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  • Males  (3)
Collection
Years
  • 1
    Publication Date: 2021-05-19
    Description: 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.
    Description: Published
    Keywords: 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
    Type: Journal Contribution , Refereed
    Format: pp.87-98
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  • 2
    Publication Date: 2021-05-19
    Description: 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.
    Description: Published
    Keywords: Population dynamics ; Growth ; Mortality ; Spawning ; Palaemon elegans ; Sampling ; Length ; Shrimp ; Females ; Males ; Fecundity ; Growth
    Repository Name: AquaDocs
    Type: Journal Contribution , Refereed
    Format: pp.109-126
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  • 3
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    In:  http://aquaticcommons.org/id/eprint/23734 | 18721 | 2018-07-21 17:15:15 | 23734 | Iranian Fisheries Science Research Institute
    Publication Date: 2021-07-15
    Description: 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.
    Keywords: 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
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 87-98
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