Acute toxicity test of pesticide abamectin on common carp(Cyprinus carpio)

Objective:To determine acute toxicity of abamectin(abamectin used for agricultural fields and also is a common acaridae used in farms)to common carp(Cyprinus carpio).Methods:In this research,common carps were exposed to abamectin for 96 h.LC_(50) values of 24 h,48 h,72 h and 96 h were attained by probit analysis software SPSS Version 16.Fish were exposed to different concentrations(1,2,3,6,12 and 15 mg/L)of abamectin for 96 h and physicochemical properties of water used for these experiments were stable and every mortality was recorded daily.Results:The 96 h LC_(50)of abamectin for Cyprinus carpio was 1.243 mg/L.Conclusions:Eventually toxicity values indicated that abamectin has same toxicity in studied other specie and we can state lower value of LC_(50)for studied specie in compare with most species.

Recent advance on aspect of fisheries: A review

In recent years the fishery always has been a growing industry. However, fishery like the other industries had faced with some limitations. Pollution of water resources, fight disease and efforts to increase production efficiency have been important challenges of fishing industry in recent years. Also, world statistics show that the fishing did not have much grown in recent years. On the other hand, aquaculture of marine fish as new industry can be a reliable solution for the management of aquatic ecosystems and restore these reserves, and in recent years, it always has been a significant growth in the production. So far, several species such as Mahimahi (Coryphaena hippurus), European seabass (Dicentrarchus labrax), Cobia (Rachycentron canadum) and silver pomfret (Pampus argenteus) have been successfully produced and marketed with different aquaculture methods (i.e. cage culture and pen culture). The aim of this study was to summarize marine fish production methods with an emphasis on the production of silver pomfret, as a commercial species and the study of the opportunities and challenges facing this sector in the future.

Acute toxicity of trichlorofon on four viviparous fish:Poecilia latipinna,Poecilia reticulata,Gambusia holbrooki and Xiphophorus helleri(Cyprinodontiformes:Poecilidae)

Objective:To determine toxicity and safety margins of trichlorofon in different species as trichlorofon toxicity has a large variation in the susceptibility of different species.Methods:In this research,four viviparous aquarium fish were exposed to trichlorofon for 96 h.LC_(50)of 24 h,48 h,72 h and 96 h were attained by probit analysis software SPSS Version 16.Fish samples were exposed to different concentrations of trichlorofon(5,10,20 and 40 mg/L)for 96 h and mortality were recorded,separately.Results:The 96 h LC_(50)of Poecilia latipinna,Poecilia reticulata a,Gambusia holbrooki and Xiphophorus helleri were 9.80,9.80,9.95 and 7.99 mg/L,respectively.Conclusions:According to the results of this research,LC_(50)values indicated Xiphophorus helleri was the most resistant and Gambusia holbrooki,with a few differences,was the most sensitive species compared with the fishes examined.

Negative effect of 17-beta-estradiol on growth parameters of goldfish(Carassius auratus)

Objective:To evaluate the effects of 17-beta-estradiol on growth factors of goldfish(Carassius auratus).Methods:To perform the test,17-beta-estradiol was given 3 months period to fish at different doses as followed:control group,Group 1:10 mg/kg food,Group 2:25 mg/kg food and Group 3:50 mg/kg food.For this purpose,a solution of hormone in pure ethanol used to spray on food.Feeding was done 3 times daily as an appetite.Comparing the mean values measured for length and weight using ANOVA.Results:Indicated with increase length and weight,the effects of the hormone get more distinct,so that with increase concentration of hormone,reduce weight and length.Conclusions:Estradiol along with testosterone and progesterone regulates final stages of oocyte maturation and ovulation.Various studies have proven the different concentrations of this hormone has different effects on the growth of different fishes.The aim of this study was to assess the effects of this hormone on growth factors of Carassius auratus.

Morphological variations of common carp(Cyprinus carpio)by fixation and preservation in 10%formalin

Objective:To determine the effects of morphological characteristics of common carp(Cyprinus carpio)by fixation and preservation in 10%formalin.Methods:Fish samples were collected from the Research Center of Aquaculture of Barabadi Fazli martyr,Gorgan University of Agricultural Sciences and Natural Resources,Gorgan,Iran.After initial assay on morphological characters such as total length,standard length and head length,samples were fixed in 10%formalin for 12 weeks.After this period,samples were taken away from the formalin and the morphological characteristics and evaluation of color features were assayed once again.Results:The results indicated that shrinkage was usual in all the specimens and changes in body and fins color were clear and their color was opaque.Formalin preservation is usually causing a reduction in the length of fishes.Conclusions:Different rates of change in body length and color of preserved sample are observed after a standard period of preservation in different preservatives and it can be suggested that the decrease of color intensity in fixed samples in formalin does not have inhibition effects in color identification keys.

Acute toxicity of trichlorophon on two ornamental fish:tiger barb(Systomus tetrazona)and glowlight tetra(Hemigrammus erythrozonus)

Objective:To determine the acute toxicity of trichlorophon(an organ phosphorus compound used in agricultural fields and a common disinfectant used for fish diseases)towards two ornamental fish Systomus tetrazona and Hemigrammus erythrozonus.Methods:In this research,two aquarium fish were exposed to different concentrations of trichlorophon(5,10,20 and 40 mg/L)for 96 h and physicochemical properties of water used for these experiments were stable and every mortality was recorded daily for 96 h.LC_(50) of 24 h,48 h,72 h and 96 h were attained by probit analysis software SPSS version 16.Results:The 96-h LC_(50) of trichlorophon for Systomus tetrazona and Hemigrammus erythrozonus were 8.74 and 8.88 mg/L,respectively.Conclusions:Eventually,toxicity values indicated that trichlorophon has the same toxicity towards the studied species and the lower value of LC_(50) for studied species in comparison with that of most species can be stated.