IRANIAN JOURNAL OF ICHTHYOLOGY
Year:2017 | Volume:4 | Issue:4 |Papers Count:7

The systematics, morphology, distribution, biology and economic importance of the livebearers of Iran are described, the species are illustrated, and a bibliography on these fishes in Iran is provided. There are four species including Gambusia holbrooki, Poecilia latipinna, P. reticulata and Xiphophorus hellerii. All of these species are exotics.

This study was carried out from February to June 2016 in Zav Stream (Northern Iran). A total of 195 specimens including 87 females and 107 males of Alburnoides tabarestanensis were collected from this stream. Even though the sex ratio was obtained 1: 1. 22 in favor of males, however, there were no significant differences in sex ratio from 1: 1 statistically. Means of the length and weight (± SD) were determined as 6. 38± 1. 28cm and 4. 26-2. 71g for males, 6. 2± 1. 84cm and 4. 64± 4. 48g for females. The maximum age was observed as 5+ in both sexes. Length-weight relationship (LWR) was estimated as W=0. 0151TL2. 9784 for males, W=0. 0119TL3. 1214 for females and W=0. 013TL3. 067 for combined sexes, indicating that growth model is negative allometric for males and positive allometric for females and total population. The highest and lowest values of condition factor were observed in May and February. The VBGF was and Lt=12. 90(1 – e– 0. 23(t+0. 664)) and Lt =13. 97(1 – e– 0. 23(t+0. 156)) for males and females respectively. Information provided here could be used in the conversation and management of this cyprinid fish species.

For sustainable exploitation and conservation of biodiversity in riverine ecosystems which have been exposed to considerable modifications by human activities, it is necessary to understand the habitat requirements of the species inhabiting these ecosystems. The Zarin-Gol River in the east of Alborz Mountains, Golestan province, is one of the environments inhabited by the native Hircanian stone loach, Paracobitis hircanica. This stream has been exposed to human activities such as rural discharges, agriculture, fish farm effluents and ecotourism. Habitat requirements of this species and the impacts of human activities were determined in 17 stations along the Zarin-Gol River. Binary Logistic Regression was implemented to develop the distribution model of P. hircanica according to habitat variables. Finally, according to the best model selected by the Akaike Information Criterion (AIC), stream surface width, depth, vegetation cover, altitude and discharge were determined as the most significant parameters for the presence of P. hircanica. Also, other suitable models according to AIC values showed that the stream surface width and depth are the most important independent variables affecting the presence of this loach. Therefore, it was concluded that most significant factors affecting the presence and distribution of P. hircanica are stream surface width, depth, substrate and flow rate.

The objective of this study was to investigate the effects of combination of Dimethoate pesticide and Bio-fertilizer, two frequently used chemical in agriculture, on blood biochemical and physiological parameters of common carp, Cyprinus carpio to understand their potential hazard to freshwater organisms. A total of 270 fish specimens were selected and allocated into nine treatments including: control group, A (0. 016 mg/L pesticide), B (0. 032 mg/L pesticide), C (0. 1 ml/L fertilizer), D (0. 2 ml/L fertilizer) and combined treatments: AC, AD, BC, BD, in triplicate. After 14 days of experiment, bloods were sampled from caudal vein. The blood biochemical enzymes including Acetylcholinesterase (AChE), Alkaline Phosphatase (ALP), Aspartate aminotransferase (AST), Lactate dehydrogenase (LDH), Alanine aminotransferase (ALT) and Creatine phosphokinase (CPK), were measured. AChE showed a decreasing trend in all treatments except in control fish. ALP significantly decreased in groups received higher doses of fertilizer and combined treatment of lower doses of pesticide with both doses of fertilizer (D, AC, AD treatments). AST and LDH did not show any significant differences in all treatments compared to the control group. ALT in combined AD treatment showed a significant increase compared to the control group and other treatments. CPK in B and combined treatments significantly increased in comparison with the control group. The results of this study showed that the effects of combined treatments of dimethoate pesticide and bio-fertilizer were significantly different from those in separate treatments of given chemicals.

This study was conducted to investigate the effects of dietary synthetic astaxanthin on the growth performance and skin and muscle pigmentation of sexually immature rainbow trout. Four astaxanthin supplemented diets were prepared to contain 50, 100, 150 and 200mg astaxanthin kg-1 diet. The basal diet without astaxanthin supplementation was used as a control. Juvenile rainbow trout of the similar size (20. 07± 1. 45g) were fed with these experimental diets for 30 days. Results showed that there were no significant differences in weight gain, specific growth rate, condition factor, survival rate and feed conversion ratio among all treatments (P>0. 05). The skin carotenoid content was significantly affected by the dietary supplementation (P<0. 05) and the lowest carotenoid content was measured in the treatments of the control and the fish fed 50 mg astaxanthin kg-1 diet (P<0. 05). However, the fish fed 200mg astaxanthin kg-1 diet demonstrated the highest carotenoid content in the skin (P<0. 05). Although the muscle carotenoid content increased in all groups, this augmentation was significantly prominent in the fish received the higher concentration of astaxanthin through the feed. According to the obtained results, it is proposed that in sexually immature rainbow trout, astaxanthin is mainly deposited in muscle in compared to skin. Also, diet supplementation with astaxanthin is necessary for skin pigmentation in rainbow trout.

A new species of nemacheilid fish, Oxynoemacheilus ciceki sp. n. is described from the Sultan Marsh, Kayseri Province, Turkey. The species differs from its congeners in the combination of the following characters: flank yellowish brown or pale gray with irregular spot; cheeks with numerous tiny spots; lacking scale; thinner caudal peduncle; complete lateral line; 4 central and 4 lateral pores in the supra-temporal canal; lower lip thick with a deep median interruption and marked furrows and small median incision in upper lip.

This study documents length-weight relationships (LWRs) for a total of 411 specimens belonging to 8 ponyfish species (Leiognathidae) mainly caught as bycatch using gill nets, pelagic and demersal trawls, by medium sized commercial vessels operated in the northern Arabian Sea. Significant length-weight relationships with high correlation coefficients were found for all species. The coefficient of determination r2 value ranged from 0. 90-0. 99. The LWRs for Nuchequula blochii and Secutor interruptus are recorded for the first time and new maximum total length (26. 5cm) for Karala daura is reported for the first time.