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Age and growth of marbled sole Pleuronectes yokohamae werer estimated from growth increments in otolith. The samples were collected with commercial set nets and an experimental bottom trawl net in Kikonai Bay and the nearby waters, southern coast of Hokkaido, from May 1994 to July 1995. Monthly changes in the percentage occurrence of oltoliths with translucent edge in one band and the marginal increments on the other hand verified that the translucent zone was formed once a year after their spawning season in May, indicating availability of outer margin of translucent zone as an annulus. The regression method as well as Fraser-Lee's method was used to estimate the back-calculated lengths. Growth of marbled sole was expressed by the von Bertalanffy asymptotic growth function: TL_t=361.78[1-exp-^{0.390(t-0.098)}) for males and  TL_t=438.15[1-exp-^{0.323(t-0.145)}) for females using back-calculated lengths by the regression method and TL_t=367.04[1-exp-^{0.388(t-0.114)})] for males and TL_t=436.05[1-exp-^{0.323(t-0.147)}) for females by the Fraser-Lee's method, where TL_t is total length (millimeters) at estimated age t.
The theoretical lengths predicted by these two methods at all estimated ages were very similar. It was found that the growth rate of marbled sole in this study area was relatively high compared to those obtained in the Inland Sea of Japan as. However, the highest growth rate was observed with regard to the population off Fukushima Prefecture, although the bottom water temperatures were similar to those in Kikonai Bay. It is inferred that the geographical variation in the growth rates of marbled sole is influenced by the hydrographic and food conditions.

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Gelatin was extracted from hydrolyses of collagen muscle bonds. Gelatin was of two types. Type A was obtained from acidic and type B from alkaline procedures. In the present study we used sturgeon fish skin to produce 25 samples of gelatin. Microbiological and chemical examinations were conducted on the gelatin samples. Based on the results obtained from the chemical examination, gelatin type A and B were composed of 15.40% and 15.30% total nitrogen, 0.30% and 0.25% CaO, 6.48% and 7.26% moisture, 1.59% and 2.89% ash, and 1.51% and 1.2% fat, respectively. The pH of gelatin A was 4.23 and that of B type was 7.00. Total count obtained from microbiological examinations was 10-70 cfu/g. The quality of gelatine prepared from sturgeon skin met the requirements of standard gelatin. Time required for production of gelatin using acidic procedure was one week whereas the production of gelatin using the alkaline procedure lasted 3 weeks. The yield of gelatin obtained from alkaline procedures (4.52%) was less than that of acidic gelatin (6.33%).

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Impact of Atlantic salmon (Salmo salar) cage culture in Mjoifjordur, Eastern Iceland on the chemistry of the sediment was investigated. Sediment samples were collected using a Shipek grab in December 2003. A core sub-sample was taken from each grab for analyzing total organic matter, total organic carbon, total nitrogen and phosphorus in different depths from three stations at various distances from the cage. These parameters were analyzed in the top layer of additional four stations. The results showed significant increase in all analyzed parameters in station 1, at 5m from the cage (p<0.05). The difference between reference station (600 m from the cage) and station 2 at 95 m to the cage was insignificant (p>0.05), indicating localized impact of cage farming to the vicinity of cage. The analyzed parameters in various depth did not show significant differences (p>0.05). The value of analyzed parameters in the perimeter of the cage and their differences with reference stations showed small magnitude and localized impact on the chemistry of sediment. It might be due to deep water and moderate velocity of water current in this fjord. The magnitude of impact may differ during the summer season when biomass and feeding rate would be at the maximum level.

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Ensiling as one of the best methods for utilization of tuna wastes was investigated. docosahexaenoic acid [DHA C22:6(n-3)]- rich products were obtained from the wastes (viscera and dark meat) of four tuna species, namely longtail, skipjack, yellowfin and kawakawa by a procedure involving ensiling in organic acids followed by neutralization. Identification of fatty acids in the samples was performed by comparison with chromatograms of fatty acids standard.
Total lipid content of silages varied from 10.41% in skipjack dark meat silage to 22.01% in kawakawa viscera silage, but all lipids contained high percentages of DHA and EPA [eicosapanteoneic acid C20:5(n-3)]. The highest DHA ratio (15% of total lipids) was found in the lipid of skipjack viscera silage and the highest ratio of EPA (11% of total lipids) belonged to the lipids of kawakawa dark meat silage.
ANOVA test results indicated that DHA ratio was significantly high before silage preparation and linolenic acid [C18:3(n-3)] content significantly differed between the species (p<0.05).

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Non-compliance with fishing regulations by Iranian fishermen in three provinces of Khuzestan, Bushehr, and Hormozgan along the Persian Gulf was investigated. Using a questionnaire and a stratified random sample method, a total of 566 fishermen were interviewed. The legitimacy variables (outcome and process) that can explain the observed noncompliance with zoning regulations for the shrimp fishery were examined. A Tobit econometric technique was used to estimate the violation decision by Iranian fishermen in the study area. The model was classified into two types: the basic model and the extended model. The key results indicate that one of the factors influencing fishermen to violate the regulation is the differential in the potential income between shrimp fishing zone and other areas. The results also indicate that the moral judgment variable (MCODE) and exogenous variables of probability of detection and conviction play a key role in the violation decision of fishermen. In general, the extended model using an exogenous determinant of probability of detection and conviction in the Tobit estimation technique gave better results than the enriched model using raw probabilities.
 

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Population structure of three kilka fishes (Clupeonella spp.), particularly anchovy kilka (C. engrauliformis), in Iranian waters of the Caspian Sea was surveyed in 2003. A total of 3230 biweekly samples were collected from commercially landed kilka at 3 stations in Mazandaran and Guilan provinces. Catch and effort statistics were obtained from the relevant organization. Results showed a great decline in the commercial kilka catch from 95000 tons in 1999 to 15497 tons in 2003. The contribution of anchovy kilka to the total kilka fishery also showed a decline from 71% in 1999 to 52.5% in 2003, while common kilka (C. cultriventris) increased from 13.7% in 1999 to 48.9% in 2003. Fork length range of anchovy kilka showed an increase from 89.2±12mm in 1999 to 100.4±4.9mm in 2003. The age composition of anchovy ranged between 1+ to 7+ years and the dominant group was 5+ years old (age group of 4+ and 5+ comprised 84.6% of population). The K value and L∞ calculated 0.598/year and 110.13 mm respectively. Natural, fishing and total mortality coefficient was estimated 0.69, 0.31 and 1 per year respectively. The results showed a sex ratio of F: M= 68.2: 31.8.
 

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This paper examines the changes in the population biology and biomass of common kilka (Clupeonella cultriventris caspia) in the Iranian waters of the Caspian Sea from 1995-2004. For most years during this 10-year period, we estimated the age structure of the catch, length-weight relationship, von Bertalanffy growth parameters, condition factor, sex ratios, maturity stages determined from ovarian analysis, natural and fishing mortality, age at first capture and biomass. Growth parameters were estimated as L¥=132mm, K=0.259/yr, t₀=-1.285/yr. The instantaneous coefficient of natural mortality was estimated at 0.506/yr and the instantaneous coefficient of fishing mortality varied during the 10-year period between 0.125/yr to 1.487/yr. Biomass of the common kilka increased from about 16,000mt in 1995 to more than 41,000mt in year of 2002. This increase in common kilka was simultaneous with a sharp decline in anchovy kilka, changes in zooplankton abundance and composition, and especially increase in zooplankton species used by common kilka. We concluded that at the present time, the stock of common kilka is being over-fished.

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Age structure of the Caspian Sea anchovy kilka, Clupeonella engrauliformis, was estimated for the first time by back-calculation methods. Otolith growth and the rate of increment in anchovy kilka were examined to determine whether otoliths could be used to back calculate body sizes at various life stages. Sampling was carried out on commercial fishing vessels board along the Iranian coast in 2007. The age structure of the samples ranged from 2 to 7 years old which was dominated by the third year class (38.6%). The largest fish measured was 137.2mm fork length. The relationship between fork length (FL) and otolith radius (OR) was described by the following equation: FL=13.77+ 82.78*OR (r²=0.92). Three proportional back-calculation methods, Fraser-Lee, Whitney & Carlander and Dahl-Lea models, were compared by using data sets of anchovy kilka otoliths, and we validated back calculation by comparing them with observed lengths. Back calculated lengths generally corresponded well with observed lengths in anchovy kilka age classes. Variance of the back calculated length data obtained from three models indicated no significant difference (P>0.05).

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Common carp (Cyprinus carpio) represents one of the most economically important fish species in the Caspian Sea. In this study, growth and mortality parameters among population of common carp was investigated. Sampling was carried out weekly, using beach seine in the south of the Caspian Sea from October 2006 to September 2007. As a contribution to elaborating management programs for common carp, the age and growth of this species was calculated via scale, growth parameters and mortality rate by length frequency data obtained from commercial fishing and research beach seines. Ten age groups were recorded from 1+ to 10⁺ years old, being dominated by 4 and 5 year-old fish. The growth parameters based on scale reading data by length at age analysis were FL¥= 71.52cm and K = 0.16 per year for total population, FL¥= 70.54cm and K = 0.15 per year for males, and FL¥= 72.00 cm and K = 0.16 per year for females, whereas by length frequency analysis, these values were estimated as FL¥ equals 72.0, 69.3 and 73.0cm and K equals 0.18, 0.15 and 0.18 per year for total population, males and females, respectively. The total, natural and fishing mortality rates were 0.71, 0.29 and 0.42 per year, respectively.

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  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 NaA indicated a significant difference in formation of free fatty acids in comparison with other sodium salt-treated samples on 9 and 12 days after storage. Sticks dipped in NaL had a maximum 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.

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 Microbiological, chemical and sensory changes of fish burgers prepared from deep flounder (Pseudorhombus elevatus) and brushtooth lizardfish (Saurida undosquamis) were determined during storage at -18ºC 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 5^th 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.

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  In the present study, the effect of stirring speed and the type of cross linking agent on the size and formation of microencapsulated Silver carp (Hypophthalmichthys molitrix) oil were investigated. The gelatin/gum Arabic was used for encapsulating and the capsules were prepared by complex coacervation. Microcapsules were analyzed by optical microscopy technique and particle size analyzer. Results suggested the use of glutaraldehyde as the cross-linking agent instead of formaldehyde can caused the Microcapsules become spherical shape, smooth surface with no obvious dents and narrower particle size distribution. The average particle sizes were 537.2±0.8 μm, 84.4±0.5 μm, 12.98±0.4 μm, 8.24±0.5 μm, and 4±0.7 μm at the homogenization stirring speed of 100, 300, 500, 750 and 1000 rpm respectively. The best conditions of experiment were with 25% glutaraldehyde at 1000 rpm of stirring speed.

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  The aim of the present study was to investigate the age structure, length-weight relationship, sex ratio, sexual maturity stages, growth parameters, natural and fishing mortality coefficients of three species of kilka including common, anchovy and bigeye kilka. The fork length–weight relationship of common, anchovy and bigeye kilka were calculated as W=0.000153 FL^2.37, W=0.000349 FL^2.18 and W=0.00160 FL^2.97, respectively. The parameters of the von Bertalanffy growth curve for length were L_∞ = 143.5 mm, K = 0.30 yr^-1 and t₀ = -1.02 yr for common kilka L_∞ = 151.9 mm, K = 0.28 yr^-1 and t₀ = -1.12 yr for anchovy kilka L_∞ = 148.6 mm, K = 0.46 yr^-1 and t₀ = -0.18 yr for bigeye kilka. The instantaneous coefficient of natural mortality of common, anchovy and bigeye kilka were estimated as 0.671, 0.633 and 0.881 yr^-1, respectively. The current exploitation rates of three species were estimated as 0.55, 0.41 and 0.26, respectively. The results suggest that common kilka stock is under over-fishing now.

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  The effect of gamma radiation (1, 3 and 5 kGy) on microbial quality of farmed rainbow trout (Oncorhynchus mykiss) fillets which were stored under frozen conditions (-20° C) was studied by measuring microbiological changes in 5 months. Gamma irradiation and increasing of frozen storage time had significant effects (P<0.05) on the reduction of microorganism's population. The total count showed that all samples maintained acceptable microbiological quality until the end of the fifth month of frozen storage. The lowest microbial load at the end of the fifth month of frozen storage was related to irradiated samples at 3 kGy (2 Log CFU/g). Yeasts and molds were below the detection levels in both irradiated samples at 1 and 5 kGy until the end of the third month and in irradiated samples at 3 kGy throughout the frozen storage. The population of yeasts and molds increased in irradiated samples at 1 and 5 kGy in the fourth and fifth month of frozen storage. Growth of coliform bacteria and Salmonella wasn't observed in control and irradiated samples due to good hygienic quality of fish breeding, fishing, handling, filleting and packaging and also effect of freezing on elimination and inactivation of mesophilic microorganisms.

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  For this study one species of Shyrnidae family caught along Persian Gulf in Bandarabbas city. Sphyrna lewini were transferred to the laboratory on spring 2007. The antimutagenic activity of the Methanolic and Chloroforamic extracts of muscle, liver and cartilage of Sphyrna lewini with the Ames test was investigated. The use of antimutagens and anticarcinogens in everyday life is the most effective procedure to prevent human cancer and genetic diseases. Since angiogenenesis is a key factor in tumor growth, inhibiting this process is one way to treat cancer. In this study the antimutagenic effect of the Chloroformic and Methanolic extracts of muscle, liver and cartilage on the damage induced by two mutagens was studied. The results driven from this study were inhibitory effect of two extracts. The highest antimutagenic effect was determined in the Potassium Permanganate and Sodium Azide as a mutagen was Methanolic extracts of cartilage . There is a general correlation between mutagenesis and the initiation stage of carcinogenesis. Mutagens appear to initiate the process by inducing the primary DNA lesion. These are called initiators and the damage they cause is generally irreversible.

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  Artificial reefs are used to compensate the destruction of marine ecosystems. In the present study, the effects of artificial reefs were compared to natural sites. For this purpose, five treatments including four different forms (Reef ball (R), Laneh Mahi (L), used materials (U) and R+L+U) of artificial reefs and one control were established. The reefs were deployed at Bandar Lengeh, the Persian Gulf. At each site, the fish sampling were carried out every three months for one year. According to data, significant differences (p<0.05) were found between the artificial reefs and the control sites in terms of Catch Per Unit Effort (CPUE). Among the reef treatments, the best enhancement of CPUE was for the mixed form of reefs compared to other forms and control. The present study indicates that the artificial reefs deployed have enhanced the fish community.

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  Estimates of age, growth parameters, length-weight relationship and length and age at first maturity of the otolithes ruber are required for fishery management. We used counting annuli on the section of sagittal otoliths to age O.ruber from the Northwest Persian Gulf in south of Iran. Estimated ages ranged from 0 to 6 years, and maximum frequency of fishes was observed in age-group 1. The values of growth parameters L_∞, k and t_o were calculated by von Bertalanffy model and the results were 67.57 (cm), 0.27 (year^-1) and -0.43 respectively. Parameters b and an in length-weight relationship were calculated 3.19 and 0.005 respectively. Length and age at first maturity were estimated 28 cm and 1.55 year.

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 The present work has been carried out to investigate the probable effects of fish cage culture on benthic communities as a pollution and stress indicator and to evaluate the biotic health condition using BOPA index, in Ghazale Creek (Khowre-Mussa - Persian Gulf). Monthly sampling from 4 stations was carried out from June 2007 to March 2008 (during nine months). Stations were selected from under the cage to 400 m distant (as control site) in Ghazale Creek. Three samples were taken at each station for macrobenthos and one for sediment grain size and total organic matter (TOM), using a 0.0125 m² van veen grab. Also physical-chemical parameters sampling from three stations was done (during nine months). Stations were under cage station, 50 m and 400 m far from cages in Ghazale Creek.The percentage of total organic matter (TOM) in sediment ranged from 6.11 to 23.26 and the range of silty-clay percentage was from 4.76 to 97.47. The dominant macrobenthos groups were Polychaets (60.62%), Mulluska (19.67%), Crustacea (16.49%). Macrobenthic abundance, biomass and diversity index values in the under cage station were less than that in the control station. Comparing the results of BOPA with the guidelines shows that all stations had bad environmental conditions. The under cage station was more polluted than the control station. The range of physical-chemical parameters in water were: DO _­(6.5-11.43) ppm,­ BOD ­(1.5-10.9) ppm, Salinity (43-45.6) ppt, NO₂^- (0.006-0.29) ppb, NO₃^- (3.98-32.2) ppm, Turbidity (14-70)­ NTU temperature (11.8-32.5) ° C.

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  In this study changes in fatty acids profile during frozen storage at -18°C of Cobia (Rachycentron canadum), caught from the Persian Gulf (Bandar Abbas) were studied. Changes in saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), EPA+DHA/C16, n-3 PUFA/n-6 PUFA (n-3/n-6) and polyunsaturated fatty acids /saturated fatty acids (PUFA/SFA) were investigated during a six- month storage at -18°C. Eighteen fatty acids were found in Cobia, with higher percentage of saturated fatty acids (46.07%), monounsaturated fatty acids (33.72%) and polyunsaturated fatty acids (15.44%). The MUFAs and PUFAs reduced from 33.72 to 26.26% and 15.44 to 10.78%, respectively. Palmitic acid (C16:0, 27.42% of total fatty acids) and stearic acid (C18:0, 12.62%) were the dominant saturated fatty acids. The major unsaturated fatty acids were determined as docosahexaenoic acid (C22:6n3, 5.76%), oleic acid (C18:1n9, 25.76%) and linoleic acid (C18:2n6, 4.38%). As a result of the frozen storage (up to 6 months), marked content decreases were found in fatty acid groups such as monounsaturated, polyunsaturated and n-3 polyunsaturated, as well as in the n-3/n-6 ratio and it means that the nutritional value of Cobia has decreased.

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The present study was carried out during 2006-2007 along the southern Caspian Sea. The species composition showed that the common kilka, Clupeonella cultriventris caspia, is dominant species with 89% and then anchovy, C. engrauliformis, has shown only 8.7% while it was already dominant species in the past decades. The overall results indicated that common kilka was replaced with anchovy kilka as previous dominant kilka species due to invasion of Mnemiopsis leidyi to the southern Caspian Sea. Anchovy suffered greatly from M. leidyi so that the total catch dropped from 95000 mt in 1999 to less than 20000 mt in 2007. In our survey, 1415 fish specimens were collected randomly, including 221 anchovy, 281 bigeye and 913 common kilka. The mean length of anchovy was 117.8 ± 0.27 mm, while it was about 93.0 mm during 1995 to 1998 before the invasion of M. leidyi. Analysis of age classes indicated the mean age of 4.5 ± 0.04 years for anchovy, 3.6 ± 0.03 for common kilka and 4.6 ± 0.08 for big eye C. grimmi. According to the age and the length structure of the specimens in this study, it could be concluded that in recent years, young fish population of anchovy has been decreased in comparison with the last decade. The results showed that some biological characteristics of kilka population were affected by M. leidyi. Recently fishing activities take place in shallow waters where schools of kilka are in suitable density for fishing. According to our results, ctenophore occupied the anchovy habitat where it was mainly more than 50 m depth. The fishing has moved to areas with depths less than 50 meters where it was the main reason to change in species composition.