ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Epidemiological study on some environmental and management parameters affecting on WSD occurrence in Fenneropenaeus indicus and Penaeus vannamei (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: For the first time white spot disease (WSD) was reported in shrimp farms of khoozestan province, in southwest of IRAN in 2002. Then in 2005 the neighbor province, boushehr, was contaminated. In 2008 WSD outbreak reported in sistan-bloochestan province in southeast of Iran. In 2015 all of southern shrimp farms of country except Hormozgan, the middle southern province, which has remained free of WSD, are being contaminated. White Spot disease suspended shrimp culture in thousands hectares of shrimp farms. Considering that white spot disease has not been observed in Hormozgan province yet, the question is; to what extent environmental and management factors participated in preventing WSD outbreak or cause WSD outbreak. In this study (20102012), the effects of environmental factors and management, stressors that decrease immune system function of shrimp are discussed. In addition, the role of pathogen as the main factor of outbreak is discussed. The goal of this study is to define environmental parameters and management practices associates with outbreak of white spot disease in affected provinces and discover reasons of being Hormozgan province free of this disease. In this study the role of the local environmental factors and management practice stressors in susceptibility to WSD was determine. Both the effects of environmental factors in water of ponds including total ammonia, nitrogen, dissolved oxygen, pH, salinity, transparency, and temperature and management issues related to biosecurity are studied. There were overlaps on physical and chemical parameter values obtained in clear areas with contaminated areas .Results of the data analysis suggest that lack of association with WSD incidence was 7 times greater than WSD incidence despite of disease outbreak in sistan-bloochestan province, so other sources of white spot disease virus incidence was suspected in affected areas. Histopathological examinations and polymerase chain reaction (PCR) tests during project performance did not reveal white spot disease virus evidences in post larvae examined from khoozestan province stocked in farms but disease outbreak was happened in that farms , so we suspected to management practice include feed , pond preparation and carrier of disease . Recorded values of temperature and salinity in some months during inspection in Hormozgan province specified stressful condition that may lead to WSD outbreak, however the disease did not appear. Therefore the hypothesis that the water physical and chemical conditions are reasons to prevent disease outbreak in Hormozgan province is being rejected. The policy of Hormozgan’s fishery authorities, to replaced Fenneropenaeus indicus with specific pathogen free Litopenaeus vannamei, that is more resistant to some of diseases, before incidence of WSD in farms and to before being endemic in the Hormozgan province, made an advantage compare to affected southern provinces that introduced Litopenaeus vannamei after WSD prevalence to their farms. However it does not guarantee to maintain current trend of being Hormozgan province farms free of white spot disease. Therefore establishing the principals of biosecurity are strongly emphasized. Strategies taken by the proficient authorities in preparation of SPF shrimp broodstock can be the most important factor in preventing WSD. Regarding biosecurity principals purchased feed must be free of shrimp head powder. Construction the new shrimp farms should be as far as it could be away from contaminated areas.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Environmental ; Physical ; Chemical ; Epidemiological study ; WSD ; Fenneropenaeus indicus ; Penaeus vannamei ; Shrimp ; White Spot Disease ; Temperature ; Salinity ; PCR ; Polymerase Chain Reaction ; Ammonia ; Nitrogen ; Dissolved oxygen ; pH ; Transparency
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 468pp.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 2
    facet.materialart.
    Unknown
    Molecular identification of bacterial and fungal pathogens in certain disease-free shrimp (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: At present, the aquaculture industry to provide proper instructions in the field of health management, including production of Specific Pathogen Free shrimp (SPF), require sensitive and reliable methods for the detection and identification of pathogenic microorganisms. Molecular methods which used in the detection of microorganisms have a high discriminatory power in the taxonomy and in relation to libraries in the world. On the other hand, the accurate identification of microorganisms, providing the genetic data bank of shrimp pathogens and maintenance of these strains is the step to promote further research on the mechanisms of pathogenesis of pathogens, diagnosis, treatment, prevention of disease, identify indigenous production kits, diagnosis re emerging and emerging diseases and their origin. Therefore, in this project, by using ribotyping technique, native isolated pathogenic bacteria and fungi were identified and recorded in the gene bank database center. During sampling of shrimp and water of Specific Pathogen Free shrimp center, 40 bacterial strains were isolated, which 8 of them had the most frequency and identification based on 16S rDNA sequencing was performed. Bacteria identified are: Vibrio nigripulchritudo strain IS013(GenBank:KP843725), Vibrio brasiliensis strain IS014 (GenBank:KR186076), Vibrio rotiferianus strain IS015 (GenBank:KR186077), Vibrio azureus strain IS012 (GenBank:KJ018724.1), Vibrio owensii strain IS016 (GenBank:KR186078), Agarivorans gilvus strain IS017 (GenBank:KR186079), Vibrio brasiliensis IS018 (GenBank:KR186080) and Vibrio alginolyticus strain IS019 (GenBank:1817854), which were recorded in The World Bank genes. In this study fungal isolates were not detected.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Bacteria ; Fungi ; Ribotyping ; 16S rDNA ; Shrimp ; Specific pathogen free ; Vibrio rotiferianus ; Vibrio owensii ; Vibrio brasiliensis ; Vibrio azureus ; Agarivorans gilvus ; Vibrio alginolyticus ; GenBank
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 64pp.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 3
    facet.materialart.
    Unknown
    Survey on White Spot Virus infection in wild shrimps and crabs in Bushehr province costal waters (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: After severe mortality due to white spot disease incidence in cultured shrimps of Helleh grows out farms, disease spread to Delvar,Mond, Boeyrat and Bandar Rig sites in Bushehr province during 2005. Many crustaceans keep this virus in the body, act as a carrier, and can spread of the infection. In order to investigate status of contamination of wild shrimp and crab's population to white spot virus in Bushehr province waters (north of Persian Gulf), samples were collected and tested by Nested PCR for detection of WSV from estuaries and input and output channels water around the Helleh, Shif and Mond sites during 2007 and 2008. Total tested shrimps were 401 peaces, includes green tiger shrimp (Penaeus semisulcatus) 220 pieces, white shrimp (Metapenaeus affinis) 181 pieces, also total tested crabs were 292 pieces includes Ocypode rotundata 68 pieces and Portunus pelagicus 224 pieces. All the samples showed negative results of WSV contamination. However, it can never be sure that the population is free from WSV unless we collect a random sample of 300 pieces from each species and test them individually for WSV. Therefore, we will be confident up to 95% that the wild sources in that area have no prevalence of 1% or upper WSV contamination.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: White spot disease ; WSV ; Shrimp ; Crab ; Nested PCR ; Survey ; Coastal waters
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 55pp.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 4
    facet.materialart.
    Unknown
    Monitoring Green tiger Prawn Stock In Bushehr Province Waters (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: The results of 30 months of trawl sampling on P. semisulcatus, De Hann 1848, obtained through operational phase of MONITORING GREEN TIGER PRAWN RESOURCES project, along with results of another available 28 months of the data of the same structure prior to this, has formed an invaluable time series of data as a proper basis for the further analysis. The survey area is located at North-west of the Persian Gulf from Bahrekan to Dayer waters. The ultimate goal of this study is to come to a better understanding of behavioral pattern of Green Tiger Prawn in its exploited phase after recruitment to the fishery. In this study, the confirmation of the life cycle of P. semisulcatus, to the general life pattern of Penaeidae shrimps was observed. Of the peculiarities of this pattern are the yearly bi-modal spawning and two corresponding peaks of recruitment. There exist two spring and autumn generations, which the major spawning in autumn produces the main recruitment in summer and the autumn generations stem from spring spawning. The spatial and temporal distribution of shrimp is highly variable by month and year. Depending on the year, higher shrimp densities are often found in early summer between Lavar and Rostami and/or Rostami to Bushehr and extend north and south in August. This result can be used in better design of sampling scheme for nursery studies. The main recruitment, which the fishery is depended upon, is in July to August and a second one occurs December-February. The timing and strength of both recruitments vary inter-annually. The proportion of prerecruits in southern area is always higher and the modes more prolonged than in northern area. The period of major recruitment starts earlier and lasts longer in the south than the north. A consistent pattern is not seen for the secondary recruitment, which, usually occurs in December-January. It is hypothesized that 1- the secondary recruitment might occur in Kuwait and/or Saudi Arabia waters, 2- insufficient number of spawners in spring or 3- high mortality in summer could cause the weakness of secondary recruitment. The spatial distribution of the mature female shrimps in spawning months indicates that the northern part of study area is an aggregation ground. It is also found that this aggregation grounds are close to two main fresh water sources (Helleh and Mond rivers), and these phenomena can be somehow related. The average length at 50% maturity varies inter- annually and is estimated to be 15.3 Cm. Length-frequency distribution of shrimps by sex reveals 1 to 3 modes depending on the month and year. In southern part a more complicated and less consistent pattern of recruitment and growth between years was observed. There is multiple or/and continuous recruitment especially during summer months. The von Bertalanffy growth parameters were estimated. The Findings are used to design new sampling schemes to cover the whole life cycle of this species enabling one to explain the variations in their response to the environment and fishery. The results of this study, lead us in building appropriate assessment and management models.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Penaeidae ; P. semisulcatus ; Monitoring ; Green Tiger Prawn
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 77pp.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 5
    facet.materialart.
    Unknown
    Investigation on Effects of ergosan^TM and vibromax^TM in control of White spot disease (WSD) and Vibriosis in shrimp Litopenaeus vannamei (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: Complementary feedstuff extract from Laminaria digitata and Ascophylum nodosum that containing 1% alginic acids as shrimps stimulating of immune system for control of WSSV is used in this study. The test shrimps Litopenaeus vannamei in larvae stage (Z1-PL1), post larvae stage (PL1-PL10) and juvenile (from 30th day to 40th day) fed by complimentary feedstuff comprised control group. The other condition in test and control group was the same manner. Both groups after 40 days exposed to WSSV by oral inoculation. The clinical sign and mortality recorded for 10 days. The results showed the survival rate of exposed group was higher than the control group and it was significant (p〈0/05). The result also show the mortality observed in exposed group 48 hours later than the control group. This study can led us to new methods for control of White spot disease.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Clinical ; See weed ; Laminaria digitata ; Aschophylum nodossum ; Litopenaeus vannamei ; Control ; White spot disease ; Alginic acid ; Shrimp ; Larvae ; Juvenile ; Mortality
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 32pp.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 6
    facet.materialart.
    Unknown
    Investigation on possibility of survival and growth enhancing by selected seaweeds from Persian Gulf in post larvae shrimp Litopenaeus vannamei (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: The use of antibiotics in aquaculture has been limited. Scientifics seeking for natural substitutes to prevent of aquatic animals diseases. Considering seaweeds are rich of nutritions and bioactive compounds, the propose of this study is: investigation the potential and use possibility of native seaweeds from Persian Gulf in shrimp aquculture industry to improve growth, survival of postlarvae and to resistance against pathogens such as vibriosis. For this propose 7 macroalgaes species from Bushehr province coast, inclouding: green algae (C.iyengarii), brown algae (S.angutifolium and S.ilicifolium) and red algae (L.snyderiae, K.alvarezii and G.corticata) were collected and identified. Then seaweed extracts abtained by Water, Ethanol, Methanol and Chloroform solvents by soaking method. In vitro antibacterial activity of extracts against Gr+ bacteria (S.aureus and B.subtilis) and Gr- bacteria (V.harveyi,V.alginolyticus and E.coli) was conducted by Agar diffusion, MIC and MBC methods. Antioxidant activity also by DPPH and EC50 methods was investigated. According to results of these two tests four seaweeds species (S.angutifolium, L.snyderiae, K.alvarezii and G.corticata) were selected for use in shrimp postlarvae (PL22) diets by Bio-Encapsulation (Artemia enrichment). Before of enrichment, toxicity effect of extracts to Artemia naplii were evaluated by determination of LC50 24 h method. From results of this section Ethanol extracts were selected to bioencapsulation. After encapsulation shrimp postlarvae divided to 12 groups in triplicate, namely: C-, C+, S (200), S (400), S (600), L(200), L(400), L(600), G(300), G(600), K(300) and K(600). During 30 days of reared period C- and C+ use of basal diet and unenriched Artemia, but the other groups use of basal diet and enriched Artemia. Except C-, the shrimps in first day of culture put in 107 cfu/ml v.harveyi suspension for 30 minutes, and after water exchange 10 ml of this dose was added to reared aquaria. After 30 days survival percentage, obtained weight and SGR% were investigated. To evaluate vibrio loadind, every 10 days 5 postlarvae were sampled randomly for vibrio count. Results showed that vibrio count in C- was less than the others and in C+ was more than the others. In treatments vibrio count in L(200) was the most and L(600) was the less. Survival rate in C- was the most and after that G(600) with 79.4±6.6% and then S(300) and K(600) were 73.3±7.3% and 70.6±6.6% respectively that were significantly compare the other (P 〈 0.01). Also the C+ was the less with 33.3±6.6% that difference was significant (P〈 0.01). In this study growth parameters of all groups that fed by enriched Artemia were better than C+ (P〈0.05). After cultre period 10 shrimp of every aquarium disinfected and reared for 10 days like before treatment. After 10 days the shrimps were challenged by 3×108 cfu/ml V.harveyi and mortality was recorded for 7 days. The all of animals in C- were survive but more than 90% of C+ were dead. And survival in all of treatments were better the C+ (P〈0.05). the study showed the ethanol extracts of selsected seaweed from Persian Gulf is a good source for growth, Survival and disease control in shrimp larviculture.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Survival ; Growth ; Seaweeds ; Post larvae ; Shrimp ; Litopenaeus vannamei ; Antibiotics ; Aquaculture ; Diseases ; Nutrition ; Macroalgae ; C.iyengarii ; S.angutifolium ; S.ilicifolium ; S.aureus ; B.subtilis ; Artemia ; Larviculture ; Nauplii
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 98pp.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 7
    facet.materialart.
    Unknown
    Role of aflatoxin B1 on hematological factors, histopathological changes, tissue residual, growth and survival rate of Fenneropenaeus indicus (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: Role of aflatoxin B1 on hematological indexes, histopathological changes, tissue residual, growth and survival rate of Fenneropenaeus indicus Some similar cases of aflatoxin chronic poisoning were reported from cultured shrimps in Iran. In this study, Indian white shrimp, Fenneropenaeus indicus, with a weight of 11.79 ± 1.76 grams were fed with diets containing 0, 20, 50, 100, 200, 400, 800 and 1600 ppb levels of AFB1 for 8 weeks. Growth performances, survival rate, residue in muscles and cephalothorax, hematological and histopathological changes were determined after 4 and 8 weeks. The results showed that after 8 week of feeding shrimps with values of 20, 50 and 100 ppb aflatoxin B1, did not affect the growth rate, but with increased levels of Aflatoxin B1 in feed, the growth is reduced and the correlation (r) minus the final weight equal to - 0.312. After eight weeks doses of AFB1 in the diets showed negative correlation to the survival rate, total haemocyte count (THC), total plasma protein (TPP) equal to -0.603, -0.237 and -0.649 respectively. Histopathological changes were variety necrosis, degeneration and atrophy of epithelial and secretory cells lining the tubules, infiltration of fibroblasts in the walls of hepatopancreas tubules, separated muscle bundles in Muscle tissues and intestinal mucosal necrosis and detachment. Possible amelioration was examined by feeding control and treated shrimp (after eight weeks exposure to AFB1) by dietary without AFB1 for four weeks. The Recovery was observed in all parameters of 20, 50, 100 and 200 ppb AFB1 treatments but shrimps fed with the 1600 ppb and 800 ppb concentrations of AFB1 exhibited slower growth, more reddish discoloration disseminated over the body and lack of consistency in the hepatopancreas at 4th week recovery period. After eight weeks, the highest level of aflatoxin B1 residues in shrimp muscles was observed in 100 ppb treatment that its value was 1.55 ppb, but the highest level of aflatoxin B1 residues in cephalothorax was observed in 1600 ppb treatment that its value was 7.1 ppb. In terms of public health, these amounts of aflatoxin in shrimp body are less than permissible limit for human consumption.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Histopathological ; Fungus ; Mycotoxin ; Shrimp ; Fenneropenaeus indicus ; Tissue ; Survival
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 88pp.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 8
    facet.materialart.
    Unknown
    Study on health and Immunity index of vaccinated Litopenaeus vannamei against white spot virus disease (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: In this study, the inhibitory effect of Radio-Vaccine against white spot disease on white shrimp (Litopenaeus vannamei) was studied. This vaccine was prepared by Nuclear Science and Technology Research Institute of Atomic Energy Organization of Iran. 14,000 L. vannamei postlarvae were used in treatments after adaptation. Eight treatments, four positive and two negative controls were considered in triplicate. Initially, three meals a day for a month in the hours of 8, 16 and 24 were feeding. Three times in day at 8, 16 and 24 clock were feeding in first mount. Waste food and fecal remaining in the tanks were removed. In the second and third months of treatment, feeding frequency increased to three and four times in day which is at 6, 18 and 24 were given concentrate feed and Artemia nauplii at 12 clocks. Vaccination was carried out by immersion. Vaccination was performed in two doses with an interval of 10 to 14 days. For biometric testing and evaluation of immune cells throughout the experiment, three samples were taken randomly from the tanks. To assess the health status of shrimp, indices of Total Hemocyte Count and Total Plasma Protein was determined. Phagocytic activity of hemocytes was evaluated to assess immune setuation of shrimps. The results of this study showed that the shrimp immune system, as in many reports, the effect of recombinant vaccines and passive safety in memory as "Alternative adaptive immune responses" after experimental infection of white spot virus (WSSV) in wild and farmed shrimp is confirmed, will respond to vaccination against white spot disease.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Immunity index ; Litopenaeus vannamei ; White spot virus ; Disease ; White shrimp ; Feeding ; Artemia nauplii ; Samples ; Hemocyte ; Plasma Protein
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 48pp.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 9
    facet.materialart.
    Unknown
    Monitoring, Isolation and identification bacterial and parasitic agents in specific pathogen free shrimp production (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: Aquaculture is the fastest growing food industry in the world. Shrimp culture industry is also part of it, unfortunately, like other marine animal culture economic losses caused by the disease has been one of the major challenges of this industry. The major cause of mortality in shrimp hatcheries and rearing centers is related to water quality and the presence of pathogenic bacteria and parasites. These are common opportunistic microorganisms in the hatchery, rearing centers, flora and living food but poor conditions of culture are caused diseases. Since the development of aquaculture in the countries need health management, one of the important additional rings in the shrimp strategic plan is specific pathogen free shrimp production, which has been addressed in this plan. Specific pathogen free shrimp define as the shrimps which are free of the specific pathogens listed in world organization for animal health (OIE). These factors should be conclusively diagnosed and can be isolated from shrimp hatcheries and culture system. Therefore in this project screening and surveillance of shrimp in several generations according to the list of OIE were done and they were monitored for of bacterial pathogens (Necrosis Hepatopancreas Bacteria) and parasites (Microsporidian and Gregarins). At total 756 pieces of shrimp, 6 sample of dry food and 97 samples of live foods were controlled and tested. 1.35 percent of live foods were positive for NHPB and 5.6 percent of pre broodstocks have eppicommensal and microsporidia which were disposed in quarantine phase. Because of biosecurity and surveillance system establishment, there were no bacterial or parasitic isolation or diagnosis during SPF shrimp production.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Litopenaeus vannamei ; SPF ; Bacteria ; Parasite ; Aquaculture
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 60pp.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 10
    facet.materialart.
    Unknown
    Opening and closure of fishing season and estimation of biomass for green tiger prawn in Bushehr waters (2018)
    Iranian Fisheries Science Research Institute | Tehran, Iran
    Details
    Publication Date: 2021-05-19
    Description: From December 1998 to March 2001, (28 month) a survey in Iran waters were completed. Each month, 50 stations in four depth stratums that is, below 10 m, 10-20 m, 20-30 m and above 30 meters from Bahrekan to dayyer were trawled. Some Biological parameters such as sex stages, sex ratio, total length, species composition and some environmental factors such as water temperature, air temperature, salinity, soluble oxygen, acidity of seawater were measured. In this survey, the effects of environmental factors on shrimp behavior and landings were assessed. According to analysis, spawning season extends from January to May. Maximum percentages of mature stage (4th stage of maturity) were observed to be 53.4% in April 1999 and 47.6% in May 2000. Water temperature and salinity were 23.1 centigrade and 37.2 PPT and 21~'C and 38.7 PPT in spawning seasons of 1999 and 2000 respectively. The catch composition of shrimp in fishing season (July to September) for the years 1999 and 2000 has been observed to be 60.2% and 66.4% for 〈i〉Penaeus semisulcatus〈/i〉, 37.1% and 30.4% for 〈i〉Metapenaeus affinis〈/i〉, and 2.5% and 2.8% for parapenaeopsis stylifera respectively. Maximum catch per unit effort (CPUE) in fishing season of 1999 and 2000 were observed to be in depth ranges of lower than 10 meters and 10-20 meters respectively. Analysis of length frequency data shows that the first schools of juvenile tiger shrimps appear in middle region of Persian Gulf from May to June (in low density). In later months (July to August), the schools of juvenile shrimps gradually appear in northern areas. After closure of shrimp fishery (late September) the density of adult shrimps in northern area increase. These shrimps have an average length of more than 15 Cm and are sexually matured. Analysis of sex ratio shows that in fishing season, the number of Male and females are almost equal (sex ratio=1). In Nov. and Sep., the number of females increases (decrease of sex ratio). In spawning season the number of females decrease (increase in sex ratio) but approaching to the coming fishing season the sex ratio tends to become 1 due to recruitment. Observations show that during fishing season the sperm sacs of Male gradually evolve so that at the end of fishing season, the sperm sacs are seen as two white tissue under the last pairs of Pereopods. In other observations, some of sperm had come out from steam of pereopods and cleave to legs of shrimp (both males and females). These observations show that shrimp schools come to fishing grounds for copulation. The stock-recruitment relation has not been proved to be correct and environmental factors has had more effect on size of shrimp stock. A linear relationship with a high correlation coefficient of r〈super〉2〈/super〉=0.9 between prefishing season CPUE and the landings of the same year was established. (Landing =56 CPUE+286). Finally, it is shown that, lower water temperature in spawning season results in better spawning and thus higher yield
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Season ; Estimation ; Biomass ; Green Tiger Prawn ; Opening ; Closure
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 83pp.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...