Benthic foraminiferal community structure and its response to environmental factors revealed using high-throughput sequencing in the Zhoushan Fishing Ground, East China Sea.

Benthic foraminifera are excellent tools for monitoring marine environments and reconstructing paleoenvironments. This study investigated the structure and diversity of benthic foraminiferal communities in 20 superficial sediment samples obtained from the Zhoushan Fishing Ground (ZFG) using high-throughput sequencing based on small subunit ribosomal DNA and RNA amplification. The results revealed Rotaliida as the most dominant group, with spatial heterogeneity in foraminiferal distribution. Total benthic foraminiferal communities exhibited higher species richness and diversity compared to active communities. While heavy metal pollution in the ZFG was moderate, areas with elevated concentrations of heavy metals exhibited low diversity and richness in foraminiferal communities. Total foraminiferal community structure was primarily influenced by factors such as water depth and Hg, Pb, Cd, and Zn levels. Notably, Hg levels emerged as a critical factor impacting the structure and diversity of the active foraminiferal community. The dominant species, Operculina, exhibited tolerance toward heavy metal pollution.

Occurrence and accumulation of microplastics in commercial fish in the coastal waters of the Lvsi fishing ground in China.

In recent years, there has been an exponential increase in the research popularity of microplastics (MPs) in offshore marine environments. However, there is still a gap in the research on the accumulation of MPs in different tissues of aquatic organisms and the trophic transfer of MPs between aquatic organisms. The common occurrence of MPs in the gills and guts of 11 species of commercial fishes was examined in the coastal waters of the Lvsi fishing ground (LSFG). The obtained results showed that >85 % of MPs existed in the gills and guts of these fish, and the abundance was 2.39 ± 1.38 pieces/fish and 2.56 ± 1.42 pieces/fish, respectively. Fibrous and blue are the most common colors and shapes of MPs, and PET is the main polymer type. At the species level, the abundance of MPs in the gills and guts of a few fishes (e.g., Larimichthys polyactis, Setipinna tenuifilis, Collichthys lucidus) decreased with increasing body length and body weight (P < 0.05). At the community level, this situation was not significant (P > 0.05). With increasing trophic level (TL), MPs tended to decrease in the gills (trophic magnification factor, TMF = 0.86) but did not significantly vary in the gut. We believe that MPs are multidimensional pollutants, and their accumulation in tissues/organs of organisms has not been accurately and qualitatively determined. To establish the relationship of MP transport and trophic transfer among water, sediments and organisms, we suggest that more efforts should be made to investigate MPs in aquatic organisms in the coastal waters of LSFG and to increase the examination of MPs in the water column and sediments. This study will help us improve our understanding of MPs pollution, and provide a good reference and basis for the management, monitoring and implementation of pollutants in marine organism of coastal water.

Construction of chub mackerel (Scomber japonicus) fishing ground prediction model in the northwestern Pacific Ocean based on deep learning and marine environmental variables.

Accurate prediction of the central fishing grounds of chub mackerel is substantial for assessing and managing marine fishery resources. Based on the high-seas chub mackerel fishery statistics and multi-factor ocean remote-sensing environmental data in the Northwest Pacific Ocean from 2014 to 2021, this article applied the gravity center of the fishing grounds, 2DCNN, and 3DCNN models to analyze the spatial and temporal variability of the chub mackerel catches and fishing grounds. Results:1) the primary fishing season of chub mackerel fishery was April-November which catches were mainly concentrated in 39°âˆ¼43°N, 149°âˆ¼154°E. 2) Since 2019, the annual gravity center of the fishing grounds has continued to move northeastward; the monthly gravity center has prominent seasonal migratory characteristics. 3) 3DCNN model was better than the 2DCNN model. 4) For 3DCNN, the model prioritized learning information on the most easily distinguishable ocean remote-sensing environmental variables in different classifications.

Accumulation of microplastics in fugu (Takifugu bimaculatus): A comparative study between fishing grounds and aquafarms.

Microplastics (MPs) in fish have attracted attention recently, for their ecological and food safety risks. However, knowledge gaps still exist regarding MPs in fugu, a special poisonous but precious seafood, especially that accumulated in its tissues. Accordingly, this study investigated the characteristics of MPs in cultured Takifugu bimaculatus which raised on three aquafarms and in wild individuals from three fishing grounds. More than 98.85 % of T. bimaculatus were contaminated by MPs and the average MPs abundance in wild fugu (4.25 ± 2.63 items/individual) was lower than that of cultured fugu (7.91 ± 2.16 items/individual). The abundance of MPs in fugu's tissues under different life patterns shows significant differences. There were marked differences in size of MPs presented in various tissues. This study adds to the knowledge on MPs accumulation in the tissues of wild and cultured fugu, providing warnings about its transmission and ecological risks in the food chain.

Distribution and Transformation of Mercury in Subtropical Wild-Caught Seafood from the Southern Taiwan Strait.

Wild-caught seafood contains significant amounts of mercury. Investigating the mercury accumulation levels in wild-caught seafood and analyzing its migration and transformation are of great value for assessing the health risks of mercury intake and for the tracking of mercury sources. We determined the concentrations and stable mercury isotopic compositions (δ202Hg, Δ199Hg, Δ200Hg, and Δ201Hg) of 104 muscle samples collected from 38 species of seafood typically harvested from the Taiwan Shallow Fishing Ground (TSFG), Southern Taiwan Strait. Overall, the concentrations of total mercury (THg) and methylmercury (MeHg) ranged from 11 to 479 ng/g (dry weight, dw) and 10 to 363 ng/g (dw), respectively, and were below the threshold value established by the USEPA and the Chinese government. Demersal and near-benthic species accumulated more mercury than pelagic or mesopelagic species. The characteristics of mercury isotopes in wild-caught marine species differed in terms of vertical and horizontal distribution. Considering the known peripheral land sources of mercury (Δ199Hg ≈ 0), the mercury in seafood from the TSFG (Δ199Hg > 0) did not originate from anthropogenic emissions. The ratio of Δ199Hg and Δ201Hg (1.18 ± 0.03) suggested that the photoreduction of Hg (II) and the photo-degradation of MeHg equally contributed to mass-independent fractionation. Based on the values of Δ199Hg/δ202Hg (1.18 ± 0.03), about 67% of the mercury in seawater had undergone microbial demethylation prior to methylation and entering the seafood. Additionally, the vertical distribution of Δ200Hg in seafood from different water depths implies that mercury input was in part caused by atmospheric deposition. Our results provide detailed information on the sources of mercury and its transfer in the food web in offshore fishing grounds.

Microplastic contamination of fish gills and the assessment of both quality assurance and quality control during laboratory analyses.

Microplastic pollution has received substantial international attention in terrestrial and marine environments and in the atmosphere. In this study, we assessed microplastic pollution and analyzed the accumulation of microplastics in the gills of fish caught in the Zhoushan fishing ground from September 2017 to March 2018. The average abundance of microplastics was 0.49 ± 0.54 particles/gill and frequently found chemical polymers was polyethylene terephthalate. We also conducted experiments on microplastic pollution in the water and the working solutions used during the analytical process and found that the source of microplastic contamination was the solutions used. Moreover, we evaluated and scored experimental quality control and quality assurance adapted from the 'Total Accumulated Score' method. Valuable steps are recommended in order to produce reliable results and improve the quality of results in microplastic analyses.

Seasonal distributions of microplastics and estimation of the microplastic load ingested by wild caught fish in the East China Sea.

Microplastic (MP) pollution in marine environments and organisms has received substantial international attention. However, long-term field studies of MPs are scarce. Here, we assessed the seasonal variation in MP abundance in the Zhoushan fishing ground (ZFG), one of the most abundant and productive fishing grounds worldwide, and analyzed the long-term MP accumulation in fish gastrointestinal tracts from September 2017 to June 2018. The most common MP particles in the ZFG were polyethylene terephthalate and polypropylene. After four seasons of continuous monitoring, we did not find accumulation of MPs in the fish after 10% KOH digestion. In total, 254 MP particles were removed from the gastrointestinal tracts of all fish. The average number of particles per fish was lower than that reported in previous global marine studies. There were significant differences among species. Moreover, this study provides the calculation of the weight of MPs ingested by fish and an estimate of the load of accumulated MPs in fish. According to the estimation, the load of MPs ingested by fish annually was approximately 3 kg in ZFG. These findings provide the long-term evidence of MP contamination in biota from the ZFG. The amounts of MPs ingested by fish require more detailed and improved investigation and estimation in further studies.

Persistence and sustainability of fishing grounds footprint: Evidence from 89 countries.

This paper focusses on the examination of the fishing ground footprint in a group of 89 countries using fractional integration. The fishing ground footprint is one of the components of the ecological footprint. Nevertheless, it has not been investigated very much from an empirical viewpoint. We contribute to the existing literature on fishing ground footprint by using fractional integration techniques to examine the persistence of the series. Our results are very heterogeneous across countries though we find that most of the series are nonstationary and non-mean reverting, with most of the countries belonging to the upper-middle and high income levels. On the other hand, most of the 14.4% of countries that show a stationary pattern belong to lower-middle and low income countries. One of the implications of the study is that policies aimed at reducing fishing grounds footprint are likely to be effective in most of the investigated countries.

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.

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We measured the ratio of δ13C and δ15N values to estimate the trophic level of main organisms based on a fisheries resource survey in coastal water of Lyusi fishing ground carried out in September 2018. The results showed that δ13C values of the main organisms ranged from -24.27‰ to -13.24‰, with an average of (-17.15±1.85)‰. The δ15N values ranged from 4.30‰ to 14.61‰, with an average of (11.21±1.90)‰. Results from cluster analysis demonstrated that the main organisms in the coastal water of Lyusi fishery ground could be divided into four trophic groups. The first group was consisted mainly by middle and small fishes, shrimps and other invertebrates. The second group included the small-sized fishes like Konosirus punctatus, Mugil cephalus, etc. and shrimps like Exopalaemon annandalei, Exopalamon carincauda, etc. The phytoplankton belonged to the third group. The fourth group was zooplankton. In the trophic spectrum, the trophic levels of fish, shrimps and crabs, shellfish were 3.2-4.7, 3.2-4.2 and 2.0-4.1, respectively. Most species belonged to the category of middle and high-level consumers. In this survey, the average trophic level of the same species in the coastal waters of Lyusi fishing ground was 0.6, which was higher than that in the East China Sea and Yellow Sea. There was niche overlap of most fish, shrimps and crabs. Those results indicated the growth environment and nutrient structure of most living organisms in this area were generally similar.

Biomagnification and risk assessment of polychlorinated biphenyls in food web components from Zhoushan fishing ground, China.

Trophodynamics and risks of polychlorinated biphenyls (PCBs) in organisms from the Zhoushan fishing ground (ZFG), China were studied. Σ22PCBs varied from 1.36 to 36.75 ng/g wet weight, which were far below the maximum residue levels allowed in fishery products. However, estimated daily intake and hazard ratio calculations present possible adverse effects due to PCB pollution. Significantly positive correlations appeared between wet-weighted concentrations of target chemicals and trophic levels (TLs) of the organisms, with trophic magnification factors (TMFs) from 1.15 to 9.72. The TMF values first increased with an increase of compound's KOW values, and then decreased, with log KOW around 7.0 as an inflection point. TL is suggested as the key factor controlling contaminant burden among the species for only PCBs 105, 138, 153, and 171. For the remaining PCBs, lipid content of the organism or metabolite capacity of the compound may be more important influence on their bioaccumulation.

Geochemical background and ecological risk of heavy metals in surface sediments from the west Zhoushan Fishing Ground of East China Sea.

Surface sediment grain size as well as the spatial distribution, pollution status, and source identification of heavy metals in the west Zhoushan Fishing Ground (ZFG) of the East China Sea were analyzed to study the geochemical background concentrations of heavy metals and to assess their potential ecological risk. Our results show that surface sediments in the eastern part of study area were mainly composed of sand-sized components. Spatial distributions of heavy metals were mainly controlled by grain size and terrigenous materials, and their concentrations in the coarsest grain sediments formed primarily during the Holocene transgressive period could represent the element background values of our study area. Contamination factor suggests that there was no pollution of Pb, Zn, and Cr generally in our study area and slight pollution of Cu, Cd, and As (especially Cu) at some stations. In addition, ecological harm coefficient indicates that the ecological risk of each heavy metal, except for Cd, at two stations was low as well. These results are consistent with the pollution load index and ecological risk index, which suggest both the overall level of pollution and the overall ecological risk of six studied metals in sediment were relatively low in our study area. Enrichment factor indicates that the heavy metals came mostly from the natural source. Summarily, the quality level of sediment in our study area was relatively good, and heavy metals in sediments could not exert threat to aquatic lives in the ZFG until now.