Iranian Journal of Ichthyology
Volume:3 Issue: 4, Dec 2016

The systematics, morphology, distribution, biology, economic importance and conservation of the burbot (Lota lota) of Iran are described, the species is illustrated, and a bibliography on this fish is provided. The chin barbel and two dorsal fins, both lacking spines, are distinctive characteristics of this fish. This species favours well-oxygenated, cool, clear rivers and large, deep lakes where it is most active at night or at twilight (crepuscular). Lota lota species is found rarely in the Caspian Sea basin.

Oxynoemacheilus parvinae, new species, from the tributaries of the Iranian Sirvan River drainage, belongs to a group of Oxynoemacheilus having a suborbital groove in males and elongated body. It is distinguished from the other species of this group in the Tigris River drainage by a combination of the following characters: 8½-9½ branched dorsal-fin rays, large to medium dark-brown spots especially on the post-dorsal part, emarginated caudal fin, angular shape of bony capsule of swim bladder with developed posterior process, longer head and shallower body. It is also diagnosed from its nearest species (O. bergianus and O. longipinnis) by two fixed, diagnostic nucleotide substitutions in the mtDNA COI barcode region, and a K2P nearest-neighbour distance of 1.4% to O. longipinnis. Maximum Likelihood and Bayesian phylogeny reconstructed based on COI barcode region place the sequenced nemacheilid fish into a monophyletic clade which show between 1.4 % (O. parvinae vs. O. longipinnis) and 16.3 % (O. longipinnis vs. O. merga) K2P sequence divergence.

The cellular architecture and histochemical nature of the enzyme secretory acinar cells of pancreas have been investigated in two species of fish, Labeo calbasu and Mystus gulio having different feeding habits. Histological analysis illustrates that the exocrine pancreatic tissues are scattered within the hepatic parenchyma as hepatopancreas and spleen as spleenpancreas in L. calbasu. The structural analysis also shows that exocrine as well as endocrine pancreatic tissues are also diffused in the adipose tissues in between the intestinal coiling of L. calbasu. In M. gulio the discrete pancreatic tissue is attached to the outer wall of the stomach and formed cluster of acini interspersed with small areas of islet of Langerhans and blood vessels. The exocrine pancreatic acinar cells are provided with conspicuous nuclei and densely packed acidophilic zymogen granules. The endocrine component of pancreas, islet of Langerhans is encircled by a thin connective tissue and comprised of α, β and δ cells. Different cell types in the islets are differentiated based mainly upon their shape, position, staining intensity and density of the cytoplasmic secretory granules. α cells contain sparse cytoplasm and densely stained nuclei, are generally located to the periphery of the islet Aldehyde fuchsin positive β cells bear spherical nucleus and granular cytoplasm, are in the center of islet of Langerhans contacted with blood vessels. δ cells are few in number with light stained nuclei disperse in the pancreatic islet. Histochemical detection displays that the zymogen granules of exocrine acinar cells showing variegated intensities of tryptophan reaction, the precursor of numerous pancreatic enzymes which probably related to the food and feeding habits of the fishes concerned. The zymogen granules are larger in size and heavily deposited in the acinar cells of hepatopancreas of L. calbasu in comparison to M. gulio may be correlated with the herbivorous feeding habit in respect to secretion of digestive enzymes.

A new cyprinid fish, Hypselobarbus kushavali, is described from Kali River, Karnataka, India. Hypselobarbus kushavali is diagnosed from its closest congener, H. dobsoni, by having more upper transverse scale rows, more circumferential scale rows and more lateral line to pelvic scale rows, and from H. bicolor and H. jerdoni by having fewer lateral-line and fewer circumpeduncular scale rows. Diagnostic features for H. kushavali are also provided relative to other species of the genus.

Harike wetland is a wetland of international importance (Ramsar site). It is a source of numerous direct and indirect values like water for drinking and irrigation, habitat for natural flora and fauna, fishing and navigation. From last three decades this fragile aquatic ecosystem receives continuous waste water discharge from agricultural, sewage and industrial sources including heavy metals, hence, the purpose of this study was to investigate the presence and percentage of heavy metal (Cu, Zn, Pb, Ni, Cd, Cr, Fe, and Al) in the scales of five fish species (Labeo rohita, Catla catla, Cirrhinus mrigala, Labeo calbasu and Cyprinus carpio) of Harike wetland employing energy dispersive X-ray microanalysis (EDX) technique. The result has shown the most common heavy metals detected in Harike wetland are cadmium (Cd), Chromium (Cr), Copper (Cu), Nickel (Ni), Lead (Pb), Zinc (Zn), Iron (Fe) and Aluminum (Al). The occurrence of these metals is different in different fish species. Some other pollutants like Carbon (C), Sulphur (S) and Silicon (Si) were also detected in scales. Various abnormalities have been identified in the scale structure due to alteration of elemental composition like dislocation and uprooting of lepidonts from their point of attachment to circuli, broken and disorganized circuli and hole-like depression formed by uprooted lepidonts.

The present study was conducted to examine the relationship between the biochemical composition and energy content of the golden gray mullet (Liza aurata) fillet and its breeding season and habitat in the southern coast of the Caspian Sea. A total of 100 adult golden gray mullet were caught from 10 sites in various coastal areas (wetland and deltaic) during the spring and fall. The fish bioassay results showed the highest weight and total length to have been detected in Anzali (the eastern part of the wetland mouth) and the lowest in Hojanepes (before Gorganroud delta). A significant increase was noticed in the protein content of the fish in the eastern regions of the delta's and wetland's mouth compared to the west coast. Based on the results, the season and the living environment affect the total length, weight, protein, fat and water content of the fish, and the differences in these variables are significant. The fat content of the fish body is highly influenced by the changes in the breeding season. The mean protein, fat, water, ash and energy content of golden gray mullet of the southern coast of the Caspian Sea was 22.33, 3.08, 77.76, 1.40% and 649.71kJ per 100g of fillet respectively. Golden gray mullet fillets contained lower amounts of fat, protein and energy during the fall (i.e. the breeding season) than during the spring.

Selectivity of sorting grid for eight fish species were studied under commercial conditions in the trawl fishery of Antalya Bay, in the eastern Mediterranean Sea. Trawling’s were operated from October to December 2012, using a traditional bottom trawl net. The fish totally retained in upper codend (catchees), and bottom codend (escapes) were used to estimate the selectivity parameters. Selectivity data analyzed as covered codend method by means of a logit function of Maximum Likelihood Method. The Kolmogorov-Smirnov test was applied in order to determine the difference between size groups of escapes and catchees codends. Fifty percent retention lengths (L50) of Spicara flexuosa (Picarel), Boops boops (Bogue), Mullus surmuletus (Surmullet), Mullus barbatus barbatus (Red mullet), Upeneus moluccensis (Goldband goatfish), Trachurus mediterraneus (Mediterranean horse mackerel) Trachurus picturatus (blue jack mackerel) and Saurida undosquamis (Brushtooth lizardfish) were calculated as 13.31; 13.47; 15.58; 12.07; 13.52; 18.49; 17.81 and 20.3cm, respectively. Results showed that sorting grid installed trawl nets provided high selectivity for all fish species.