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Genetic structure of golden mullet (Chelon auratus, Risso 1810) stocks by 16SrRNA-mtDNA sequencing on the southwestern basin of the Caspian Sea (Guilan province)
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Mohammad Hassanzadeh Saber1 *   , AliNaghi Sarpanah1 , Omid Jafari1 , Shirin Jamshidi1 , Mahmoud Mohseni1 , Esmail Abdolahzadeh1 , Keyvan Abbasi2 , Siamak Bagheri2 , Maryam Forouzad3 , Mohammad Sayyad Bourani2 |
1-International Sturgeon Research Institute, Iranian Fisheries Science Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Rasht, Iran , saber.merag@gmail.com
2- Inland Waters Aquaculture Research Center, Iranian Fisheries Sciences Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Bandar Anzali, Iran
3- Iranian Fisheries Science Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran |
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Abstract: (39 Views) |
Introduction: The golden mullet (Chelon auratus) and kutum (Rutilus frisii) are among the valuable and economic species in the southern basin of the Caspian Sea bony fish stocks, accounting for over 85% of the total catch of these fish. A review of the reproduction and catch statistics of kutum and mullet over various years shows these stocks result from artificial reproduction and mass release of juveniles, and the share of natural reproduction in the restoration of stocks has decreased and reached its lowest point. This trend has side effects and will gradually cause the destruction of genetic stocks and the gradual destruction of the gene bank, which will cause a decrease in growth rate, a decrease in average length, a decrease in the percentage of spawning, and an increase in deformed larvae over 25 to 40 years. Therefore, knowledge of the genetic structure of these fish, obtained by examining population estimates and obtaining the level of genetic diversity and inbreeding and the adverse effects resulting from it, seems essential for the conservation and sustainable production of this economic species.
Material and Methods: In order to investigate the possibility of genetic differentiation and to compare the genetic structure of mullet population using DNA sequencing methods, 9 mullets from the eastern, middle and western regions of the Caspian Sea (coasts of Guilan province) using a purse seine in June 2021 were sampled from the mentioned areas. DNA from three samples of each area was extracted using the ammonium acetate method; their quantity and quality were determined using 1% agarose gel and a Nanodrop device (ND1000), respectively. One pair of primers (Forward and Reverse) of 16SrRNA gene were designed and synthesized using GeneRuner software. In order to determine the sequence of the 16SrRNA gene, mullet DNA were amplified by PCR. Then, the PCR product was run on a 1% agarose gel, and bands were produced between 500 and 600 bp. Evolutionary difference (maximum likelihood), neighbor-joining and phylogeny relationships were obtained using MEGA11 software.
Results and Discussion: The results show the mullet samples in the three areas have 96% similarity and 4% evolutionary differences with each other. The phylogeny tree of mullet samples was drawn using Maximum parsimony, maximum Likelihood and neighbor-joining methods. In order to compare among three methods in the golden mullet from the three areas, the samples of western and central areas are located together in one cluster and on the same branch, which indicates the slight distinction of these two populations according to the 16S rRNA gene. In the present study on golden mullet, the short geographical distance of sampling stations in the coastal waters of the Caspian Sea in Guilan Province and the absence of physical barriers such as heat, salinity, etc. (Rezvani et al., 2012) confirm the existence of gene flow in the three sampled areas, indicating little genetic differentiation in this species. The results obtained indicate that the inappropriate method of reproduction and release of larvae can be the main reason for the lack of differentiation, as well as the cause of the occurrence of a genetic bottleneck among the studied populations of golden mullet.
Conclusion: Providing the possibility of natural reproduction of the broodstock is the best way to prevent the continuation of this process. Considering the need for artificial reproduction, it is necessary to consider the separation of populations during artificial reproduction and release. |
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| Keywords: Genetic distinct, Golden mullet population, Sothern west of the Caspian Sea, 16SrRNA |
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Type of Study: Research |
Subject:
Special
Received: 2025/07/1 | Accepted: 2025/08/28
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