---

Population structure, growth, and reproductive characteristics of Kavar, Squalius lepidus, a native species of Cyprinidae family in Zayandeh-Rud River were investigated by monthly sampling from October 2006 to August 2007. A total of 415 individuals were collected. Age groups of males and females ranged between 1+ and 4+. The male:female sex ratio was 1:3. The largest female was 163.0mm in fork length and 63.71g in weight whereas the largest male was 156.0mm in fork length and 50.45g in weight. The minimum, maximum, and mean absolute fecundity was 1161, 12953, and 4279±2169, respectively, and relative fecundity was 148.4±49.3 eggs/g of body weight. Gonadostomatic Index (GSI) values suggested that spawning of Squalius lepidus occurs from May to June. Thus, Squalius lepidus is considered an intermittent spawner species. Growth parameters for both sexes were stated by the von Bertalanffy growth function as k = 0.162, L = 232mm, to= -0.427 years for females and k = 0.136, L =217mm, to =- 0.847 years for males. The weight-length relationship was described as W = 0.00005L2.827 (r2 = 0.860) for males andW = 0.00005 L 2.855 (r2 = 0.859) for females. The slope of the regression line (b) fitted through the weight-length data suggested a negative allometric growth for both females and male (P<0.05). *Corresponding author

---

As a part of a major ecological study of Hanna Wetland, Semirum Region, Isfahan Province, parasitic infestation of 3 native and one introduced fish species were investigated. A total of 120 fish specimens were collected by both cast net and a series of gillnets between fall and winter 2007, and spring and summer 2008. Some of the observed parasites are reported for the first time as new host records of: Trichodina perforata on gill and skin of Carassius auratus auratus and three species of leeches namely: Glossiphonia heteroclite, Thromyzon tessulatum and Hemiclepsis marginata on the skin and fin bases of Capoeta damascina. Moreover, 14 internal and external parasites including: one protozoan Ichthyophthirius multifiliis and two myxosporeans Myxobolus varicorhini, Myxobolus sp., three monogeneans Dactylogyrus lenkoran, Dactylogyrus intermedius and Gyrodactylus sp., two immature digeneans Diplostomum spathaceum, Tylodephys sp., two mature digeneans Allocreadium isoporum and A. layman, one unknown cyst, one Acanthocephalan Acanthocephalorhynchoides sp., one cestoda Khawia armeniaca. The highest prevalence of Diplostomum spathaceum (100%) was observed in Aphanius isfahanensis and Alburnus sp. However, the lowest prevalence was related to A. layman in Capoeta damascina in winter (0%), and autumn and spring (11%). Leeches infection were only observed in Capoeta damascina and Alburnus sp. in winter and summer, respectively. The maximum average (±SD) infection intensity belonged to K. armeniaca in intestine of C. damascina in spring (12.50±3.40, range: 8-16). Among the parasites identified in the region, D. spathaceum showed the highest mean (±SD) abundance (41.67±11.79) in C. auratus auratus in spring. In general, a relatively high diversity of fish parasitic fauna exists in this water body which could jeopardize fish populations and the whole ecosystem if the ecological status of the Hanna Wetland is neglected.

---

Age and growth of the king soldier bream, Argyrops spinifer (Forsskal 1775) in the Persian Gulf (Bushehr coasts) were investigated. A total of 622 samples were obtained from June 2010 to May 2011. Total length (TL) of fish ranged from 13.5 to 64.2cm (females) and 15 to 61.2cm (males). Male and female fish age ranged between 2+ to 25+ and 2+ to 21+ years, respectively. Values of the von Bertalanffy growth function were calculated in females, males and total population by using the backcalculation method and otolith reading data. The values of these parameters according to otolith reading data were K=0.061, L∞=82.10cm (TL), t0=- 2.39 years for females and K=0.082, L∞=67.90cm (TL), t0= - 2.88 for males and K=0.065, L∞=75.50cm (TL), t0=-3.21 for total population and according to backcalculation method were K=0.088, L∞=76.37cm (TL), t0=-0.329 years for females and K=0.101, L∞=65.71cm (TL), t0=-0.168 for males and K=0.094, L∞=74.55cm (TL), t0=-0.191 for total population. The results of the study provide the direction for the future management models for the continued sustainable exploitation of this species in the Persian Gulf region.

---

Parasitic infestation of two native fish species in Behesht-Abad River were investigated at spring 2013. In this study 52 Chondrostoma regium and Aphanius vladykovi (26 from each species) were sampled and transferred to the laboratory. Then the weight and total length of fish were measured and investigated their infestation to parasites by microscope and stereomicrpscope. Some of the observed parasites are reported for the first time as new host records of: Philometra sp on the abdominal cavity of C. regium, Moreover, some external and internal parasites identified to the species and genus level including: Ichthyophthirius multifiliis in skin and gill of C. regium and A. vladykovi, one immature digenean; Allocreadium isoporum on the intestine of A. vladykovi and Trichodina sp on gill and skin of C. regium and A. vladykovi. The highest frequency of I. multifiliis (96.15%) was observed in gill of A. vladykovi and the lowest frequency  was related to Tricodina sp in skin of C. regium (23.07%). A. isoporum Infestation was only observed in the intestine of A. vladykovi (mean±SD; 5.42±3.73) and philometra sp infection was only observed in the abdominal cavity of C. regium (mean±SD; 3.25±.82). The maximum average (±SD) infection intensity belonged to I. multifiliis in skin of C. regium (69.9±72.07, range: 12-196).