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  • Fisheries  (5)
  • Sex ratio  (3)
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  • 1
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    Reproductive characteristics of Neogobius caspius from the southwest coasts of the Caspian Sea, Guilan Province of Iran (2018)
    Details
    Publikationsdatum: 2021-05-19
    Beschreibung: Neogobius caspius is an endemic fish species in the Caspian Sea belonging to the family Gobiidae that ecologically play important role as a predator fish in the food chain .The main objective of this research was determination of some reproductive properties of N. caspius in the southwest coasts of the Caspian Sea. Sampling was carried out with a bottom trawler in three stations (Astara, Anzali and Chabuksar) from October 2004 until September 2005. The species was identified based on meristic parameters. The maximum gonadosomatic index (GSI) was recorded at 7.52% for male and 100.12% for female fish in June. A sharp decrease in GSI value from June to the end of September in both sexes was observed and we found that the spawning of the species takes place several times each year. Hence, the species is considered a late spawner. Female to male sex ratio was 1.47:1. Absolute fecundity was in the range 212-1234 eggs and the relative fecundity fluctuated between 18.73 and 29.89 eggs per each gram of the body weight. The correlation between absolute and relative fecundity with age was positive and with total length and full weight was negative. Egg diameter was in the range 0.06 to 0.23mm. The correlation between egg diameter, age and total length was positive.
    Beschreibung: Published
    Schlagwort(e): Food chains ; Endemic species ; Brackishwater fish ; Neogobius ; Gobiidae ; Neogobius caspius ; Brackish ; Biological surveys ; Sex ratio ; Males ; Gonadosomatic index ; Fecundity ; Fish physiology ; Reproductive cycle ; Body size ; Reproduction ; Females
    Repository-Name: AquaDocs
    Materialart: Journal Contribution , Refereed
    Format: pp.87-98
    Standort Signatur Erwartet Verfügbarkeit
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    ARTIKEL (OA)
  • 2
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    Biological study and population dynamics of Carassius auratus gibelio in Anzali Lagoon (2018)
    Details
    Publikationsdatum: 2021-05-19
    Beschreibung: Considering the reduction of valuable commercial fish in Anzali lagoon during last decades and presence of the silver crucian carp with high frequency; the research project or 'Biological aspects and population dynamics or Carassius auratus" was designed. The study area was stratified to four regions (Abknar, Siah-keshim, Markazi and Sheyjan). Sampling were carried out bi-weekly by using electro-shocker. The mean fork length and mean weight for both sexes were measured 19.5±5.8 cm, and 196.8±137.4 g respectively. Also, the mean age was estimated 2.6±1.3 years (n=750) and minimum and maximum fork length were measured 2.5 and 31.5 cm respectively. The mean length, weight and the age of silver crucian carp in Siah-keshim region were higher than the other regions. The spawning season of this species was found from May to June. The results showed a sex ratio of F:M=99.3:0.7. Some calculated population parameters were as follows: exploitation rate = 0.47, L∞ = 36.0 cm and K = 0.23 per year.
    Beschreibung: Published
    Schlagwort(e): Biological ; Commercial ; Population ; Carassius auratus gibelio ; Fish ; Silver crucian carp ; Carassius auratus ; Sampling ; Length ; Age ; Weight ; Spawning ; Species ; Sex ratio
    Repository-Name: AquaDocs
    Materialart: Journal Contribution , Refereed
    Format: pp.57-70
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
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    Diet of Rutilus frisii kutum x Ctenopharyngodon idella hybrid (2018)
    Details
    Publikationsdatum: 2021-05-19
    Beschreibung: This research project was carried out in Gulian Fisheries Research Center in 1998. For this purpose, two ponds were selected: Pond No. 1 with 450m2 area and pond No.2 with 250m2 area and then 3500 pieces/hectar of hybrids with 5-7g weight were added to the ponds. In order to determine their main food, they were fed by pelletes and grass according to their mean weight. Meanwhile, by adding mineral and organic fertilizers to the water, a suitable media including phytoplanktons, zooplanktons and benthoses were prepared for feeding of fishes. The stomach contents observations of 160 specimen of hybrids showed that this hybrid is a herbivorous fish and macrophytes were their main diet; and phytoplanktons could be considered as the secondary random food.
    Beschreibung: Published
    Schlagwort(e): Rutilus frisii kutum ; Grass Carp ; Hybrid ; Diet ; Fisheries ; Weight ; Fertilizer ; Phytoplanktons ; Zooplanktons ; Benthoses ; Specimens
    Repository-Name: AquaDocs
    Materialart: Journal Contribution , Refereed
    Format: pp.31-42
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
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    Effect of age on reproductive performance in female Caspian brown trout (Salmo trutta caspious, Kessler 1877) (2021)
    In:  http://aquaticcommons.org/id/eprint/21695 | 18721 | 2017-11-27 11:56:25 | 21695 | University of Guilan, Faculty of Natural Resources, Iran
    Details
    Publikationsdatum: 2021-06-28
    Beschreibung: Caspian brown trout (Salmo trutta caspius) is one of the economically valuable species in the Caspian Sea.Artificial propagation and production of larvae are the main problems in the early culture of this species.The purpose of this paper is to study the effect of reproductive performance of female broods on opposition reproduction efficiency in Caspian brown trout in the breeding season of 2009. Three groups of female broods (4, 5 and 6 years old) were fertilized with 9 male fish individually. The results showed that,6 year old females have maximum body weight (2150.0 ± 86.6 g), total length (59±2 cm), eggs weight (255.0 ± 30.51 g), egg size (5.37 ± 0.058 mm) and absolute fecundity rate (3060 ± 366.15), while highest average number of ovules in each gram of body weight (16.33 ± 0.58) and relative fecundity (2.08 ± 0.12) belonged to 4 years old females. There were significant differences in mean fertilization rate and survival rate until absorption of yolk sack stage (p〈0.05) among the treatments studied. The present study showed that the eggs produced from fertilization of 6 year old female eggs and male mixed milt showed maximum average fertilization percentage (97.5 %), survival rate until eyed stage (92%), hatching percentage (93%), and survival rate until absorption of yolk sack (94.5%).
    Schlagwort(e): Biology ; Fisheries ; age ; reproductive ; performance ; female ; Caspian Sea ; Salmo trutta caspious ; Iran ; larvae ; weight ; male
    Repository-Name: AquaDocs
    Materialart: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 97-103
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  • 5
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    Occurrence and intensity of parasites in pike (Esox lucius) in River of Chamkhaleh (2021)
    In:  http://aquaticcommons.org/id/eprint/23643 | 18721 | 2018-07-14 23:48:04 | 23643 | Iranian Fisheries Science Research Institute
    Details
    Publikationsdatum: 2021-07-14
    Beschreibung: Pike (Esox lucius) of Chamkhaleh River in Langrood (Iran) was studied from winter 2003 to autumn 2004. We collected 123 specimens of the fish and sent them live to the lab for examinations. Biometrical measurements, age and sex determination were conducted on the samples. The eye, skin, gill, digestive system, muscle and other organs of the specimens were examined for parasite infestation. Seven parasites: Raphidascaris acus, Camallanus lacustris, Diplostomum spathaceum, Tetraonchus monenteron, Triaenophorus crassus, Corynosoma strumosoum, Lernaea sp. were found in the pikes of the Chamkhaleh River. The most prevalent parasite was R. acus (37.39%) and the least were C. strumosum and Lernaea sp. (0.81% each). The highest mean intensity of the parasites was related to T. crassus (8.45 specimens) and the lowest was detected for Lernaea sp. (0.01). The highest range in parasite infection was seen for R. acus (1-45) and the lowest for Lernaea sp. with only one individual parasite. We observed seasonal, age and sex differences in infection rate with the parasites. This is the first time report of the pike as a host for C. strumosum.
    Schlagwort(e): Fisheries ; Health ; Age ; Skin ; Freshwater fish ; Digestive system ; Gills ; Freshwater ; Sex determination ; Eyes ; Muscles ; Tetraonchus monenteron ; Raphidascaris acus ; Diplostomum spathaceum ; Esox lucius ; Camallanus lacustris ; Corynosoma strumosoum ; Triaenophorus crassus ; ISW ; Guilan Province ; Iran
    Repository-Name: AquaDocs
    Materialart: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 37-50
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
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    Parasites of some bonyfish species from the Boojagh wetland in the southwest shores of the Caspian Sea (2021)
    In:  http://aquaticcommons.org/id/eprint/21694 | 18721 | 2017-11-27 11:53:23 | 21694 | University of Guilan, Faculty of Natural Resources, Iran
    Details
    Publikationsdatum: 2021-06-28
    Beschreibung: The Boojagh international wetland with a surface area of 80 hectares and 25 fish species is located in the southwest shores of the Caspian Sea (Guilan province, Iran), but there is no report about fish parasites in this wetland. In the present study, a total of 553 individuals of 8 fish species including Cyprinus carpio (n=71), Abramis bjoerkna (n=153), Carassius auratus gibelio (n=89), Esox lucius (n=39), Rutilus rutilus caspius (n=36), Rutilus frisii kutum (n=81), Scardinius erythrophthalmus (n=119) and Tinca tinca (n=4), were collected in October 2001 through November 2003. Eight parasite species were identified in the fishes consisting of 1 nematode: Raphidascaris acus (in E. lucius and S. erythrophthalmus); 1 cestode: Caryophyllaeus fimbriceps (in R. rutilus caspius and C. carpio); 2 digenean trematodes: Asymphylodora tincae (in T. tinca) and Diplostomum spathaceum (in all of the fish species except for T. tinca and S. erythrophthalmus); 2 monogenean trematodes:Tetraonchus monenteron (in E. lucius) and Dactylogyrus sp. (in C. carpio, A. bjoerkna and C. auratus gibelio); 1 crustacean: Lernaea cyprinacea (in A. bjoerkna, T. tinca and R. rutilus caspius) and 1 leech : Piscicola sp. (in R. rutilus caspius and C. carpio). The occurrence of R. acus in S. erythrophthalmus and also that of C. fimbriceps in R. rutilus caspius are reported for the first time as new host records.
    Schlagwort(e): Biology ; Fisheries ; parasites ; bonyfish ; species ; Boojagh wetland ; Caspian Sea ; Iran ; Guilan province ; records
    Repository-Name: AquaDocs
    Materialart: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 47-53
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
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    Reproductive characteristics of Neogobius caspius from the southwest coasts of the Caspian Sea, Guilan Province of Iran (2021)
    In:  http://aquaticcommons.org/id/eprint/23734 | 18721 | 2018-07-21 17:15:15 | 23734 | Iranian Fisheries Science Research Institute
    Details
    Publikationsdatum: 2021-07-15
    Beschreibung: Neogobius caspius is an endemic fish species in the Caspian Sea belonging to the family Gobiidae that ecologically play important role as a predator fish in the food chain .The main objective of this research was determination of some reproductive properties of N. caspius in the southwest coasts of the Caspian Sea. Sampling was carried out with a bottom trawler in three stations (Astara, Anzali and Chabuksar) from October 2004 until September 2005. The species was identified based on meristic parameters. The maximum gonadosomatic index (GSI) was recorded at 7.52% for male and 100.12% for female fish in June. A sharp decrease in GSI value from June to the end of September in both sexes was observed and we found that the spawning of the species takes place several times each year. Hence, the species is considered a late spawner. Female to male sex ratio was 1.47:1. Absolute fecundity was in the range 212-1234 eggs and the relative fecundity fluctuated between 18.73 and 29.89 eggs per each gram of the body weight. The correlation between absolute and relative fecundity with age was positive and with total length and full weight was negative. Egg diameter was in the range 0.06 to 0.23mm. The correlation between egg diameter, age and total length was positive.
    Schlagwort(e): Biology ; Biological surveys ; Sex ratio ; Males ; Gonadosomatic index ; Fecundity ; Fish physiology ; Reproductive cycle ; Body size ; Reproduction ; Females ; Food chains ; Endemic species ; Brackishwater fish ; Neogobius ; Gobiidae ; Neogobius caspius ; Brackish ; Caspian Sea ; Caspian Sea Eurasia ; Iran
    Repository-Name: AquaDocs
    Materialart: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 87-98
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
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    Population dynamics and some biological aspects of Palaemon elegans in the Guilan Province waters (2021)
    In:  http://aquaticcommons.org/id/eprint/24787 | 18721 | 2018-08-06 16:19:16 | 24787 | Iranian Fisheries Science Research Institute
    Details
    Publikationsdatum: 2021-07-15
    Beschreibung: Samplings were carried out weekly in coastal waters of the Guilan province (Caspian Sea) by a hand net with 0.5mm mesh size during 1996-1997. The results of one year sampling showed that the mean total length(T.L.) of this shrimp (pooled data of females and males) was 28.58±5.58mm (x±SD), and were 26.46±4.30 and 30.01±6.30mm in males and females, respectively. For ovigorus females, mean T.L was 36.16±3.13mm, also the minimum and maximum T.L of the males were 12.6 and 41.1mm, respectively. In females these figures were found 10.7 and 43.4mm, respectively. The length-weight relationship for the males and females were determined as W=0.0002 TL2.97 (R2=92.13) and W=0.00002 TL2.98 (R2=92.84), respectively. Spawning season was determined from May to September. The average absolute fecundity was 796±320, with a range of 360 and 1660. There is a direct retationship between fecundity and T.L. Females provided 59.42% and males 40.56% of the population, the sex ratio deviated from 1:1 (P〈0.05). The growth coefficient of Loa for females, males and pooled data based on powell-wetheral methods were 42.6, 34.4 and 42.5, respectively. The growth coefficient of K based on Shepherd method were 2.1, 2.3 and 2.5 for females, males and pooled data, respectively. Natural mortality rate (M) calculated as 2.29, 2.29 and 2.28 per year for females, males and pooled da1a, respectively. Total mortality rate was calculated as 2.38, 2.50 and 2.61 per year for females, males and pooled data, respectively.
    Schlagwort(e): Biology ; Fisheries ; Population dynamics ; Growth ; Mortality ; Spawning ; Palaemon elegans ; Caspian Sea ; Guilan province ; Iran
    Repository-Name: AquaDocs
    Materialart: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 109-126
    Standort Signatur Erwartet Verfügbarkeit
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