Some biological aspects and catch trend of mullets in the southern Caspian Sea

Mullet and other bony fishes are caught by beach seine in Iranian coastal zone in Golestan, Mazandaran and Guilan provinces. The catch and CPUE trend of mullets were compared during 1993 to 2001 and some biological characteristics such as: species composition, length, weight, K and age of Liza aurata and L. saliens were analyzed. In 1990s, the results showed that amount of catch has been increased and the maximum catch occurred in 2001. CPUE decreased from 114 kg (in each seine) in 1993 to 43 kg in 1996 whereas 2001 increased to 66.4 and 78.4 kg in 2000 and 2001, respectively. The mean fork length, weight and K for L. aurata species were measured 32.7 and 32.3 cm, 418.3 and 419.8 g and 0.61 and 0.93 and for L. saliens species were 27.5 and 25.1 cm, 224.7 and 179.1 g and 0.91 and 0.71 for years 2000 and 2001, respectively. According to this data in spite of increasing in catch, CPUE of L. aurata has increased and there are no changes in respect of biological aspect. Therefore, it was concluded that this species is harvested of a sustainable level

Determination of catchability bony-fish and optimized exploitation in the Caspian Sea

To accomplish the stock assessment that pre-planned for bony-fish resources investigation started by considering two pivotal act. First gathering biometric data and second using catch statistics information for stock analyses. Implementing the research programmes five itinerant groups in Anzali, Keyashahr, Noshahar, Babolsar, Torkaman have been organized during fishing season. The biometric data were supplied in computer that distincted by each fish species and subdivided into age groups. In analyses the samples, Bertalanffy formula used for calculating average length and age, also for growth coefficient. Total mortality rate calculated by using Pauly formula, and the biomass status estimated through Cohort analysis. The catch by beach seiner cooperatives recorded 8630 metric tons, but estimation including. Poacher catch raised the harvest to 15.6 thousand tons. The total catch of Kutum reduced by 1400 tons compared with previous year, but the estimation revealed the biomass of Kutum 18.5 thousand tones, the stock stowed reduction in quantity relative to past years. Harvest exceeding the limit, fishing pressure. And employing higher fishing effort, combining releasing the Kutum seedling with shorter average length in recent years, leaded the shrinkage of biomass of Kutum resources. The Golden Grey mullet catch has been estimated 3437 metric tons, the figure showed 1500 tons increment, in comparison with previous year, nearly 24% of catch was shorter than Lm50% of this species. In Guilan province higher number of sub - size golden mullet captured, this development occured less in Mazandaran and Golestan province. Higher rate of exploitation, reduction of catch in recent years, dominating small size fish in catch composition indicated the population undergoing stress in ecosystem. Thin - lipped grey mullet only comprised 9.2% of the mullet catch - Length - structure of this fish species population formed mainly by young small size fish, the biomass of latter estimated 1100 metric tons. Catch further than maximum sustainable yield, by higher exploitation rate, and gradual diminishing of harvest, represented the resources of this fish species suffering both by high fishing pressure and un - sustainable effort, which ultimately declined the fishery of this fish species. Carp catch and its resources in Anzali region become very low, it is necessary to enhance the stock by Sea-ranching programmes. The carp resources in Gorgan region enjoy better status, but catch practices do not compatible with rule and regulation in Gorgan and Gomeyshan area. The standing stock of Gorgan carp estimated nearly 6000 tons. The information concerning carp resources indicate the stock experiencing pressure and likely the catch will diminish in future. The total catal catch of carp calculated 1900 tons. In recent years the Caspian roach resources are increasing but the bulk of harvest fished illegally and by gill - nets. The total catch of the roach during 1998-1999 estimated 1700 tons. Considering the semi - artificial propagation of roach in Golestan province, if has been concluded the multiplication of this fish species also should be planned by fisheries authorities for Anzali region. It is also advisable catching of this fish species to be regulated soon and selective catch are proposed. The catch of pike - perch during the year of 1997 - 98 jumped to 95 tons, but 90% of catch formed by young fish or sub – standard length size. Almost, all the increment of catch attributed to the releasing of millions of seedlings in the Sea which the plan has been implemented by Iranian Fisheries. Increasing the numbers of released seedlings, with higher average weight Identification of most suitable site for unloading the fries could ensure better survival rate and contribute the enhancement of resources and produce good catch for this desirable fish species. The total catch of Bream hit 18 tons, but most of the catch comprised by young fish with sub - standard size. The present formation of fisheries population of bream are the result of seedling releasing! In the Sea by Iranian Fisheries, since the catch of bream are negligible despite releasing programmes of seedling in a decade which 14million individuals until now, one could conclude the programmes do not contributed effectively to stock rehabilitation. The Caspian Barbus (Barbus brachycephalus) are at the threshold 01 vanishing, at present a few numbers are caught, therefore B.capito appeared in catch composition. The catch of latter species in recent two years are increasing. Total catch during the year of 1998 - 99 estimated 34.5 tons, biomass calculated 93 tons. Caspian vimba are small size fish which beach seiner (mesh size in bosom 30 millimeters) could not capture them ideally, bulk of the catch caught in illegal manner by gill nets. The total catch estimated 154 tons which the present fishing procedures surpassed total allowable catch (136 tons). In recent years the catch of this fish species are increasing. "Shemaya' similar in size with Vimba are caught less by beach seiner, illegal catch are considerable, the total catch in 1998 - 99 estimated 86 tons. The level of harvesting of this fish species are increasing in recent years and its population size become significant relative to last years. The main part of catch concerning Aspius fish species occured in Guilan coastal area, high fishing pressure reduced the population size, including low discharge of water in rivers during spawning period, impact negatively to reproduction. Catch statistic in 1989 showed 128 tons of this fish species are caught but in 1998 - 99 it has been reduced to 6.8 tons. It has been suggested artificial spawning could prevent its fate as endangering species. Caspian salmon catch estimated 78 tons during 1998 - 99, salmon population in Caspian Sea are supported by releasing reared smolts, which in recent years nearly 500 thousands fingerlings released in suitable rivers. After banning the gill nets application in Southern Caspian Sea, the catch of salmon in beach seining are increasing. It is necessary the released smolts in rivers being protected for its safe approach to Caspian Sea. The total catch of herring fish species in 1998 - 99 were nearly 700 tons. The bulk of the catch occur In Guilan fishing area, elimination of gill - nets usage in Southern Caspian Sea contributed the increment of herrings catch in beach seining. The herring resources in Caspian Sea reduced relative to past decades. The catch during 1913 – 1916 ranged between 130 - 160 thousand tons, in Caspian Sea

Biological studies of fishes (Clupeidae, Rutilus frisi kutum, Liza auratus, Cyprinus carpio, Chalchalburnus chalcoides, Vimba vimba, Abramis brama, Sander lucioperca & Liza saliens) of southern Caspian Sea

During the past decades the environmental status of the Caspian Sea has changed. Therefore, study on the biological structure such as: age, growth, Lm50%, feeding of fishes is necessary. In the present study the biological characteristics of some commercial important species including kilka, kutum, golden grey mullet and carp were studied during 2006-2010. Kutum, golden grey mullet and carp predominated in the catch composition of bonyfishes, representing 61.3, 29.6 and 7.6% of the total catch. The average fork lengths of kutum, golden grey mullet and carp were 38.4, 32.7 and 36.7 cm, and weights were 784.5, 411.0 and 977.0 g, respectively. The values of b in length-weight relationships were 3.02 and 2.97 for kutum and golden grey mullet indicating an isometric growth. The value b for carp was 2.89, indicating an allomertic growth. The maximum age of three species was 12 years. Von Bertalanffy growth equations were estimated as: for kutum: for golden grey mullet: and for carp: The sex ratio of three species showed that females were dominant. Spawning migratory of kutum was started in March. The gonadosomatic index value of kutum peaked in March and April. The spawning season of carp expended from March to August. The gonadosomatic index value of golden grey mullet peaked in September and then declined in November and December. Absolute fecundity of kutum, golden grey mullet and carp were 64400, 700800 and 131000 eggs, respectively. Length maturity (Lm50%) of three species were 39.07, 28.4 and 31.6 cm, respectively. The highest feeding intensity (Gastrosomatic index=GSI) for females and males were 313.9 ± 65.9 and 350.7±103.7 in October; and the lowest value of GSI were 19.4 ±59.2 and 144.1±85.04 in March, respectively. There are significant different between GSI with male and female in difference months (P<0.05). 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. 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. The results showed that catch of kilka decreased from 22300 mt in 2006 to 16700 mt in 2008, but the CPUE increased from 1.7 mt (Vessel×Night) to 2.5 mt, due to decrease of effort, respectively. The length frequency of three species of kilka is close and the juvenile fish did not see in catch. The age frequency had the same situation as fish lower than 2 years was not in the samples of anchovy and bigeye kilka. The parameters of the von Bertalanffy growth curve were: For common kilka: L =136.5 cm, K=0.249 yr^-1 and t0= -1.89 yr^-1 for bigeye kilka: L =148. cm, K=0.346 yr^-1 and t0= -1.123 yr^-1 and for anchovy kilka: L =131.7 cm, K=0.375 yr^-1 and t0= -1.243 yr^-1 the exploitation rate of anchovy, bigeye and common kilka were 0.51, 0.58 and 0.6, respectively. The highest of GSI for common and bigeye was recorded in May and March, respectively. For anchovy kilka it was in July and November. Main prey of anchovy and common kilka was Acartia tonsa and for bigeye kilka it was Cypris balanus. We concluded that the ecological problems caused by Mnemiopsis leidyi as well as overfishing have been collapsed kilka stocks, particularly anchovy. Therefore, sustainable fisheries management and conservation biodiversity in the Caspian Sea are real challenges now

Population dynamics and reproductive biology of crayfish (Astacus leptodactylus Eschscholtz, 1823) in Shorabil Lake (Ardabil Province), northwest of Iran

Freshwater crayfish (Astacus leptodaciylus Eschscholtz, 1823) is a very valuable macrobentic organism which was introduced Aras reservoir to the Shorabil Kake in the amount of 15000 specimens during the years 2002-2006. This species produce very good population in the Shorabil Lake. We investigate biological, biomass and MSY of the crayfish in the Lake during the years 2006-2007. Results showed that the mean total lengths and weight of this crayfish for both sexeswere 82.5±32.4mm and 82.5±32.4g, respectively. Maximum total length and weight of the caught crayfish was 196mm and 328g respectively. The sex ratios of male:female crayfish caught with a funnel trap of 10mm mesh size (stretched mesh) were estimated at 1:2.4 that was significantly difference from :1 ratio ( X2 = 479.01 ; P<0.05 ). Mean number of ovarian and pleopodal eggs were estimated at 396.6136.5 and 311.11±22.92 eggs with 95% confidence limits, respectively. The time of the first molting of the male stared from beginning of the May at a water temperature of around 14°C and ended in mid-June. The second molting of the male and the first molting of the female is done simultaneously and started in beginning of the October at a water temperature of around I 7°C. Reproduction period of this species started from beginning of the December and lasted until the mid-June in Shorabil Lake

Study of some biological characteristics of golden grey mullet (Liza aurata) in Iranian Coastal waters of the Caspian Sea

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

The study on fishing and resource management of bony fisheries within southern Caspian Sea

The project of the Study on fishing and resource management of fisheries within Southern Caspian Sea was conducted on the base of an agreement made between fisheries organization (Shilat) and the Iranian fishery research organization (IFRO) signed in 2010. In this library-based study the current situation of bony fish fisheries and biology of these species has been surveyed in Iranian waters of the Caspian Sea . In this survey internal and external environmental factors of bony fishes activities were considered. Using SWOT analysis method, current situation of fisheries was investigated..One of the most important strategies for conserving anadromous species such as Caspian kutum , common carp, roach, bream and …. is rehabilitation of the natural spawning ground in rivers, coastal lagoon specially Anzali lagoon .By conducting this strategy not only restocks of bony fishes is done ,but also reduced the cost of artificial restocking programs and releasing fingerlings .In short term , it is nessesary to enhance the stocks of the species that have low catch is done by huge releasing of the fingerlings and study the qualification of the program

Stock assessment of the bony fishes in Iranian coastal waters of the Caspian Sea (2005-2007)

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 kutum, golden grey mullet and common carp, respectively. Age groups 3 to 5 year comprised 84.2, 74.8 and 83.7 percent for Kutum, 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 Kutum 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 kutum and about 16948.0 and 4999.0 tones for golden grey mullet, respectively. Exploitation rate (E) calculated 0.71 and 0.70 for Kutum 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 tons 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 kutum, golden grey mullet and common carp, respectively

Stock assessment of the bony fishes in Iranian coastal waters of the Caspian Sea (2007-2010)

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

Hereditary leiomyomatosis and renal cell cancer presenting as metastatic kidney cancer at 18 years of age: implications for surveillance

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is an autosomal dominant syndrome characterized by skin piloleiomyomas, uterine leiomyomas and papillary type 2 renal cancer caused by germline mutations in the fumarate hydratase (FH) gene. Previously, we proposed renal imaging for FH mutation carriers starting at the age of 20 years. However, recently an 18-year-old woman from a Dutch family with HLRCC presented with metastatic renal cancer. We describe the patient and family data, evaluate current evidence on renal cancer risk and surveillance in HLRCC and consider the advantages and disadvantages of starting surveillance for renal cancer in childhood. We also discuss the targeted therapies administered to our patient

Caspian brown trout (Salmo trutta caspius) broodstock supply in south western of the Caspian Sea (Guilan province)

Caspian trout (Salmo trutta caspius ) is one of the migratory fish species which lives and feeds in the Caspian Sea .This species distributed in south and western of the Caspian Sea . In order to rehabilitation of the Caspian trout in western area, the operation of the project started from the beginning of the fishing season of the 20112012. Specimens of the Caspian trout obtained from beach seine cooperatives and have been transferred to the fish farm in Asalem region .Totally, 44 specimens of the Caspian trout has been caught in two month period .Most of the fishes was from Kargan roud river . The mean length and weight of the brood fishes were 67.7 cm and 3122.7 g respectively .As at present Shilat uses just the broods of the Tonekaboon region for restocking of this species ,we recommend to use the broods of the western region separately for rehabilitation of the stocks of this region