Hexaflumuron is a pesticide used in farms to control insects and has been introduced as a new and effective insecticide to control rice stemborer. This study investigated lethal range concentration and median lethal concentrations of hexaflumuron in common carp (Cyprinus carpio) for the first time. For this purpose, the fishes in 6 treatments received concentrations of 0, 1.25, 2.5, 5, 10 and 25 mg/l hexaflumuron to determine the lethal range concentration and fish mortality was recorded in each treatment at 24, 48, 72 and 96 hours. Then, to determine the median lethal concentration the fishes received 0, 6, 7, 8 and, 9 mg/l hexaflumuron in 5 treatments with 3 replications and the fish mortality was recorded at 24, 48, 72 and 96 hours. The data obtained from the median lethal concentration were analyzed by probit statistical analysis and the ​​(LC5-95), No Observed Effect Concentration (NOEC) and Lowest Observed Effect Concentration (LOEC) were calculated. In this study, the median lethal concentrations of hexaflumuron at 24, 48, 72 and 96 hours were obtained 9.925, 8.395, 8.075, and 7.428 mg/l respectively. Also, NOEC and LOEC were calculated as 0.7428 and 28.42 mg/l. Behavioral and physical symptoms such as lethargy, hyperemia at the base of the fins, red eyes, very slow movements and swimming, vertical swimming, lying on the floor and finally death were observed in fishes. The results of this study showed that hexaflumuron has a moderate degree of toxicity for common carp and fish mortality increases following increasing concentration and exposure to hexaflumuron consumption.

The purpose of this study was to determine the lethal concentration (LC50 96h) of copper sulfate in rainbow trout fingerlings (10.0±0.39 g). Acute static toxicity test was performed based on the standard O.E.C.D. using rainbow trout fingerlings in 96 hours. In experiments the toxicity range of copper sulfate on fish, was 1 up to 1000 mg.L-1. Within 24 to 96 hours, mortality was increased with increasing concentrations of copper sulfate. LC50 48h has decreased in compare with LC50 24h. Lethal concentration at 72 hours showed a significant reduction compared to both 24h and 48h. Lethal concentrations of 24, 48, 72 and 96 hours were 10, 8.37, 4.79 and 0.96 mg.mL-1, respectively. Since the toxicity is determined according to the LC50 96h, copper sulfate is very toxic for rainbow trout.

Rising trend of production and use of nanoparticles can lead to the possibility of their release into aquatic environments. Therefore, knowing toxic effects of these materials on aquatic organisms is of great importance. The objective of this research was to study the acute toxicity of colloidal silver nanoparticles (CAgNPs) through determining the lethal concentrations in the euryhaline teleost, Aphanius dispar. Toxicology experiments were conducted for 96 h in freshwater according to the OCED 203 standard protocol. Fish mortality was recorded every 24 h after exposure to concentrations of CAgNPs 0, 5, 10, 20, 30, 40 and 50. The actual concentration of silver in each aquarium was measured by atomic absorption and based on the actual concentration; data on mortality were analyzed using the US EPA Probit analysis program. Based on the results, the estimated 96h LC50 of CAgNPs was 10.631 mg/L. Accordingly, the tested CAgNPs should be classified according to GHS (Globally Harmonized System of Classification and Labeling of Chemicals) as “category acute 3” for Aphanius dispar; this means that presence of CAgNPs in the environment of this fish is detrimental and, therefore, its release into the aquatic ecosystem should be carefully considered.

In this study, acute toxicity of Paraquat was studied on Mesopotamichthys sharpeyi fingerling. The acute toxicity test was performed in static renewal system based in the standard method proposed by OECD during 96 h, physicochemical parameters of water including pH, dissolved oxygen and Temperature were monitored. In order to determine the lethal range of paraquat a range finding test was carried out. The acute toxicity test was preformed in 5 treatments in triplicates. The obtained data were analyzed by using Probit analysis with 0.05 confidence limit. According to the results of this study, 24 h LC50, 48 h LC50, 72 h LC50 and 96 h LC50 of paraquat on Mesopotamichthys sharpeyi was 6.84, 5.29, 2.57 and 1.49 mg/l respectively. The Maximum acceptable toxicant concentration (MATC) of paraquat on Mesopotamichthys sharpeyi was 0.14 mg/l and the lowest was observed effect concentration witch is equal to 96 h LC50 was 1.05 mg/l. in addition paraquat lethal toxicity takes place in a narrow range of toxicant concentration.

In this study, the mortality effects of commercial gasoline at different tested concentrations were evaluated on the common roach (Rutilus caspicus) and LC50 values for each time period (24, 48, 72, and 96 hours) have been determined. Roach with an average weight of 3.1 ± 0.45 g and lengths of 4 ± 0.25 cm were used in this study. After transferring the 200 fish to the laboratory, they were kept in tanks of 100 liters for one week to adapt them to the experimental conditions. After the adaptation period, 100 fish were selected randomly and divided into 14 treatments (0, 2, 5, 10, 20, 40, 60, 80, 100, 200, 400, 600, 800, and 100 ppm commercial gasoline). The treatments were completed in triplicate. The results of this study show that the 96-hour LC50 of commercial gasoline is 600.2 ± 0.44ppmand themaximumallowable concentration (MAC) is 60.02 mg/L. The study demonstrates the deadly effects of commercial gasolineonthe Caspian roach. Spillage of dieselandgasoline fuelsfromtransport tankers can enter riversandeventually the marine ecosystem, and reach nursery and spawning areas where it can become a serious threat to fish survival.

The effect of sublethal concentrations of cadmium on some haematological parameters of juvenile sterlet, Acipenser ruthenus. For this purpose, 60 fish (41.69±0.95 g and 23.98±0.14 cm) were randomly divided into four experimental groups and exposed to 0 (control), 16, 32 and 64mg/L Cd concentration, each in 3 replicates for 21 days. The hematological parameters, including red and white blood counts, differential white blood count, hematocrit (Hct), hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) and white to red cells ratio were determined using standard methods. The highest level of Hct (30.57±1.91%) was observed in fish exposed to 64 mg/L (p<0.05). The highest mean values of Hb (10.01±0.63 and 10.47±0.57 g/dL) were measured in the fish exposed to 32 and 64 mg/L of Cd, respectively, which was significantly higher than Hb values in the control (8.24±0.38 g/dL). For the rest of parameters, there were no significant differences between fish exposed to different Cd doses (p>0.05). The results indicated at least some deleterious effects of sublethal concentration of Cd on some hematological parameters of sterlet, which maybe reflecting the stress response as well as deleterious effects on haemopoietic tissues. The study of long term effects of Cd exposure of starlet is suggested.

In this study, lethal concentration (LC50) values of cinnamon hydrosol (Cinnamomum zeylanicum) on carp (Cyprinus carpio) were investigated. In practice, experimental setup was constituted 30 fish (a total of 180 fish with 30 control fish) to be placed in three replicates. Hydrosol was added into aquariums at the doses of 0.5, 1, 2.5, 5 and 10% and determined mortality times of carp exposed to these concentrations. Percentage death of fish calculated in these concentrations. Mortality was observed at all treatments exception of dose of 0.5%. The results indicate that the hydrosol had swimming changes, lethargy, lack of breath and leaning to the depth of the aquariums at all of the concentrations. The results of regression analysis indicated that the mortality rate (Y) is positively correlated the concentration (X) having a regression coefficient (R) close to one in each case. While the 1 h LC50 value (with 95% confidence limits) of the safe dose of C. zeylanicum hydrosol was estimated at LC50=4.39%, 2 h LC50 value=2.629%, and 12 h LC50 value=1.027%.

Nowadays, the use of medicinal plants and their replacement with hazardous chemicals is increasing in aquaculture industry. One of these medicinal plants is Clove oil extract, mainly used for decreasing stress, anesthesia and sedation in aquaculture industry. Eugenol is a medicinal component derived from clove oil. The aim of the present study was to investigate toxicity effects and mean lethal concentration (LC50) of eugenol on Barbus sharpeyi. Barbus sharpeyi fingerlings (average weight: 5±1 gr) were selected and transferred from Shahid Maleki hatchery to fisheries laboratory of Khorramshahr University of Marine Sciences and Technology. After adaptation, fish were exposed to different concentrations of eugenol (1, 10, 20, 30, 40, 50, 100, 150 and 200 ppm) and behavioural changes were recorded on 0, 1, 12, 24, 48, 72 and 96 hours after exposing to anaesthetic drug, and LC50 was determined. According to the results, the concentrations of 1 ppm and 40 ppm eugenol were identified as the best concentrations for decreasing stress (sedation) and anaesthesia induction in Barbus sharpeyi, respectively. In addition, Eugenol at 200 ppm induced acute toxicity. Based on statistical analysis (Probit analysis), 48-hour LC50 of Eugenol was 22.61±1.76 ppm. Based on the results, Eugenol is an anaesthetic drug with moderate toxicity on Barbus sharpeyi. Therefore, Eugenol appears to be a safe anaesthetic agent for substitution with MS222 for native fish aquaculture.

Increasing in water ammonia is one of the major problems in aquaculture. Nitrogen-containing materials are producing in different ways, including oxidation of nitrogen-containing organic matters such as proteins, manure decomposition and ammonia excretion by fish. The increase in these compounds in water recirculation systems and aquaria has always been considered as a stress-causing factor. On the other hand, either increasing and/or decreasing in: : union: : ized ammonia are affected by pH changes. In order to obtain the LC50 of ammonia, zebrafish were exposed to seven treatments including control, 0. 069, 0. 138, 0. 276, 0. 552, 1. 105 and 2. 210 mg/L of: : union: : ized ammonia. Then, in order to obtain a tolerable pH range fish were exposed to either gradual increase or decrease of pH (0. 1 units per minute) using HCl and NaOH 0. 4 N. The amount of LC50 for different time periods was determined using the probit software. The amounts of LC50 for 24, 48, 72 and 96 hours were 0. 766, 0. 634, 0. 532 and 0. 471 mg/L, respectively. Maximum and minimum average of pH tolerance threshold was 11. 64± 0. 04 and 2. 60± 0. 09 respectively. The results showed that zebrafish is a sensitive species to ammonia poisoning, but it is resistant to pH changes.

This research has been done in a static environment to determine LC50, 96h and lethal concentration of Potassium Permanganate and Copper Sulfate in Persian Sturgeon fingerlins (with the weight of 1-3 geram). Three hundred and sixty Persian Sturgeon fingerlins (Acipenser persicus) with 5 treatment and a group control each of which had 3 replicates and 36 aquariums with 20 litres capacity were used that in each aquarium 10 fingerlings were released. This research was performed based on the O.E.C.D. method. The amount of LC10, LC50, LC90 were specified by the method of Probit Analysis. During the experiment the temperature of water in aquarium was between 23.1-24.2 oc, the amount of dissolved oxygen was 6.57-7.48 mg/l, PH was 7.5-8.29 and the total hardness of the whole 330 mg/l. The result shows that the amount of LC50 of 96h Potassium Permanganate 0.41 mg/l, and Copper Sulfate is 0.16 mg/l. The amount of LC10, LC50, LC90 were specified by the method of Probit Analysis. The result shows that the amount of LC10, LC90 of 96h Potassium Permanganate 0.09, 1.939 mg/l and Copper Sulfate is 0.04, o.6 mg/l respectively. Based on (LC5096h<1) this antiseptics are considered toxic for the Persian sturgeon fingerlings.