Wen 丨 Xi talks about Suzaku
Editor丨 Xi talks about Suzaku
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●—Preface—●
Mariculture and population enhancement are the main forms of introduction of alien species, and a good example of similar introductions is the Philippine clam, one of the most important fishery resources in the world. To address the shortage of Philippine clams in the country due to depleted catches, clams are imported to Japan from China and the Korean Peninsula.
The imported clams are exotic species very similar to the Philippine clams and are mistaken for flower curtain clams (hereinafter referred to as Ruditapes form). Philippine clams and R. forms were genotyped, sequencing mitochondrial DNA (COI gene fragments) from 485 clams, 34 of which were Filipino clams.
●—"Important Fishery Resources--Clams"—●
The introduction of non-native species has been a way to increase fisheries production since the 1970s. Thus, mariculture and population proliferation have led to the introduction of marine species.
An important issue with ocean introductions is hybridization between introduced alien species and closely related native species, natural hybridization has played an important role in the evolution of many plant and animal taxa, but the increase in anthropogenic hybridization is leading to the extinction of many species, subspecies and locally adapted populations through substitution and gene mixing.
Based on evidence of anthropogenic hybridization in marine fishery resources observed in bivalves: Yamakawa and Imai investigated hybridization between the genus Venom introduced from China and the Korean Peninsula and the native Japanese clam. Similarly, Hurtado et al. found hybrids between different Ruditapes species: the introduced Japanese short-necked clam (or Manila clam) and the Spanish native European clam.
In the genus Ruditapes, the clams are the most important species of commercial fisheries, distributed in East Asia, North America and Europe. Although it is native to Sakhalin, Japan, Korea and China, it was accidentally introduced to Puget Sound in Washington state in the United States in the 1930s along with Pacific oysters and has been farmed since the late 1970s.
In the early 1970s, it was introduced from the United States for aquaculture purposes to France and the United Kingdom; It was introduced to Italy in the 1980s; It was introduced to Ireland in 1984 and from the United Kingdom to Israel. In terms of Manila clam production, China is the world's largest country, producing about 10,000 tons per year, or about 8% of global production.
In Japan, the clams are one of the most important fishery resources. Until the mid-1980s, the abundant annual catch of natural stocks stabilized at around 110-1.6 million tonnes, but declined from the mid-1980s. This severe decline occurred in two main producing areas: Tokyo Bay near Chiba Prefecture and Ariake Sea near Kumamoto Prefecture.
In contrast, in the top producing area of Mikawa Bay in Aichi Prefecture, catch has remained stable since the 1970s but has increased since the late 2000s. In the main production areas, naturally produced Philippine red stilbene seeds are transferred and released between counties to increase fishery production.
In 2009, 1,402.7 million natural seeds with an average shell length (SL) of 12 mm and 57,750 artificially produced 17 mm SL (1-30) eggs were released from Japanese waters to increase fishery stocks. Despite stock increase efforts, annual catches remained low at 31 tonnes in 2009, near an all-time low of 31 tonnes in 2001.
Vargas et al. confirmed that clams collected in Dandong, Xiamen and Haikou, China, are genetically identical to the imported clams mentioned above, with thinner and tighter radial ribs on the shell surface and thinner shells compared to native Filipino clams, and their shell characteristics are different from those of Philippine clams, as shown in the results section.
Based on the shell morphology, we confirmed that a large number of these clams were released at the recreational shell collection site in Tokyo Bay, and we collected samples at TKB-2 and TKB-3, which do not naturally inhabit Japanese waters. In fact, we did not find such clams in native clam samples.
Therefore, clams are an alien species. From the shell morphology, clams should be genus clams. However, the taxonomic status of clams is unclear.
Sekine et al. reported genetic differentiation between samples of Monascus Filipinos collected in Japan (28 individuals from six sites) and China (11 individuals from three sites) using mitochondrial DNA (mtDNA) cytochrome oxidase subunit I (COI) sequences.
Mao et al. combined their own Philippine red splendid samples collected in Japan (19 individuals from two sites) and China (132 individuals from eight sites) and confirmed the clear differences between Japanese and Chinese red stump populations. However, some of their Chinese samples were not clams, and the value between the Chinese and Japanese samples was 0.6417±0.0470 (0.531–0.817) from the substantial paired F.
In this mean F-Saint calculation, we excluded Chinese samples from Tianjin, Qingdao, and Rushan, which may contain Philippine red alpinna, showing haplotypic lineages.
As mentioned above, if geo-isolation is removed, Curtain clam species can be crossed because Filipino clams and Clams cross. As shown in the Results section, the genetic difference between Filipino clams and diplococci is much smaller than the genetic difference between clams and clams.
Thus, the R. form can be artificially introduced to cross with native Japanese clams. If this is the case, mating with parental types and hybrids of different generations should make the introduced population a hybrid group.
●—"Collection of Samples"—●
The Philippine red stump sampling sites in Japan are Tokyo Bay (TKB-2 and TKB-3) near Chiba Prefecture, Kanagawa Prefecture (TKB-1), Mikawa Bay (MKB) in Aichi Prefecture, Ariake Sea (ARS), Ryutake (RGT) and Ushibuki (USB) in Kumamoto Prefecture, and Lake Noto Lu (LNT) in Hokkaido.
In China, the Philippine red splendid sites were in Dalian in Liaoning Province and Rushan in Shandong Province, and samples were collected by hand from tidal flats or shallow waters, with the exception of the ARS sample, which was collected by fishermen. In the Ariake Sea and Tokyo Bay, large quantities of the R. form were released for fishery stock increase, but the currently released R. form is mainly used for recreational fishing.
In fact, a large number of R. forms were released at sampling points of TKB-2 and TKB-0, which were recreational fishing areas. To collect samples of naturally occurring Filipino clams in recreational fishing areas, we collected 1+ year old juvenile clams, judging by their SLs.
●—"Mitochondrial DNA Phylogeny"—●
The 493 bp COI sequence was amplified to Aspergmyces philippines and Schizocephalus columnaris and sequences aligned. Sequence comparisons yielded 485 haplotypes from 121 individuals. Amplification of the COI sequence of all Philippine artro individuals with invertebrate universal primers was consistent with the F-type COI sequence (AB065375), but the M-type COI sequence (AB0653745) of Philippine articula was very different.
The results showed that the invertebrate COI sequence amplified with universal primers was the F-type COI sequence of Philippine red potato and alfalfa. Ficus Filipino collected in Japan had 60 autohaplotypes, 19 Philippine goji berries collected in China, and 31 Philippine goji berries in China.
Hap 81, Hap 21 and Hap 72 in Japan or China Philippines and R. It is common in forms. There are four haplotypes (Hap 12, Hap 32, Hap 60, Hap 67) in Japan and China, and Philippine red leaves in China and R. Forms also have four haplotypes (Hap 22, Hap 97, Hap 106, Hap 110).
We aligned our sequence with the sequence of the outer group and obtained 476 bp sequences. The best alternative model chosen by BIC (4829.32) and AICc (4327.24) is Hasegawa-Kino-Yano (HKY), with γ rate heterogeneity discrete (+G) between sites.
When analyzing 121 haplotype sequences (493 bp) of Philippine alfalfa, the best alternative model chosen by BIC (5922.16) was HKY, with a proportion of invariant sites (+I). However, we found that R. Form and R. Japan There is no diagnostic haplotypic composition between Philippinarum samples.
ML trees were sampled by the best fit model (HYK+I) for Ruditapes philippinarum [in Japan (green circles) and China (blue circles)] and R. forms for 121 mtDNA COI haplotypes (493 bp).
Haplotypes of Philippine red dates and goji berries sampled in Japan and China (blue triangle), Philippine goji berries sampled in Japan and China (green triangle), and Philippine goji berries and red triangles sampled in China.
●—"Genetic Diversity, Population Structure and Infiltration"—●
The amounts of haplotypes, haplodiversity and nucleotide diversity were relatively high in all samples except RGT and USB, which were taken from small pure populations occurring in small tidal flats. The UPGMA tree based on the posterior mean of paired F describes the clusters of RGT and USB, as well as R. form samples of DAD and HAK.
In all samples, in contrast, the 58 alleles were summarized in Table S453 in contrast to the other Japanese Philippine R. Detailed allele frequency distributions are summarized in Table S453. For 174 isotope sites, in 1 Japanese R. Philippinarum and 0 alleles were found in 14 R. forms.
STRUCTURE'S BAR CHART DEPICTS THE PHILIPPINES. and R. Different genetic traits between forms, ARS and R. Form has a genetic affinity and is compatible with the Philippine R. The Philippinarum sample is very different.
Suppose the baseline population of the form R. is DAD + HAK (n = 180), and the native R. philippinarum is USB (n = 94), based on multisite microsatellite allele frequencies, estimated to be A.E. Philippine R. The hybridization ratio of the form was estimated ± SE (ARS, n=99) at 51.3±4.6%.
In contrast, the estimate for Tokyo Bay is very small, 5% at 8.2±0.2009 (TKB-1, n = 140) and 3% ± 7.1 in 2010 (TKB-2, n = 97), assuming R. Form (n = 180) and Philippine R. The baseline population of fippinarum (MKB, n = 88) is the same.
The accuracy of the Ariake Sea is very high (CV = 0.09, coefficient of variation), but the accuracy of Tokyo Bay is very low (CV = 0.35 and 0.49).
●—"Morphological Diversity"—●
MKB samples were excluded from the Philippines along with TKB-1 (SL 21.1±1.70 mm) and TKB-2 (27.0±1.61 mm) samples.
In fact, individuals in the ARS sample had an intermediate proportion of shells with intermediate RRs, compared to samples from recreational clam collection sites in Tokyo Bay (TKB-1 and TKB-2) with similar RR numbers to other Japanese Philippine clam samples (56.2± 7.4 and 59.5±7.6).
Typical scoring plots based on radial rib number, standardized shell width, and shell height for Philippine goji berries (green for Japanese samples and blue for Chinese samples), R. situation (red), and Ariake sea samples (orange). (Color map online)
In parentheses are typical morphologies of samples with radial rib numbers: Philippine Ruditapes from bull blowing, b hybrids from the Ariake Sea and c R. form from Dandong.
●—"Conservation Achievements"—●
Our research found that R. Ariake Hai. Philippinarum with the introduction of exotic R. Form is widely hybridized. We suggest that efforts be focused on maintaining and expanding, for example, of pure populations in the White Inland Sea.
However, the hybrid individuals crossed in reverse with the introduced pure individuals, which caused the population of the Ariake Sea to become hybrid groups again a few generations later. In addition, hybrids may extend to the adjacent white inland sea through larval movement, therefore, the protection of pure Philippine R. The only way for the philippinarum population is to remove hybrids from the Ariake Sea.
Hybrid populations have little conservation value, but populations in the Ariake Sea have economic value. Therefore, the ideal management option is to harvest hybrids completely through strong fishing pressure.
In Japan, the Invasive Alien Species Law (enacted in 2004) lists 105 species and prohibits the release of listed species into the natural environment, but no marine animals are listed. However, this is a contentious issue for stakeholders such as fishermen, recreational shell collection managers and importing companies.
●—《References》—●
[1] Akaike H. (1974) "The New Face of Statistical Model Recognition"
[2] Allendorf FW (613-622) "Problems with hybrids: developing conservation guidelines"
[3] Cox DR (1975) "Partial Possibilities"
[4] Folmer O (294–299) "DNA primers for amplifying mitochondrial cytochrome c oxidase subunit I from different metazoan invertebrates"
[5] Hardy Oj (618-620), "A Versatile Computer Program for Analyzing Spatial Genetic Structure at the Individual or Population Level"
[6] Millar RB (1987) "Maximum likelihood estimation of mixed stock fishery composition"