IRANIAN JOURNAL OF ICHTHYOLOGY
Year:2014 | Volume:1 | Issue:4|Papers Count:7

The systematics, morphology, distribution, biology, economic importance and conservation of the freshwater catfishes of Iran are described, the species are illustrated, and a bibliography on these fishes is provided. There are four families with four genera and six species, one of which is an exotic; the family Bagridae with one genus and species, Mystus pelusius in the Persian Gulf, Hormuz and Tigris River basins; the family Heteropneustidae with one genus and species, Heteropneustes fossilis in the Tigris River basin; the family Siluridae with one genus and two species, Silurus glanis in the Caspian Sea, Lake Orumiyeh and Hari River basins and Silurus triostegus in the Tigris River basin; and the family Sisoridae with one genus and two species, Glyptothorax kurdistanicus in the Tigris River basin and Glyptothorax silviae in the Persian Gulf and Tigris River basins. There are also some species in the neighboring regions which were not reported from Iran.

stimulatory effect of Ovaprim, a commercial spawning inducing agent consisting of salmon gonadotropin releasing analogue (GnRHa) and a dopamine D2-receptor antagonist, Domperidone, was studied in doctor fish, Garra rufa (Heckel, 1843) under hatchery conditions. The feeding and rearing condition effects on the survival rate of naturally produced larvae were also evaluated. Twenty-five fish were collected from Kohmareh stream (Helleh River), Fars province, Iran by electrofishing and transported to an ornamental fish hatchery. Fish were randomly divided into 5 groups and injected as follows: control fish received only 0. 7% physiological saline (group 1) and groups 2 to 5 received 0. 1, 0. 2, 0. 02 and 0. 04 ml Ovaprim per fish. Six hours after injection, fish were evaluated for ovulation or spermiation success. None of the samples in control fish spawned until the end of experiment. Higher doses of agent in groups 2 and 3 caused a100% mortality in treated fish. In group 3, two males were spermiated but none of the females ovulated. In group 4, two ovulated fish were found whereas three fish died. Feeding larvae with newly hatched Artemia naupli and rearing in temperature close to 30º C resulted in higher survival rate in comparison to fish fed a combination of phytoplankton and infusoria and compared to larvae kept in temperature lower than 24º C or higher than 34º C. In conclusion the results of this study showed that Ovaprim is effective in induction of spawning in doctor fish, but a dose much lower than those used in this study is recommended for use in hatchery to avoid brooders mortality. Feeding larvae with fresh Artemia naupli during weaning stage is also suggested for higher survival rate.

This study presents data on age structure, sex ratio, growth, length-weight relationships and condition factor of four populations (n=312) of two Alburnoides species, collected in 2005 and 2006 from the Tajan River (Caspian Sea Basin), the Ghara-Chai and Jajrud rivers (Namak Lake Basin), and Cheshmeh-Ali Spring (Kavir Basin) of Iran. Sex ratio of the fish, in the studied localities, except in Jajrud River, was not significantly deviated from the equal sex ratio. The female fish had higher weight, length and condition factor compared to the male fish. The growth pattern of the female fish in Cheshmeh-Ali Spring was isometric, but allometric in other localities. The growth pattern of all male fish, except the ones from Jajrud River, was allometric. The age groups were 0+-5+. The prevailing age groups were 0+, 1+, 2+, and 3+, in Jajrud River, Ghara-Chai River, Tajan River, and Cheshmeh-Ali Spring, respectively. Fish in Jajrud River had higher overall growth performance and K-values, compared to the other populations.

The aim of this study was to assess the effects of nucleotide on intestinal microbiota of striped catfish, Pangasianodon hypophthalmus. Different levels of the NT (0, 0. 25. 0. 5, 0. 75 and 1 % weight per weight, WW-1) were added to basal diet and then randomly allocated to triplicate groups of fish with average initial weight (1. 52± 0. 11 g) for 10 weeks. At the end of the experiment, at least 10 individual fish from each treatment were used to study quantitative and qualitative analyses of bacterial flora of intestine. The bacterial flora was identified to species level where possible. Total viable bacterial counts in the intestine of the catfish ranged from 4. 33± 0. 49×104, 5. 98± 0. 82×104, 6. 44± 1. 09×104, 5. 54± 0. 64×104 and 2. 65± 0. 46×104 colony forming units (cfu/g) for groups treated with 0-1% NT respectively without any significant difference among groups (P>0. 05). Gram negative rod shaped bacteria were dominant in all groups. Altogether 16 bacterial species of 12 genera were identified in total populations. Most of the bacterial species were common among all groups. Proteus mirabilis, Serratia liquefaciens, Bacillus cereus only were observed in NT treated fish while Alkaligenes faecalis only existed in the control group. Corynebacterium urealyticum and Staphylococcus aureus were identified in some fish belong to control-0. 25 NT and control 1-NT groups respectively. The results of this study demonstrate that although the total bacterial count number did not affected by dietary NT but some qualitative changes were clearly observed.

The aim of this study was to access the genetic differentiation of Paraschistura sp. in Kheirabad and Brim Rivers (Zohreh River System, Persian Gulf Basin), Iran. For this purpose, 60 samples including 30 male and 30 female samples from each river were collected. A total of six microsatellite loci (Bbar4, Bbar7, IC228, IC230, IC434 and IC720) were used and all of them showed high polymorphism (PIC= 0. 87). The average numbers of observed alleles per loci in Kheirabad and Brim rivers were 13. 5 and 12. 5, respectively. The mean of observed heterozygosity values were 0. 53 and 0. 59 in Kheirabad and Brim rivers, respectively. The bottleneck analysis did not show any evidence of genetic bottleneck in these two rivers. Approximately all of loci showed deviation from Hardy-Weinberg equilibrium (HWE). The genetic distance between the two populations was 0. 629, indicating high genetic diversity of these two populations. The results of Molecular Variance Analysis revealed that genetic diversity within populations was 97 percent while between them was 3 percent. The FST value was 0. 02 that indicates the low genetic differentiation between the two populations that could be explained by historical migrations in the past times. Also, the number of migrants (Nm) between the two populations was obtained 9. 142. Finally, it seems that Paraschistura sp. has an adequate level of genetic diversity in the studied habitats, but the conservation programs are needed to ensure survival of this species in all of its geographical distributions.

This paper investigates host condition factor, parasite interaction and metal accumulation in Tilapia guineesis and Host-Parasite system in Iddo Area of Lagos Lagoon, Nigeria. Eighty specimens of T. guineensis from the Lagoon were caught and dissected for intestinal helminth parasites. Condition factors of all individuals were determined. Median condition (K<2. 62 and K>2. 62) were used in grouping the individuals. Sediment, water samples, livers and intestinal parasites were analyzed for heavy metals using atomic absorption spectrophotometer. Metal concentrations in the water medium were below detectable limits, but those in sediments were; cadmium (Cd) (mg/l), 11. 29± 22. 59, Manganese (Mn)(mg/l), 0. 02± 0. 02, Iron (Fe) (mg/l), 141. 09± 15. 09, P<0. 01, lead (Pb))(mg/l), 123. 16± 8. 41, P<0. 01. Livers of infested individuals accumulated more metals than those not infected by the parasites. This was also discovered when they were grouped based on their condition status. Among the infested fish, high condition individuals (>2. 62) accumulated more metals than the low condition infested individuals (<2. 62), but irregular trend was found among the non-infested individuals. Parasite prevalence among infested individual of low condition factor were; Heterostomum sp., a trematode; 0. 25, Procamallanus sp., a nematode; 0. 75, Acanthogyrus tilapae, an acanthocephalan, 0. 05 and Proteocephalanus sp., a cestode was absent. High condition individuals had parasite load; Heterostomum sp.; 0. 45, Procamallanus sp., 0. 05, Proteocephalanus sp., 0. 05 and Acanthogyrus sp.; 0. 25. Generally, the host liver accumulated more metals than their parasites except iron among parasites of high condition individuals. Relative abundance and diversity in intestinal parasites with varying metal bioaccumulation potentials in high and low condition individuals could have been responsible for the difference in metal accumulation in their host tissue. Therefore, it is recommended that environmental monitoring studies involving the use of fish could be improved upon by including the macro-parasites, considering the significant effect they could have in the fish biology, behaviour and ecology.

As a result of our survey in February 2011, a single female specimen of N. dipterygia was found in the tidal zone of Chabahar Bay and it was caught with a small deep net. The fish was transferred in a bucket to the Fisheries Laboratory of Chabahar Maritime University and kept in a salt water aquarium for further examinations. We witnessed the birth of 6 juveniles after 3 days. The female and her juveniles were kept in the aquarium for about six months and fed with live food. After that, they died and were fixed in 96% ethanol. The female fish total length was 172. 02mm and weighed 18. 21g. The fry total length ranged from 49. 90-56. 37mm and weighed 1. 14-2. 1. 65g. The length-weight, length-disk length, disk lengthelectric organ length showed high correlations (r2>0. 85), but the relationship between electric organ width and fish weight was low (r2=0. 33). Although this species was recorded from the Arabian Sea and western Indian Ocean, this is the first record of this species from the Iranian waters.