International Journal of Aquatic Biology
Volume:3 Issue: 5, Oct 2015

The silversides or sand smelts are found in coastal areas of temperate to tropical seas and in fresh water. There are about 14 genera and 68 species with only one native species in the Caspian Sea basin, Atherina caspia. In this review, the systematics, morphology, distribution, biology, economic importance and conservation of the Caspian silverside of Iran are described, the species is illustrated, and a bibliography on this fish in Iran is provided.

Formerly the Turkmenian stone loach was the only member of the genus Metaschistura based on osteological characters. But recently, it is placed in the genus Paraschistura based on mtDNA COI data. To provide a detailed description of the osteological characteristics of Paraschistura cristata (Berg 1898), ten specimens of P. cristata were collected from the Hari River basin in Iran and their osteological characteristics were examined. According to the results, P. cristata is osteologically characterized by a foramen in the ventral part of the exoccipital, two extra urohyals, sesamoid ossifications, trapezoid-shaped prevomer, three basibranchials, five hypural, lack of bony bridge between the parietal and pterotic, having over 20 procurrent rays supporting the adipose crest. The detailed skeletal description of P. cristata showed that this species can be easily distinguished from the related genera. Despite the mtDNA COI result, the osteological data of this species showed some features to describe it as a distinctive genus, but this needs the osteological data of the all other Paraschistura species to be compared.

The plankton and semi-plankton samples examined from Mizoram state of northeast India (NEI) revealed speciose and diverse Rotifera assemblage including a total richness (S) of 162 species belonging to 19 families and 35 genera. The reports of six species new to India, four species new to NEI and 76 new records to Mizoram merit biodiversity interest. The occurrence of one Australasian, one Oriental, seven Paleotropical, one Holarctic, one cosmo (sub) tropical and five other interesting species imparts biogeographical value while several species indicate regional distribution importance. Lecanidae > Lepadellidae > Brachionidae > Trichocercidae collectively comprised 69.7% of total richness (S). Lecane > Lepadella > Trichocerca are diverse genera (~52.0% of S) while Brachionus spp. (~8.0%) deserve cautious mention. The rotifer diversity pattern is predominantly ‘tropical’ with a large component of cosmopolitans (~71.0% of S) while tropicopolitan and pantropical species contributed ~16.0%. This study indicated high richness of the littoral-periphytonic and relative paucity of planktonic taxa. Analysis of periphytic, sessile, colonial and benthic taxa, and of cryptic diversity in certain species-groups merit attention for further biodiversity update and we estimate occurrence of 250+ rotifer species in Mizoram.

Nucleotide sequences of the 12S rRNA, 16S rRNA, tRNAPhe and tRNAVal genes of mtDNA of the Mesopotamian spiny eel, M. mastacembelus was determined for the first time. The comparison of the three populations of Mesopotamian spiny eel from Turkish part of the Tigris basin based on the obtained combined mitochondrial DNA was performed. Based on the results, no differences were determined and the identity found to be 100% among three populations. Furthermore, the obtained results from molecular methods were compared with morphological findings to validate the position of the studied populations of M. mastacembelus. In addition, the phylogenetic position of the Mesopotamian spiny eel was examined among the Mastacembelidae and Synbranchioformes based on 12S rRNA and 16S rRNA. The constructed phylogenetic relationship between M. mastacembelus and some other members of Synbranchioformes order supported their taxonomic hierarchy.

Alburnus chalcoides, Caspian Shemaya, is found in the river systems of the Aral, Black and Caspian sea basins and is an economically valuable cyprinid from the southern Caspian Sea. This species has been reported as near threatened species in this basin due to damming, over and illegal fishing, destruction of its spawning grounds and water pollution. The Caspian Shemaya is an important species ecologically and economically, but information about its biology and ecology is widely scattered. Hence, in this review, its taxonomy, general characteristics and morphology, distribution, habitat and ecology, age and growth, reproduction, conservation status and threats in the southern Caspian Sea is summarized, and a bibliography on this fish is provided.

In the present study, the effect of density on transportation stress in Mesopotamichthys sharpey fingerlings was evaluated. For this purpose, four different densities, including 40, 80, 120 and 160 g/l were used as treatments each with 3 replicates. Simulation of transport procedure was carried out for 4 hrs. The blood samples were collected from the fish prior to loading from the stocking tank (control), after 4 hrs of transportation and from released fish into recovery glass tanks at 6, 12, 24, 48 and 96 hrs after transportation during recovery period. For blood sampling, fish immediately anesthetized by adding 2% 2-phenoxy ethanol and the blood samples were prepared. The cortisol, glucose and lactate value of plasma were measured. The results showed a significant increase in cortisol and glucose levels (in highest density) after transportation in all treatments (P<0.05). Lactate did not show a significant difference in experimental groups (P>0.05). The results showed that only cortisol level was significantly different with basal level at 96 hrs. Our findings showed that this species can be transported at higher densities up to 120 g/l.

Acute (24-96 hrs) toxicity of indoxacarb, a new insecticide generation, was determined in Cyprinus carpio under the semi-static condition. Fish (~5 g) were exposed to increasing concentrations of indoxacarb over 24-96 hrs at 17ºC, and over 24 hrs at 22ºC, and mortality was recorded every 24 hrs. Indoxacarb-LC50 values at 17ºC were found to be 37.55, 20.92, 18.77 and 16.85 ppm after 24, 48, 72 and 96 hrs, respectively. LC50 after 24 hrs at 22ºC was 21.55 ppm, which was significantly lower than that obtained at 17ºC. The lowest observed effect concentration (LOEC) values at 17ºC were 14 ppm for 24, 48, 72 hrs, and 11 ppm for 96 hrs. No observed effect concentration (NOEC) values at 17ºC were 11 ppm for 24, 48, 72 hrs, and 8 ppm for 96 hrs. NOEC and LOEC values after 24 hrs at 22ºC were 8 and 11 ppm, respectively. The results indicated that indoxacarb is classified as "harmful" substance in common carp and, the higher temperature, the more toxicity of indoxacarb.

Piscicidal and molluscicidal activities of aqueous extracts of many members of the family Euphorbiaceae are well-known, but the toxicity potential of Euphorbia turcomanica was not yet studied on any aquatic animals. An acute toxicity test was performed by using a four-day static renewal test to determine the LC50 value of dried powder of E. turcomanica for the euryhaline fish, Aphanius dispar. The LC50 values at various exposure periods are 0.177±0.039 g/L for 24 hrs, 0.131±0.030 g/L for 48 hrs, 0.073±0.018 g/L for 72 hrs, and 0.052±0.013 g/L for 96 hrs. The toxicity of dried powder of E. turcomanica exhibits a positive correlation between fish mortality and exposure periods. As this is the first report about toxicity of E. turcomanica on A. dispar, the results could be only compared to that of other Euphorbiaceae as well as other fishes. It is concluded that the toxicity potential of E. turcomanica is comparable and close to that of well-documented Euphorbiaceae. It has been suggested that E. turcomanica products cannot be used directly in fish-inhabiting water reservoirs.

This study evaluated the antibacterial and antioxidant effects of tamarind water solution on shelf life of silver carp (Hypophthalmicthys molitrix) fillet during refrigerator storage. Treatments of this study were unwashed samples (control), and samples washed with 1% and 2% tamarind water solution. Microbial, physicochemical and sensory analysis including total viable count (TVC), peroxide value (PV), thiobarbituric acid (TBA), total volatile base (TVB-N) and pH were measured during 15 day storage at refrigerator (with 3 days intervals). Proximate analysis of samples also measured at day 0. TVC content was 0.93, 0.50 and 0.10 log CFU/g for control and treatments 1% and 2%, respectively and reached to 6.24, 5.82 and 5.21 log CFU/g at the end of storage period. At the end of storage period, the PV, TBA and TVB-N content were 8.4, 4.3, and 3.0 meq O2/Kg for control, 2.75, 1.35, and 0.50 mg/100g for 1% treatment, and 33.17, 23.90, and 22.10 mg N/100g for 2% treatment, respectively. This results showed the positive effect of tamarind to inhibit and delay fish fillet spoilage. According to sensory evaluation, the density of 1% tamarind was selected as the best density.