Iranian Journal of Fisheries Sciences
Volume:12 Issue: 2, Apr 2012

Age determination and feeding habits of the Japanese threadfin bream, Nemipterus japonicus, was carried out in the northern Oman Sea (Chabahar area), based on 212 specimens collected between September 2009 and May 2010. The minimum and maximum fork length and body weight were measured as 145, 258 mm and 55.31, 288.12 g. The relationship between Body Weight (BW) and Fork Length (FL) for all individuals was estimated as BW= 0.0001×FL2.83 (r2 = 0.9425, n= 212). The Vacuity Index (VI) was 55.2% that shows N. japonicus is a moderate feeder. The maximum and minimum Gastro-Somatic Index for males was in autumn and winter seasons; and for females were in summer and spring. The Food Preference Indices were estimated as: crustacean (63.2%) as main food; fishes (38.9%) and molluscs (36.8%) as minor food. Age determination was done by otolith sectioning. A total of 135 sagitta were sectioned. The maximum age was 5+ years old for a female with FL= 256 mm and the youngest one was 1 year old for a female with FL= 145 mm. Based on obtained results there is a significant relationship between feeding and age namely with increase of age, the feeding rate is decreased without any changes in type of feeding and food contents.

This study was carried out to determine seasonal variation and zooplankton community structure in Karataş Lake, Southern Turkey. Zooplankton samples were collected seasonally between 2002 and 2003 in two stations using a zooplankton net of 55-µm mesh size. A total of 42 taxa were identified, including 19 taxa (45.2 %) Rotifera, 16 taxa (38.1 %) Cladocera, and 7 taxa (16.7 %). Copepoda. Among them, Keratella quadrata, Asplanchna priodonta from Rotifera, Daphnia longispina, Ceriodaphnia quadrangula, Chydorus sphaericus, Coranatella rectangula from Cladocera, and Eudiaptomus drieschi, Eucyclops speratus from Copepoda were dominant species. Spring and autumn seasons were found to be the most similar by using Sorenson index value.

This study was carried out during May 2010 – April 2011 in order to determine various biological properties of red mullet occurring in the Eastern Black Sea region. The average length and weight of 1435 specimens were determined as 13.13 cm and 23.14 g, respectively. Weight-length relationship was determined as W = 0.0088 L3.0338. The age distribution of this population ranged between I and VII. The female constituted of 66.2% whereas male 33.8%. Von Bertalanffy growth equation was, whereas for weight was. The GSI index reached its maximum value in June when relative fecundity was 2529.6 eggs g-1 body weight and the average egg size was 360.9 μm. The fecundity-total length and fecundity-weight relationships were calculated as F= 0.0651 TL5.1297 and F= 338.5W1.5128, respectively.

The freezing-thawing effect on the meat quality of whole, gutted and fillets of sea bass (Dicentrarchus labrax) were investigated. It was aimed to investigate the changes in the meat quality of whole, gutted and fillets of sea bass in multiple frozen (-18±2ºC) and thawed cycles in refrigerated conditions (4±2°C). The meat quality assessment of the sea bass groups (whole, gutted and fillets) subjected to multiple freeze and thaw cycles was performed by monitoring sensory quality, chemical analysis such as pH, total volatile basic nitrogen (TVB-N), trimethylamine nitrogen (TMA-N), thiobarbituric acid (TBA), crude protein and lipid content. The length of the thawing process caused quality changes such as dryness of the skin and undesirable odor formation. Thus the sea bass groups reached unacceptable levels after the 5th freeze/thaw process. According to the sensorial evaluation, no significant differences (P>0.05) were found in general acceptability values among the sea bass groups thawed under refrigerator conditions, but there was a significant difference in pH, TVB-N, TBA and crude protein (P<0.05) results. Significant differences (P<0.05) in TMA-N concentrations and crude fat were observed between the whole and gutted samples and also between the whole and fillet samples.

Nutritional value of freshwater mesozooplankton, fatty acid (FA) and amino acid (AA) compositions were determined in the middle of each season for a one-year period from May 2009 to February 2010 in Hanna Dam Lake, Isfahan, Iran. FA and AA composition significantly (P<0.05) varied in relation to the seasonal changes of water quality, phytoplankton and zooplankton community. The content of saturated fatty acids (SAFA), mono unsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) ranged from 22.4-29.0%, 30.9-40.4%, 11.8-20.9 % of dry weight (DW), respectively. The major SAFA were 16:0 (13.7-17.0 % DW) and 18:0 (4.9-7.0 % DW), whereas contents of MUFA were mainly 18:1n-9 (13.8-16.2 % DW), 16: 1n-7 (6.9-13.6% DW), and 18:1n-7 (5.7-10.6% DW). The major PUFA were 18: 2n-6 (2.6-11.7 % DW), 18: 3n-3 (2.4-3.1% DW), 20: 5n-3 (3.9-4.8% DW), 22: 6n-3 (0.73-0.99% DW), and 20: 4n-6 (0.56-0.73% DW). As for the ratios of n-3:n-6, the values were 0.70:1, 2.54:1, 2.10:1, and 1.73:1 in spring, summer, autumn and winter respectively. The mean essential amino acid (EAA) and non-essential amino acid (NEAA) were 28.7 and 71.3 %; 31.0 and 69.0 %; 31.63 and 68.4 %; 34.5 and 67.0 % of total amino acid in spring, summer, autumn and winter, respectively. The amount of tyrosin, isolucine, lucine, arginine, cysteine, aspartic acid, glycine and proline were higher in mesozooplankton population at summer and autumn compared to winter and spring

This study was aimed to gain knowledge on the ontogeny of digestive enzymes in common carp larvae at the governmental Warm water Fish Aquaculture Center of Shahid Rajaee in Sari, Mazandaran, Iran. The ontogenetic development of pancreatic (trypsin, chymotrypsin, lipase and α-amylase) and intestinal (alkaline phosphatase and aminopeptidase-N) enzymes were assessed in common carp larvae from first feeding (3 days post hatching) to 33 days post hatching (dph). The larvae started to feed on rotifers at day 3 to day 7. Feeding on a commercial diet was started from day-8 onwards. Specific trypsin and chymotrypsin activities feed with rotifer were 0.011 U/mg protein and 0.003 U/mg protein at day 7, respectively; then the specific activities feed with dry food reached a maximum level at 33 dph (0.028 U/mg protein and 0.028 U/mg protein, respectively) (P<0.05) compared to live prey. The elevated alkaline proteases activity can be related to adaptation of larvae to digest protein content in the food. Specific lipase activity was 0.0006 U/mg protein at 7 dph; then the activity feed with dry food reached a maximum level at 15 dph (0.0011 U/mg protein) (P<0.05) compared to live prey. Specific α-amylase activity feed with rotifer was 85.86 U/mg protein on the 7 dph; consequently, its specific activity reached a maximum level at 15 dph (128.77 U/mg protein) (P<0.05). Specific alkaline phosphatase and aminopeptidase N activities feed with rotifer were 6 U/mg protein and 0.0106 U/mg protein at day 7, respectively; then the specific activities feed with dry food reached a maximum level at 33 dph (28.66 U/mg protein and 0.58 U/mg protein, respectively) (P<0.05) compared to live prey.

White Spot Disease (WSD) is well known as a widespread viral disease in shrimps from 1992. Many studies focused on morphological, histopathological and epidemiological characteristic and pathogenecity of the disease but less on the determination of the severity of WSD using the histopathological features in target tissues. A generalized scheme for assigning a numerical qualitative value to severity grade of infection considering to histopathology and counting the inclusion bodies in different level of infection and different microscopic fielding immersion lens was accomplished before. This study was conducted in order to estimate the rate of infection (ROI) and the severity of infection (SOI) of WSD in native shrimps inthePersian Gulf.About 90 live specimens of affected cultured Penaeusindicuswere collected from Abadan region, south Iran and 150 specimens of native shrimps were captured from the Persian Gulf.Histopathological changes were observed by light microscope in target organs such as: gills, cuticular epidermis, heart, hemolymph, fore stomach and hepatopancreas. ROI and SOI were estimated respectively by standard formulas and grading between 0-4 based on the percentage of white spot syndrome virus WSSV positive cells in selected fields of microscope. The results were confirmed by conducting nested PCR method. The SOI of P. styliferawasestimated in grade fourand its ROI was about 85% as the most susceptible species.Histopathologic infection of Metapenaeusaffinisshrimp by WSD was observed also during this study

This study was conducted to investigate the effects of partial replacement of dietary fish meal with soybean meal (SBM) on some blood and serum parameters of Beluga (Huso huso) juveniles. Three isonitrogenic and isoenergetic diets, as SBM1 (Soybean meal protein (SBP): Fishmeal Protein (FP) =1:3), SBM2 (SBP: FP = 2: 3) and SBM3 (SBP: FP =1: 1) were fed to triplicate groups of fish. After 8 weeks feeding on the experimental diets, blood parameters were measured. The results revealed that of partial replacement of dietary fish meal with soybean meal had no effect on, leukocyte (WBC) levels, red blood cell counts (RBC), mean corpuscular volume (MCV), mean cellular hemoglobin (MCH) or mean cell hemoglobin concentration (MCHC) (P>0.05). However, hemoglobin (Hb) concentration and hematocrit (Hct) values were significantly decreased by increasing dietary soybean meal (P<0.05). Serum glucose had significantly affected by increasing soybean meal. While total protein, phosphorus or calcium remained unaffected between groups. These results indicated that partial replacement of dietary fish meal with soybean meal could affect on some haematological and biochemical parameters in beluga which should be studied in future

Regarding low fertilization rate of Barbus sharpeyi, one of the main Barbus species in south of Iran, saline activator solutions (SAS 1 and 2) were used for increasing of sperm activation and its sperm quality indices were assessed by using Image J software as a fish sperm adapted tools. SAS 1 (45mM NaCl, 5mM KCl, 30mM Tris, 188±2.3 mosmol/kg) and SAS 2 (50mM NaCl, 30mM KCl, 30mM Tris, 189±1.7 mosmol.kg) were added to a mixture of 12 male semen comparing with distilled and tap water and their effects on VCL, VSL, ALH, Linearity, %motility, spermatozoa path, % A, B and C spermatozoa type, fertilization, hatching and deformity rate were analyzed in triplicate. Results showed that SAS2 had the highest VCL (21.37±0.36 µm/s-1), VSL (11.6±0.3 µm/s-1) and motility percentage (85.75±1.56 %) among treatments. The highest A type spermatozoa percentage was recorded for SAS1 (47.16±3.15 %) and SAS2 (43.89±4.54%). The lowest C type spermatozoa percentage was recorded using SAS2 (14.24±1.56 %). Also, the highest fertilization rate was achieved from SAS2 (79.5±0.37%) and SAS1 (77.74±4%) respectively. Furthermore the lowest larval deformity rate (13.77±1.03%) was shown due to the use of SAS2. Final conclusion confirmed that SAS1 and SAS2 have positive and significant effects (P < 0.05) on extending the time length of sperms movement, VCL and VSL of B. sharpeyi which consequently resulted in better efficiency of propagation of this species in south of Iran

The aim of the investigation was to determine the changes in fatty acids profile and chemical quality indexes of Red Tilapia fillets during frozen storage at -18°C. The fish were filleted by hand. The prepared fillets were then placed to the polyamide pouches and stored at -18°C for 150 days. Fatty acid profile, sensory properties and chemical quality indices were determined for a five month period. Results showed that 29 fatty acids were identified in the fresh and frozen samples. Polyunsaturated fatty acids (PUFA) were found higher than saturated fatty acids (SFA) in fresh samples but after 150 days of frozen storage this ratio became reverse. Oleic acid and Linoleic acid were the major MUFA (mono unsaturated fatty acids) and PUFA in fresh and frozen samples, respectively. The ratio of n3/n6 decreased from 0.59 to 0.49. The thiobarbituric acid value (TBA. Mg malondialdehyde/kg) increased significantly (p<0.05) throughout the storage time from 0.03 to 1.26. Peroxide value (PV), Total volatile bases (TVB-N) and pH value also increased but were well within the limit of acceptability

Understanding the scale at which wild stocks of Persian sturgeon (Acipenser persicus) are genetically discrete is necessary for effective management of this commercially important species. Disomic DNA microsatellite markers are among the best tools for determining stock structure in fishes. As all sturgeon species have a polyploid ancestry of all sturgeons, most gene loci exhibit more than two alleles per individual, limiting the use of powerful analytical methods that commonly assume disomic inheritance. We scored products from 38 sets of microsatellite primers developed in lake (Acipenser fulvescens) and Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) to determine whether they would amplify disomic loci in Persian sturgeon. Samples of 45 individuals were detected.Thirty six loci (95%) were amplified successfully in Persian sturgeon. We identified; a single monomorphic locus, 12 disomic, 19 tetrasomic, three octosomic, and one locus that was ambiguous. This is the first report on development of disomic single-locus DNA microsatellite markers in Persian sturgeon. These loci could be used to characterize variation in geographically discrete populations of the Persian sturgeon in their native ecosystem including in the Caspian Sea

Heavy metals are considered as the most dangerous water contaminants because of their possibility of bioaccumulation and toxic effects. This study tried to investigate the bio-availability of heavy metals in terms of Ni, Zn, Cu, Fe, Hg, Cd, and Pb in the sediment during dry seasons in Aras River basin located in Ardabil Province, north-west of Iran. Also the metal concentration in the skin and flesh carp was measured during all four seasons in 2010 in Aras River. Sediments were collected from five stations during summer but fish sampling was carried out seasonally in five fixed stations. The results of this study indicated that there was a meaningful and positive correlation between the existence of high levels of bioavailable metals and their concentration in fish body. Among the measured metals, Fe is highly bioavailable and the highest level of Fe in the sediment was in the ST4 (93.4mg/l). This could be due to high accumulation of this element in fish body. Also, maximum concentration of Fe in fish body was in summer (1.87mg/l) as well

The present investigation was undertaken to determine temporal and spatial distribution of macrofauna in low tide regions of Bushehr province in the northern Persian Gulf. Sampling was seasonally carried out by a box corer of 0.0225 m2 in six stations including Genaveh, Farakeh, Shif, Bandargah, Rostami and Asalouyeh from summer 2008 until spring 2009. In this study, 752 specimens belonging to 29 genera were collected. Polychaetes were dominant both in terms of genus number (22) and relative abundance (77.1% of total macrofaunal abundance). The other dominant groups were crustaceans, bivalves and turbellaria. The highest number of Prinospio and Solen specimens were found in Genaveh, Farakeh, Bandargah, Rostami and Asalouyeh stations with sandy substratum; however Capitella sp. and Nicomache specimens were collected only in silt–clay substratum of Shif station. The highest (888.89 ind. m-2) and lowest (37.03 ind. m-2) annual average density of macrofauna were found in Farakeh and Asalouyeh regions, respectively. R- square in quadratic Regression equation between temperature and macrofauna density and Shannon wiener species diversity index were assessed to be 0.988 (P= 0.044) and 0.992 (P= 0.09), respectively. The annual Principal Component Analysis indicated that in stations 1- 5, the organic matter content, sediment texture and temperature have had the most influence on the macrofauna assemblage, but comparison of species composition, density and Shannon wiener species diversity index of macrofauna in Asalouyeh with previous recorded data of the region showed that manmade factors such as gas and petrochemical industries have had the most effect on the macrofauna community structure during sampling period

A reproductive biology study of blue swimming crab, Portunus segnis (Forskal, 1775) in the northern Persian Gulf and Oman Sea, was conducted from May 2010 to October 2011. The results showed that the annual sex ratio is not M: F=1:1, with 51.9 % female. All the five stages of ovarian development of P. segnis were observed throughout the year. The size of ovigerous crabs varied from 103 to 155 mm. carapace width. This crab can spawn all year round with a spawning peak in mid-winter to early of spring season. The fecundity of ovigerous crabs ranged from 521027 to 6656599 eggs, with average fecundity of 2397967 eggs. The minimum carapace width (CW) of female crabs that reach sexual maturity was 92-138 mm and the length at which 50% of all ovigerous females was 113 mm carapace width.

In this study, a water quality model of Haraz basin was used as an evaluative tool to estimate the spatial distribution of variables that are related to water quality and nutrient loads of the Haraz River. Previous studies performed in this river indicate that trout culture activity along the Haraz River have led to various changes in the water quality parameters. In the present work, the possible effects of two additional fish farms with a production capacity of 50 tons, located on the Haraz within 1 km distance from each other were evaluated in terms of their effects on the streams water quality. A water quality model was developed in order to investigate the spatial distribution of water quality variables. The model also used to estimate the dissolved oxygen (DO), biological oxygen demand (BOD5) and nutrients along the stream.

This study was conducted to evaluate the possibility of replacing Z. multiflora instead of antibiotics and chemicals in shrimp aquaculture industry to protect the environment and prevention of microbial resistance. In vitro MIC of Z. multiflora essential oil against Candida albicans and Fusarium solani obtained 0.004% and 0.008% respectively, also MFC of Z. multiflora essential oil against C.albicans and F.solani was 0.004% and 0.04%, respectively. The results showed that 0.0002% dosage of Z. multiflora essential oil against total count of fungi in sea water (salinity 39±1ppt) can decrease growth of fungi after 6 h and 0.0004%, 0.0008% and 0.0016% dosages can decrease the total count of fungi in sea water. But very low dosage of Z. multiflora essential oil in shrimp Litopenaeus vannamei leads to mortality. Lethal dose of Z. multiflora essential oil in shrimp postlarvae, juvenile (2±0.2g) and adults (10-12 g) was 0.00050%, 0.00045% and 0.00035%, respectively. The results indicated that Z. multiflora have a significant anti-fungal effect but is toxic for L. vannamei. We recommend that Z. multiflora essential oil can be used in non-living environment, such as disinfecting tanks and equipments

The effects of starvation and subsequent re-feeding on compensatory growth performance, blood serum metabolites and IGF-ImRNA expression in liver and muscle were investigated in juvenile Persian sturgeon. Growth indices including body weight, SGR, CF, and HSI significantly decreased after starvation. However, after re-feeding sturgeons that were starved for 1 week reached the same weight as the control, indicating that complete compensatory growth had occurred. Conversely, sturgeon in longer periods of starvation showed only partial growth compensation. HSI values decreased significantly during starvation, although they returned to the control fish levels after re-feeding. Plasma levels of glucose and insulin during starvation and re-feeding did not significantly change. This suggests that sturgeon is able to maintain glycaemia during starvation, probably due to their non-carbohydrates source dietary. Plasma total lipid level in un-fed treatments, however, was found to increase, possibly as a mechanism to utilise lipids as a fuel during starvation. IGF-I mRNA expression in liver and muscle increased during starvation and decreased after re-feeding. However, changes in the IGF-ImRNA expression were not significantly different among treatments. These results indicate that a periodic short-term starvation in Persian sturgeon does not adversely sacrifice overall fish weight gain and sturgeon can realise compensatory growth