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  • 1
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    In:  http://aquaticcommons.org/id/eprint/21765 | 18721 | 2017-11-30 07:11:15 | 21765 | University of Guilan, Faculty of Natural Resources, Iran
    Publication Date: 2021-07-01
    Description: One of the possible threats in increasing use of nanomaterials is the emergence of toxicity in humans and other animals which is discussed in nanotoxicology. In addition to toxic effects of nanomaterials themselves, different chemical precursors which are usually used in bottom-up approaches for production of nanomaterials may have secondary toxic effects in living organisms. In contrast, less use of chemicals in top-down approaches may reduce these secondary effects. To test this hypothesis, toxic effects of two types of silver nanoparticles (AgNPs) produced by physical (top-down) and chemical (bottom-up) methods were investigated and compared on the tadpole, Rana ridibunda survival. The estimated 48 h LC50 values of AgNPs produced by chemical and physical methods for tadpoles were 0.055 ± 0.004 and 0.296 ± 0.085 mg.L-1, respectively. No observed effect concentration, lowest observed effect concentration, maximum acceptable toxicant concentration and median lethal concentration of AgNPs produced by chemical method were respectively 3.42, 4.50, 4.84 and 5.38 times less than those produced by physical method. Therefore, approving the mentioned hypothesis, it was revealed that AgNPs produced by chemical method are more toxic than those generated by physical method. However, it seems totally that AgNPs regardless of the method used for their production, have toxic effects on aquatic organisms and so, inhibiting their accidental or intentional entrance into the aquatic ecosystems should be more considered.
    Keywords: Biology ; Chemistry ; Environment ; Rana ridibunda ; Iran ; tadpole ; chemical ; methods ; physical ; toxicity ; comparison ; silver ; nanoparticles
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 383-390
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  • 2
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    In:  http://aquaticcommons.org/id/eprint/22966 | 18721 | 2018-06-08 20:17:50 | 22966 | Iranian Fisheries Science Research Institute
    Publication Date: 2021-07-12
    Description: Effect of different feeding levels on water quality, growth performance, survival rate and body composition of Pacific white shrimp Litopenaeus vannamei post larvae were studied in zero water exchange system. Shrimp post larvae with mean weight of 74.46± 6.17 mg were fed for 32 days in 300L fiberglass tanks containing 130L water at density of 1 post larvae L^-1. There were five treatments including control and four biofloc treatments with different feeding levels of 15%, 15%, 12%, 9%, 0% of body weight per day, respectively. The results showed that there were no significant differences in water parameters such as dissolved oxygen and pH between different treatments (p〉0.05). There were significant differences in water ammonia level between different treatments (p〈0.05). The maximum (0.39 mg/L) and minimum (0.12 mg/L) levels of ammonia were observed in control and biofloc treatment with minimum feeding level (9%BW/day), respectively. The highest body weight gain (1.55g), growth rate (48.50 mg per day), specific growth rate (9.64%/day), biomass gain (182.1g) and body length increase (33.62mm) were observed in biofloc treatment with maximum feeding level. The highest feed conversion ratio and the lowest feed efficiency were obtained in control (p〈0.05). The proximate body composition analysis revealed an increase in lipid, protein and ash in biofloc treatments. Results showed that using biofloc technology can decrease water exchange amount and improve feed utilization in nursery culture of Pacific white shrimp. Moreover, presence of biofloc improved the water quality which led to the enhancement in growth performance in nursery stage of shrimp.
    Keywords: Aquaculture ; Biology ; Chemistry ; Biofloc technology ; Zero-water exchange system ; Water quality ; Growth performance ; Body composition ; Nursery ; Pacific white shrimp ; aquaculture ; Iran
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 1465-1484
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  • 3
    Publication Date: 2021-07-07
    Description: In this study, effect of different feeding levels on water quality, growth performance and survival of western white shrimp Litopenaeus vannamei post larvae were studied in biofloc rearing system. Shrimp postlarvae of PL10 with mean weight of 3±0.7 mg and mean length of 4.4± 0.93 mm were fed for three weeks in fiberglass containers with 200 liters volume of water and density of 10 post larvae per liter in four tretments including one control with water exchange and three biofloc treatments at different feeding levels of 25, 20 and 15% of body weight. According to the results, in the values of water quality parameters including salinity, dissolved oxygen, pH, nitrite and nitrate, no significant differences were observed among the groups (p〉0.05). The highest increase in body weight (58.42 mg), growth rate (2.78 mg per day), specific growth rate (15.09 %/day), biomass (84020 mg) and survival rate (71.9%) were obtained in biofloc treatment at 25% feeding level. The highest feed conversion ratio (2.05) and the lowest feed efficiency (48.62%) were obtained in water exchange treatment without floc, showing significant difference compared to the other treatments (P〈 0.05). The results from this study reveals that by using biofloc rearing technology can decrease the amount of water exchange and feed utilization compared to body weight in culture of western white shrimp post larvae. Moreover, the presence of biofloc improves growth performance and production of L. vannamei post larvae in biofloc rearing system.
    Keywords: Aquaculture ; Biology ; Ecology ; Biofloc technology ; Water quality ; Growth performance ; Survival ; Litopenaeus vannamei ; feeding ; levels ; white shrimp ; biofloc ; application ; Iran
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 13-28
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  • 4
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    In:  http://aquaticcommons.org/id/eprint/22822 | 18721 | 2018-05-24 22:49:02 | 22822 | Iranian Fisheries Science Research Institute
    Publication Date: 2021-07-10
    Description: Black pomfret Parastromateus niger is a commercially important fishery resource in the Persian Gulf but harvesting its stocks lacks genetic identification of populations. AFLP technique was applied to analyze genetic diversity and population structure of 32 fish from coastal waters of Bandar Abbas, Bushehr and Abadan with 7 EcoRI/MseI primer pair combinations. In total, 381 bands were produced of which, 46 were polymorphic (12.07%). Percentage of polymorphic bands was higher in Bushehr samples (91.30%) than in Abadan (84.78%) and Bandar Abbas (73.91%) samples. The highest level of heterozygosity based on Nei’s coefficient and Shannon’s index was observed in Bushehr fish (0.38±0.16 and 0.54±0.21). Observed and effective alleles ranged from 1.73±0.44 and 1.53±0.40 in Bandar Abbas samples to 1.91±0.28 and 1.70±0.34 in Bushehr samples. The average Fst was 0.19 indicating high genetic differentiation among the three locations. Gene flow with mean of 1.93 was the lowest level between Bandar Abbas and Abadan (1.24). Nei's genetic identity revealed the least genetic similarity between the samples of Bandar Abbas and Abadan (0.77). AMOVA analysis demonstrated 81% of the genetic variation within populations and 19% among populations. The UPGMA dendrogram clustered all 32 individuals into 3 groups. In some cases individuals from the same region were grouped together but in most cases, gene exchange was observed to be common among the groups. Analyses provided evidence for genetic differentiation among the three locations, indicating separate populations of black pomfret in the northern Persian Gulf.
    Keywords: Biology ; Fisheries ; Black pomfret ; Parastromateus niger ; AFLP molecular markers ; Population structure ; Genetics ; Bandar Abbas ; Bushehr ; Abadan ; Persian Gulf ; Iran
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 857-875
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  • 5
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    In:  http://aquaticcommons.org/id/eprint/22784 | 18721 | 2018-05-22 17:50:27 | 22784 | Iranian Fisheries Science Research Institute
    Publication Date: 2021-07-10
    Description: The maintenance of the endangered Caspian brown trout Salmo trutta caspius populations in Iran depends on its artificial breeding. There is no information on how current hatchery breeding protocol influences effective population size of breeders (Ne), which is a critical parameter to maintain genetic diversity in future generations. The current hatchery protocol (CHP) was comparatively evaluated with a balanced hatchery protocol (BHP), where mixtures of equal amounts of gametes per male and female breeder were used to balance parental contributions to progeny. To evaluate putative differences in viability between families, individual crosses were performed and fertilized ova of different families were mixed to constitute balanced family pools. 1440 alevins were totally sampled in the crosses performed from the 11 breeders. An exclusion-based parentage approach using three polymorphic microsatellite markers unambiguously assigned more than 93% of progeny to a single pair of parents. Significantly different contributions of breeders to progeny were observed in CHP (p〈0.05). The primary constraint on Ne in BHP was the unbalanced contribution of males, which seemed a consequence of sperm competition in mixed fertilization caused by differences in sperm quality. Sperm motility duration was positively correlated with the number of sired progeny by each male. The results illustrate the limitations of the BHP in minimizing the loss of genetic diversity observed in CHP. A protocol based on mixture of equal number of fertilized ova from individual male × female crosses emerged as the best alternative for conservation of Caspian brown trout.
    Keywords: Aquaculture ; Biology ; Conservation ; Fisheries ; Caspian brown trout ; Salmo trutta caspius ; Mixed milt fertilization ; Effective population size ; Sperm competition ; Microsatellite ; aquaculture ; Caspian Sea ; Iran
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 393-408
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  • 6
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    In:  http://aquaticcommons.org/id/eprint/21750 | 18721 | 2017-11-30 03:53:46 | 21750 | University of Guilan, Faculty of Natural Resources, Iran
    Publication Date: 2021-06-30
    Description: Feeding habits of yellowfin seabream (Acanthopagrus latus) was investigated in coastal waters of the Northern Persian Gulf. This investigation was conducted by monthly sampling of thirty fish from September 2011 through August 2012. Fish size ranged from 17.98 ± 2.07 to 32.31 ± 6.52 cm in total length and from 134.01 ± 45.62 to 720.46 ± 292.58 g in weight. The highest value of gastro-somatic index was obtained in September (5.22 ± 0.04) and the lowest in December (1.61 ± 0.03) with annual average of 2.50 ± 0.60. The result of gastro-somatic index revealed that the highest feeding activity of A. latus was during autumn. The highest level of vacuity index was observed in summer (34.95 ± 4.71) and the lowest in autumn (25.88 ± 2.71) indicating that the highest number of empty stomachs was in summer. Annual average of vacuity index was 30.14 ± 5.72 exhibiting that A. latus was comparatively gluttonous in the Northern Persian Gulf. Bivalves and shrimps were the major food items found in the stomach of A. latus showing food preference indices of 45.86% and 30.67%, respectively. Other food items included crabs (12.66%), aquatic plants (4.05%), animal derivatives (4.52%) and gastropods (2.23%). According to the results, animal derivatives, aquatic plants and gastropods were eaten accidentally and were not the food items of A. latus in coastal waters of Hormozgan. The average relative length of gut was 1.41 ± 0.15 showing that A. latus was omnivorous in this region.
    Keywords: Biology ; Fisheries ; Feeding habits ; yellowfin seabream ; Acanthopagrus latus ; Persian Gulf ; Iran
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 31-39
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  • 7
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    In:  http://aquaticcommons.org/id/eprint/25928 | 18721 | 2018-11-22 07:18:23 | 25928 | Khorramshahr University of Marine Science and Technology
    Publication Date: 2021-07-16
    Description: Conservation of genetic diversity of juveniles used for restocking of natural populations requires serious attention in artificial breeding protocol of the Caspian brown trout Salmo trutta caspius. Unbalanced contribution of male and female breeders to progeny in present artificial breeding has resulted in the reduction of effective population size in breeders. Equalization of milt volume did not also result in balanced contribution of breeders. With regard to the possible effect of sperm concentration on contribution of breeders to production of progeny, effective population size in breeders and genetic diversity of progeny were determined in mixed milt fertilization of 6 male and 2 female breeders with equal sperm concentration and ova number. Parentage assignment was performed using exclusion method in FAP program by analyzing 9 microsatellite loci and choosing the 3 most polymorphic ones, Str 58, Str 73 and Str 591, in breeders. More than 91% of progeny were assigned to their parents. Effective population size was calculated as 5.24 (0.65) and the number of alleles and expected heterozygosity decreased in progeny (6.67 and 0.726 ± 0.011) compared to parents (7.33 and 0.808) significantly (P〉0.05). In conclusion, equalization of sperm concentration of male breeders did not result in the balanced contribution of male breeders to ova fertilization and production of progeny in mixed milt fertilization of Caspian brown trout and genetic diversity of progeny remained significantly decreased.
    Keywords: Biology ; Iran ; Equalization ; Sperm ; Concentration ; Male ; Salmo trutta caspius ; Fertilization ; Genetic ; Diversity ; Progeny
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 45-57
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