Agricultural Research,Education and Extension OrganizationIranian Scientific Fisheries Journal1026-13548419991222Age Composition and Prediction of Optimum Fishing Mortality (Fmsy) for the Beluga, Stellate Sturgeon, Persian Sturgeon and Russian Sturgeon in the South Part of the Caspian SeaAge Composition and Prediction of Optimum Fishing Mortality (Fmsy) for the Beluga, Stellate Sturgeon, Persian Sturgeon and Russian Sturgeon in the South Part of the Caspian Sea12811639110.22092/isfj.1999.116391FAA. TaghaviJournal Article20180508Eight years (1990-1997) of the Beluga, Stellate Sturgeon, Persian Sturgeonand Russian Sturgeon in the south part of the Caspian Sea were analyzed for age composition. Yield-per-recruit curves were derived for each species based on growth parameters and mortality rates, and the optimum fishing mortality in terms of yield-per-recruit was calculated as a basis for sturgeon fishery management in the Caspian Sea. The results of eight years catches from this part of the Caspian Sea show that the age structure of all species has changed and a trend to become younger for fish of both sexes is apparent.On the other hand, fishing composition, is confied to some special age groups. Inspection of yield-per-recruit model confirms the overfishing of the strugeons in the Caspian Sea and suggested that the fishing mortality showed be reduced by decreasing fishing effort. It seems that the population of the Beluga, probably because of the higher quality of its caviar, are more depleted, therefore inorder to maintain the spawning stock, the harvesting of Beluga showed be much restricted for several years.Eight years (1990-1997) of the Beluga, Stellate Sturgeon, Persian Sturgeonand Russian Sturgeon in the south part of the Caspian Sea were analyzed for age composition. Yield-per-recruit curves were derived for each species based on growth parameters and mortality rates, and the optimum fishing mortality in terms of yield-per-recruit was calculated as a basis for sturgeon fishery management in the Caspian Sea. The results of eight years catches from this part of the Caspian Sea show that the age structure of all species has changed and a trend to become younger for fish of both sexes is apparent.On the other hand, fishing composition, is confied to some special age groups. Inspection of yield-per-recruit model confirms the overfishing of the strugeons in the Caspian Sea and suggested that the fishing mortality showed be reduced by decreasing fishing effort. It seems that the population of the Beluga, probably because of the higher quality of its caviar, are more depleted, therefore inorder to maintain the spawning stock, the harvesting of Beluga showed be much restricted for several years.Agricultural Research,Education and Extension OrganizationIranian Scientific Fisheries Journal1026-13548419991222Study on Some Biological Characteristics of Liza saliens in the Southern Part of the Caspian SeaStudy on Some Biological Characteristics of Liza saliens in the Southern Part of the Caspian Sea294211639310.22092/isfj.1999.116393FAH. FazliJournal Article20180508This survey was conducted from Babolsar to Bandar-e-Torkaman in the southern part of the Caspian Sea. Specimens were collected from commercial catchs (Beach seine net, mesh size 5 mm). Sampling was carried out monthly (from Sep. 1993 to Sep. 1994 ) to evaluate the biological charactristics, including total and fork length, weight, age, gonad weight and sex. The results indicated that the scales and operculum were suitable for determining the age though the operculum gave better results than the scale. Since the first annulus has not appeared on the scale and it is very difficult to distinguish annuli on the scales of old specimens. This study also shows that the maximum growth rate is belong to the age of 3 years. The b value regression between fork length and weight was 2.940. The relation between scale radius and circuli number, and growth were: C = 4.609 R <sup>0.8282</sup> , L(t) = 322.4 [1-exp(-0.361(t+0.013))]. Sex ratio was 1:3.14 and female dominated. The Gonado Somatic Index (GSI) indicates that the spawning activity occures on July-August. Males ripen earlier than females. Furthermore the numbers of circuli in different ages and condition factor (k) relation between total length and fork length and between age and weight were obtained.This survey was conducted from Babolsar to Bandar-e-Torkaman in the southern part of the Caspian Sea. Specimens were collected from commercial catchs (Beach seine net, mesh size 5 mm). Sampling was carried out monthly (from Sep. 1993 to Sep. 1994 ) to evaluate the biological charactristics, including total and fork length, weight, age, gonad weight and sex. The results indicated that the scales and operculum were suitable for determining the age though the operculum gave better results than the scale. Since the first annulus has not appeared on the scale and it is very difficult to distinguish annuli on the scales of old specimens. This study also shows that the maximum growth rate is belong to the age of 3 years. The b value regression between fork length and weight was 2.940. The relation between scale radius and circuli number, and growth were: C = 4.609 R <sup>0.8282</sup> , L(t) = 322.4 [1-exp(-0.361(t+0.013))]. Sex ratio was 1:3.14 and female dominated. The Gonado Somatic Index (GSI) indicates that the spawning activity occures on July-August. Males ripen earlier than females. Furthermore the numbers of circuli in different ages and condition factor (k) relation between total length and fork length and between age and weight were obtained.Agricultural Research,Education and Extension OrganizationIranian Scientific Fisheries Journal1026-13548419991222Identification of Different Fish Species in Koohrang, Bazoft and Zayandeh Rood River in Chahar Mahal-e-Bakhtiary ProvinceIdentification of Different Fish Species in Koohrang, Bazoft and Zayandeh Rood River in Chahar Mahal-e-Bakhtiary Province435611639410.22092/isfj.1999.116394FAH. Ghorbani ChafiJournal Article20180508Identification and distribution of fishes were studied in the three major river of Chahar Mahal-e-Bakhtiaty province including: Bazoft, Koohrang and Zayande rood during 1996-1992. 22 stations in order to sampling were chosen. Fishery was conducted seasonal during a year. Ten species were recognized which were belonged to 7 genera, 3 familes and 2 order. Cyprinidae family with 5 genera and 8 species was the various family among them. These species are: Capoeta aculeata, C. damascina, Alburnus alburnus, A.maculatus, Barbus lacerta, B. barbulus, Chondrostoma regium, Cyprinus carpio ; from Balitoridae family 1 genera named Nemachilus sp. and from Salmonidae family Oncorhynchus mykiss. The Zayandeh rood river with 8 species was more miscellaneous than Bazoft and Koohrang river with 2 species.Identification and distribution of fishes were studied in the three major river of Chahar Mahal-e-Bakhtiaty province including: Bazoft, Koohrang and Zayande rood during 1996-1992. 22 stations in order to sampling were chosen. Fishery was conducted seasonal during a year. Ten species were recognized which were belonged to 7 genera, 3 familes and 2 order. Cyprinidae family with 5 genera and 8 species was the various family among them. These species are: Capoeta aculeata, C. damascina, Alburnus alburnus, A.maculatus, Barbus lacerta, B. barbulus, Chondrostoma regium, Cyprinus carpio ; from Balitoridae family 1 genera named Nemachilus sp. and from Salmonidae family Oncorhynchus mykiss. The Zayandeh rood river with 8 species was more miscellaneous than Bazoft and Koohrang river with 2 species.Agricultural Research,Education and Extension OrganizationIranian Scientific Fisheries Journal1026-13548419991222Study on Fishing and Immigration Process of Cuttle Fish in Waters of Bushehr Province (1996-1997)Study on Fishing and Immigration Process of Cuttle Fish in Waters of Bushehr Province (1996-1997)577211639510.22092/isfj.1999.116395FAN. NiamimandiJournal Article20180508The survey for opening cuttlefish catch season has started from January. According to the results it has been allowed to begin fishing in Motaf and Tangistan areas on 24 February and Bahr-e-Kansar to Bushehr areas on 2nd March. The survey continued to study of biological behavior during the catch. In the begining of fishing season, the number of males and females was equal but in the end of catch period, the females were more than males. The diameters of eggs were recorded from 3mm to 11mm. The numbers off eggs were various in adults. The number of these eggs was 720 in Max. and 230 in Min. Catch reduction begins from April. The closure of fishing season has been announced in April. because of their migration to neighboring. The results show that cuttlefish migrates from Saudi Arabia, Kuwait and Iraq coastal waters to Iranian waters and return to the first place after spawning.The survey for opening cuttlefish catch season has started from January. According to the results it has been allowed to begin fishing in Motaf and Tangistan areas on 24 February and Bahr-e-Kansar to Bushehr areas on 2nd March. The survey continued to study of biological behavior during the catch. In the begining of fishing season, the number of males and females was equal but in the end of catch period, the females were more than males. The diameters of eggs were recorded from 3mm to 11mm. The numbers off eggs were various in adults. The number of these eggs was 720 in Max. and 230 in Min. Catch reduction begins from April. The closure of fishing season has been announced in April. because of their migration to neighboring. The results show that cuttlefish migrates from Saudi Arabia, Kuwait and Iraq coastal waters to Iranian waters and return to the first place after spawning.Agricultural Research,Education and Extension OrganizationIranian Scientific Fisheries Journal1026-13548419991222Study on Changes in Fishing in Anzali Lagoon (1992-1996)Study on Changes in Fishing in Anzali Lagoon (1992-1996)738811639610.22092/isfj.1999.116396FAA. ValiporD. HaghighiJournal Article20180508According to 5 years period from 1992 to 1996 the total catch in 1992-1996 was 2335158 kg with annual average of 467032 kg, and the catch during years of 1989, 90, 92, 93, 94, 95 and 96 was 100, 314, 598, 630 and 367 ton respectively. The maximum catch in this five years was in Autumn (131146 kg) and in October (50024 kg) and the minimum catch was in winter (98444 kg) and April (29482 kg). C auratus, E lucius and C carpio with 40%, 17.6% and 15% constitute the most catch respectively. The presence of S. lucioperca, A. brama, R frisii kutum, R. rutilus, A. boyeri and C wagneri in the catch indicate that biological condition of lagoon is toward amelioration.According to 5 years period from 1992 to 1996 the total catch in 1992-1996 was 2335158 kg with annual average of 467032 kg, and the catch during years of 1989, 90, 92, 93, 94, 95 and 96 was 100, 314, 598, 630 and 367 ton respectively. The maximum catch in this five years was in Autumn (131146 kg) and in October (50024 kg) and the minimum catch was in winter (98444 kg) and April (29482 kg). C auratus, E lucius and C carpio with 40%, 17.6% and 15% constitute the most catch respectively. The presence of S. lucioperca, A. brama, R frisii kutum, R. rutilus, A. boyeri and C wagneri in the catch indicate that biological condition of lagoon is toward amelioration.Agricultural Research,Education and Extension OrganizationIranian Scientific Fisheries Journal1026-13548419991222Ichthyobodosis in Oncorynchus mykiss FryIchthyobodosis in Oncorynchus mykiss Fry899211640110.22092/isfj.1999.116401FAA. Asadzadeh ManjiliJournal Article20180508On Februray 1998 in one of the trout farm of Kohkiloieh & Boyer Ahmad province was observed the mass mortality of trout fry with 3 centimeters total length. The rate of mortality was 40%. The sampling was done randomly from various traphs of hatchery hall and 200 fish fry sampled. Wet smears provided from skin and gill of 100 pieces of fish showed 100%infection to parasite Ichthyobodo which the contamination in skin was severe and about gills, it was moderate. Treatment procedures recommended of increasing water flow, decreasing fish density, formalin bath with proportion of 1:4000 for one hour with use of aeration in order to supplying dissolved oxygen needed (synchronously). Above recommendations were effective in decreasing of contamination load and mortality rate.On Februray 1998 in one of the trout farm of Kohkiloieh & Boyer Ahmad province was observed the mass mortality of trout fry with 3 centimeters total length. The rate of mortality was 40%. The sampling was done randomly from various traphs of hatchery hall and 200 fish fry sampled. Wet smears provided from skin and gill of 100 pieces of fish showed 100%infection to parasite Ichthyobodo which the contamination in skin was severe and about gills, it was moderate. Treatment procedures recommended of increasing water flow, decreasing fish density, formalin bath with proportion of 1:4000 for one hour with use of aeration in order to supplying dissolved oxygen needed (synchronously). Above recommendations were effective in decreasing of contamination load and mortality rate.