A survey of feeding habits of economic benthic feeder fishes in the southern of Caspian Sea (Rutilus frissi kutum, Rutilus rutilus caspicus, Cyprinus carpio, Liza auratus and Liza saliens)

Present study analyzed the stomach contents of individuals belonging to five fish’s species in order toInvestigate seasonal changes in feeding strategy and diet composition in the South coast of the Caspian Sea (Gilan and Mazandaran provinces) from late March until late May 2010 using the research ship Gillan and fishing with batoom trawl nets and fishing blades insoles bony fishes in the depths of less than 60 meters. The average length and the total weight of Rutilus frisii kutum, Rutilus rutilus caspicus, Cyprinus carpio, Liza auratus and Liza saliens respectively were 36/9 ± 8/5 cm , 562/9 ± 353/2 g, 23/2 ± 3/2 cm , 202 ± 101/6 g, 24/6 ± 8/1 cm , 249/8 ± 242 g, 32/2 ± 8/9 cm , 320/9 ± 242/8 g, 22/7 ± 2/6 cm and 82/9 ± 52/2 g repectively. Using the method of Shorygin and Costello highly nourishing food strategy and different species of fishes were studied. The results of this study showed that Rutilus frisii kutum fed generally of Balanus and Cerastorderma In order of importance after Bivalvia, Gastropoda, Crabs, Fish eggs, Filamentous alge in GI Rutilus frisii kutum presence, but feeding it of Bivalvia (in particular Cerastorderma) was much more than the other food. The results of present study showed that under the influence of compatibility and behavioral mechanisms, ecological, physiological and nutritional importance of Rutilus frisii kutum Bivalvia. The results of studies were showed that Bivalvia was feeding the dominant Rutilus frisii kutum , while the results of this study showed that despite Bivalvia present importance in feeding the of this species, it seems that its presence in such digestion decreased. As well as the dominant food of Rutilus rutilus caspicus was fish, but generally from Detrite fed. This study showed that feeding the dominant species of Cyprinus carpio, Liza auratus and Liza saliens of Detrite was. The most important food items after ditrit for the Cyprinus carpio in order of importance include the Bivalvia, Gastropoda, Oligochaeta, Abra ovata, Nereis, Fish eggs, Filamentous alge, was. The Liza auratus dietary habits also showed that after ditrit the most importance in nutrition related to Foraminifera, Porifera and Balanus, and for Liza saliens to Gastropoda, Bivalvia and Porifera. The results showed that the mullet the greater the intensity of feeding fishes than other species were, Rutilus frisii kutum in between of Cyprinidae the greater the intensity of feeding fishes than other species were (0/05 > P). The values of this indicator in the lower longitudinal in all fish species investigated were more than high longitudinal groups. The feeding intensity at different times of sampling for all species investigated showed that in all species at times extremely reduced the reproductive index (0/05 > P). As well as the diversity foods in the lower longitudinal in all fish species investigated were more than high longitudinal groups. In conclusion, our results demonstrated Food strategy have changed based on physiological changes, metabolism activity, behaviour, and the amount of food available

Study forming of growth rings in the Caspian bony fishes (Step 1: Common carp Cyprinus carpio Linnaeus, 1758)

The ichthyology studies at fish tagging was referred to more than 100 years ago. Tagging is utilized for the estimation of stock amount, population frequency and project or calculating of survival and growth value. There are many various methods for fish tagging are used for juvenile to adult fish. The current study was carried out at Ghare-su research station during 2011-2013. 250 of carp fingerlings (Cyprinus carpio) were tagged by bath with tetracycline manner (pH=6, 500mg/l). The fork length and weight of fish were 10-12 mm and 2-4 g, respectively. Also, fish were fed twice a day. The second and third tagging stages were performed at November 2012 and July 2014, respectively. After otolith was extracted, it was washed water and dry at lab room air. The tagged rings or loops (annuali) were observed by lab loupe with 10X and 40 X magnifications. The results showed that a narrow band was formed after the first tagging of carp fingerlings, as it was seen at the end of otolith edge. It was demonstrated that tetracycline was absorbed and the tagged ring or loop (annuli) was newly formed at external or out of othlith edge. There was not observed any fish death, when carp fingerlings were tagged by OTC bath manner. It said that the first OTC band will be seen, the first sign of the formed OTC band was observed at external margin of otoilith after 6th month , of course , from 4th month, this sign was formed at the most external of otoilth edge but with added the following region, it can be hardly distinguished. The formed band in relative to second tagging was similar to the first band but there was no discrepancy or difference with together

Age, growth, feeding regime reproduction and sexual maturity of Rutilus frisii Kutum in Iranian coastal waters of Caspian Sea

The project of Age, growth, feeding regime and fecundity of Kutum (Rutilus frisii Kutum) survey started in south of the Caspian Sea from 2006 to 2007. The aim of project was related to determination of length maturity (Lm50%), identification of feeding animals, and investigation some of biological aspects uncluded in sex ratio, growth and age structure in southern of the Caspian Sea. Total 2706 specimens of Kutum were surveyed. The age structure of Kutum has nine age groups that included in 1, 2, 3, 4, 5, 6, 7, 8, and 9 years. The result showed that maximum frequency was about 39.3 % and were belong to 4 years and minimum frequency which was about o.1 % were belong to 9 years. The maximum and minimum fork length and weight were 58 and 21cm with mean (±SD) 38.4 (± 6.4) cm; 2450 and 104g with mean (±SD) 784.2 (± 383.30) g , respectively. There are significant different between fork length and weight in male and female of Kutum at difference months (ANOVA, P<0.05). The sex ratio of males to female was 0.65: 1 (males: females). The least and high condition factor was 1.5 in January and 2.17 in October, respectively. Length maturity (Lm50%) was 39.07cm. Minimum and maximum absolute fecundity was varied from 15713 to 130737 eggs with mean (±SD) 69961.7 (± 3836.4). Significant different was between absolute fecundity with fork length and weight (p<0.05). Gonadosomatic index (GSI) mean for females were 2.5±0.2 (autumn) and 17± 0.2 (spring); 1.2± 0.1 (autumn) and 4.1± 0.2 (spring) for males, respectively wich coincided to spawning period. The highest feeding intensity (Gastrosomatic index) for females was 313.9 ± 65.9 in October and 119.4 ±59.2 in March; 350.7 ±103.7 in October and 144.1±85.04 in March for males, respectively. There are significant different between GSI with male anfemale in difference months (ANOVA, p<0.05). The Bertalanffy growth equation for all populations of Kutum was L (t) = 63.92[1-e ^0.19 (t (-1.00)]. Main prey mature of Kutum was Cerastoderma lamarki; Gastropoda and Balanus were subordinate, and Crab, Hypanis, Fish (Neogobous sp.) Algae, egg, and scale were random preys. Planktone groups comprise to Exuviaella, Nitzchia, Osillatoria, Synedra, Nematoda, Navicolla, Diatoma, Rholcosphenia were preys juvenile of Kutum. Based on ISI (Important species index), Cerastoderma lamarki and Balanus were dominant species in feeding of Kutum. As a result, growth, fecundity and length maturity of Kutum declined which may due to loss natural breeding area, overfishing (overlapping between fishing and spawning period) and artificial breeding that commenced since 1982. Hopefully, this information can be used in fisheries management

Spatiotemporal and estimation of washed out seaweeds biomass in Sistan and Baluchistan coasts

In order to studing and determination of Seaweed biomass in the Oman Sea coast (Sistan & Baluchestan Province), according to obtained reasults and experiments and observations on seaweed studies in 15 years ego, Beris, Chabahar, Pozm and Tang were high density zones and Jood and Lipar were low density zones in west and east of chabahar respectively that were selected for study stations. Total length of sistan and balochistan coasts from Gwatr area with geografical position 25˚ 10′ N & 61˚ 30′ E to Mydani with geografical position 25˚ 24′ N & 59˚ 5′ E were 354.3 Km. Among this length, 54.6 Km were rocky coast and 299.7 Km were sandy coast. Among this, 18.2 Km were high density zone and 281.5 Km were low density zone. Washout Seaweeds area in intertidial zones determind by measuring and recording of geographic positions by meter and GPS, then were obtained 2 transects determind with equal distance in high density area and 1 transects in low density for monthly sampling. The length of these transects were 100 meter and cross of Each transects were seaweed washed out average. The transects divided to 10 bluck and sampling were done randomly monthly from 5 bluck or 50 persent. The samples were transfered to the lab and the weight of each species was obtained after being cleaned, and separating. The biomass of each species per area unit and in the total area was obtained after determing the average weight of species and also determind geografical position by GPS. In relation to this project were done water sampling for recording of fisical chemistry factors. Total data for analysis recorded in this computer. During this research 9 species were collected. Among these seaweeds, 2 species green algea (composed of 2 families and 2 orders), 6 species brown algae (composed of 3 families and 3 orders) and 1 species red algae were identified. Wet biomass of Sargassum in the total area of Sistan & Baluchestan coasts were 445.9 ton in 2012. Among this biomas, 269.1 ton (%60.35) high density area (Beris 112 ton or %25.11, Pozm 83.7 ton or %18.76, Chabahar 59 ton or %13.22 and Tang 14.5 ton or %3.26) and low density zone 176.8 ton (%39.65). Monthly average were estimated about 74.3 ton (high density zone 44.9 and low density zone 29.5 ton). The maximum biomass was obtained 270.4 ton (high density zone 155.5 and low density zone 114.9 ton) in Azar and minimum biomass was obtained 3.5 ton in Esfand. At last, were suggested, This project were done in persian gulf coasts nessesery

Marine food web dynamics of small-sized pelagic fish in the Caspian Sea (Iranian’s water)

A mass-balance Ecopath model of coastal areas in the Caspian Sea has been constructed for a quantitative description of the trophic structure of the ecosystem. The model is used to estimate the important biological parameters and relationships among the different ecologically important groups. Twenty five species were used in the present analysis. The model is based on the data collected of Kilka fisheries, beach seining (Bony fish fisheries), and set Gillnet (Sturgeon Fisheries) and also dietary information. Total landings along the Iranian portion of southern Caspian coast reached 39647 t, including sturgeon (41 t), kilka (22873 t) and bony fishes (16733 t) in 2014. Two species of kilka (Common kilka and Anchovy) are important commercially in the Caspian Sea, together accounting in the past decade for > 60 % of the total catch, as well as being a crucial part of the food chain. The mean average trophic level was estimated at 3.17 by Ecopath software. In this research, the mean level were studied between eight species varied from 2.56 to 4.04, Sander lucioperca occupy the highest and the as vimba vimba was the lowest level. The ranges of total mortality varied from 0.5 to 2.56 per years. The food consumption rate was estimated about 101.56 per year Mixd trophic level index (MTI) showed small pelagic fishes as prey, have crucial role in feeding of pelagic predators population such as invasion of the ctenophore Mnemiopsis leidyi, bream fish and benthic fish such as sturgeon. In general, niche overlap was greater in more species such as Alburnus chalcoides, Rutilus rutilus, Clupeonella cultriventris, Rutilus kutum and M. leidyi who consumed large amounts of plankton. In conclusion small pelagic fish exert a major control on the trophic dynamics of the Caspian Sea ecosystems and constitute midtrophic-level populations

The survey statistical and biological of sturgeon in the southern Caspian Sea (Mazandaran waters)

This study have been conducted entitle biological and statistical sturgeon in the southern Caspian Sea (Mazandaran waters)” from 2009 to 2013. Sampling was manthly. Overal, 1859 specimens of different species of sturgeon was caught including Acipenserpersicus (69%), A. stellatus (19%), Husohuso (6%), A. nudiventris (4%) and A. guldenstaedtii (2%). Totally, the meat and caviar of five species were found 53263.6 kg and 5633 kg respectively and caviar to meat ratio was 10.6%. The results show that ration of meat and caviar whole species reduced from 2009 to 2012 in which the meat and caviar of A. persicus was declined from 12146 to 4465 kg in meat and caviar from 1358 to 487 kg were extremely reduced respectively. The CPUE (catch per unit effort) of sturgeon has fluctuated from 2009 to 2012. Totally, the CPUE of A. persicus was decreased from 0.150 (2009) to 0.130 (2012) kg boat per day, A. stellatue from 0.009 (2009) to 0.021 (2012) kg boat/day, A. guldenstaedtii from 0.002 (2009) to 0.003 (2012) kg boat/day, A. nudiventris from 0.027 (2009) to 0.001 (2012) kg boat/day and H. huso from 0.123 (2009) to 0.018 (2012) kg boat /day. 1061 specimens of fish has been caviar including A. persicus with 69%, A. stellatus (18.1%), H. huso (5.5%), A. guldenstaedtii (2.7%). The frequency of caviar categorize was included 1 , 2, 3 and massive with 49.6%, 38%), 10.6% and 1.9%, respectively. The highest of meat and caviar belong to A. persicus with 31414 kg and 3515.7 kg, respectively were found and the lowest was 841kg and 105.9 kg pertain to A. guldenstaedtii. The results show that 65.9% of sturgeon was caught by legal catch (landing) and 34.1% by beach seine remained. 391 individuals was age determined that the minimum and maximum age was 9 and 41 year comprised to H.huso and A. stellatus, respectively. A. persicus and A. stellatus were majority caught compare to other species. A. persicus has the highest frequency in 14-15 year age groups with 50% and 57% in 2009 and 2011, respectively and 15-16 year age group with 41% and 56% in 2010 and 2012, respectively. The results show that mean of fork length, body weight, caviar weight of A. persicus was declined because the FL and weight average (±SD) obtained from 152.4±16.7cm and 25.8±9.2 kg in 2009 to 146.5± 18.7cm and 22.1±9.2kg in 2012, respectively. In contrast, the average (±SD) FL and weight of H. huso was increased from 218.8±41.1cm and 137.3±96.6kg in 2009 to 231.3±45.2cm in FL and 146.2±78.5kg body weight in 2012, respectively. Consequently, the results show that stocks of sturgeon in the Caspian Sea has a trend declined because of some species in IUCN categorize list was Endangered in 2006 but at this moment lie in Critically Endangered list of IUCN categorize were down which could be a serious alarm for the valuable sturgeon fish in the Caspian Sea. Therefore, recommendation that trade catch of sturgeon in the Caspian Sea must be forbidden and continue legal catch for spawner fish that needede to artificial propagation only

Study on the growth status of mullets with viral nervous necrosis disease in the southern Caspian Sea

Mullet and mullet products have considerable economic importance at a regional level, especially around the Caspian Sea. The leaping mullet constitutes an important part of their production. This study is the first detailed work on the age and growth of the leaping mullet (Liza saliens) from September 2012 to March 2013 in the Southern coast of the Caspian Sea. Age and growth determinations were based upon the scale samples taken from 102 fish. Marginal increment analysis was used to validate age determination. The back-calculated lengths stage estimated from the scale showed no differences between in this study. The maximum age of leaping mullet in the Southern coast of the Caspian Sea was 5 years for males and 6 years for females. The von Bertalanffy growth functions were Lt=30.415(1-e-0.275(t+0.645)) for males and Lt=34.832(1-e 0.211(t+1.009)) for females. A large spread and length overlap characterized the age groups. The estimated Length Weight relationships were common for the two sexes (W=0.079L3 ). The slope (b) values of the length-weight relationship showed that weight of leaping grey mullet in Mazandaran increased associated with length in isometric. The mean condition factor for males, females and all specimens were determined as 0.908, 0.900 and 0.897, respectively. According to sex groups, the mean condition factor of males was slightlyhigher than that of females. The total length for leaping grey mullet was determined as 23.3 cm