Hybridization of Acipenser nudiventris X Acipenser stellatus and comparing the hybrid species growth to the growth of Acipenser stellatus

In the present experiment, which was carried out for the first time in Iran, the crossbreeding of Acipenser nudiventris with Acipenser stellatus was subjected to a study. During the hybridization process, which was carried out using five brooders in one treatment, 633000 ova were obtained and the 174937 produced crossbred larva as well as 27648Acipenser stellatus larva, used as controls, were also studied. The results of this study revealed that the fertilization rate in the hybrid species was 79%, while it was very lower in the control species, only 30%. On the other hand the hatching rate in the hybrid species was only 6%, which was very lower than the hatching rate in the Acipenser stellatus. During the breeding process the hybrid fries grew and survived better than the Acipenser stellatus fries. The average daily growth of the hybrids was 55.22 mg, while the controls grew 34.62 mg daily. The morphometric study on the hybrid fries revealed that they resembled more Acipenser nudiventris, however they lacked the characteristic lip notch of the Acipenser nudiventris. Further studies on 29 morphological parameters indicated that with respect to 17 of these parameters, there were significant differences between the hybrid fries and the control fries, which could be employed for identifying the hybrid fishes

An investigation on the feeding behavior of common kilka (Clupeonella cultriventris caspia) in the southern Caspian Sea, Mazandaran Province, Iran

Monthly samples of common kilka (Clupeonella cultriventris caspia) were collected at night on board of kilka fishing vessel during the years 2004-2005 in Mazandran province. The decreasing kilka population in the Caspian Sea and the associated economic loss of fisheries sector were the main reasons encouraging the research. The stomach contents of common kilka and biotic and abiotic factors at the fishing areas were examined in this project. The length and weight of common kilka fluctuated between 100 ±7 to 113 ±5 mm and 7.0 ±1.9 to10.3 ±1.0g, respectively. The highest feeding activity was observed in April with 280 plus or minus 153 individuals of prey weighing 2.9 plus or minus 1.6mg per fish consisted of 7% Acartia and 93% Balanus nauplii and cipris. The zooplankton population taken in during March to September was composed of Balanus nauplii and cipris (67% to 100%) but the biomass of copepoda (Acartia) was dominant from October to February. We observed that with increasing temperature in spring, Balanus reproduced and the stomach contents of kilka comprised more than 90% Balanus cipris and nauplii. In winter, Copepoda was observed more in stomach contents of kilka while Balanus decreased

Distribution of zooplankton in the southern Caspian Sea

The zooplanktons were studied in spring, autumn and winter in the southern Caspian Sea in 1996. Sampling carried out in four season. In each season, 180 specimens were identified and their frequency calculated per m^3. 55 species of zooplanktons were identified including 55% Cladocera, 15% Copepoda and 11 % Rotatoria, 9% other groups such as meroplanktons. The maximum species diversity was observed for Cladocera and the maximum frequency were observed for Copepoda. The Copepoda affected on abundance of zooplanktons as this frequency included in spring, summer, autumn and winter that were 38% to 97%, 22% to 92%, 71 % to 99% and 31 % to 92%, respectively. In summer, the Copepoda and lamellibranchiata larvae had main role in formation of zooplankton population in western region of the southern Caspian Sea, but in autumn, 70% of zooplankton population were copepods. The frequency of zooplanktons in spring, summer, autumn and winter were calculated 4081 to 20143; 7812 to 65741; 10850 to 34406 and 4510 to 20576 inch/m^3, respectively. The maximum biomass was observed during summer with 200 mg/m^3

Biological aspects of kilka (age, growth, feeding and reproduction) in southern of Caspian Sea

In the changing environmental of the Caspian Sea specifically pelagic zone following the introduction of the comb jelly Mnemiopsis leidyi has been continued ,particularly kilka catch ,biological characteristic and feeding . In this investigation which had been done in commercial catch regions (where discharged theirs catch) in three ports Babolsar ,Amirabad (in Mazandaran) and Anzali (in Guilan), estimated catch and catch per unit effort, the age structure of catch ,length- weight relationship, von Bertalanffy growth parameters, condition factor, sex ratios ,maturity stags ,age at first capture and spawning and feeding .The result shown that catch of kilka in Iranian coastal in 2006 decreased from 22300 ton to 16700 ton in 2008.But CPUE increased from1.7 ton (Vessel ×Night) to 2.5 ton at that time due to dropped effort .The length frequency of kilka is close and the juvenile fish did not see in catch as increased the length mean (P>0.000).The age frequency had the same situation as fish low than 2 years did not see for anchovy and bigeye ,so collapse juvenile stock cause poor recruitment in the species .The parameters of the von Bertalanffy growth curve were For common kilka L_∞= 136.5mm k= 0.249y t0= 1.890y Q= 3.883; For bigeye kilka L_∞= 131.7mm k= 0.346 t0= 1.123y Q= 3.688; And for anchovy kilka L_∞= 148mm k= 0.375 t0= 1.243y Q= 3.814 The exploitation rate of anchovy, bigeye and common kilka were 0.51, 0.58 and 0.6 respectively. The highest of GSI recorded in May and March for common and bigeye and in Jul, Nov for anchovy kilka .Main prey was Acartia tonsa by anchovy and common kilka and Cypris balanus by bigeye kilka. We concluded that the ecological problem causes by Mnemiopsis leidyi as well as overfishing has been collapsed kilka stocks, particularly anchvy.so sustainable fisheries management and conservation biodiversity in the Caspian Sea are real challenges now

The study of diversity, distribution and abundance of zooplankton in the southern of Caspian Sea

This survey was carried out in 8 lines of southern area of Caspian sea consisting of Astara, Anzali, Sefid roud, Tonekabon, Noshahr, Babolsar, Amirabad and Torkman in depths of 5, 10, 20, 50 and 100m in 4 seasons (spring, summer, autumn and winter) of the year 2008. The goal of this survey was identification of different species, distribution, density and Biomass of the zooplankton community in different regions and also their frequency in the different layers and depths and the population fluctuations in whole of year. The most abundance and biomass of the zooplanktons were 28005±24212 ind./m^3 and 180.58±149.03 mg/m^3 in 5 min spring and they were reduced gradually to depths. Copepoda comprised between 9 to 16 percent, Rotatoria comprised between 5 to 13 percent and Lamellibranchiata larvae comprised between 27 to 70 percent of marin zooplanktons. The most abundance and biomass were 11746±7921 ind./m^3 and 47.07±31.96 mg/m3, 5281±5521 ind./m^3 and 29.03±31.68 mg/m^3 in 5m of summer and autumn seasons, respectively. Copepoda comprised more than 95 percent of marine zooplanktons in all of depths in these seasons. The most abundance and biomass were 19030±16518 ind./m^3 and 198.99±217.23 mg/m3 in 5 m in winter. Copepoda comprised between 17 to 49 percent and Rotatoria comprised between 32 to 70 percent of marine zooplanktons in all of depths and the abundance of other groups was not considerable in zooplankton community

Study on distribution of the Ctenophore Mnemiopsis leidyi in the Caspian Sea (Iranian Coasts)

In the early 1980s, an alien ctenophore Mnemiopsis leidyi already known as a gelatinous zooplankton was transported (likely via ballast waters) to the Caspian Sea from its introduced or native water of the Black Sea or western Atlantic which caused negative impacts. In this report, distribution of M. leidyi, planktonic and benthic organisms had been investigated in the Southern Caspian Sea (Iranian waters) in 6 transects consisted of Lisar, Anzali, Sefidroud, Nowshar, Babolsar and Amirabad at 26 stations during 2005 and 2006. As a whole, 1422 samples had been analyzed included 258, 346, 217, 117 and 484 belong to ctenophore, phytoplankton, zooplankton, benthos and physicochemical parameters, respectively. M. leidyi abundance and biomass were fluctuated between 284-2751 ind.m^-2 and 16.9- 390/9 g.m^-2 respectively in 2005 while maximum abundance and biomass were recorded in autumn and minimum in winter. In 2006, its mean abundance and biomass were 184-2150 ind.m^-2 and 9.1- 209/8 g.m^-2 respectively. M. leidyi maximum abundance and biomass were noted in summer and its minimum in spring and winter months. Overall, mean M. leidyi abundance and biomass were recorded in 20 m within 1202 ind.m^-2 and 139.5 g.m^-2 respectively. Maximum size of the ctenophore was recorded as 55 and 60 mm in 2005 to 2006 respectively, while less than 10 mm length frequency consisted 83.16 and 82.88 per cent of total population. Spatial_ temporal distribution of M. leidyi in different regions showed it was more abundant in west and east (714- 4494 ind.m^-2) ratio to central parts (13-1519 ind.m^-2) of the Southern Caspian Sea. Species composition of zooplankton had shown the negatively impacts of M. leidyi invasion in the period of sampling as the only 17 holozooplankton were determined with Rotatoria (7 species), Copepoda (4 species), Ciliophora (4 species) and cladocera (1 species). Zooplankton maximum abundance and biomass were recorded in February (3039742901 ind.m^-3 and 372.1575.4 mg.m^-3) respectively and its minimum were in July (12211601 ind.m^-3 and 6.9 7.7 mg.m^-3) respectively which was belonged to Rotatoria (76%) and Copepoda (10%). In this study, 21 species of benthic fauna were deter minted belong to Pseudocumidae (5 species), Gamaridae (4 species) Amphartidae (3 species), Oligochaeta, Balanidae, Xantidae, Nereidae, Scarbicularidae, Carididae, Mytilidae, Herpobdellidae and Chironomidae (each 1 species). Oligocheata was recorded with maximum abundance (943 2502 ind.m-2) and Bivalve consisted of higher biomass (68.7162.5 g.m^-2). From five phyla of phytoplankton, 172 species were determined of Chrysophyta (74 species), Cyanophyta (32 species), Chlorophyta (32 species), Pyrrophyta (24 species) and Euglenophyta (13 species), in which Chrysophyta and Pyrrophyta were noted as main groups with their maximum abundance (up to 65%) and biomass (93%). Maximum water temperature was recorded in August with 29.52.5 ֯C and minimum in February by 9.31.3 ֯C. Mean value of salinity was 12.010.90 ppt, secchi disk ranged between 0.2 to 7 m and oxygen demand varied from 5.95 to 10.54 mg. l^-1). Moreover, silicate concentration was recorded between 200 to 300μg.L^-1, Phosphate measured from 31-47 μg.L^-1, Ammonia varied in 10-29 μg.L^-1, Nitrite (0.6- 1.7 μg.L^-1), Nitrate (0.06-4.20 μg.L^-1, which mainly accumulated in coastal waters of the southern Caspian Sea

The study of physico-chemical characteristics, heavy metals and plankton of water in the warm water fish ponds using organic (cow dung) and chemical fertilizer

Currently, different kinds of chemical fertilizer such as urea, nitrate, sulphate and ammonium phosphate–potash are using in fish ponds of carp (Hypophthalmychthysmolitrix, Hypophthalmychthysnobilis). Chemical fertilizers, especially phosphate fertilizers can cause environmental pollution. Therefore, the use of alternative one, particularly organic fertilizer (manure) can reduce environmental issues. This study is conducted to effects of liquid cow manure on abundance, biomass and community structure of phytoplankton, zooplankton, physico-chemical chractrestics and heavy metal of water in the warm water fish ponds. For this purpose, the effects of three different types' fertilizers have been searched on fish ponds water. The ponds number 1 and 3 treated by chemical fertilizer and liquid cow manure respectively. Both of the two fertilizers (liquid cow manure and chemical fertilizer) were used in the pond number 2. Results showed that acidity of liquied cow manure was low (pH=7-8), however the total hardness and alkalinity were high. Meanwhile, percent of nitrogen were more than percent of calsium and phosphorus liquid cow manure. The concentrations of Pb, Fe and Zn elements were higer than critical level but some of them such as Cd, Cr, and Hg were lower than detection limit. As a conclusion, biomass of phytoplankton, zooplankton and physico-chemical parameters in fertilized pond treated by liquid cow manure were more convinence than pond treated by chemical fertilizers

The study of abundance and dynamic zooplankton in the Southern of Caspian Sea

The Caspian Sea is the largest lake, both by its area and volume. Zooplankton are very important in the food web since many animals eat them. The Sampling was done in 4 transacts in Anzali, Tonekaboun, Noushahr and Amirabad at 3 different depths including 5, 10 and 20 m. Sampling was carried out in four seasons of spring, summer, autumn and winter in 2013. The annual changes of zooplankton was between 392±113 ind./ m^3 in autumn (Amirabad) to 8065±11735 ind./m^3 in winter (Amirabad). The lowest density of zooplankton in the spring was 2207 ind./ m^3 in Anzali. The density of zooplankton in Tonekabon and Amirabad was 2.0 and 2.8 fold more than other transects respectively. The results showed that the abundance of zooplankton in summer was between 1964±470 ind./m^3 (Amirabad) to 5706±6088 ind./m^3 (Tonekabon). The biomass was 30.02, 52.22, 22.98 and 18.31 in Anzali, Tonekabon, noshahr and Amirabad respectively. The abundance of zooplankton in the autumn reached the lowest value. The lowest value was 392 ±113 ind./m^3 and 3.71±0.19 mg/m^3 (Amirabad) and highest value was 2280 ±1435 ind./ m3 and 20.23±14.50 5mg/m^3 (Anzali). The highest density was observed in Amirabad (8065 ind./m^3) and Anzali (8061 ind./m^3) in winter. The aim of this study was diversity, distribution, density and biomass of zooplankton in the southern of Caspian Sea

Hydrology and hydrobiology and environmental pollutions in lower than 10 meters depths of Caspian Sea

The present project in related to survey of factors and hydrology and hydrochemical features (water temperature, dissolve oxygen saturation, pH, clearance, salinity, nitrogen, phosphorus and silicon) hydrobiology (zooplankton, phytoplankton, macrobenthos) and survey of bio environment pollution (oil, heavy metal, detergent) executed in lower 10m in different water larger in southern Caspian Sea in 2002-2003. For sampling 8 lines number were vertical on coast that selected from Astra in west to Gomishan in east in southern Caspian Sea basin. The result indicated the average physical factors such as pH were 8.11 and salinity12.12 ppt ,and disolve oxygen6.7 mg/l. Average chemical factors such as NO_2 , NO_3 and NH_4 were 1.2 µg/l, 25.7 µg/l, 13 µg/l respectively.Total nitogen and organic nitrogen and inorganic nitrogen were 690.2 µg/l , 667.6 µg/l , 41.6 µg/l. Average silicat were recrded 266.35 µg/l . Total Phosphorus was observed 37.35 µg/l and average of organic Phosphorus concentration was and 20.25 µg/l .Average of Total organic matter (T.O.M) was 4.98% maximum amount were observed in Lisar and minimum in Nooshahr . Concentration of heavy metal during sampling were respectively ,Fe>Mn>Zn>Cr>Ph>Co>Cd>Cu. Maximum concentration of Fe were determined in winter in Nooshahr and Babolsar respectively 13/3 µg/l 17/1 µg/l. In many stations and different Season, the amount of heavy meta were lower standard of in marine water. The concentration of oil hydrocarborate (PAHs) in autumn was 0/13 ppb and in winter 0/12 ppb. The amount of (PAHs) in Southern Caspian Sea were Lower than other parts of Caspian Sea. The average of detergent concentration (LAS) was 0/036 µg/l that was two fold higher than determined in 2001. Total 107 species of phytoplankton belong to 5 phylum were identified. The numbers of species of phytoplankton groups were respectively, chrysophyta (42 species), cyanophyta (17 species), pyruphyta (17 species), chlorophyta (21 species) and euglenophyta (9 species). The maximum diversity of phytoplankton observed in summer and minimum in autumn. High diversity of chrysophta and cyanophyta observed in summer and phyrophyta and chrlophyta in spring. The composition of phytoplanhkton groups were respectively, chrysophyta (70%), phyrophyta (9%) and chlorophyta (7%) and euglonophyta (1%). Maximum density of phytoplankton was observed in autumn and minimum in winter. Total 19 species of Zooplankton were identified. Maximum diversity was observed in summer and minimum in winter. Zooplankton changes during sampling, showed amount of density of zooplankton in 5m were more than 10 m depths. Total (17 species macrobenthos were identified. The composition of macrobenthos groups were respectively , Annalida (92/7% ) , Bivalvia (2/7%) gumarida (108%) cumacea ( 1/5%) , Balanidae 103% . max . density were observed in Astara and min . in Sefied roud Average of density were 1218 0/851 ind /m^2 and biomass 14 15 g/m^2 High density were recorded in autumn and low density in winter . Correlation of phytoplankton and zooplankton with physicochemical parameter and also relation between total organic matter and sediment grain size were calculated.Ecological indicies (simpson diversity evenns diversity and shanoon-wiever diversity) were calculated for macrobenthos. Data were shown impact of cetenephora (Mnenemiopsis leidyi) on zooplankton and phytoplankton and macrobenthos density

Limnologic study Sabalan run off Dam for aquaculture fish cold water

Limnological study of Sabalan run off Damfor aquaculture cold water fish was conducted in sixtimesat four stations from July to December 2009. Average minimum and maximum parameters measured in different stations were included water temperature, dissolved Oxygen, total hardness, electrical conductivity, pH, BOD5, COD, TDS, NH4, NO2, NO3, PO4, TN, TP, SiO2, respectively (10/3±9/5-14±8/7°C), (9±1/2-11/4±2/1 mg/liter), (367±19/8-381±17/8mg/liter), (0/95±0/07-1/05±0/07 mz/cm), (8/3±0/1-8/4±0/1), (3/3±1/14-3/88 ± 0/71mg/ liter), (15/5 ± 3/1-16/3 ± 3 mg/liter), (0/48 ± 0/04-0/54 ± 0/06mg/ liter), (0/08 ± 0/02-0/13 ± 0/07 mg/liter), (0/004 ± 0/003- 0/05 ± 0/1 mg/ liter), (0/6 ± 0/2-0/64 ± 0/29 mg/ liter), (0/19 ± 0/07-0/22 ± 0/07 mg/ liter), (10/48 ± 0/6-10/98 ± 0/54mg/liter), (0/39 ± 0/11-0/44 ± 0/18 mg/liter), and(9/9 ±0/6-11/1 ± 1/4 mg/liter). Average minimum and maximum of water heavy metalswas included of Cd, Pb, Zn, Fe, Cuand Ni respectively was measured as ND(No Deliver), ND, ND- 0/242, ND- 1/075, ND- 0/018 and ND-0/014inmg/ liter. Also among the 16 organochlorinecom pounds measured the highest amount of was belonged totoxin Hexachlorine Benzene (1/5 mg/ liter). The results of the analysis of water quality parameters showed that parameters except ofCOD, TDS, PO4, TP, Zn, Fe and water temperature, other parameters do not haveany restrictions foraquaculturecold water fish in therunoffDam. Based on data results it was noticed that there was temperature restriction up to November at downstream and station 2 showed less temperature fluctuation and more suitable condition compared to other stations. BOD5 value was within the allowable range for growing trout, in which station 2 somewhat with lower volatility of value had the most suitable BOD5 condition. In the present study, the amount of TDS in the study area was somewhat higher than the limitation and since TDS values increased with distance from the dam, therefore station 2 had somewhat better conditions for fish farming. In addition the amount of EC in the study area, indicating the inappropriateness of it for various activities in the fisheries. Although none of the stations in terms of the amount of phosphorus didn't show favorable conditions for rainbow trout fish propagation, it appears between the researches stations, station 2 had the most favorable terms. The results of this study (regardless of the unseen), it seems that in August and September; Zn had overestimated value for cold fish propagation. Recent study showed that among heavy metals, Fe in water, sediments and fish was over limitation value. Also, Fe value was measured of 1.08 at station 4, which showed over normal value for cold fish propagation. Therefore, station 2 at downstream seemed to have suitable cold fish propagation due to lower Fe value. On the based on the recent study, planktonic biological index did not endorse water quality for fish propagation. In this study, aquatic plant such as Potamogeton pectinatus and Pheragmitie saustralis was found at water of higher and somehow polluted organic matter. Probably, based on the results it was noticed that downstream water of dam was polluted to organic matter. At the recent study, resisted maroinvertebrates to organic matter (Chironomidae) was consisted noticeable frequency compared to other sensitive invertebrates to organic matter (EPT).Statistically, it can be expressed that probably organic pollution resulted to increase of resistance invertebrates and decreased of sensitive groups. In recent study, EPT/CHIR index was measured 0.6 in station 2 and 1.74 in station 4. This ration was less to many other mountain rivers. As ETP sensitive invertebrates has higher sensitive to other groups with the regards of environmental condition and pollution, unpredicted increase of Chironomidae compare to sensitive groups resulted of EPT/CHIR value which showed environmental stress. In this study, HFBI index was measured as 7.49 at station 2 and 7 in station 4. Based on HFBI index, station 2 was classified as a high organic pollution and station 4 with noticeable organic pollution. At the recent study, station 2 was catch more fish to station4. For instance, Squaliuscephalus and Alburnoides pinctatus were catch in station 2 and were not found in station 4. As a whole, Biological indicators whichwas included Plankton Bioindicator, EPT / CHIR. ,Hilsenh off Biological Indicator, diversity and distribution ofaquatic plants and fish, showed water situation in run off Damrich inorganic matter. Finally, the study area was approved for fish farm about 50 tons and needs management arrangements with the increased production rate