IRANIAN JOURNAL OF ICHTHYOLOGY
Year:2016 | Volume:3 | Issue:2 |Papers Count:5

Hypselobarbus kurali (Menon & Rema Devi, 1995) consists of multiple species with similarity in the color pattern of the tip of their caudal fins being orange and black. This complex of species possesses two pairs of barbels. Inspection of collections of H. kurali from the senior author’ s samples from various streams/rivers of Western Ghats covering the Indian states of Tamil Nadu, Kerala and Karnataka revealed that an additional species has gone unrecognized. This new species, Hypselobarbus keralaensis, is diagnosed from its likely closest relative H. kurali by having fewer transverse breast scale rows (16 vs. 21-23) and fewer pre-anal scale rows (38-39 vs. 43-46).

The Iranian species of the genus Garra are reviewed, and diagnoses are presented for all recognized species. Garra gymnothorax, G. lorestanensis, G. mondica, G. nudiventris, G. persica, G. rossica, G. rufa, G. typhlops and G. variabilis are considered valid. Discognathus crenulatus Heckel, 1847 is considered as a synonym of G. rufa. One new species is described, Garra amirhosseini, from the Tigris River drainage in Iran distinguished from its congeners by having 7½ branched dorsal-fin rays, breast and belly with very small scales which are fully covered by a thick epidermal layer, and 9+8 branched caudal-fin rays. Garra amirhosseini is also distinguished from all other of congeners in the Persian Gulf basin except a species without a mental disc, G. elegans, by having two fixed, diagnostic nucleotide substitutions in the mtDNA COI barcode region. Maximum Likelihood based estimation of the phylogenetic relationships placed the sequenced fishes into 16 groups which showed between 0. 62% (Garra amirhosseini vs. Garra elegans) and 17. 6% (Garra variabilis vs. Garra barreimiae) K2P sequence divergence in their COI barcode region.

In the present work, due to the lack of information on population dynamics of the Caspian goby, Neogobius caspius, we aimed to investigate growth and mortality parameters of this species captured from the south part of the Caspian Sea (Mazandaran Province) during a year from April 2014 until March 2015. Growth and mortality rates were assessed using age calculation. By using least squared method, L∞ and K of the specimens were 16. 83 cm and 0. 67 year-1 in female specimens and 17. 76 cm and 0. 83 year-1 in male specimens, respectively. Comparison of the growth curves resulted by likelihood ratio method showed a significant difference between two sexes (P<0. 05). The maximum estimated age for female was 4. 47 years old while 3. 61 years old for male. According to Pauly’ s empirical equation, natural mortality rate was calculated 1. 25 and 1. 41 year-1 for female and male, respectively. Sex ratio (male: female) was 1: 1. 14, indicating no significant difference (P>0. 05). Based on the results presented here, the present investigation can be regarded as basis for future studies on the Caspian goby.

Measurement of hematological parameters of fish exposed to toxicant are used to predict the toxic effects of toxicant. Experimental carps weighing 55. 49± 6. 09g divided into 9 different groups contains 12 fish, were fed daily at 3% of their body weight for 8 continuous weeks. The diets contained copper as sulfate salt (25. 18 or 38. 15mg Cu/kg diet) and zinc as chloride salt (96. 09 or 120. 28mg Zn/kg diet) and control group was fed with diet containing no additional copper or zinc. A full factorial combination of above treatments (3×3) was performed. At the end of experiment, five fish were randomly withdrawn from each tank and blood samples were taken from the caudal peduncle vein. The blood was used for determination of Hb (Hemoglobin), Hct (Hematocrit) and RBC (Red Blood Cell) count. Erythrocyte indices, including MCV, MCH and MCHC were also calculated. Our results showed that manipulation of copper and zinc contents in Cyprinus carpio diet induce changes in some hematological parameters. The RBC, Hb and MCHC showed a significant decrease in single zinc-treatments (P<0. 05). There was a significant difference among RBC count and MCHC of single copper-treatments and control group (P<0. 05). There was significant differences between RBC, MCV, MCH and MCHC indices of combined treatments and single (P<0. 05). No changes in Hct levels was observed (P>0. 05). Changes in the amounts of copper and zinc in diet resulted in altering hematological parameters in carp. Although copper and zinc are essential trace elements for fish, it needs to be carefully used as a supplement, because its high concentration in diet may reveal some adverse effects.

Present study was conducted to elucidate the nutritional value and histological events of gastrointestinal tract (GT) between mature and maturing female and male Caspian lamprey (Caspiomyzon wagneri) during their spawning migration to the freshwater rivers in southern Caspian Sea (Shirud River, Mazandaran Province, Iran). From the upstream migrating Caspian lamprey population, 60 fish specimens were randomly collected. After checking the intestine content, samples from intestine and liver tissues were removed for histological studies for two groups of mature and maturing specimens either in female or male separated based on external and internal sexual characteristics. According to the histological observation, many folds, connective tissues, interstitial fluid, goblet– shaped cells, enterocytes and numbers of intestinal villi were observed in the intestine. Also, there was an intermediate structure named “ typhlosole” in the entire intestine. Furthermore, height and folds of the typhlosole were smaller at the beginning and the end of it. Significant differences were observed in the numbers of fold of intestine in mature and maturing females (P<0. 05). Hepatocytes were consisted the majority of liver cells in mature and maturing females, whereas in the male group it was totally dwindled and gone.