Osmoregulatory capabilities of zander (Sander lucioperca) fingerlings in different salinities of the Caspian Sea

Osmoregulation capabilities of two size groups (1 and 2g) of zander, Sander lucioperca, fingerlings were investigated survival rate, plasma osmolarity, sodium (Na+), chloride (Cl-) ion concentrations and cortisol level within 0, 6, 24, 72 and 240 h after abrupt transfer from freshwater to 7 and 12‰ salinity. Also, some hematological parameters were measured at 240h. The plasma osmolarity and ion concentrations (Na+, Cl-) increased immediately after the transference to 7 and 12‰ salinity, reaching maximum at 72h in 1g and at 24 h in 2g fingerlings, and significantly decreased at 240 h, while the freshwater control group maintained almost constant during 10 days which showed lower than the salinity groups. The pattern of cortisol level changes was similar in two size groups after exposure to different salinities and it reflected stress of handling. There were no significant differences between hematological values of two salinity treatment groups than the freshwater control at 240h. The result showed, not only 2g zander fingerlings acted better than 1g in faced with salinity but also the fingerlings weighing 1g could survived and tolerate Caspian Sea water salinity up to 12‰. It is suggested that the release of zander weighing from 1g would help to restocking management of this species in the southern Caspian Sea

The study of establishment of rainbow trout culture and hatchery farms on Zayanderood’s River region in Caharmahal and Bakhtiyari Province

The aim of this study was to find the best location for establishment of rainbow trout culture and hatcheries farms on Zayanderood’s river region in Charmahal and Bakhtiyari province. This survey carried out over ten station along Zayanderood’s river. The result of physical and chemical analysis showd that the annual average of air temperature varied from 9.5oC - 10oC where the pH annual average value were between 7.5 and 8.8. the dissolve oxygen concentration in stations except in rainbow trout farm effluent were above 10 mg/l. the other chemical , pollutant as well as pesticides levels were under the limiting concentration for rainbow trout culture and Hatcheries activity. The plankton survey showed that the Bacillurophyta were the dominant group of phytoplankton where protozoa constituted the most abundant group of zooplankton the Benthic organisms sensitive to pollutant in particular Epirus were dominant group in all stations. In regard to fishes presence in river, five species of Ciprinidae, one species from Balitoridae and one species from salmonidae families were identified. The capacity for development of rainbow trout culture for tow phase period in Zayanderood’s river region with respect to self purification potential (self purification potential were determined from the oxidation of the effluent of the only active trout farm of the river region), minimum of 10 L/s water requirement for production of trout in concrete canal and pond system and 1 L/S water need for production in semi circular closed system were estimated to be 5202 metric tons

Some Biological Survey of the Clupeonella engrauliformis (Anchovy-like Kilka) in Guilan Coastal Region, the South-West of Caspian Sea, in 1996-97

According to a survey in 1996, among three species of kilka, living in the South-West of Caspian sea, anchovy-like kilka composes 90.3% of total kilka catch. In all seasons of a year, anchovy-like kilka, in the second stage Of gonadal maturation, shows higher abundance in the catch, compared with other maturation stages. This indicates anchovy-like kilka shows more positive phototaxis, at the begining of its sexual maturation.Sex ratio shows females dominancy is 54.8-60, 7-75.9 and 82 percent in spring, summer, autumn and winter respectively. The average length of this fish in the four seasons with above order were 98.6±10.8, 97.7±10.3, 99.6±10.6, 100.1 ± 10.6 and the mean weight were 8.24±1.1, 7.5±1.7, 7.3±1.96 and 6.9±1.56 gr. The age composition of anchovy caught on spring in 1997 ranged between 2-5 years old and the dominate group was 3-year-old. The K value and infinite length calculated 0.27 and 147.8 mm respectively. No significant differences were observed between male and female concerning fat reserve and feeding intensity