Social-ecological vulnerability and risk of China's marine capture fisheries to climate change.

Climate change is a new disrupter to global fisheries systems and their governance frameworks. It poses a pressing management challenge, particularly in China, which is renowned as the world's largest fishing country and seafood producer. As climate change continues to intensify in the region and climate awareness grows within the country's national policy, the need to understand China's fisheries' resilience to the escalating climate crisis becomes paramount. In this study, we conduct an interdisciplinary analysis to assess the vulnerability and risk of China's marine capture fisheries in response to climate change. This study employs a spatially explicit, indicator-based approach with a coupled social-ecological framework, focusing on 67 species and 11 coastal regions. By integrating diverse sets of climatic, ecological, economic, societal, and governance indicators and information, we elucidate the factors that could hinder climate adaptation, including a limited understanding of fish early life stages, uncertainty in seafood production, unequal allocation and accessibility of resources, and inadequate consideration of inclusive governance and adaptive management. Our results show that species, which have managed to survive the stress of overfishing, demonstrate a remarkable ability to adapt to climate change. However, collapsing stocks such as large yellow croaker face a high risk due to the synergistic effects of inherent biological traits and external management interventions. We emphasize the imperative to build institutional, scientific, and social capacity to support fisheries adaptation. The scientific insights provided by this study can inform fisheries management decisions and promote the operationalization of climate-resilient fisheries in China and other regions.

Phylogenetic relationships and cryptic species in the genus Sthenoteuthis (Cephalopoda: Ommastrephidae) in the South China Sea.

Large squids of the genus Sthenoteuthis are commercially relevant species that include two truly oceanic squids. They are large nektonic predators being widely distributed throughout tropical and subtropical waters of the Atlantic and Indo-Pacific Ocean. The present study investigates different morphs varying in size at maturity, and assesses the genetic divergence in Sthenotheutis in relation to geographic patterns in the South China Sea. We obtained sequences using a mitochondrial (cytochrome c oxidase subunit I) and a nuclear (Histone H3) gene marker from 111 individuals in 23 locations of the South China Sea. In combination with sequences available in public databases, we performed tests on DNA taxonomy, mostly based on molecular phylogenies. Our results suggest that the genus Sthenoteuthis includes at least three species. The Indo-Pacific purpleback squid Sthenoteuthis oualaniensis contains at least two genetically distinct lineages that can be considered separate species, a dwarf species and a medium-sized species, separated by both the mitochondrial marker and the more conserved nuclear marker. We also assessed whether the few cases of mitonuclear discordance could be the result of genetic introgression and past hybridization or incongruence lineage sorting. The medium-sized species is more widely distributed and dominant in the South China Sea than the dwarf species. The medium-sized species inhabits the whole South China Sea, whereas the dwarf species is restricted to the equatorial waters of the South China Sea. The medium-sized species has two further genetic clades, one distributed in the East Pacific Ocean and the other in the South China Sea. This high level of genetic differentiation is in agreement with the discriminant analysis on the morphological measurements, clearly separating the dwarf and medium-sized species, indicating the presence of a complex of pseudo-cryptic species in S. oualaniensis, clearly identifiable by differences in DNA sequences and in body size, and statistically differentiated in their body measurements.

Bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in wild marine fish from the coastal waters of the northern South China Sea: Risk assessment for human health.

Little data are available on polycyclic aromatic hydrocarbons (PAHs) in marine fish associated with oil and gas activities from the South China Sea (SCS). Twenty-one wild marine fish species from the northern South China Sea were collected for analysis of the presence of polycyclic aromatic hydrocarbons (PAHs). The total concentration of the PAHs (∑16PAHs) ranged from 199 to 606 ng·g-1 d.w., indicating moderate contamination. PAHs in fish species found in the Pearl River Delta (PRD) were significantly higher than those from the Yachen (YC) gas fields (p < 0.05). Planktivorous fish exhibited significantly higher concentrations of PAHs than carnivorous and omnivorous fish (p < 0.05). The PAHs were dominated by three ring compounds. Source identification analyses indicated that the PAH pollution originated from petroleum inputs. The cancer and non-cancer risk assessments concluded that the probable risk associated with the intake of PAHs via fish consumption is minimal. Long-term monitoring is necessary to determine the ecological impacts of PAHs associated with oil and gas activities.

Fuzzy comprehensive assessment of heavy metals and Pb isotopic signature in surface sediments from a bay under serious anthropogenic influences: Daya Bay, China.

The fuzzy comprehensive assessment was undertaken to evaluate the marine sediment quality in Daya Bay, China based on the monitoring data of 2015 and China National Standard for Marine Sediment Quality (GB 18668-2002). The results demonstrated that the average metal concentrations (mg/kg) were 0.08 (Cd), 51.30 (Pb), 91.30 (Cr), 29.63 (Cu), 143.42 (Zn), 0.03 (Hg), and 7.31 (As), which were clearly higher with respect to their corresponding background values. Cr was the major pollutant based weight matrices calculated. Taken as whole, the membership degree of class I was a range from 0.65 to 1, suggesting that the marine sediment quality in Daya Bay belongs to class I. Pb stable isotopic analysis coupled with geographic information system (GIS) approach showed the sedimentary Pb mainly originated from petrochemical industry at northwest coast of Daya Bay.

[Effects of PM2.5 exposure on Klebsiella pneumoniae clearance in the lungs of rats].

OBJECTIVE: To investigate the effects of PM2.5 exposure on susceptibility to Klebsiella infection and bacterial clearance, and to discuss its possible mechanisms. METHODS: Eighty-six healthy male SD rats were randomly divided into 4 groups: a control group, a Klebsiella pneumoniae infection group(infection group), a PM2.5 group and a PM2.5+ Klebsiella pneumoniae infection group (combined group) .We developed a rat model in which the animals were given Klebsiella pneumoniae, PM2.5 exposure and PM2.5 exposure followed by infection with Klebsiella pneumoniae respectively. The clinical scores were evaluated. The total mortality of each group was assessed. Bacterial load in the BALF was quantified and the infection rate of each group was assessed.Lung histopathological changes were detected by HE staining. The concentrations of IL-6 and TNF-α in serum were detected by ELISA. Cells in the BALF were counted for each group by microscopy. The changes of tracheal membrane epithelial cells were observed by scanning electron microscope. RESULTS: The total mortality in the combined group (n = 14) was higher than that in the control group (n = 0), infection group(n = 4) and PM2.5 group(n = 4). The infected cases in the combined infection group (n = 13) was higher than that in the infection group (n = 6). The total number of WBC in BALF in the combined group on the first day[(11.96 ± 0.56)×10(5)/L] and seventh day [(15.68 ± 0.81)×10(5)/L] was higher than that in the control group, the infection group and the PM2.5 group. The neutrophil number in BALF in the combined group on the first day[(5.76 ± 0.44)×10(5)/L] and seventh day [(9.41 ± 0.64)×10(5)/L] was higher than that in the control group, the infection group and the PM2.5 group. The lung pathological changes were much more severe in the combined group as compared to those in the control, the infection and the PM2.5 groups. Concentrations of TNF-α in serum in the combined group on the first day [(829 ± 90) ng/L] and the seventh day [(1055 ± 91) ng/L] were higher than those in the control group and the PM2.5 group. Concentrations of IL-6 in serum in the combined group on the first day [(1.26 ± 0.16) ng/L] and seventh day [(1.95 ± 0.18) ng/L] was higher than those in the control, the infection and the PM2.5 groups. Tracheal cilia in the PM2.5 group showed signs of disorderly arrangement, adhesion and ecclasis. CONCLUSIONS: PM2.5 exposure increased the susceptibility of the rats to Klebsiella pneumoniae infection and decreased bacterial clearance.Its mechanism may be related to impairment of the bronchial mucociliary system and interaction of cytokines.

Risk Factors for Preoperative Cerebral Infarction in Infants with Moyamoya Disease.

There have been few reports on the risk factors for preoperative cerebral infarction in childhood moyamoya disease (MMD) in infants under 4 years. The aim of this retrospective study is to identify clinical and radiological risk factors for preoperative cerebral infarction in infants under 4 years old with MMD, and the optimal timing for EDAS was also considered. We retrospectively analyzed the risk factors for preoperative cerebral infarction, confirmed by magnetic resonance angiography (MRA), in pediatric patients aged ˂4 years who underwent encephaloduroarteriosynangiosis between April 2005 and July 2022. The clinical and radiological outcomes were determined by two independent reviewers. In addition, potential risk factors for preoperative cerebral infarction, including infarctions at diagnosis and while awaiting surgery, were analyzed using a univariate model and multivariate logistic regression to identify independent predictors of preoperative cerebral infarction. A total of 160 hemispheres from 83 patients aged <4 years with MMD were included in this study. The mean age of all surgical hemispheres at diagnosis was 2.17±0.831 years (range 0.380-3.81 years). In the multivariate logistic regression model, we included all variables with P<0.1 in the univariate analysis. The multivariate logistic regression analysis indicated that preoperative MRA grade (odds ratio [OR], 2.05 [95% confidence interval [CI], 1.3-3.25], P=0. 002), and age at diagnosis (OR, 0.61 [95% CI, 0.4-0.92], P=0. 018) were predictive factors of infarction at diagnosis. The analysis further indicated that the onset of infarction (OR, 0.01 [95% CI, 0-0.08], P<0.001), preoperative MRA grade (OR, 1.7 [95% CI, 1.03-2.8], P=0.037), and duration from diagnosis to surgery (Diag-Op) (OR, 1.25 [95% CI, 1.11-1.41], P<0.001) were predictive factors for infarction while awaiting surgery. Moreover, the regression analysis indicated that family history (OR, 8.88 [95% CI, 0.91-86.83], P=0.06), preoperative MRA grade (OR, 8.72 [95% CI, 3.44-22.07], P<0.001), age at diagnosis (OR, 0.36 [95% CI, 0.14-0.91], P=0.031), and Diag-Op (OR, 1.38 [95% CI, 1.14-1.67], P=0.001) were predictive factors for total infarction. Therefore, during the entire treatment process, careful observation, adequate risk factor management, and optimal operation time are required to prevent preoperative cerebral infarction, particularly in pediatric patients with a family history, higher preoperative MRA grade, duration from diagnosis to operation longer than 3.53 months, and aged ˂3 years at diagnosis.

The complete mitochondrial genome of the tropical oyster Saccostrea echinata (Bivalvia: Ostreidae) from the South China Sea.

Saccostrea echinata is a rock perched oyster with wide distribution and tremendous potential for commercial mariculture. However, the taxonomy of this genus is confused. In this study, we described the complete mitochondrial genome of medium-sized form of Saccostrea echinata. The genome is 16,282 bp in length, encoding the standard set of 12 protein-coding genes (PCGs), 23 tRNA genes, and two rRNA genes, with circular organization. The overall base composition of the whole mitochondrial genome was A (26.78%), T (36.64%), G (21.99%), and C (14.59%) with an AT bias of 63.42%. The longest PCG of these species was ND5, whereas the shortest was ND4L.

The complete mitochondrial genome of loliginid squid (Uroteuthis chinensis) from Minnan-Taiwan bank fishing ground.

The squid Uroteuthis chinensis is commercially important fishery species in many coastal regions of Asia. In this study, we described the complete mitochondrial genome of U. chinensis. The genome is 17,353 bp in length, encoding the standard set of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, with circular organization. The overall base composition of the whole mitochondrial genome was A (39.56%), T (31.71%), G (9.05%) and C (19.68%) with an AT bias of 71.27%. The longest protein-coding genes of these species was ND5, whereas the shortest ATP8.

The complete mitochondrial genome of middle-sized form of Sthenoteuthis oualaniensis (Cephalopoda: Ommastrephidae) from the South China Sea.

The purpleback flying squid (Sthenoteuthis oualaniensis) is a pelagic squid with tremendous potential for commercial exploitation. Sthenoteuthis oualaniensis comprises two forms in the South China Sea, medium-sized form and dwarf form. In this study, we described the complete mitochondrial genome of medium-sized form of S. oualaniensis. The genome is 20,309 bp in length, encoding the standard set of 13 protein-coding genes, 20 tRNA genes, and two rRNA genes, with circular organization. The overall base composition of the whole mitochondrial genome was A (35.86%), T (33.36%), G (11.63%), and C (19.15%) with an AT bias of 69.22%. The longest protein-coding gene of these species was ND5, whereas the shortest ATP8.

The complete mitochondrial genome of oceanic puffer (Lagocephalus lagocephalus) from South China Sea.

Lagocephalus lagocephalus is one of genus Lagocephalus and widely distributed in tropical and temperate oceans. In this study, we described the complete mitochondrial genome of L. lagocephalus. The genome is 166,443 bp in length, encoding the standard set of 13 protein-coding genes (PCGs), 22 transfer RNA genes, 2 ribosomal RNA genes, and a non-coding D-loop, with circular organization. The overall base composition of the whole mitochondrial genome was A (27.95%), T (25.07%), G (16.14%), and C (30.83%) with an AT bias of 53.03%. The longest PCG of these species was ND5, whereas the shortest ATP8.

Diversity of marine planktonic ostracods in South China Sea: a DNA taxonomy approach.

Ostracods (Crustacea, Ostracoda) are small bivalved crustaceans, contributing over 200 described species to the marine zooplankton community. They are widely distributed and are relatively abundant components of the mesozooplankton, playing an important role in the transport of organic matter to deep layers. However, identification of ostracods based on micro-morphological characters is extremely difficult and time-consuming. Previous fragmentary taxonomic studies of ostracods in the South China Sea (SCA), were based solely on morphology. Here, by analysing the mitochondrial COI gene, we explore the taxa across the SCA using molecular tools for the first time. Our results show that sequence divergence among species varies within a large range, from 12.93% to 35.82%. Sixteen of the taxonomic units recovered by DNA taxonomy agree well with morphology, but Paraconchoecia oblonga, Conchoecia magna and Halocypris brevirostris split into two clades each, each of which contains cryptic species.

The complete mitochondrial genome of flyingfish (Cheilopogon spilonotopterus) from South China Sea.

Flyingfishes are epipelagic specialists that are easily distinguished by their enlarged fins, which are used for gliding leaps over the surface of the water. In this study, we described the complete mitochondrial genome of Cheilopogon spilonotopterus. The genome is 16,527 bp in length, encoding the standard set of 13 protein-coding genes, 22 tRNA genes and two rRNA genes, with circular organization. The overall base composition of the whole mitochondrial genome was A (28.86%), T (26.96%), G (16.66%) and C (27.52%) with an AT bias of 55.82%. The ATG initiation codon is used in all protein-coding genes except COX1, and the stop codons of all the 13 protein-coding genes were complete.

Complete mitogenome of two dolphinfishes (Coryphaena hippurus and Coryphaena equiselis) from South China sea.

The Coryphaenidae family comprises of single genus, Coryphaena, which includes two species: Coryphaena hippurus and Coryphaena equiselis. In this study, we described the complete mitochondrial genome of the two species in Coryphaena. The assembled mitogenome of C. hippurus and C. equiselis consists of 16731 bp and 16690 bp, respectively. Two mitogenomes contain the typical gene complement including 13 protein-coding genes, 22 transfer RNAs, 2 ribosomal RNA genes and a non-coding D-loop. The longest protein-coding genes of these species was ND5, whereas the shortest ATP8. The length of D-loop is 1168 bp (C. hippurus) and 1206 bp (C. equiselis).

The complete mitochondrial genome of Perciformes fish (Brama dussumieri) from South China Sea.

Brama dussumieri is one of the members of the family Bramidae and is widely distributed in the North Pacific Ocean. In this study, we described the complete mitochondrial genome of B. dussumieri. The genome is 16,996bp in length, encoding the standard set of 13 protein-coding genes, 22 tRNA genes, and 2 rRNA genes, with circular organization. The overall base composition of the whole mitochondrial genome was A (26.21%), T (25.65%), G (16.83%) and C (31.31%) with an AT bias of 51.86%. The ATG initiation codons are used in all protein-coding genes except COX1, and the stop codons of all the 13 protein-coding genes were complete.

Changes of the Macrobenthic Faunal Community with Stand Age of a Non-native Mangrove Species in Futian Mangrove National Nature Reserve, Guangdong, China.

Ya-Fang Li, Fei-Yan Du, Yang-Guang Gu, Jia-Jia Ning, and Liang-Gen Wang (2017) Sonneratia apetala, a non-native superior rapidly growing mangrove species with wide environmental tolerance, has been introduced to Futian National Nature Reserve in Shenzhen, Guangdong, China, for mangrove restoration since 1993. However, the community structure of the associated macrobenthic fauna, a vital component of energy ow and nutrient recycling, remains obscure. The present study analyzed the macrobenthic faunal community, associated habitat characteristics and physico-chemical properties of sediment in rehabilitated S. apetala forests at stand ages of 8, 9, 14, 16 and 20 years from November 2014 to May 2015. Habitat complexity and stand structural heterogeneity varied with stand age. Sediment physico-chemical properties were similar for all stands analyzed, although soil organic matter (SOM) content was significantly higher in the 20-year-old stand than in others. Shannon-Weaver (H') and Pielou's evenness (J) indices of macrobenthic fauna were highest in 14- and 16-year- old stands, respectively, and lowest in 8-year-old stands. In contrast, abundance and biomass peaked in 8-year- old stands and were lowest in 16-year-old stands. Multivariate analysis (cluster, ANOSIM and SIMPER) showed that the macrobenthic faunal community in the 20-year-old stand was different from other stand ages because of a greater abundance of small-sized mollusks and opportunistic species. Spearman correlation analysis showed that H' was positively correlated with salinity. The distance-based linear model suggested that SOM was a significant predictor variable correlated with the macrobenthic faunal community. However, SOM was the only significant predictor variable explaining 12.7% of the total variation; this implies that the spatial variation of the macrobenthic faunal community here was mostly independent of the sediment properties measured. Therefore, we conclude that habitat characteristics such as vegetation characteristics can potentially explain the majority of the variation.

A new set of primers for COI amplification from purpleback flying squid (Sthenoteuthis oualaniensis).

Despite the contribution of DNA barcoding towards understanding the biodiversity and distribution of species, the success of the mitochondrial cytochrome c oxidase subunit I gene (COI) amplification has been quite variable when it comes to Cephalopoda. Some species in this class such as Sthenoteuthis oualaniensis seem to be more difficult to amplify COI than others due to failed amplifications with universal primer and lack of specific set of primers. In this study, we developed new Sthenoteuthis - specific primer set, which significantly increased average amplification success. The new primer set will aid the recovery of barcodes from this difficult group and facilitate further studies in phylogeny and cryptic diversity of Sthenoteuthis oualaniensis.

Heavy metals in fish tissues/stomach contents in four marine wild commercially valuable fish species from the western continental shelf of South China Sea.

The concentrations of heavy metals (Cd, Pb, Cr, Ni, Cu and Zn) were determined in four commercially valuable fish species (Thunnus obesus, Decapterus lajang, Cubiceps squamiceps and Priacanthus macracanthus), collected in the western continental shelf of the South China Sea. Concentrations of Cd, Pb, Cr, Ni, Cu, and Zn in fish muscles were 0.006-0.050, 0.13-0.68, 0.18-0.85, 0.11-0.25, 0.12-0.77, and 2.41-4.73µg/g, wet weight, respectively. Concentrations of heavy metals in all species were below their acceptable daily upper limit, suggesting human consumption of these wild fish species may be safe, with health risk assessment based on the target hazard quotients (THQ) and total THQ, indicating no significant adverse health effects with consumption. The average concentrations of Zn were higher in gills than in stomach contents, backbones or muscle, while conversely, the other heavy metals had higher concentrations in stomach contents than in other tissues.

Polycyclic aromatic hydrocarbons in surface sediments and marine organisms from the Daya Bay, South China.

Polycyclic aromatic hydrocarbons (PAHs) were investigated in the marine ecosystem of the Daya Bay, South China. The PAH concentrations ranged from 340 to 710 ng/g dry weight in the sediments and from 110 to 520 ng/g wet weight in marine organisms, respectively. The dominant compounds were three- and four-ring PAHs in the sediments (53%-89%) and two- and three-ring PAHs in the marine species (67%-94%), respectively. PAHs mainly originated from both pyrolytic and petrogenic sources. Comparison with the effects-based sediment quality guideline values suggested that the ecological risk caused by the total PAHs was relatively low (less than 25% incidence of adverse effects) in the sedimentary environment. The median cancer risk level via seafood consumption (1.6 × 10(-5) for urban residents and 1.2 × 10(-5) for rural residents, respectively) was slightly higher than the maximum admissible level (10(-5)) set by US EPA, but lower than the priority risk level (10(-4)).

Complete mitochondrial genome of the sixbar grouper Epinephelus sexfasciatus (Perciformes: Epinephelidae).

In this study, we presented the complete mitogenome for the sixbar grouper Epinephelus sexfasciatus. The complete mitogenome of E. sexfasciatus is 16,786 bp in length with the typical mitochondrial gene order and composition in vertebrates. Overall base composition was 28.40% A, 27.93% C, 27.21% T and 16.45% G. The COI gene used GTG and the ATP6 gene used CTG as the start codon. The tRNA-Ser2 lost the dihydrouridine arm and replaced with a simple loop. Both the maximum likelihood (ML) and Bayesian inference (BI) methods yielded the same tree topology using available mitogenomes of the genus Epinephelus. Epinephelus sexfasciatus was nested to E. akaara. E. awoara and E. fasciatomaculosus, and then combined with E. stictus formed a clade.

Heavy metal concentrations in wild fishes captured from the South China Sea and associated health risks.

Heavy metal concentrations were measured in 29 marine wild fish species from the South China Sea. Concentrations (wet weight) were 0.51-115.81 ng/g (Cd), 0.54-27.31 ng/g (Pb), 0.02-1.26 µg/g (Cr), 8.32-57.48 ng/g (Ni), 0.12-1.13 µg/g (Cu), 2.34-6.88 µg/g (Zn), 2.51-22.99 µg/g (Fe), and 0.04-0.81 µg/g (Mn), respectively. Iron concentrations in all and Mn in some fish species were higher than the acceptable daily upper limit, suggesting human consumption of these wild fish species may pose a health risk. Human health risk assessment, however, indicated no significant adverse health effects with consumption.