The effect of thyroxine on percentage of hatching (Hypophthalmichthys molitrix)

Studies showed that Thyroxine can play an important role on fish growth, osmoregulation system, and other physiological activities. Since the direct effect of thyroxine on growth and metamorphose of bony fish larvae has not been yet approved, therefore, present study were carried out in Shahid Ansary propagation and cultivation farm in order to find out the way of effect of this hormone on the survirval rate and early growth stage of silver carp (Hypophthalmichthys molitrix) fertiled eggs that were bathed in thyroxin with concentrations of 0.1, 0.5 and 1.0 ppm (each one, replicates) for 6 hours. Then they were transfered into large incubators (zoog) with running water. After hatching all larvae were placed in mentioned thyroxin concentration bath for another 6 hours before being transfered into large incubators. Larvae stayed inzoogs until the yolk-sac was absorbed. Finally, live silver carp larvae were counted in separated plates. Results of present study indicated that the ra tio of hatched eggs in 0.5 ppm of thyroxin concentration was higher than other treatment

Effects of total protein and cholesterol on spermatology traits of common carp (Cyprinus carpio)

Seminal plasma has contained organics factors same as proteins and cholesterol. The information about role and variety of fish seminal plasma and relationship with other factors especially in common carp is rare. The aim of this study was evaluation of effects of total protein and cholesterol on physical and biochemical factors of cultural common carp milt in Khouzestan province. For this study 40 fish have been bought (20 in March and 20 in April) and examinations of physical and biochemical were tested. Base on the results, total protein in March and April was 0.29±0.14 and 0.37±0.35 g/dl respectively, cholesterol in March and April was 9/95±8.83 and 14/12±12.73 mg/dl respectively. The total protein and cholesterol in April compared to March increased non significantly. The ions of calcium, chloride, sodium and potassium in April compared to March increased. Based on the results there was significant and positive correlation between total protein and Albumin, cholesterol and K in march and significant and negative correlation with Cl but total protein in April had significant and positive with Cl, P, spermatocrite, cholesterol and Albumin and negative and significant correlation with weight of fish. Cholesterol in March had significant and positive with albumin and negative significant correlation with Cl and P but cholesterol in April had positive significant correlation with spermatocrite, Albumin, P and Cl. According to the data of this study, total protein, cholesterol, calcium, chloride, sodium, potassium of the Common carp seminal plasma increased in April compared to March. So because of these factors have effects on fertility, quality and quantity of common carp sperm so it is possible to adjust the parameters of protein, cholesterol and minerals of dietary in spawning season increase the quality of common carp sperm

A Practical Guide to Meta-Synthesis Method for Identifying Professional Competencies of Teachers in Teaching Nature of Science

Qualitative meta-synthesis is a new interpretive integration of qualitative findings that provide coherent descriptions or explanations of phenomena, events, or concepts. Considering the increasing rate of qualitative research, such interpretive synthesis is vital to provide a cohesive vision or a new theory with putting all scattered research together. Therefore, in the present study, the practical guide to the methodology, principles, steps, and other details of the meta-synthesis are explained using the six steps of meta-synthesis presented by Sandelowski and Barroso (2007). Along with each step of the methodological description, the process of presenting a model for the professional competencies of teachers in teaching the nature of science with reviewing 50 articles is also provided as an example for clarifying the methodology. The model suggests that teachers should have knowledge, skills, and attitudes competencies to be able to teach nature of science properly. This article can be used as a guideline by researchers who want to offer a comprehensive model of existing studies in their field of interest

Lethal and sublethal effects of endosulfan, imidacloprid and indoxacarb on first instar larvae of Chrysoperla carnea (Neu.: Chrysopidae) under laboratory conditions

The common green lacewing is an important natural enemy used for pest control in greenhouses. It is also very common in many agricultural systems. Hence, studying lethal and sublethal effects of insecticides on this predator would be useful. Toxicity of endosulfan, imidacloprid and indoxacarb was assessed on 1st instar larvae of Chrysoperla carnea (Stephens) in laboratory. Residual bioassays were carried out in glass Petri dishes. The LC50 values, for endosulfan, imidacloprid and indoxacarb were estimated 251, 24.6 and 133 mg ai/l, respectively. Imidacloprid was the most toxic among insecticides tested. To assess the sublethal effects, the 1st instars were treated with LC25 of each insecticide. Thereafter, these effects were studied using fertility life table experiments. The analysis of variance revealed significant difference between treatments and control with respect to developmental time of the 1st instar larvae. However, no significant difference was observed among endosulfan, imidacloprid and indoxacarb treatments considering the larval developmental time. Differences between treatments and control were not significant for the developmental time of the 2nd and 3rd instars, pupae, sex ratio, adult longevity, and adult fertility. The results showed that only net reproduction rate (R0) was significantly affected by treatments. The gross reproductive rate (GRR), intrinsic rate of increase (rm), doubling time (DT), mean generation time (T) and finite rate of increase (λ) were not affected. The highest and the lowest amounts of rm were 0.178 and 0.169 in control and indoxacarb, respectively. Imidacloprid was the most toxic of the insecticides tested on the 1st instar followed by indoxacarb and endosulfan. If results similar to laboratory findings are obtained in field conditions, these insecticides might be appropriate candidates for IPM programs

Determination of biomass of fishes in Shadegan Wetland

Biomass estimation of fishes were done by depletion method in Shadegan Wetland in 2011-12. Fishing effort and landing catch amount per unit effort was done via random oversea in fixed landing area monthly. Fishermen and catch statistics were obtained from census. Total catch was calculated from multiplication of effort and average catch. Fishes biological characteristics survey indicated that Golden barb (Barbus luteus) and Berzem (Barbus pectoralis) has maximum (62 kg/ha) and minimum (4 kg/ha) biomass respectively. Maximum and Minimum biomass was in spring (380 kg/ha) and in winter (58 kg/ha) respectively and mean biomass was estimated 249 kg/ha in whole area during one year. Number of fishermen were about 1317 and maximum fishing effort was in April, May and June. Total fish landing was 4300 tons per year in which 1119 tons was calculated in April. Large scaled barb (Barbus grypus) and Abu mullet (liza abu) had maximum and minimum mean length and weight. The range length of most of fishes was low and their spawning season was in winter and spring. Length- weight relationship indicates their isometric growth. Despite of 45% decrease of number of fisherman to previous time (2008), catch effort and exploitation was increased (20%). Regarding fish living area (70000 ha), total biomass was 17430 tons

Ecological study in ponds of Litopenaeus vannamei

This study has carried out on five earth ponds of Litopenaeus vannamei shrimps investigation and Mahan Siraf farm s which located at Helleh site in the Bushehr province from may 2007. main objectives’ were: (1) Measurements of quality factors in water and sediment, Planktons and benthoses, (2) quality factors’ effects on growth and survival of Litopenaeus vannamei. With respect the time of shrimp stocking and harvesting, the frequencies of water and sediment sampling were done per 10 day and once per month, respectively. both sediment sampling of the pond beds have done before and after harvesting. The measured factors in the water ponds were: pH, salinity, dissolved oxygen, transparency, temperature (Twice a day in the morning and the afternoon), chlorophyll-a, nitrate, nitrite, orthophosphate, iron, biochemical oxygen demand, TSS, TDS, Planktons. The parameters (pH, total organic matter, iron) were measured in sediment. The measurement of grain size has done in two times (before and after harvesting). Independent variables including nitrate, Ammonia, orthophosphate, iron and chlorophyll-a had significant correlations with shrimp weights as dependent variable. Nitrate showed the highest correlation with the shrimp weights (r=0.921). overall correlation of fifth most important factors with the shrimp weights, namely nitrate, orthophosphate, Ammonia, iron and chlorophyll-a was estimated to r=0.999. The results show low concentration of the essential nutrient such as phosphate and nitrate, high concentration of ammonia, undesirable’s transparency, and a great amount of clay in pond beds. On the basis of above description, required to renewing management in fertilizing, feedings, liming qualities of the bed

Effects of imidacloprid, indoxacarb and endosulfan on egg, third-instar larva and pupa of green lacewing Chrysoperla carnea (Neu.: Chrysopidae)

The common green lacewing is a known biocontrol agent because of its wide geographical distribution, high compatibility with different agricultural systems, high searching ability and ease of rearing. Adults and larvae were reared on artificial diet and eggs of Anagasta kuehniella (Zell.) respectively. The toxicity of insecticides was assessed on eggs (dipping method), third-instar larvae (contact method), and pupae (topical application) of Chrysoperla carnea Stephens. In order to study the sublethal effects, the third-instar larvae were treated with recommended field rate of each insecticide. The effects of the insecticides were assessed using demographic toxicology methods. Rearing conditions were 26 ± 2ºC, 60 ± 10% relative humidity and a photoperiod of 16: 8 h (L: D). The results revealed that the insecticides did not affect eggs even at doses higher than recommended field rates. The LD50 values, of endosulfan, imidacloprid and indoxacarb for pupal stage were estimated to be 144, 33, and 21 µg ai/insect respectively. Since the insecticides did not affect the third-instar larvae at the recommended field rate, the LC50 was not estimated for this stage. The results showed that, only net reproduction rate (R0) was significantly affected by treatments. The highest and lowest amounts of rm were 0.176 and 0.152 for control and indoxacarb treatmnets respectively. Based on both acute toxicity and demographic toxicology methods, the rate of toxicity of the tested insecticides was as follows: indoxacarb > endosulfan > imidacloprid