Iranian Journal of Fisheries Sciences
Volume:9 Issue: 1, Jan 2010

Mahisefid, Rutilus frisii kutum, is a cyprinid fish which is distributed from Turkmenistanto Azerbaijan along the Caspian Sea. It is one of the economically important fish in theregion. As part of the Iranian Fisheries Company s policy to improve the stocks of thisspecies, every year, fingerling of Mahisefid are released into the southern basin of theCaspian Sea. The main objective of this study was to determine populations in different ofrivers. In total, 387 fish were collected from four rivers, including Lemir, Sefidrood, Shirrood and Tajan, where this fish migrates for spawning, in spring 2005. Thirteen conventional morphometric factors, 13 ratio and 12 Truss morphometrics were measured and calculated in this study. Conventional and Truss morphometric data were analyzed using two-way ANOVA Principal Component Analysis and discriminant. Average of coefficient of variation (CV%) of morphometric in males was 14.95, 10.28, 17.47 and 16.56 and in females was 21.35, 19.74, 18.25, and 19.74 in Lemir, Sefidrood, Shirrood and Tajan River, respectively, showing that all morphometric characters were significantly different (P<0.05) among four sampling sites (populations). The first component of morphometrics 44.32% in males and 68.94% in females were positive, indicating that the conventional morphometric was good descriptor of the body shape variation among the populations, especially in females. The total cumulative variances were 76.6% and 87.8% in males and females, respectively, suggesting that this can be considered as a useful discriminator. The total cumulative variances were 64.27% and 64.21% in males and females, respectively. The first component of truss was 87.7% and 81.3% of the total variance, in males and females, respectively. The results of the present study suggest that each sampling site represents independent population in each river.

This study was conducted to evaluate the efficacy of live food (Artemia urmiana) andcommercial diet in rearing of Oncorhynchus mykiss larvae. Experiment started when larvaewere 0.12g in weight. Triplicate groups of fish were offered one of four treatments: (1) acommercial starter food; (2) live Artemia urmiana nauplii (for 3 days); (3) live Artemiaurmiana nauplii (for 7 days); and (4) combination of live Artemia nauplii (5% of food) andthe commercial starter food. They were fed four times daily starting at the onset ofexogenous feeding, for 1 week. After 1 week, the fish of all groups were shifted to thecommercial diet for an additional 3-weeks period to determine the impact of any differences in weight of fish. The result of the present study showed that those larvae fed with combination of Artemia nauplli and a commercial starter food grew significantly faster than other groups for 4 weeks. Larvae fed with other composition were similar in length and weight (P>0.05). Survival rates of the trout larvae ranged 86-96% after 1 week and 67-84% after 4 weeks. Larvae survival after 1 and 4 weeks were significantly higher (P<0.05) in trout larvae fed only on Artemia nauplii (treatments 2 and 3) than other treatments. The body chemical composition analysis of trout larvae showed only small differences, with the exception of the crude protein and lipid at 4 weeks. The data were analyzed to determine significant differences among treatments by one-way ANOVA. (Statistica v.9, StatSoft Inc.).

The aims of the present study were to determine the best time for egg stripping after ovulation and to study oocyte over-ripening in the Caspian brown trout (Salmo trutta caspius). Eggs were retained in the female abdominal cavity for 40 days post ovulation (DPO). Partial volumes of eggs stripped from 10 individually identified females at 10 days intervals and fertilized with a pool of semen obtained from 8 males. The biochemistry and histology of the eggs and the biochemistry of the ovarian fluid were studied. The eyeing and hatching rate of the eggs declined with over-ripening time, which decreased from 90.60±6.28% for eyeing and 86.33±6.82% for hatching in newly ovulated eggs (0 10 DPO) to 1.34±0.67% for eyeing and 0.98±0.49% for hatching in over-ripenedeggs (30 40 DPO). However, larval abnormalities remained constant for 30 days after ovulation.During the course of oocyte over-ripening, the pH of the ovarian fluid significantly decreased and the concentration of glucose, protein, calcium, iron, and aspartate aminotransferase activity significantly increased. Moreover, the concentration of protein, triglycerides, and aspartate aminotransferase activity in the eggs changed with over-ripening. In the newly ovulated eggs, the yolk consisted of homogenous tissue and its perivitelline space diameter had no considerable differences. With over-ripening, the yolk became heterogeneous, and while chorion diameter did not change, the perivitelline space diameter varied among different areas. The present study demonstrated that the best time to take Caspian brown trout eggs after ovulation at 7±0.6°C was upto 10 DPO. Among the studied parameters of the egg and ovarian fluid, egg quality was related to both ovarian fluid parameters (pH, protein, aspartate aminotransferase, glucose, cholesterol, triglycerides, calcium) and egg parameters (iron, aspartate aminotransferase), suggesting that these parameters can be used as egg quality biomarkers for Caspian brown trout.

Apparent digestibility coefficients (ADC) were calculated by using chromic oxide in the dietas an indigestible marker to evaluate the Iranian Cottonseed meal (CSMP). Then, thenutritional value of cottonseed meal (CSM) as soybean meal (SBM) substitute in quality lowcost rainbow trout (Oncorhynchus mykiss) ration was investigated. In this study, sixformulated feeds consisting different levels of CSMP (0, 20, 40, 60, 80, 100%) substitution of SBM were fed to a total of 540 rainbow trout with initial mean body weight of 50 ± 5 g. Fish were randomly stocked into eighteen 100L fiberglass tanks with 30 fish per tank and 3 tanks per diet and fed to apparent satiation 3 times a day and 7 days per week for 60 days. The ADC of CSMP and SBM were measured as of dry matter, 62.7 and 69.2%; crude protein, 82.4 and 87.3%; fat, 66.6 and 78.5%, respectively. After an 8 week feeding trial, the average weight gain of fish fed with diets 1 to 6 was: 100.6, 102, 102.9, 103.3, 103.9, and 103.4g, respectively. Average feed conversion ratio (FCR) of fish fed diets 1 to 6 was measured as of 1.28, 1.31, 1.31, 1.27, 1.29, and 1.25, respectively. For all six treatments, the survival percentage was more than 99%. ADC value for most nutrients of CSMP was different from those of SBM. Weight gain, specific growth ratio (SGR), daily weight gain (DWG) and survival rate were not significantly different (P>0.05) for fish fed with CSMP diets compared to the control diet but the differences of FCR were significant among different diets (P<0.05).In the feasibility study, complete replacement of SBM by CSMP revealed to be economic and based on the gossypol analysis, total gossypol levels was not observed for toxicity on liver of fish fed by CSMP, indicating the possibility of total replacement of SBM by CSMP inrainbow trout fed formulations.

Recently, the nutritional requirements of marine finfish larvae have received considerableattention, and studies have shown that docosahexaenoic acid (DHA) and icosapentaenoic acid (EPA) and arachidonic acid (ARA) affects the growth and survival of marine finfish larvae. This study investigated the effects of different Artemia enrichments containing variable amounts of DHA and EPA on the growth and survival of larval Persian sturgeon (Acipenser persicus). Four different Artemia enrichments ICES30/4 (with 20.90mg/g DW DHA and 6.29mg/g DW EPA), Sturgeon Ovary Oil (SOO) (with 2.76mg/g DW DHA and 7.55mg/g DW EPA), Cod Liver Oil (CLO) (with 7.64mg/g DW DHA and 11.39mg/g DW EPA) and Linseed Oil (LO) (with 0.00mg/g DW DHA and 0.03mg/g DW EPA) in seventy five aquaria (each 45 liter, with three replicates per treatment) were used. The resultant Artemia contained a different concentration of DHA (0.00-5.99mg/g DW) and EPA (0.69- 4.97mg/g DW). Larvae were fed with Artemia from 3 to 20 days after active feeding at 250 prey l-1. Results showed that there were significant differences between treatments regarding to the total length and wet weight but no significant differences were found in dry weight between the larvae reared on different treatments. However, larvae reared on LO were significantly higher (in weight) than larvae reared on ICES30/4 and SOO. Larval survival on the SOO enriched Artemia (93.3±1.6) at 20th day was significantly higher than other treatments. Our results showed a positive effect of Artemia DHA proportions on growth and survival of the Persian sturgeon, and demonstrated that larvae of this species require a high ratio of dietary DHA to EPA.

This study was carried out to investigate the rate of lipid oxidation in fresh rainbow trout(Onchorhynchus mykiss) and in the sticks treated by (2.5% w/v) sodium acetate (NaA),sodium citrate (NaC) and sodium lactate (NaL). The pH value, free fatty acid (FFA),thiobarbituric acid (TBA) and sensory evaluation (odor, flavor and color) were determined on 0, 3, 6, 9 and 12 days of storage. The results showed that TBA and FFA in control were significantly higher than those in the other groups (P<0.05). Sticks immersed in NaAindicated a significant difference in formation of free fatty acids in comparison with othersodium salt-treated samples on 9 and 12 days after storage. Sticks dipped in NaL had amaximum level of pH at the end of the storage, whereas samples treated by NaA achieved significantly the lowest value of pH, 9 days after storage. Organoleptic assessments of the samples expressed more acceptability of sticks immersed in sodium salt solutions than the control after 3 days of storage. These indicated that sodium salts, particularly sodium acetate, have antioxidant properties.

The aim of the present study was to investigate the population dynamics of Liza klunzingeri, in Hormouzgan province waters located in northern coasts of the Persian Gulf and Oman Sea. This study was carried out from October 2007 to September 2008. samples were collected from commercial stake traps. The relationship between weight and fork length was found to be W= 0.0214 F.L2.8233 suggesting that Liza klunzingeri shows isometric growth. Lengthbased stock assessment using the FiSAT software package showed an asymptotic length (L) of 20.3cm FL and growth coefficient of 0.6.yr-1. These results gave a growth performance index (?) of 2.39. The total mortality coefficient was estimated to be 2.31, a natural mortality of 1.09 and fishing mortality of 1.22. The estimated total mortality which, in relative terms, is considered average (2.31.yr-1), coupled with the currently observed exploitation rate of 0.52 for L. klunzingeri, estimated from the mortality rates, suggested that the species is moderatelyexploited.

the size of the animal, the liver weight can increase to 0.04 g. The oil yielding capacity of the liver was assessed by four different methods namely Soxhlet, Blighand Dyer, Direct steaming and Solar extraction. The percentage of oil yield was high inSoxhlet method (67.7%), but it was 54.3% in Bligh and Dyer method, 42.5% in directsteaming method and minimum of 32.0% in solar extraction method. The solidification point of all the extracted oils remained at 29 0.5oC. The specific gravity (0.95 to 0.96) and refractive index (1.42μ to 1.48μ) of the oil extracted by the four different methods were not varied significantly. The cholesterol contents of the oil extracted by Bligh and Dyer and direct steaming extraction methods were at the highest level (1991.00 and 2059.00mg 100ml-1) but it was 50% less in other methods. The percentages of PUFA in the total fatty acid of the oils were 13.78, 20.46, 19.07 and 22.54% (by weight) in solar extraction, direct steaming, Soxhlet and Bligh and Dyer methods, respectively. Thus the physico-chemical properties of liver oil of O. niger were found to be influenced by the extraction adopted methods. Also it is clear that Bligh & Dyer method is the suitable method for the extraction of liver oil from marine fishes without much loss of nutrients.

Microbiological, chemical and sensory changes of fish burgers prepared from deep flounder(Pseudorhombus elevatus) and brushtooth lizardfish (Saurida undosquamis) were determined during storage at -18?C for 5 months. Microbiological counts were including total plate count (TPC), total coliform (TC), Staphylococcus aureus, Psychotropic and Escherichia coli decreased throughout the frozen storage Reduction of microbial load in brushtooth lizardfish was higher than that in deep flounder, except for Staphylococcus aureus counts that was almost equal in both groups. There was a significant increase in pH value in both groups (P<0.05) in first and second months of storage only. Moisture content increased in both groups at the end of 5th month, with increase of moisture in deep flounder fish burgers being higher than that in brushtooth lizardfish burgers. TVB-N values in both groups increased significantly (P<0.05 and P<0.008 for deep flounder and brushtooth lizardfish burgers, respectively) at the end of the second month, however, there was a decrease or no significant change afterward. TBA value of deep flounder fish burgers had a significant decrease (P<0.05) as storage time continued, however, it increased significantly in brushtooth lizardfish burgers at the end of second month (P<0.006) following by a decrease at the end of storage period. Peroxide value (PV) in both groups increased significantly (P<0.05 and P<0.002 in deep flounder and brushtooth lizardfish burgers, respectively) during storage time but a significant decrease was observed at the end of third and fourth months (P<0.005 and P<0.001 in deep flounder and brushtooth lizardfish burgers, respectively). Sensory parameters (color, texture, taste and general acceptability) for two groups decreased significantly (P<0.003 for all parameters in 2 groups) during storage with deep flounder fish burgers receiving higher scores than brushtooth lizardfish burgers at the beginning and end of the storage period.

Neogobius caspius is an endemic species of the Caspian Sea which plays an important rolein food chain as a predatory fish. The main aim of this study was to investigate selectedfeeding characteristics of Neogobius caspius in the south west coasts of the Caspian Sea.Monthly sampling was carried out using a bottom trawler at three stations (Astara, Anzaliand Chabuksar) in three depths (0-5, 5-10 and 10-15m) on a monthly basis from October2004 to September 2005. Relative gut length (RLG) was less than one suggesting that this species is carnivorous. RLG was significantly lower in older fish but gut length was longer (P<0.05). Intensity of fullness was below the favorite degree (IF<400) from October to March, however, it was higher (400

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In the present study, the impacts of various concentrations of Aflatoxin B1 (AFB1) on Beluga, Huso huso, under controlled conditions were investigated. Belugas (120±10g) were fed on diets containing 0, 25, 50, 75, and 100 ppb AFB1/kg of diet for 3 months. Results showed various levels of AFB1 do not significantly affect the specific growth ratio (SGR) (P<0.05) of fish in different treatments. However, weight gain and food conversion ratio (FCR) were varied significantly (P<0.05 between control and treatments with diets contaminated with 75 and 100ppb AFB1/kg after 90 days). The increase AFB1 level of did not affect on the percent of survival rate(SR) and no mortality was observed in treatments (SR=100%) suggesting that various AFB1 levels under experimental conditions of the present study affect some growth factors, such as, weight gain and FCR but have no significant impact on SR and SGR.Histopathological studies showed that different level of AFB1 can cause broad range ofchange in liver tissue, including progressive fat deposition, hepatocyte degeneration andnecrosis, particularly at concentration of 75 and 100ppb AFB1/kg of diets after 60 days.

Fungal infection in the eggs of freshwater fish is well known as a problematic disease. Theaim of the present study was to isolate and identify parasitic and saprophytic fungi fromaffected eggs of rainbow trout at two fish hatchery in Kermanshah province. The samplewere inoculated in culture media (SDA,CMA,GPA and stilled water with cotton seed culture) at room temperature (18-24°C).17 species of fungi isolated from the fungal eggs. Five fungi species that isolated in this study were belonged to the saprolegniaceae family including Saprolegnia paraitica, Saprolegnia lapponica, Saprolegnia ferax, Saprolegnia hypogyna and Saprolegnia diclina. Another fungi that isolated in this study were, Fusarium oxyparum, Fusarium npoa, Fusarium sp., Penicilium citrinium, Penicillium expansum, Aspergillus treuse, Aspergillus clavatus, Cladosporium sp., Alternaria sp., Helmintosporium sp., Pscilomyces sp., Mocur. It seems that Saprolegnia parasitica with 26.8 percent of isolation was the most important fungal infestation of egg in kermanshah trout hatcheries. Mocur with 19.6% had the most frequency after S. parasitic and Fusarium, Aspergillus and Pescillomyces with 2.45% had the lowest frequency. In this study S. ferax, S. hypogyna and S. diclina are reported from Iran for the first time.

The population parameters and spawning season of the Spangeld emperor (Lethrinusnebulosus) were studied in coastal waters of Hormouzgan province. The monthly calculated mean values of gonadosomatic index (GSI) of females were indicate to increase from February, reach the highest in March and decline in June. The spawning season peak of L. nebulosus occurred in March. The Von Bertalanffy growth parameters, L, K and t0 were estimated as, 67.2cm, 0.16.year-1 and -1.161 year, respectively. The relationship between weight and length (Fork Length) can be expressed as W=0.051 L2.722, which indicates that Spangled Emperor has negative alometric growth.Using length converted catch curve, total mortality (Z) was estimated as 1.13 year-1 andnatural mortality was estimated using Pauly''s equation, as 0.57 per year. Finally, the fishingmortality (F) was 0.56, which gives an exploitation rate (E) of 0.50.

Khark and Kharko Islands are located at far northern point of fringing coral reefs in theIranian coast of the Persian Gulf. These coralline are the habitats of the wildlife refuge with total area of 2400ha and located in the territory of Bushehr province. The present study was carried out from July 2006 to June 2007 over 12 stations. Sampling was conducted obliquely from bottom using Bongo-net plankton sampler with 500μ of mesh size. In total, 1808 specimens, both in pre and post flexion stages were collected and examined. They were belonging to 45 families from different ecological groups (21 coralline and 24 non coralline fish larvae families). 96% of examined fish larvae were in preflexion stage. Some families are new ones from the area. Among identified families, Clupeidae, Blenniidae, Sillaginidae, Atherinidae and Tripterygiidae; were dominant families in studied area and the peaks were estimated in spring. The mean abundance of total fish larvae was 18.71 per 10m² of sea surface. The most abundant families were Clupeidae, Sillaginidae, Blenniidae, Atherinidae and Tripterygiidae in which comprised 65% of fish larvae. Abundance in spring showed significant difference with other seasons. The distribution pattern of fish larvae changed seasonally in both groups, increasing in east coasts of Khark Island and in three coastal stations during summer and autumn and in west coast of Khark in spring. The distribution of fish larvae seemed to be correlated to sea currents.

This study was done to investigate of some hematological and biochemical factors of rainbow trout (Oncorhynchus mykiss) fry in west of Mazandaran in Iran. About 50 pools of blood samples from diseased fry were collected within 30 months from November 2002 till March 2005 from three hatchery farms in western part of Mazanderan province. In addition 30 pools of blood samples as control group were collected randomly from mentioned farms. Each blood samples were examined for whole blood examination and blood enzymes measurement. It consist of total leukocytes (WBC) and erythrocytes counts (RBC), hemoglobin (Hb) content, hematocrits (PCV), leukocytes differential count and blood indices such as MCV, MCH and MCHC. Also blood serums were analysed for total protein (TP) and blood enzymes. All the calculations were made using the SPSS© and t-test statistical method.In hematological findings nine parameters were revealed significant differences (P<0.05)with control group in t-test. It consisted of total WBC, Lymph, Neut, Hb and HCT, MCHC,AST, DL and total protein plasma. Also in total white blood cell count, Lymph and Neut had significant differences as compared with the control fish (P<0.05). Also blood serumcomponents analysis revealed that only LDH and AST amount showed obvious significantdifferences (P<0.05). Regarding to results it could be concluded that hematological andbiochemical studies could be a valuable tool for prognosis and primary diagnosis in someinfectious diseases. So it could be recommended for monitoring and surveillance programs in coldwater hatchery health status in Iran.