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The Caspian Sea is an important source of water in terms of having valuable resources of sturgeon and bony fish is taken into consideration roach(Rutilus rutilus caspicus (L.)) is one of the most important commercial species in the southern coast of the Caspian Sea in Iran , the catch of this species has declined substantially in the last 10 years, The management and exploitation need of comprehensive review of its biology .This study as part of a comprehensive study of feeding , spawning and growth of this species.In this study, using samples caught in beach seine along the southern coast of the Caspian Sea coastal ( Iranian waters ) took place. The fork length and total weight ranged between 12.5 to29.5(cm) and 29 to293( grm),10.5 to23(cm) and17.2 to21(grm) in Golestan and Gilan Province respectively. The b value of the length-weight relationship ranged 3.02 to 3.25 and 3.28 to 3.75 for female and male, in Golestan and Gilan Province respectively. The age composition of the catch was from 1 to 4 year in both Province, there was one spawning peak and Fecundity variations were high and ranged 7260 to 231965 eggs. Average growth in length was described with the Von Bertalanffy growth model: L (t) = 30.94(1-exp (0.42(t-0.18) and L (t) = 20.49(1-exp (0.53(t-1). The percent of empty stomach and prey dominant evaluated during different seasons by specific formula. Result showed that gastropod, Polychaete worms and molluscs were dominated and specific food items respectively. Shrimp, fish, insects, zooplankton and clams were scare of prey. Iranian Fisheries Science Research Institute Published

Distribution of freshwater shrimp (Macrobrachium nipponense) in the freshwater ecosystems such as Alagol, Almagol, Ajigol lagoons, Gomishan lagoon and Gorganrud River. Sampling were done from may 2009 to my 2010 parameters such as, length frequency, growth rate, sampling, feeding, environmental factors and sedimentation were investigated. 3689 females and 8551 males were collected and biometrical parameters were recorded. Total length ranged between 3.2 to 98.7 mm. The parameters b of length-weight relationship in Alagol, Almagol, Ajigol were 3.49, 3.15, 3.45, 3.22 and 3.22, 3.28 for male and female, respectively. It shows in all lagoons for male and female growth is positive Allometric. Spawning period was from May to June. The length first at maturity (total and/or carapace) for three lagoons was 50.5 mm and 133 mm, respectively. The minimum and maximum of egg volume were 0.12 mm3 in Ajigol and 0.07 mm3 Alagol, respectively. The relationship between fecundity and length was found to be linear regression models for Alagol, Ajigol and nonlinear regression models for Almagol lagoon. Result showed that this species is omnivorous. The minimum and maximum temperature was 6.5ْ C in fall and 33ْ C in summer. The lowest and highest fluctuations of pH level in Ajigol and alagol lagoons were 8.2-9.2 and 7.2-9.8. Among three lagoons, the most EC was 5.9 Ms/c in Alagol lagoon. The Gorganrud River shows the maximum EC, 16.7 Ms/c.

In the years 2007-2007, 2008-2009 and 2009-2010 the exploitation of bony fishes resources (by 131 beach seines) started on 12 October but finished on 9 April, 9 April and 13 April, respectively. During these periods the total catch of bony fishes were 23537.8, 20045.5 and 18664.8 tonnes, respevtively. During these periods, kutum predominated and represented the highest proportion of total catch at 73.1, 74.0 and 66.9% , followed by golden grey mullet at 18.3, 13.9 and 18.7%, respectively. K values calculated 0.22, 0.15 and 0.14 year-1 and L∞ were 66.0, 62.7 and 70.0 cm for kuttum, golden grey mullet and common carp, respectively. The instantaneous coefficient natural mortality were estimated as 0.386 and 0.35 year-1 for kutum and golden grey mullet, respectively. During three periods, the exploitation rates were 0.789, 0.584 and 0.614 for kutum and 0.71, 0.75 and 0.61 for golden grey mullet, respectively. In the years 2007-2007, 2008-2009 and 2009-2010, the total biomass, from the biomass-based cohort analysis were 56600, 62090 and 61590 tonnes for kutum and and MSY estimated about 24733.7 and 8550.4 tones for kuttum and 11040, 11900 and 14460 tonnes for golden grey mullet, respectively. The ABC (acceptable biological catch) were estimated as 8000 and 2200 tonnes. Iranian Fisheries Science Research Institute Published

Distribution of freshwater shrimp (Macrobrachium nipponense) in the freshwater ecosystems such as Alagol, Almagol, Ajigol lagoons, Gomishan lagoon and Gorganrud River. Sampling were done from may 2009 to my 2010 parameters such as, length frequency, growth rate, sampling, feeding, environmental factors and sedimentation were investigated. 3689 females and 8551 males were collected and biometrical parameters were recorded. Total length ranged between 3.2 to 98.7 mm. The parameters b of length-weight relationship in Alagol, Almagol, Ajigol were 3.49, 3.15, 3.45, 3.22 and 3.22, 3.28 for male and female, respectively. It shows in all lagoons for male and female growth is positive Allometric. Spawning period was from May to June. The length first at maturity (total and/or carapace) for three lagoons was 50.5 mm and 133 mm, respectively. The minimum and maximum of egg volume were 0.12 mm3 in Ajigol and 0.07 mm3 Alagol, respectively. The relationship between fecundity and length was found to be linear regression models for Alagol, Ajigol and nonlinear regression models for Almagol lagoon. Result showed that this species is omnivorous. The minimum and maximum temperature was 6.5ْ C in fall and 33ْ C in summer. The lowest and highest fluctuations of pH level in Ajigol and alagol lagoons were 8.2-9.2 and 7.2-9.8. Among three lagoons, the most EC was 5.9 Ms/c in Alagol lagoon. The Gorganrud River shows the maximum EC, 16.7 Ms/c. Iranian Fisheries Science Research Institute Published

The Caspian Sea is the biggest lacustrine water source. Common carp is very important commercially in south coastal line of Iranian Caspian Sea waters, especially in east coastal line, because eighty percent annual catch of this species has been caught in this area in particular. Despite the common carp importance and value in Iran, but there is a little information about its biology in natural system. This study is comprehensive research on reproduction, growth and feeding. The specimens were caught by beach seine net in coastal line of Iranian waters. The fork length ranged between 5.6 and 2866.2 g. The b value of the length-weight relationship ranged from 2.843 to 2.924 for female and male, respectively. The age composition of the specimens was from 1 to 11 year. The gonadosomatic ratio (GSR) changed from 2 to 12. There were two peaks of GSR in April and December, so that the latter peak was much shorter than the first that. Fecundity variations were high and ranged 77448 to 430745 eggs. It observed linear significant correlation in fecundity- weight (r=0.98) and fecundity-length (r=0.88) relationships. Average growth in length was described with the Von Bertalanffy growth model: L (t) = 60.5(1-exp (0.19(t-0.65). The percent of empty stomach and prey dominant evaluated during different seasons by specific formula result showed that in Cyprinus carpio prey Molluscs was dominated and specific food items. Empty stomachs in winter and spring were higher and lower, respectively. Iranian Fisheries Science Research Institute Published

The marine survey for sturgeon stock assessment was conducted in summer, winter and spring in the years 2006 and 2009 to estimate the relative and absolute abundance and percentage composition of each species in the Guilan, Mazandaran and Golestan Provinces. This survey was carried out in the Iranian waters of the Caspian Sea on board the Sisara2 and Guilan vessels using trawl nets at 2-100 m depths. Trawling was carried out in 85 stations that were selected using a stratified random design. The number of stations in each scope was based on the area of the scope in terms of the total area. Trawling and sampling in shallow water up to 10 m were carried out using 9 m trawl nets whereas 24.7 m trawl nets were used for depths more than 10 m. Trawl surveys were carried out in the daytime. Trawling velocity was kept at 2.5-3 kts and trawls lasted half an hour in order to calculate abundance, and biomass of sturgeons using the swept area method. Catch per unit area (CPUA) in the winter 2006 survey was 3853 specimens nm2 , in the summer and winter 2007 survey was 1854 , 2912 specimens nm2 at depths less than 10 m respectively . CPUA for sturgeons in spring 2008 survey was 2103 specimens nm2 at depths less than 10 m and 393 specimens nm2 at depths greater than 10 m (10-100 m depth). These values in the winter 2008 survey dropped to 44 specimens nm2 at depths at depths above 10 m. CPUA for sturgeons in the spring 2009 survey was 300 specimens nm2 at depths less than 10 m and 307 specimens nm2 at depths greater than 10 m. In all the surveys conducted CPUA for A. persicus was higher than that for the other sturgeon species. Based on the calculations carried out in the marine survey in winter 2006 the estimated absolute abundance for sturgeons was about 2977.363 thousand. The total biomass of sturgeon was estimated as 131.713 tons. In the summer 2007 survey total abundance was estimated 1432.398 thousand, and total biomass of sturgeons was estimated at about 312.161 tons. In the winter 2007 survey total abundance for sturgeons was estimated at about 2250.105 thousand, and total biomass was estimated 578.08 tons. In the spring 2008 survey total abundance was estimated at about 3002.832 thousand. The total biomass was estimated at about 2533.318 tons .In the winter 2008 survey total abundance was estimated at about 152.722 thousand, and total biomass in winter 2008 was estimated 170.540 tons. Total abundance in spring 2009 survey was 1310.232 thousand and total biomass was estimated at 2019.tons. Investigation of stomach content of sturgeon Acipenser persicus caught under 10m depth in 2006 to 2007 surveys showed that there is significant difference in the consumed food. Polychaeta is the major food consumed and crustacean an the minor one(P>0.05).Also no new types of food( such as bony fishes or benthic) have been observed in food chain of Acipenser persicus only the food consumption rate has been related to the season of year and increases or decreases in warm or cold seasons, respectively For physiological study and determination of sexual maturation stages in sturgeon,119 gonad sampling prepared. The results showed that 63 % of fishes were females and 37 % of them were males. Gill microscopic study shows complications such as hyperplasia, curvature, adhesion, embowed, shorting and lengthen of secondary filaments and fraught bloody. Microscopic study on liver indicates signs of cloudy inflammation, fatty degeneration, dispersion of billed secretions and cell atrophy. The population genetic structure of Persian sturgeon (Acipenser persicus) in Sefidrood and Gorganrood rivers watershed analyzed based on microsatellite markers during sturgeons assessment in 2006-2008. Results showed that Acipenser persicus in two region of south part of Caspian Sea are two independent populations. Iranian Fisheries Science Research Institute Published

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

Exploitation of bony fishes resources started on 12 October 2005 and finished on 9 April 2006 in 2005-2006. 142 beach seines caught about 14333.4 tons of bony fishes by 47101 hauling. The total catch was estimated 21844.7 tones (Includes illegal fishery). Kutum, mullets and common carp comprised more than 97 percent of total catch. Length classes 39-40, 31-32 and 40-41 cm predominated for kuttum, golden grey mullet and common carp, respectively. Age groups 3 to 5 year comprised 84.2, 74.8 and 83.7 percent for Kuttum, golden grey mullet and common carp, respectively and age group 4 year was dominant with 42.0, 35.9 and 43.0 percent, respectively. K value and L∞ calculated 0.26 (/year) and 58.3 cm for Kuttum and 0.15 (/year) and 61.5 cm for golden grey mullet, respectively. The total biomass and MSY estimated about 24733.7 and 8550.4 tones for kuttum and about 16948.0 and 4999.0 tones for golden grey mullet, respectively. Exploitation rate (E) calculated 0.71 and 0.70 for Kuttum and golden grey mullet, respectively. In 2006-2007, the exploitation of bony fishes resources started on 12 October 2006 and finished on 7 April 2007 in 2006-2007. 134 beach seines caught about 14120.0 tones of bony fishes by 48470 hauling. The total catch was estimated 23801.8 tones (Includes illegal fishery). Kutum, mullets and common carp comprised more than 98.5 percent of total catch. Length classes 39-40 and 38-39 cm predominated for kutum and common carp, respectively and length classes 27-28 and 29-30 cm predominated for golden grey mullet. Age groups 3 to 5 year comprised 80.2 and 71.8 percent for kutum and golden grey mullet, respectively and age groups 4 to 6 year comprised 71.8 percent for common carp. Age group 3, 4 and 5 year was dominant with 35.5, 32.1 and 27.1 percent for kutum, golden grey mullet and common carp respectively. K value and L∞ calculated 0.27 (/year) and 60.7 cm for Kutum, 0.2 (/year) and 58.4 cm for golden grey mullet and 0.19 (/year) and 66.7 cm for common carp, respectively. The total biomass and MSY estimated about 46654.9 and 14801.4 tones for Kutum, about 19549.0 and 5748.4 tones for golden grey mullet and about 10584.3 and 2186.0 tones for common carp, respectively. Exploitation rate (E) calculated 0.69, 0.53 and 0.52 for kuttum, golden grey mullet and common carp, respectively. Iranian Fisheries Science Research Institute Published

During last 65 years the catch of mullets had increasing trends with some fluctuations in the Iranian coastal water of the Caspian Sea .In this period about 138 thousand tons of mullets have been caught. Mullet’s account for 35% of total catch annually .In recent years species composition of mullets has chanched in the Iranian coastal water of the Caspian Sea and catch composition of golden grey mullet increased from 76% in 1995 to 98% in 2006. In this survey some biological characteristics of golden grey mullet have been studied in Iranian coastal water of the Caspian Sea .Fish samples have been gathered from commercial catch of beach seine cooperatives monthly in Iranian coastal water of the Caspian Sea over 2006 and 2007. In the laboratory fishes have been measured biometrically and biological parameters have been calculated .Also catch statistics of mullets during 2006-2007 have been obtained and discussed. Results showed that the catch of mullets in beach seine cooperatives during 2006 and 2007 was 4181 and 3685 tons respectively that golden grey mullet contribute 99% and 98% of the catch composition of mullets respectively. Length range of golden grey mullet caught by beach seine cooperatives was 19-50.2 cm with mean length of 32.7 ± 6.4 (± SD) and weight range was 67-1475 gr with mean weight of 411 ± 255 gr. The age structure of this species was comprised 2-10 years old fish with mean age of 4.42 years old. In this survey totally the sex ratio of male: female of golden grey mullet was 356: 434 that was significant variation from equal sex ratio. Pick of the spawning in Guilan province was in October and in Mazandaran and Golestan provinces was in November. In October the proportion of spawning females declined from western area (Guilan province) towards eastern parts (Golestan province).The highest proportion of spawning females was in December in Golestan province. The highest GSI index value was observed in September and October and it was decreased in November and December and it was consistent during January till April. The mean absolute fecundity was 700881±429987 eggs with minimum and maximum fecundity of 200112 and 2282862 eggs respectively. The Lm 50% for female golden grey mullet was calculated as 33.6 cm.

In this study the frequency of the sturgeon population in the lower depth (