Determination of genetic interactions and variations between natural and cultured populations of common dentex (Dentex dentex) and sharpsnout seabream (Diplodus puntazzo) fishes in Aegean Sea by molecular markers and prediction of future status

Along with the negative effects of global warming, it is expected that the production area and capacity of aquaculture will increase all over the world in order to meet the animal protein needs of people in the face of the rapid increase in the world population. However, this increase will inevitably have impacts on the natural ecosystem. One of these effects is the risk of decreasing genetic diversity due to fertilization between individuals of the same species, which are genetically more heterozygous in the natural environment, and individuals of the same species, which are genetically more homozygous and escape from aquaculture environments to the natural environment for various reasons. It is important to understand these relationships in order to ensure ecologically sustainable production as far as possible. Common Dentex (Dentex dentex) and Sharpsnout Seabream (Diplodus puntazzo) are fish species farmed in the Aegean and Western Mediterranean regions of Turkey. The aim of this study was to determine the genetic interactions and variations between the natural and cultured populations of these two species by molecular markers and to predict the future status. Seven different locations in the Aegean Sea and Western Mediterranean, namely Karaburun, Çeşme, Kuşadası, Güllük, Bodrum, Çanakkale and Antalya were determined for the fish materials. A total of 53 specimens of Common Dentex fish and 58 specimens of Sharpsnout Seabream fish, both cultured and natural, were examined. There was no statistical difference (p>0.05) between the groups in terms of Ct and Tm values. On the other hand, there was a statistically significant difference (p<0.05) in Ct values between the groups representing the regions where the individuals were taken. The HRM profiles obtained were grouped in 2 different groups in the Common Dentex species. In Sharpsnout Seabream species, HRM profiles were collected in 4 different groups. The total number of haplotypes h= 26 was determined in 53 individuals belonging to the Common Dentex species and the total average haplotype diversity Hd= 0.7632. It was determined that 22 of the total haplotypes were found in only one animal in the individuals obtained from the stations and constituting the study. The total number of haplotypes in 58 individuals belonging to the Sharpsnout Seabream species was determined as h= 45 and the total average haplotype diversity was determined to be Hd= 0,9816. Looking at the nucleotide diversity (π) data in the Common Dentex population, the average nucleotide diversity was determined as 0.004423. The highest value was observed in "Karaburun culture" with π= 0.00967 (+0.00122) and the lowest value was observed in "Karaburun natural" population with π=0.00140 (+0.00074). Looking at the nucleotide diversity (π) data in Sharpsnout Seabream population, the average nucleotide diversity was determined as 0.0103. The highest value was observed in "Çeşme natural" with π= 0,01935 and the lowest value was observed in "Kuşadası natural" population with π= 0.00771. The total number of nucleotides analyzed in the Common Dentex species is 477 bc. The nucleotide distribution was as follows: T: 30.7%; C: 28.6%; A: 23.9%; G: 16.8%. The overall bias for transposition/transversion for the Common Dentex samples was calculated as R= 0.70. The total number of nucleotides analyzed in Sharpsnout Seabream species is 465 bc. The nucleotide distribution was as follows: T: 31.6%; C: 27.3%; A: 25.0%; G: 16.1%. The total bias for transposition/transversion was calculated as R= 1.419 for the Sharpsnout Seabream samples. It is seen that the values are within acceptable limits. The closest genetic distance between "Karaburun culture" and "Güllük natural" among the stations belonging to the Common Dentex species was determined as 0.00080. The closest genetic distance between "Karaburun natural" and "Güllük natural" and "Bodrum natural" stations of Sharpsnout Seabream species was 0.000106, 0.00060 respectively. This situation is an indication that the populations in the stations may be due to the high similarity rate. The neighbor joining tree containing the results of DNA sequencing with 53 individuals belonging to the flycatcher species and the sequence of the sea bass species (JQ623929.2) taken from the universal gene pool for control purposes consisted of 7 groups. The neighbor joining tree containing the DNA sequencing results of 58 individuals belonging to the Sharpsnout Seabream species and the sequence (KP975556.1) of the sea bass species taken from the universal gene pool for control purposes consisted of 4 groups. In Tajima's D-value and Fu's Fs tests, the values of all populations were found to be negative and the total values were found to be negative and therefore mostly statistically insignificant in the data of the Common Dentex species and Sharpsnout Seabream species. According to the modeling between cultivated and natural specimens of the flycatcher species, the genetic interaction time was estimated as t = 2.1584 years. According to the modeling between cultivated and natural specimens of Sharpsnout Seabream species, the genetic interaction time was estimated as t = 5.1367 years. As a result, it was determined that there was a genetic interaction between the culture and natural stations in the Common Dentex and Sharpsnout Seabream samples examined, albeit at different levels. Geographical conditions are thought to be a factor for the study area not having challenging conditions for the migration of populations. With the modeling done under certain assumptions, it is predicted that the genetic diversity between cultured and natural fishes will be very low within 40 years for Common Dentex and Sharpsnout Seabream species. In order to preserve the genetic diversity in the natural environment, the broodstock that make up the gene pools in the hatcheries, which are the heart of the production facilities, should be renewed in certain periods and broodstock selections from different populations should be made within the framework of a program. In addition, it is recommended that innovative technologies such as artificial intelligence, sensors and the internet of things should be used in an integrated manner within the production ecosystem in order to minimize the escape from cages. In order to achieve these, there is a need to establish an aquaculture policy that prioritizes the protection of natural stocks. On a specific scale, a species and/or region-specific ERP (Enterprise Resource Planning) model can be created.