INTERNATIONAL JOURNAL OF AQUATIC BIOLOGY
Year:2018 | Volume:6 | Issue:1 |Papers Count:6

Our plankton and semi-plankton collections from India revealed 14 species of Testudinellaincluding two undetermined species yet awaiting descriptions. The Oriental endemic T. insinuata isa new record from India while the Australasian T. walkeri and the palaeotropical T. brevicaudata andT. greeni are other globally interesting species. Testudinella amphora, T. brevicaudata, T. dendradena, T. greeni, T. parva semiparva, T. tridentata and T. walkeri are characterized bydistribution restricted till date to northeast India (NEI); T. insinuata is restricted to the floodplains ofthe Kashmir valley of Jammu and Kashmir state of western Himalayas; and T. incisa andT. mucronata are known for valid reports from Tamil Nadu and Jammu and Kashmir, respectively.T. emarginula, T. patina and T. tridentata are believed to be cryptic species-complexes and thusdesired ecological and genetic analysis of local populations. This study merits interest vis-à-visbiodiversity and distribution of the Indian Rotifera.

Kawakawa, Euthynnus affinis contributes to the tune of 35, 466 tonnes forming 1% to thetotal marine fish landings of India. Investigations on growth and mortality were of this species carriedout based on the length frequency data during 2008-2012. The length-weight relationship for thepooled samples were derived for intercept a=0.0286, slope b=2.857 and coefficient of determinationr2=0.917. The values obtained for growth parameters of L∞ was 67.86 cm, for growth coefficient (K) 0.70 and for to -0.26y-1. The natural, total and fishing mortalities recorded as 0.86, 1.48 and 0.62y-1, respectively. The exploitation ratio (F/Z) was observed as 0.42. The M/K ratio was estimated at1.23. The average fork length of 46 cm and weight of 2024 g were estimated in the samples collected.The length at the end of 1st year to 5th year was observed to be 33, 52, 64, 70 and 75 cm, respectively.The fishing mortality derived in this study is more than the optimum and limit value indicated thesign of overexploitation.

In the present study, the effects of safflower (Carthamus tinctorius) extract on serum antibacterial activity of rainbow trout (Oncorhynchus mykiss) against Aeromonas hydrophila, Streptococcus iniae and Yersinia ruckeri was studied. In this regard, 450 fish with average weight of 100±10 g were stocked into fifteen fiberglass tanks. This experiment consisted of 3 treatment groups (received 50, 100 and 200 mg/kg BW safflower extract via IP injection), one positive control group (just received normal saline) and one negative control group (with no injection). Blood samples were taken at the 3th, 7th and 10th days after the injections, and antibacterial activity of serum were determined in vitro using CFU method. The results showed that safflower extract injection had no significant effects on serum anti-bacterial activity against A. hydrophyla and Y. rukeri during 10 days post injection. However, in the fish receiving 100 mg/kg safflower extract, serum bactericidal activity against S. iniae was significantly higher than the other groups. This study demonstrated that safflower extract at the doses of 50-200 mg/kg via IP injection did not cause significant changes in serum antibacterial activity against A. hydrophila and Y. ruckeri, but injection of 100 mg/kg extract led to an increase in the serum antibacterial activity against S. iniae, in rainbow trout.

For comparison of meristic characters of Squalius turcicus, in 12 rivers of Caspian Seabasin, 535 specimens were captured. Some 14 meristic characters were counted. Classification ofmeristic characters showed that most specimens of all populations have 8 soft dorsal rays, 9 soft analrays, 19 branched caudal fin rays, 15 soft pectoral rays, 9 soft pelvic rays, 41-47 lateral line scales, 7-9 scales above LL, 3-5 scales below LL, 18-21 predorsal scales and 14-16 circumpeduncle scales.The results showed significant differences (P<0.05) in means of all meristic characters except dorsal, pelvic and pectoral fin spins between the populations. The PCA and CVA showed overlapping amongthe populations, although some populations were separated from the others. Also, cluster analysisdivided Divandareh River population in a separate group and it was distinct from other populations.Generally, the results of meristic characters cannot well-separate the populations of this species fromeach other.

Heavy metals are released to aquatic ecosystems from natural and anthropogenic recoursesand accumulate to the body of organisms. This study aimed to assess the accumulation of As and Cdin the gill, liver, and muscle of the toothed carp Aphanius arakensis in salt water exposed to threeconcentrations of Cd and As (5, 10 and 20 mg L-1) for 18 days. The specimens were collected fromthe Shoor River with an average weight of 1.5±0.3 g (mean±SD) and length of 3.4±0.4 cm. Thefindings showed that the bio-concentration factor (BCF) of Cd and As were in the following order: liver>gill>muscle, however, for 5 ppm of As the order was gill>liver>muscle. BCF in Asconcentrations were more than Cd concentrations. Also, the highest BCF was found at 5 ppm. Thepresent study showed that the liver is the organ that accumulates the highest concentrations of Asand Cd.

The present study investigates the effects of dietary lysozyme on growth performance andhaematological indices of rainbow trout (Oncorhynchus mykiss) fingerlings. One hundred andtwenty Juvenile rainbow trout fish (initial average weight 5.46±0.05 g) were fed on varying levels ofdietary lysozyme (0, 0.5, 1 and 1.5 g kg-1) for 8 weeks. Thereafter, growth performance as well ashaematological indices including WBC, RBC and Hct were measured. Evaluation of growthperformance showed no significant increase in fishes fed on different levels of dietary lysozyme (P>0.05). Also, feeding on dietary lysozyme significantly increased WBC compared control (P<0.05); the highest level was detected in 1.5 g kg-1 treatment. Furthermore, RBC of fish fed 1 or1.5 g kg-1 lysozyme were significantly higher than other treatments. The same results were noticedin case of Hct which was higher in fish fed treated diet. These results indicated that dietary lysozymeaffect haematological parameters rather than growth performance.