Study of parasites occurrence and intensity in fishes of Anzali Lagoon

Tish survey prolonged from summer 2011 trough summer 2012. During this period 574 samples of different fish species were investigated for their parasites. Totally 30 species of parasites isolated of the fishes. Some of the isolated parasites are recorded for the first time in Iran. Rafidascaris acus Orientocreadium siluri, Silurotaenia siluri, Acanthocephalus lucii , Argulus foliaceus has recorded for the first time from European catfish, Silurus glanis, and Dactylogyrus inexpectatus has recorded for the first time from Gibel Carp, Carassius auratus gibelio, in Anzali wetland. Statistical comparison of parasites infections and intensity between the different area of Anzali wetland were done. Infection of Pike, Esox lucius, to Diplostomum spathaceum, Raphidascaris acus and Monogenean in western parts of wetland were significantly different from the Eastern and Central areas (p<0.05). So based on the data have concluded the eastern and central regions of the wetland are more polluted than the western part. Comparing the results of the present study with before ones showed that the composition of parasite species has been changed over time, while the prevalence, intensity and abundance of parasites have been increased. It may be due to changing environmental conditions such as increasing discharge of effluent, eutrophication of the wetland. This results accents to necessity of reconstruction of Anzali wetland with preference of eastern and central regions

Experiments on polyculture of pike, Esox lucius, with carps

The Goal of project implementation was survey of biological roles of Northern pike, Esox lucius, in decreasing of Coarse fish and other un economics organisms in carps ponds and also increasing of final crops in hectare and determination of Suitable ration of pike in ponds. This project implemented by 5 treatment with 3 replicates for every ones in 2 years. The pike density was 200, 350, 500 and 650 fish individuals per hectare for 1, 2, 3 and 4 treatment, respectively, and fifth treatment was without pike. The treatments of 1 and 3 conducted in first year and other in second year of test period. At first, about 26 brooders Caught from Anzali Lagoon, and reproduced by artificial and semi - natural methods in Sefidroud Fisheries Research Station in 12–14 °c temperature. Produced larvae reared in earthen ponds and fries reached to weight of 10 -12 g after 45 days. Mean weight, length and survival rates of fish was 12.27 and 32.5 g, 11.44 and 15.83 cm, and 40 and 21% after 45 and 60 days, respectively. The carp density in ponds was 3500 fish individuals per hectare and stocking rates were 55 % silver carp, 20 % common carp, 10 % bighead carp and 15 % grass carp. In throughout of the experiment period, physico– chemical factors measured and plankton (phyto and zoo), benthos, un wanted fish and other organisms investigated. The biomass of unwanted fishes reduced to 76/81 and 60/6 % in first and second year of experiments respectively. The results showed that Esox lucius had effect in increasing of objective fish produce about 17.9 % and 3.9 % in first and second period of project implementation respectively. The average of fish produce in pond unit (2400 m^2)was 842 kg (3508 kg/ha ), 825 kg (3439 kg/ha) and 776 kg (3232 kg/ha) in first , second and control treatments first year of test period , and also in second year was 865 kg (3603 kg/ha), 877 kg (3652 kg/ha) and 848 kg (3531 kg/ha) in second , fourth and control treatments , respectively. A significant different found in final weight mean of common carp between treatments and Control ponds (P <0/05), as the weight of common carp in treatments ponds was 220 % in first year and 191 % in second year more than control pond. In end of the trial, the mean weight of Esox lucius was 265 ± 74, 276 ± 104, 159 ± 33 and 265 ± 89 g in 1, 2, 3 and 4 treatment, respectively. Survival rate of Northern pike in 1 to 4 treatment was 43.8, 55.2, 40 and 35.6 %, respectively

Study on viral nervouse necrosis (isolation, characterisation and pathogenesis) in golden grey mullet in the Caspian Sea and study of pathogenecity and possibility of transmission to the other fish species (Sturgeon fishes, Rutilus frisii kutum and reared Rainbow trout and Carp)

Study on Viral Nervouse necrosis (isolation, characterisation and pathogenesis) in Golden grey mullet in the Caspian Sea and study of pathogenecity and possibility of transmission to the other fish species (Sturgeon fishes, Rutilus frisii kutum and reared Rainbow trout and Carp) Viral Nervous Necrosis (VNN) is a worldwide disease affecting several species of cultured marine fish. For the past two decades, betanodavirus infections that cause Viral Nervous Necrosis (VNN) have emerged as major constraints on the culture and sea ranching of marine fish in almost all parts of the world. More than forty species mainly of marine origin have been so far affected and this number is likely to rise in future following the introduction of new species and the increase of aquaculture trade. Unknown acute mortality occurred in wild golden grey mullet Lisa auratus and Liza saliens in Iranian waters of Caspian Sea in recent years. In order to isolation and confirmation of causative agents of golden grey mullet mortality in the Caspian Sea, a complementary research investigation project was designed in 2005 and approved immediately in Iranian Fisheries Research Organization (IFRO). Many diagnostic aspects such as Virology (Cell culture and Elctereone Microscopy), Hemathology, Bacteriology, Histopathology, Molecular biology (NestedRT-PCR), Heavy metals measuerment and Serology (IFAT and IHC) were employed in mentioned multidiciplinary project. About 322 moribund fish samples which revealed skin darkening, erratic swimming behavior such as spiral and belly-up at rest and high distention of swimming bladder. Suspected samples were collected from coastal capture sites in iranian north proviences in 2006 till 2009. Targets tissue such as brain and eye were removed in strile condition and then kept in -80oC frezzer for cell culture and Nested-RT-PCR. Other tissue samples from liver, kidney, intestine, stomach, gill, skin and muscle, gall bladder and gonads were taken and fixed in 10% buffer formalin and same parts fixed in glutaraldehyde 3% for histopathology, IHC and EM respectively. Cytopathic effect (CPE) was observed in those cell cultures just six days after inoculation with the dilutions of the tested 312 homogenate supernatants. CPE in monolayers of cells cultured (SSN-1 cell line) was characterised by thin or rounded, refractile, granular cells with vacuoles. Nine samples were positive in virology assay. Nested- RT-PCR was done on suspected tissue samples and supernatant of CPE positive samples and 21 tissue samples and all CPE positive samples were positive. IFAT was selected as a confirmatory method for identifying viral strains replicating on cell cultures and carried out with rabbit anti-betanodavirus serum on suspected tissue samples and some smears of CPE positive samples. Some bright points approved betanodavirus antigen and confirmed cell culture and Nested-RT-PCR findings. In fixed tissue samples widespread and massive vacuolation were observed in brain, spinal cord, retina and optical nerve. In order to confirmation of diagnostic findings , IHC was done with monoclonal antibody antibetanodavirus and some red-brown points were observed. Theses findings revealed expected viral antigens and confirmed previous results. Moreover, virus particles with 25-30 nm in diameter were visualized in infected brain and retina using positive staining in TEM. Also pathogenicity test was employed to confirm the obtained results. So Guppy fish Poecilia reticulata and sturgeon fry were used instead of the experimental host due to ease of handling and susceptibility. After 15 days post infection, guppy bathed in VNN-infected tissue culture with 104 TCID50 showed clinical signs similar to naturally infected Golden grey mullet, and the mortality rate reached up to 100% in 75 dpi. When target organs were examined by cell culture isolation, serology, and histopathology, all revealed the presence of virus in the Guppy. Suspected supernatant injected to sturgeon fry through intravitreous injection and widespread vacuolation were observed in brain and spinal cord buy IHC and Real time PCR were negative. In conclusion, with attntion to obtained results in this investigation such as ecological factors, clinical signs, histopathological, virological and bacteriological results, molecular analysis, (IHC, IFAT, PCR), TEM demonstration, serological and hematological findings, it could be confirmed that VNNV was the main causative agent for disease outbreak in Golden grey mullet in Southern coastline of Caspian Sea