CL was 5.2 and 17.5mm respectively. For this region, we found the length weight relationship as w=0.0035 CL 2.0956 P. adspersus were found in all depths. Parallel with the air temperature increase, the shrimp density showed an increase at the depth of 2-10m. The estimated biomass of this species in the Gorgan Bay was 1999kg and in the south east region was 1160kg.

A survey of parasitological infections of Acipenseridae fishes in the southern parts of the Caspian Sea were done from 2002 to 2004. Altogether, 338 brood stocks of Acipenser persicus were examined. In the laboratory, the weight and length of the fishes were measured and after dissection presence of different parasites in the fish was examined. According to the results of this study, during three years of examinations, six different parasites were detected.These parasites were Cucullanus sphaerocephalus, Skrjabinopsolus semiarmatus, Eubothrium acipenseinum, Corynosoma strumosom, Leptorhynchoides plagicephalus, and Amphilina foliaceae. The prevalence and mean intensity of infection with Cusullanus sphaerocephalus and Skrjabinopolus semiarmattlm were the most.

Culture of Gracilaria was carried out in two 0.25 ha earthen ponds from October 2000 to September2001. Data were acquired for 4 seasons. Culture system was fixed bottom line method. We could culture 500 grams of Gracilaria on each line in about 9 weeks. The seaweed reached a maximum growth in 6 to 7 weeks with its biomass being 2.3 times of the initialbiomass in Autumn, 2.6 times in Winter, 2.7 times in Spring and 2.4 times in Summer. Oneway ANOVA showed that average weight was not similar in various seasons. The avearagedaily growth rate in different seasons was between 4.3 to 34.3 grams.

We used electroshocker, cast net and gillnet twice a week in four areas of Anzali Lagoon from April to September 2001 to sample common carp (Cyprinus carpio). Specimens were subjected to biometric measurements in the lab. In all, eighteen morphometric and seven meristic measurements were done on the samples. We determined the equation for the fish total fork length and body weight for males and females. Also, Van Berta1anffygrowth model was applied to the male and female fish.

Fifteen specimens of Neogobius spp. were randomely selected from the southern part of the Caspian Sea and examined in spring 2006 for parasitic infestation. The fishes were transferred alive to the laboratory, then, their weight and length were measured and after dissection were examined for different parasites. During the examinations, the tubular parts of kidney of four fishes were found to be infected with the spores of Ceratomyxa caspia. The spores were symmetrical, crescent-shaped, and had horn-like ends. The mid-region of the spore was convex while cornua was extremely narrow. Spherical polar capsules and sporoplasm occupied the convex part of the spore. Length of the spores was measured as 11.5 mm, the distance between ends of cornua was 19.5 mm, horns were about 11.5 mm and diameter of polar capsules was 5 mm. In the infected fishes plasmodia of the parasite was not seen, due to the time of sampling. The fishes were caught at the end of the spring, when the mature plasmodia had already released the spores. This is the first report of Ceratomyxa caspia in the Southern part of the Caspian Sea.

The normative of two Acipenser persicus broodstoks were scored during spawning season in 2002-2003. The breeders were caught from the southern part of the Caspian Sea. 158 breeders of Shahid Rajaii fish farm and 269 of Shahid Marjani were investigated. After checking egg quality and hormonal injection of fish, harvested egg were fertilized by common sturgeon hatchery method. Incubation temperature was about 17-22°C and hatchery period lasted 5-7 days (110-115 degree-days). About 55 percent of breeders had response to hypophysis injection. The range of somatic index (G.V) of spawned fish was varied from 4.4 to 9.9 in Shahid Rajaii farm and 4.73 to 10.96 in Shahid Marjani farm. In immature breeders it was more than 11. The optimum temperature spawning was from 15.5 to 18°C and 17 to 20°Cin Shahid Rajaii and Shahid Marjani farm respectively. The average weights of breeders were 28.14 in Shahid Rajaii farm and in Shahid Marjani farm were 30.31. The average of fork length, GV and fertilization rate, that are important normative factors in breeding of sturgeon were 169.96,7.58 and %75.31 in Shahid Rajaii farm, 158.83,7.93 and %64.57 in Shahid Marjanii farm respectively and there was significant difference between two station (P<0.05). Correlation and regression between 15propagation normatives were statistically analyzed and discussed.