Iranian Journal of Fisheries Sciences
Volume:20 Issue: 3, May 2021

Four feeding levels (40%, 60%, 80% and 100% of satiation) were designed as the different treatment groups to assess its effects on water quality and plankton community structure in the yellow catfish rearing enclosure ecosystem. The results showed that the weight gain and specific growth rate decreased significantly as the feeding level decreased. The soluble nutrients (except for NO2-N) concentrations were significantly affected by the feeding level with the prolonging of rear time. A significant increase in phytoplankton biomass before 9 days was observed in all the treatments, and then decreased significantly until 21 days, while the zooplankton biomass was significantly increased during the entire experiment. Both the phytoplankton and zooplankton biomass were significantly affected by the feeding level. Our results suggested that the increment of nitrogen compounds before 9 or 12 days could be explained by the input of compound diets, while the decrement of nitrogen compounds afterward and phosphorous compounds could be explained by the changes of zooplankton biomass. Based on water quality and plankton structure, moderate nutrient restriction (60%-80% of satiation) is a feasible feeding strategy for better growth performance as well as better water quality and balanced plankton structure. On the other hand, input of moderate phosphorus by dietary supplementation and/or fertilization is necessary in yellow catfish culture both for the better plankton structure and the health of fish. In addition, the polyculture of the minority members of zooplankton filter feeders might be a feasible strategy to control the excessive zooplankton.

The appropriate temperature and growth supplementary factors such as fetal bovine serum (FBS) are the necessities needed for cell growth in culture medium. In this regards, the effect of Leibovitz-15 (L-15) medium containing different concentrations of fetal bovine serum (FBS) was assessed on growth and proliferation of cultivated liver cells of klunzingerchr('39')s mullet, Liza klunzingeri, incubated at various temperatures. Ten fish were dissected and the liver was removed and cut into small pieces. The hepatocytes were then disconnected using collagenase type IV. The cells were cultivated for 2 weeks in L-15 containing 0, 5, 10 and 20% FBS and incubated at 20, 25, 28 and 30oC. According to the results, an increase in temperature up to 30°C led to an increase in growth and number of cultured cells, but temperature rise above 30°C had no significant effect on growth of cultivated liver cells from L. klunzingeri. Cells cultivated at 20°C did not attach to the culture plate and died. Growth rate and the number of cultivated hepatocytes increased dose dependently and the maximum amount of growth was recorded in cells treated with 20% FBS at the end of the experiment. In conclusion, the general conditions for primary culture of hepatocytes from L. klunzingeri reported in the present study represented a foundation to establish an in vitro system for L. klunzingeri liver cell culture.

Sumac (Rhus coriaria L.), belonging to the Anacardiaceae family, grows in Mediterranean countries, North Africa, South Europe, Afghanistan and Iran. The sumac berries contain biological activities such as antioxidant, antimicrobial, hypoglycemic and antidiabetic. The present study examined the effects of water extract of sumac on the chemical, microbiological and sensory quality on silver carp (Hypophthalmichthys molitrix) fillets during storage at 4๐C. Treatments in the present study included the following: Control without extract of sumac, 1, 2.5 and 5 % (w/v) the water extract of sumac. After 18 days of storage, the results showed that the lowest total viable count (TVC) (7.34 log 10 cfu g-1), psychrophilic total counts (PTC) (7.21 log 10 cfu g-1), pH (6.43), total volatile basic nitrogen (TVB-N) (23.38 mg N 100g-1), Thiobarbituric acid (TBA) (1.66 mg MDA kg-1) and peroxide value (PV) (5.28 meq kg-1) were recorded in 5% sumac water extract treated samples, while the highest TVC (9.01 log 10 cfu g-1), PTC (8.97 log 10 cfu g-1), pH (7.15), TVB-N (38.71 mg N 100g-1), TBA (2.82 mg MDA kg-1) and PV (9.41 mEq kg-1) occurred in the control group. The best outcome of sensory evaluation was acquired in samples that treated with 5% sumac water extract and was significantly different (p≤0/05), when compared to the control group after 18 days of storage. Natural preservatives such as sumac extract can be used as a safe method for storage of silver carp fillets, which is quite promising for food industry.

The present study represents a comprehensive molecular assessment of some family of freshwater fishes in Iran. We analyzed cytochrome oxidase I (COI) sequences for five genus of cypriniform fishes from Iran. The present investigation provides data on genetic structure of some species of Nemachilidae including Paraschistura bampurensis, Oxynoemacheilus kiabii and Turcinemacheilus saadii and Leuciscine cyprinids Alburnoides bipunctatus and Alburnus  alburnus from inland waters of Iran. The DNA sequences of the mitochondrial COI gene in all fishes were amplified, and the resulting sequences were compared to entries in GenBank using the Basic Local Alignment Search Tool for nucleotide data. Individuals were assigned to groups using COI gene sequence divergence analysis which was determined using Kimura 2-parameter distances. Results revealed two major clusters which were inconsistent characterized by mediocre genetic divergence (mean 0.8%). The sequences of P. bampurensis showed that specimens collected from four rivers (Beshar, Khersan, Shapour and Fahlian Rivers, southwest of Iran), with 1.89% for Nemacheilian loaches and 0.8% for two Leuciscine cyprinids within-species Kimura two parameters distance, shared haplotype in Neighbor-joining (NJ) tree. Some clusters showed haplotype sharing, or low levels of divergence between species, hindering reliable identification. We discussed the importance of further DNA barcode studies for native and invasive cyprinid species and subsequent submission to GenBank databases for more reliable species match and inference.

This study aimed to assess the adjuvant effect of Montanide ™ ISA 763 AVG and Licorice extract (Glycyrrhiza glabra) on the immune responses and disease resistance of rainbow trout (Oncorhynchus mykiss) immunized with Formalin inactivated whole cells of Lactococcus garvieae vaccine. Rainbow trout with an average initial weight of 72±3 g were randomLy divided into four experimental treatments: non-vaccinated fish (C), fish immunized with the vaccine without adjuvant (V), fish immunized with vaccine plus MontanideTM ISA 763 A VG (VM), and fish immunized with containing Licorice extract (VL). Sixty fish were used for each treatment group in three replicates each with 20 fish. Fish were immunized via intraperitoneal (IP) injection after being anesthetized with clove oil. The results showed that the highest lysozyme activity, antibody titer and hemolytic activity of the alternative complement pathway were obtained in the VM group followed by VL and V groups compared to the control fish at 8 weeks post-vaccination. After challenge through IP route with Lactococcus garvieae, the highest survival rate (96.7%) was observed in VM group, followed by VL (76.7%) and V (76.7%) compared to 20% survival in the control group. In conclusion, the results of this study showed that inclusion of Montanide and lactococcosis vaccine can enhance the potency and efficacy of the vaccine in immunized rainbow trout, but fish immunized with vaccine plus Montanide was superior to fish immunized containing licorice extract.

Mahyaveh is an Iranian fermented fish sauce produced from fish, salt, spices and water during fermentation period. The main problem related to this product is very high histamine content of it. Effects of starter cultures (Lactobacillus plantarum and Paenibacillus polymyxa) on reduction of histamine in mahyaveh, as “Southern Iran Fermented Fish Sauce” were investigated. This study was performed in 4 experimental groups, including control and treatments on 30th and 45th days of the product. Chemical analysis of treated and control samples revealed that pH, salt percentage, TVB-N content decreased significantly (p<0.05), and acidity increased significantly (p<0.05) in treated samples compared to control samples. Also inoculate starter culture (Lactobacillus plantarum and Paenibacillus polymyxa) reduced the amount of histamine content to about 0.347 and 0.326 mg mL-1 from 0.473 and 0.368 mg mL-1 in control and treated samples, respectively. Results of microbial evaluation revealed that populations of Halophiles, Enterobacteriaceae and fungi decreased significantly in treated samples compared to those of control samples (p<0.05), but colony populations of Bacillus and LAB increased significantly in treated samples compared to those of control samples (p<0.05). In general, addition of starter culture had a positive effect in reducing the amount of histamine and improving other chemical properties and microbial quality of the fermented fish sauce.

In the present research, the Catch-only method was used to determine the biological reference points (BRPs) of Longtail tuna (LOT) in Iranian southern waters (Persian Gulf and Oman Sea). Depletion-based stock reduction analysis (DBSRA) and Catch maximum sustainable yield (CMSY) models were used to estimate BRPs by applying data from 1997 to 2018.The B/BMSY was calculated as smaller than 1.0 in both models, while F/FMSY was mostly higher than 1.0, which indicates the overfishing of Longtail tuna in this area. In 2012, the F/FMSY ratio has exceeded over 1.01 and the B/BMSY ratio with 2 years delay was declined in 2014. Consequently, the biomass reduction followed in 2016, declined to the below of BMSY and the fishing pressure was not adjusted to combat. In comparison, DBSRA model indicated more cautious than CMSY in BRPs estimation for LOT in Iranian southern waters. Based on BRPs, it is recommended to implement an adjustment of annual harvest (around 55 thousand tons) as the simple (even quick) fisheries management strategies in order to guarantee the sustainable yield of this species in southern waters of Iran. We also recommend that catch-only methods could be treated as a temporary stepping-stone while sufficient data (e.g. size or age composition) is available for more reliable methods to be applied.

The aim of the present study was to explore seasonal variations in the diet of Saurida tumbil, Netuma thalassina and Pomadasys kaakan in the Iranian coasts of Oman Sea during 2018-2019. These abundant fishes share same habitats in the Oman Sea .Diet analysis including frequency of occurrence of prey, feeding intensity index, the index of empty stomachs and length weight relationship for 1166 individual were calculated.Based on Gastrosomatic (GaSI) and vacuity index, the maximum feeding intensity was noticed for S.tumbil and P. kaakan during post monsoon and for N. thalassina in pre monsoon time. S. tumbil showed the lowest GaSI index and the highest empty stomachs in monsoon.The findings of food composition indicated remarkable dietary overlap between species in this research, especially between N. thalassina and P.kaakan on decapods , gastropods and fishes (dominant prey) during all seasons. For S. tumbil, the most important prey items were fishes, following, cephalopod and penaeidae and it was determined that the feeding intensity of P. kaakan and N. thalassina could not be altered by monsoon but  remarkable seasonal  variation was noticed in their diet composition contents. The results showed that the pre-monsoon, monsoon and post-monsoon periods have significant effects on the diet composition of all three species under study, which could be explained by changes in resource abundance, availability and diversity of prey.

The present study was conducted to mapping the groundwater quality of Yazd-Ardakan plain to find the appropriate areas for the integrated aquaculture and agriculture. An integrated analysis of spatial and filed data from multiple sources including cations, anions, hardness, alkalinity, pH, salinity, dissolved oxygen, carbon dioxide, and the temperature was performed in 37 agricultural wells. The geographic information system was carried out to prepare the different data layers and classified based on the standards for warm water (Carps) and cold water (Trout) aquaculture. The comparison of maps indicated that concerning the obtained data, it has no possibility to explore a unique region with the highest desirability towards the followed purpose. Furthermore, the northern parts of the study area were dominantly illustrated more appropriate for the culture of cold-water fish, accordingly. The main limiting factors for the warm-water fish were sulfate and magnesium ions in the water resources accounted for 118-354 mg/L and 1132-3085 mg/L, respectively. Conclusively, the agri-aqaculture development strongly depended upon the applied aeration equipment to reduce restricting ions.

The present study was conducted to evaluate the potential of black cricket (Gryllus bimaculatus) meal (BCM) as an alternative protein source in the practical diets for the whiteleg shrimp, Litopenaeus vannamei juveniles. Six dietary treatments with different levels of BCM at 0, 10, 20, 30, 40, and 50% (namely BCM 0–BCM 50, respectively) were prepared, and each diet was fed to triplicate tanks of L. vannamei juveniles (initial body weight 0.73±0.01 g) for 40 days. At the end of the experiment, shrimps fed the BCM-included diets (BCM10, 20, 30, 40 or 50) generally attained the higher weight gain (WG), specific growth rate (SGR), survival percentage, and the better feed conversion ratio (FCR) than that fed the control diet (BCM0). Nevertheless, the shrimps fed BCM50 attained the highest WG (1124.6%), SGR (2.71%/ day), survival percentage (88.3%), and the best FCR value (1.83) among the BCM-included dietary treatments, and these results were significantly higher (p<0.05) than those from the control group. In conclusion, the BCM protein can replace 50% of fish meal protein in the practical diets for L. vannamei juveniles without any adverse effects on the shrimp growth performance and survival.

In parallel with the increased use of nano-sized metallic materials, the possibility of their release into the environment has increased in recent decades. However, there is not sufficient information on the toxic potential of these materials on different aspects of the life history of aquatic organisms. In this study, we investigated the impact of zinc oxide nanoparticles (ZnO-NPs) on goldfish by studying histopathological alteration and Hsp70 gene expression in gill and liver tissues. The results showed that after exposure to different concentrations of ZnO-NPs, severe lesions were observed in the gill and liver tissues of goldfish. Expression of Hsp70 significantly increased in comparison with the control group and this increase was observed especially in the initial sampling times. Also expression pattern of Hsp70 is relatively similar in gill and liver tissues of goldfish. Based on the results of the present study, ZnO-NPs, as widely used nanoparticles can endanger the health of goldfish and further studies are needed to evaluate its potential toxic effects.

Variations of lipid and fatty acid profile of Perna viridis and Perna indica were assessed from Kanyakumari district.  Lipid compositions varied and were measured as 8.92±0.03% in P. viridis and 6.73±0.01% in P. indica. The percentage composition of individual fatty acids as a ratio of total muscle lipids of P. viridis ranged from 0.11±0.01% to 25.09±0.03% whereas in P. indica it ranged from 0.10±0.01% to 33.2±0.05%.  Highest proportions of fatty acids were of palmitic acid which was present in both species. The ratio of Omega-3 and Omega-6 fatty acids was 0.35±0.05 - 3.09±0.04 in P. viridis while in P. indica it was less than 1. Both the mussel species contained essential fatty acids particularly eicosapentaenoic acid and docosahexaenoic acid for promoting good health, as well as prevention and healing of diseases in humans. P. viridis and P. indica were recommended for human beings due to the presence of high content of unsaturated fatty acids.

This study aimed to investigate the growth performance of three length groups (50, 100 and 150mm) of carnivorous fish species, Channa marulius and Mystus seenghala, under sub-lethal (1/3rd of LC50) exposure of water-borne copper, in terms of increase/decrease in average wet weights (g) and total lengths (mm), condition factor, feed intake (g) and feed conversion efficiency (%). A group of 10 fish of each species and length group, with three replications, was separately exposed to water-borne copper, for 120 days, at constant conditions of water temperature (28°C), pH (8) and total hardness (250 mg L-1). Weekly data on all growth parameters of fish were collected and analyzed statistically. Results showed that treated fish species exhibited significantly lower average wet weight and total length increments than control fish that followed the order: C. marulius>M. seenghala. Among three length groups of both fish species, 150 mm length group exhibited significantly higher growth in terms of average wet weight and total length increments than 100 mm and 50 mm length groups suggesting that younger fish became more susceptible to copper stress hence showed lesser growth than older fish. The “K” values computed were significantly higher for treated than the control fish. Copper treated fish exhibited significantly lower feed intake than control fish. However, among three length groups of fish, order of feed intake was 150 mm>100 mm>50 mm. C. marulius exhibited significantly higher FCE as compared to M. seenghala. Overall, it was concluded that sub-lethal copper exposure caused significant reduction in growth of carnivorous fish.

This study was carried out to evaluate natural resources of some Indus creeks using geospatial technologies. The first phase of the study was a detailed monthly water quality and fish stock survey for one year along with associated environmental observations, which was analysed via Landsat 8 imagery for 2014. In the second phase of the study, appropriate indicators were selected in weighted overlay on ArcGIS platform to perform creek productivity analysis. For this purpose, 13 creeks of Indus delta were selected for detailed analysis. These creeks were chosen using GIS techniques based on accessibility, depth and size. Results obtained from a total number of 65,085 fish catch from 252 identified fisheries important species in which 134 species were estuarine, 107 species marine and 11 species belonged to freshwater. Out of these, six species of Penaeus indicus, Pennahia anea, Stolephorus indicus, Escualosa thoracata, Charybdis sp. and Acanthopagrus arabicus were selected for spatial distribution analysis. It is observed that creeks of west of Jhang River known as Issaro, Waddi Khuddi, Patiani, Mal, Dabbo, Chann, Richhal had higher fish abundance and species richness than those of eastern creeks. The important fisheries species showed strong correlation with mangroves, salinity and temperatures. This study indicated that all parameters were strongly dependent on anthropogenic interventions at the study area and these activities seriously affected fish catch and growth of species mainly because of recent environmental changes. It has been revealed from the creek productivity analysis that the study area is still highly productive and intact as an ecological unit.

The present study aimed to investigate the physiological effects of a natural antioxidant, olive oil, and a synthetic antioxidant, butylated hydroxytoluene (BHT), on growth indices, blood and biochemical parameters, and immunity of farmed Persian sturgeons (Acipenser persicus). Three hundred and fifteen juveniles Persian sturgeon, with a mean weight of 108±0.02 g, were randomly assigned to seven treatments each with three replicates (15 fish in each replicate) following the adaptation to brackish water of the Caspian Sea. The fish in three replicates were fed with diets containing 1%, 3%, and 5% olive oil (only as an antioxidant) and other treatments were fed with diets containing 100, 150, and 200 (mg per kg diet) of BHT. A group of fish was fed with the basal diet (containing no olive oil or BHT) as the control. The fish were fed 2-3 times a day for two months. At the end of the trial, blood sampling and biometry were done to determine the growth indices and blood indices. The results showed that the lowest FCR and the highest SGR, BWI, and GR were found in fish fed with 3% olive oil. The highest hemoglobin (Hb) concentration and the lowest hematocrit (Hct) level were observed in olive oil 1%, whereas the highest Hct was observed in 200 mg/kg BHT. The results indicated that there was no significant difference between experimental treatments and the control group in terms of MCV, MCH, and MCHC. The highest percent of neutrophil and monocyte and the lowest percent of lymphocyte were observed in olive oil 5%. Eosinophils were observed in groups of 3% and 5% olive oil, and 200 mg/kg BHT in diet, and its highest level was related to 3% olive oil. The highest cholesterol and triglyceride levels were observed in 200 and 150 mg/kg BHT in diet, respectively. The results of the study demonstrated that albumin levels significantly increased in 5% and 100 mg/kg BHT in diet compared to the others and the control group (p<0.05). The lowest glucose level was found in olive oil 1% and 3% and the highest protein level was observed in 5% olive oil and 100 mg/kg BHT in diet. The results showed that the mean blood plasma IgM of fish in diet containing 5% olive oil was significantly higher than the other treatments and control. In addition, CH50 level in 5% olive oil was significantly higher than the other treatments and control group (p<0.05). The study findings generally suggested that the addition of olive oil in the diet of juvenile Persian sturgeon can positively improve their growth indices, blood and biochemical parameters, and immunity.

The study aimed to evaluate and compare the nutrient cycling efficiencies of bacterial biofilms of a moving-bed filter and three aquatic plants (Lemna minor, Hygroryza aristata and Phyllanthus fluitans) as biological filters in recirculating aquaculture systems (RASs). The nutrient cycling capacities were tested in 12 independent RASs used for culturing common carp (Cyprinus carpio L.) in greenhouse conditions. The efficiencies were determined by comparing fish survival and growth performance, water quality parameters and removal rates of NH4-N, NO₂-N, NO₃-N, PO43-P and TP among biofilters. All biofilter types were efficient in maintaining water quality parameters, removing nutrients and providing an acceptable environment for fish growth and survival. However, the bacterial biofilm filter had the highest removal efficiencies of NH4-N and NO₂-N than those of the other filters; while H. aristata and L. minor filters had higher removal efficiencies of NO₃-N and PO43-P than those of P. fluitans and bacterial biofilm filters. The bacterial biofilm filter had a higher ability to deal with higher concentrations of NH4-N and NO₂-N; whereas plant based filters were more effective in maintaining NO3-N concentrations. Nutrient uptake capacities of selected plants differ and are strongly influenced by the growth rate of plants. The present study suggests that plant based filters in this filtration technique could be beneficial in removing nutrient overload in RASs, adding harvestable product and reducing the overall cost of RASs; whereas bacterial biofilm filter is a superior filter in maintaining ammonium and nitrite concentrations in RASs.

This study was conducted in two experiments. Experiment 1 aimed to investigate the growth promoting and anti-oxidative effects of Azolla nilotica (AZN) and Spirulina platensis (SP) in Oreochromis niloticus. Seven fish groups (G1-G7), each in three replicates, were fed a basal diet (control), AZN 5%, AZN 10%, SP 0.5%, SP 1%, a mixture of Azolla nilotica 5% and Spirulina platensis 1% (AZN 5 %-SP 1% mix), and a mixture of Azolla nilotica 10% and Spirulina platensis 1% (AZN 10% - SP 1% mix), respectively, for 3 months. The results showed a significant increase in growth indices (weight gain, specific growth rate, average length gain, feed efficiency ratio), and a decrease in the feed conversion ratio in all supplemented groups compared to control. Hepato-somatic index in G4 and G5 groups, and intestinal-somatic index in G4 - G6, and in G5 and G6 were obviously higher than control. Spleno-somatic index and antioxidant enzymes (GSH-px, SOD and CAT) markedly increased in G5 and G6 compared to control. Significant increase (p<0.05) in white blood cells was recorded in G2 and G4. Experiment 2 verified the effect of one-month supplementation of SP 1% on males and females O. niloticus fecundity. Males fed with SP 1% had an enhanced fertility as indicated by an increase in sperm density, spermatozoa motility and livability rates compared with the control. There was a significant increase in eggs number and the fecundity index in unripe females and a tendency of egg size to increase in ripen fish. It could be concluded that SP 1% and AZN 5% supplementation is advantageous to improve O. niloticus growth and fecundity.

Benthic foraminifera in coastal sediments of the Persian Gulf were studied at four stations in summer and winter (August and February 2017), to identify and determine the species diversity. Sedimentary specimens were collected by a corer down to the depth of 5cm and by the diver down to the depths of 3, 5 and 10m at every station and transferred to the laboratory after being fixed (by 5% formalin solution). In this study, 10 species belonging to 8 genera and 5 families were identified. The highest abundance of the species is related to family Rotaliidae. Ammonia beccari and Qunqueloculina bicostata were dominant species in the region.The environmental factors including depth, temperature, dissolved oxygen, salinity, water pH, electrical conductivity and total dissolved solid using CTD and total organic matter concentration and sediment particle diameter were measured. The results of PCA test  showed that temperature, salinity and dissolved oxygen have an effect on the density of the foraminiferal communities. Also the study results showed that sediment particles (sand / silt + clay, sand / silt, sand and calcium carbonate) are important in determining species densities.

The purpose of this study is to evaluate the effects of Sodium diformate (NDF) and Formic acid salt on the growth performance, nutrition indices, innate immune system, and digestive enzymes activity of 420 Huso huso (30.55±1.72 g) were randomly divided into seven experimental treatments. All groups were fed with the experimental diets for 60 days. The experimental diets contained 0.05%, 0.1% and 0.15% NDF and 0.05%, 0.1% and 0.15% Formic acid. Diet control was without any Acidifier. Results show that the best FCR and SGR were observed in the group fed with 0.1% supplemented food by NDF and formic acid (p<0.05) on the 30th and 60th day , respectively. The results show that the immunological parameters including total immunoglobulin (by 0.1% NDF), serum bactericidal activity (by 0.1 %NDF and 0.1 %Formic acid), and lysozyme activity (by 0.05 and 0.1% NDF) were affected significantly by Acidifier (p<0.05). The highest activity of trypsin and chymotrypsin was significant in groups 0.1 % supplemented food by NDF (p˂0.05) in the first 30 days. It can be concluded that the addition of 0.1% of NDF to beluga diets improves growth parameters decreases FCR, increases immunity levels and digestive enzymes activity.

Reproduction biology and feeding habits of black mouth croaker, Atrobucca nibe, was investigated monthly from September 2013 to August 2014 in the Oman Sea. The specimens were collected by bottom trawl in the Northwest of Oman Sea. A total of 637 fish specimens examined, 284 males and 353 females were sexed. The average sex ratio was F: M= 1.24:1, showing dominance of females over the males. Spawning season of A. nibe was mostly observed in June and October but spawning might be occurred in all year long . The mean absolute fecundity was calculated 97008±55553 eggs, with a moderate linear relationship between absolute fecundity and total length (Fecundity= 10802TL-280712, R2=0.7624). The mean length at first sexual maturity (Lm50 %) was 35 cm for females. A. nibe is an abstemious feeder according to the high vacuity index (VI=86.5±16.8 %). Skinny cheek lanternfish (65%), Japanese threadfin bream (13%) and deep-sea shrimps (11%) were the frequent food items of this species. Results showed that  bony fishes were consumed by all size-classes, skinny cheek lanternfish (42.1%) and Japanese threadfin bream (79.4%) were more pronounced in size-class of 34-38 cm, and also  crustacean were more frequent (29%) in 22-26 cm size classes.

Vibriosis is one of the major diseases which cause problems in the aquaculture industry. The disease is a bacterial infection responsible for the mortality of breeding shrimp around the world. This study aimed to isolate and identify V. alginolyticus contaminated shrimp samples in Bushehr city, Southwest Iran. Shrimp samples were collected from Persian Gulf waste water. Identification of bacterial isolates was performed by phenotypic and biochemical and molecular tests (PCR and sequencing) by using forward primer (5-GAGTTTGATCCTGGCTCAG-3) and reverese primer (5-ACGGGCGGTG+GTRC-3). Antibiotic susceptibility profile of isolates was detected. isolate of V. alginolyticus was detected with resistance to ampicillin, but susceptible to cefotaxime, ceftazidime, chloramphenicol, ciprofloxacin, gentamicin, and imipenem and tetracycline disks.  V. alginolyticus is participated in shrimp contamination which lead to food destroy and also human impairments. Key words: Vibrio alginolyticus, primer, Vibriosis, 16srRNA sequencing