Corresponding author: Yuan Li ( liyuan@tio.org.cn ) Corresponding author: Longshan Lin ( linlongshan1974@163.com ) Academic editor: Jolanta Kiełpińska
© 2021 Cheng Liu, Jing Zhang, Shigang Liu, Puqing Song, Ying Guan, Binbin Shan, Yuan Li, Longshan Lin.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Liu C, Zhang J, Liu S, Song P, Guan Y, Shan B, Li Y, Lin L (2021) Genetic diversity of the yellowfin seabream, Acanthopagrus latus (Actinopterygii: Perciformes: Sparidae)—An enhancement species in Dongshan Bay. Acta Ichthyologica et Piscatoria 51(3): 281-287. https://doi.org/10.3897/aiep.51.66894
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Dongshan Bay is located on the west side of the Taiwan Strait, which had abundant fishery resources in the past. With the increase in fishing pressure, resources have declined. To restore the fishery resources in Dongshan Bay and to increase fishing yield, much enhancement and release work has been carried out in Dongshan Bay. The yellowfin seabream, Acanthopagrus latus (Houttuyn, 1782), is an important enhancement species in Dongshan Bay that is also frequently captured. Due to yearly progress in enhancement and release, it is necessary to study the current status of the genetic diversity of yellowfin seabream in Dongshan Bay. The results show that all yellowfin seabream populations have high genetic diversity, which is mainly related to its breeding habits and growth rate, and this ensures a large recruitment stock in the natural seas. The current population has differentiated from the historical population due to a change in genetic structure, and many historical haplotypes have been lost. The results of this study provide a reference for fishery management departments to formulate management measures and conservation policies specifically for yellowfin seabream. In particular, yellowfin seabream is a hermaphroditic and protandrous species. Targeting an older age group as the main fishing subject is not conducive to its breeding protection and resource growth, and therefore, fishing of an older age group should be restricted in fishery production.
Dongshan Bay, genetic diversity, resource decline, stock enhancement, yellowfin seabream
Located on the west side of the Taiwan Strait, Dongshan Bay is a typical subtropical estuary semi-closed bay. The bay is affected by the offshore water of the South China Sea, by the Taiwan warm current in the summer, and by the Fujian–Zhejiang coastal current as well as the Taiwan Strait inversion thermocline in the fall. It originally had rich fishery resources and was a good place for various economic species to inhabit, reproduce, and grow. With the rapid development of industry and agriculture since the reform and opening up, the development and utilization of sea areas and the continuously growing aquaculture industry have aggravated the ecological environment of the sea area in the bay, leading to a significant decline in fishery resources (
To restore the fishery resources in Dongshan Bay, the government of Dongshan County launched a program for enhancement and release some economically important shellfish and finfish species, Penaeus japonicus, Penaeus penicillatus, Pagrus major (Temminck et Schlegel, 1843); Acanthopagrus schlegelii (Bleeker, 1854); and Acanthopagrus latus (Houttuyn, 1782). By releasing a large number of artificially bred seedlings into natural seas to restore decreased populations and increase fishing yields, enhancement and release are of great significance for replenishing and restoring the population structure of biological resources, improving the ecological environment of waters, replenishing fishery resources, and increasing fishermen’s income. However, the genetic impact of released species on wild resources has also received increasing attention (
The yellowfin seabream, Acanthopagrus latus, an important economic fishery species in Dongshan Bay, is an important species for enhancement and release in this sea area. It is a warm water shallow coastal fish species that can adapt to rapid changes in salinity and generally does not migrate long distances. It is widely distributed in the East China Sea and South China Sea (
Mitochondrial DNA (mtDNA), as an important genetic information library, has the advantages of maternal inheritance, a fast evolution rate, high copy numbers, and easy amplification. Therefore, it is often employed in research on species diversity and phylogeny with wide applications (
A total of 75 individuals of four yellowfin seabream populations, Dongshan I (DSI; wild individuals, 2009.11), Dongshan II (DSII; wild individuals, 2019.10), Dongshan III (DSIII; cultured individuals, 2019.11), and Xiamen (XM; wild individuals, 2019.10), were collected from November 2009 to November 2019 (Fig.
Sampling sites, date, number, number of haplotype and genetic diversity indices for each population of Acanthopagrus latus.
Sampling site | ID | Collection date | Sample size | h | π | k | No. of haplotype |
---|---|---|---|---|---|---|---|
Dongshan I | DSI | Nov 2009 | 20 | 0.9895 ± 0.0193 | 0.0163 ± 0.0088 | 8.9632 ± 4.3104 | 18 |
Dongshan II | DSII | Oct 2019 | 22 | 0.9957 ± 0.0153 | 0.0178 ± 0.0095 | 9.7922 ± 4.6616 | 21 |
Dongshan III | DSIII | Nov 2019 | 14 | 0.9670 ± 0.0366 | 0.0129 ± 0.0072 | 7.0879 ± 3.5401 | 11 |
Xiamen | XM | Oct 2019 | 19 | 1.0000 ± 0.0171 | 0.0161 ± 0.0087 | 8.8246 ± 4.2585 | 19 |
Total | 75 | 0.9960 ± 0.0030 | 0.0196 ± 0.0100 | 10.8090 ± 4.9731 | 65 |
A Qiagen DNeasy kit was used to extract the genomic DNA of yellowfin seabream. DNA with a quantified concentration was amplified by PCR. The amplification primers were DL-S (5′-CCCACCACTAACTCCCAAAGC-3′) and DL-R (5′-TTAACTTATGCAAGCGTCGAT-3′) (
The same primers employed for PCR amplification, were used to manually edit and correct the raw sequences for the CR of the yellowfin seabream with SeqMan in the DNASTAR software package. The genetic diversity indexes, such as the mutation sites, haplotype numbers, and population genetic diversity parameters, were calculated using ARLEQUIN 3.5 (
A total of 75 sequences were obtained from all populations. After manual alignment, the lengths of the obtained target fragments were 548–550 bp, of which only one sequence was 548 bp in length, 549-bp sequences were dominant (71), and three sequences were 550 bp long. There were 87 mutation sites in all sequences, 54 parsimony informative sites, 33 singleton variable sites, and three insertions/deletions. The contents of each base were as follows: A, 34.67%; T, 32.04%; G, 13.79%; and C, 19.49%. The A + T content (66.71%) was higher than the G + C content, demonstrating a certain AT preference.
The 75 sequences defined 65 CR haplotypes. The number of haplotypes in each population ranged from 11 to 21. Four (6.15%) haplotypes were shared by two or more populations. There were 61 (93.85%) unique haplotypes. DSIII had a shared haplotype (Hap_11, Hap_17, and Hap_47, respectively) with each of the other three populations, DSI had a shared haplotype (Hap_11 and Hap_17, respectively) with DSIII and XM, and DSII had a shared haplotype (Hap_20) with DSIII; there was no shared haplotype between DSI and DSII (Table
DSI | DSII | DSIII | XM | Total | DSI | DSII | DSIII | XM | Total | ||
Hap_1 | 1 | 1 | Hap_34 | 1 | 1 | ||||||
Hap_2 | 1 | 1 | Hap_35 | 1 | 1 | ||||||
Hap_3 | 1 | 1 | Hap_36 | 1 | 1 | ||||||
Hap_4 | 1 | 1 | Hap_37 | 1 | 1 | ||||||
Hap_5 | 2 | 2 | Hap_38 | 1 | 1 | ||||||
Hap_6 | 1 | 1 | Hap_39 | 1 | 1 | ||||||
Hap_7 | 1 | 1 | Hap_40 | 2 | 2 | ||||||
Hap_8 | 1 | 1 | Hap_41 | 1 | 1 | ||||||
Hap_9 | 1 | 1 | Hap_42 | 1 | 1 | ||||||
Hap_10 | 2 | 2 | Hap_43 | 1 | 1 | ||||||
Hap_11 | 1 | 1 | 2 | Hap_44 | 1 | 1 | |||||
Hap_12 | 1 | 1 | Hap_45 | 2 | 2 | ||||||
Hap_13 | 1 | 1 | Hap_46 | 1 | 1 | ||||||
Hap_14 | 1 | 1 | Hap_47 | 1 | 1 | 2 | |||||
Hap_15 | 1 | 1 | Hap_48 | 1 | 1 | ||||||
Hap_16 | 1 | 1 | Hap_49 | 1 | 1 | ||||||
Hap_17 | 1 | 1 | 2 | Hap_50 | 1 | 1 | |||||
Hap_18 | 1 | 1 | Hap_51 | 1 | 1 | ||||||
Hap_19 | 1 | 1 | Hap_52 | 1 | 1 | ||||||
Hap_20 | 1 | 2 | 3 | Hap_53 | 1 | 1 | |||||
Hap_21 | 1 | 1 | Hap_54 | 1 | 1 | ||||||
Hap_22 | 1 | 1 | Hap_55 | 1 | 1 | ||||||
Hap_23 | 1 | 1 | Hap_56 | 1 | 1 | ||||||
Hap_24 | 1 | 1 | Hap_57 | 1 | 1 | ||||||
Hap_25 | 1 | 1 | Hap_58 | 1 | 1 | ||||||
Hap_26 | 1 | 1 | Hap_59 | 1 | 1 | ||||||
Hap_27 | 2 | 2 | Hap_60 | 1 | 1 | ||||||
Hap_28 | 1 | 1 | Hap_61 | 1 | 1 | ||||||
Hap_29 | 1 | 1 | Hap_62 | 1 | 1 | ||||||
Hap_30 | 1 | 1 | Hap_63 | 1 | 1 | ||||||
Hap_31 | 1 | 1 | Hap_64 | 1 | 1 | ||||||
Hap_32 | 1 | 1 | Hap_65 | 1 | 1 | ||||||
Hap_33 | 1 | 1 |
The entire yellowfin seabream population demonstrated high haplotype diversity (0.9960 ± 0.0030) and low nucleotide diversity (0.0196 ± 0.0100). Among them, the wild XM population showed the highest diversity (1.000 ± 0.0171), followed by the current wild Dongshan population (0.9957 ± 0.0153), and the historical wild Dongshan population (0.9895 ± 0.0193); the current cultured Dongshan population showed the lowest diversity (0.9670 ± 0.0366).
The NJ tree was constructed based on 65 mitochondrial CR haplotypes of yellowfin seabream, showing that two large haplotype lineages existed in the four yellowfin seabream populations, with low confidence. No pedigree structure corresponding to geographic locations was detected (Fig.
The pairwise FST values were estimated based on the mtDNA CR sequences, ranging from 0.0005 to 0.4288 (Fig.
AMOVA was performed to examine the population genetic structure of yellowfin seabream (Table
Source of variation | Percentage variation | F-Statistics | P |
---|---|---|---|
One gene pool (DSI, DSII, DSIII, XM) | |||
Among populations | 22.92 | 0.2292 | 0.000 ± 0.000 |
Within populations | 77.08 | ||
Two gene pool (DSI, DSII, DSIII), (XM) | |||
Among groups | –19.17 | –0.1917 | 1.000 ± 0.000 |
Among populations within groups | 34.83 | 0.2923 | 0.000 ± 0.000 |
Within populations | 84.34 | 0.1566 | 0.000 ± 0.000 |
Two gene pool (DSI), (DSII, DSIII, XM) | |||
Among groups | 36.27 | 0.3627 | 0.253 ± 0.011 |
Among populations within groups | –0.09 | –0.0015 | 0.420 ± 0.014 |
Within populations | 63.83 | 0.3617 | 0.000 ± 0.000 |
Due to the impact of ocean currents and climate and its unique geographical location, Dongshan Bay had relatively high biodiversity and rich fishery resources. However, in recent years, with the continuous growth of the human population, the development of surrounding areas and coastal industries, and the increasing development and utilization of sea areas, the impact on the ecology of this sea area has increased, and the habitats and spawning grounds of many economic species have been damaged. Moreover, the fishing pressure of this sea area is overloaded, resulting in a decline in fishery resources (
Under normal circumstances, when the number of artificially bred seedlings released into the natural seas is greater than the carrying capacity, an intraspecies competitive relation is formed within the released population, within the wild population, and between the released population and the wild population in which individuals compete for food and living space (
However, the results of this study showed that the genetic diversity of yellowfin seabream was high in both wild and cultured populations. The genetic diversity of wild yellowfin seabream in Dongshan Bay in 2009 was largely the same as that in 2019, while that of the cultured population in 2019 was slightly lower (Table
Although the genetic diversity of yellowfin seabream in Dongshan Bay is high, the current fishery resources in Dongshan Bay have been critically overfished (
To date, many scholars have shown that breeding and release will induce certain genetic impacts on populations in natural seas and have discussed the advantages and disadvantages of the breeding and release of fishery resources from the perspective of protecting genetic diversity (
Mr Yanping Wang and Dr Weiwen Li helped us collected the samples of yellowfin seabream individuals, and Ran Zhang helped us with the experiment and data analysis. The research was supported by Open Research Fund Program of Fujian Provincial Key Laboratory of Marine Fishery Resources and Eco-environment (z820275), Scientific Research Foundation of TIO, MNR (2019017, 2019018), Science and Technology Project of Guangdong Province, China (2019B121201001). The authors declare no conflicts of interest including the implementation of research experiments and writing this manuscript.