Kilka population dynamics in the south of the Caspian Sea

Populations of kilka in the Caspian Sea have important role in the food chain. This study was conducted to determine population parameters of three species of kilka in the south of the Caspian Sea, during 2006-2007. Mean length was 102.4±9.7 mm for common kilka, 117.8±6.9 mm for anchovy and 119.5±10.9 mm for bigeye. The relationship between length and weight indicated the negative allometric growth in the all three species. Mean age for common kilka, anchovy and bigeye were 3.6, 4.6 and 4.6 years, respectively. Sex ratio (M:F) were 0.52:1 for anchovy, 0.60:1 for common kilka and 1.60:1 for bigeye. The value of growth coefficient (K) was the highest (0.321) for the common kilka, (0.267) for the bigeye, and the lowest for the anchovy kilka (0.245). Total mortality estimated from the descending of the catch curve using the age structure, Z=1.280 yr-1 for common kilka, Z=1.067 yr-1 for anchovy, and Z=1.015 yr-1 for bigeye. Natural mortality (M) were estimated using Pauly formula as M=0.622, M=0.537 and M=0.503 per year for common kilka, bigeye and anchovy, respectively. Value of fishing mortality (F) were estimated from Z and M, as F=0.658 for common kilka, F=0.564 for anchovy and F=0.478 for bigeye. The exploitation rate (E) were estimated E=0.514 for common kilka, E=0.528 for anchovy and E= 0.471 for bigeye. The estimate of MCY (Maximum Constant Yield) was calculated using the more reliable time series of commercial catch data from 2001-2007, which resulted in an estimate of MCY for the kilka fishery of 14100 tonnes

Geographical distribution of commercial bony fishes in Iranian waters of the Caspian Sea

The beach seines catch and effort data from 1996 to 2011 categorized in four periods and used in this research. Geographical coordinates of beach seines determined by portable GPS and distribution maps of important and commercial species prepared by catch per unit effort (CPUE). The concentration of beach seines in the western coast of Golestan province, Kiashahr area and eastern part of Anzali was more than another part. The daily effort in Kiashahr and Anzali area was very high, thus the fishing stress in these areas was more than another part of Iranian coastal waters of the Caspian Sea. The number of species in catch composition increased from east to west and the beach seines of Guilan province had total of commercial species, but the number of commercial species rarely was five species in Golestan province and especially in eastern coast. Relative frequency and distribution of Kuttum in the east Babolsar area and then between Sepidroud and Anzali lagoon were more than another part. The ISI index of Kuttum was high in all of the area except east coast of Golestan province. The main distribution of Mullets determined in the western coast of Golestan province and the Amirabad fishing area and in these areas, the ISI index of Mullets was high. The main distribution area of common carp determined in east coast of Golestan and the ISI index of common carp was very low in other parts. Density and distribution of Kolmeh were high in eastern and western coasts of Iranian waters of the Caspian Sea and the density of this species was very low in Mazandaran province. The density of Zander was very high in surrounding of Sepidroud River and Anzali lagoon. The ISI index of commercial species in Guilan province was more than other provinces except Kuttum, mullets and common carp

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

The study on fishing and resource management of kilka 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. The study has several phases. The final report of the fishery on fishing and resource management of fisheries within Southern Caspian Sea (Gilan, Mazandaran & Golestan provinces) is consisted of several sections such as: 1- The Survey status of biology and catch of Kilka fishes , Bony fishes and Estrogen fishes and also the status of aquatic resource conservation in the Southern part of Caspian Sea 2- Fishing analysis in the Southern part of Caspian Sea 3- Fisheries development Strategies, policies and plans in the Southern part of Caspian Sea In this survey and library-based study, internal and external environmental factors of shilat activities are considered. Using SWOT analysis method, current situation of fisheries is investigated. In this regard, all fisheries activities were divided into four groups, then, the strengths, weaknesses, opportunities and treats of internal and external environment will be analyzed. A considerable number of tables and matrixes were prepared and policies and strategies as seen of final report were carried out

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