Vessel Monitoring System(VMS) provides a new opportunity for quantified fishing research. Many approaches have been proposed to recognize fishing activities with VMS trajectories based on the types of fishing vessels....Vessel Monitoring System(VMS) provides a new opportunity for quantified fishing research. Many approaches have been proposed to recognize fishing activities with VMS trajectories based on the types of fishing vessels. However, one research problem is still calling for solutions, how to identify the fishing vessel type based on only VMS trajectories. This problem is important because it requires the fishing vessel type as a preliminary to recognize fishing activities from VMS trajectories. This paper proposes fishing vessel type identification scheme(FVID) based only on VMS trajectories. FVID exploits feature engineering and machine learning schemes of XGBoost as its two key blocks and classifies fishing vessels into nine types. The dataset contains all the fishing vessel trajectories in the East China Sea in March 2017, including 10031 pre-registered fishing vessels and 1350 unregistered vessels of unknown types. In order to verify type identification accuracy, we first conduct a 4-fold cross-validation on the trajectories of registered fishing vessels. The classification accuracy is 95.42%. We then apply FVID to the unregistered fishing vessels to identify their types. After classifying the unregistered fishing vessel types, their fishing activities are further recognized based upon their types. At last, we calculate and compare the fishing density distribution in the East China Sea before and after applying the unregistered fishing vessels, confirming the importance of type identification of unregistered fishing vessels.展开更多
Vibrio anguillarum, an important bacterial fish pathogen, expresses a variety of virulence factors contributing to its ability to cause vibriosis in fish. Many virulence factors of this pathogen remain however unknown...Vibrio anguillarum, an important bacterial fish pathogen, expresses a variety of virulence factors contributing to its ability to cause vibriosis in fish. Many virulence factors of this pathogen remain however unknown. For example, a type IV pilus system was previously reported to be potentially involved in the virulence of this bacterium but no experimental evidence was reported yet. In this study, complete genome sequencing of V. anguillarum strain VIB15, shown to be highly virulent towards sea bass (Dicen- trarchus labrax L.) larvae, revealed the presence of a PilA pilin. A V. anguillarum VIB15 pilA mutant was constructed and the pathogenicity of this mutant was assessed in a gnotobiotic sea bass system developed for virulence screening. Our results suggest that the V. anguillarum pilA gene is not crucial for virulence towards sea bass larvae. Possibly, another type IV pilus system identified in V. anguillarum, showing homology to the mannose-sensitive hemagglutinin pilin of Vibrio cholerae, may complement the pilA mutation. Alternatively, the type IV pilus system has a role in infection of juvenile or adult fish, rather than in the larval phase. As such, further research is required to unravel the potential role of type IV pili in V. anguillarum virulence.展开更多
Acid-soluble collagen (ASC) and pepsin-solubilized collagen (PSC) were prepared from the waste freshwater carp fish scales. The results of SDS-PAGE showed that purified collagens were composed of at least two differen...Acid-soluble collagen (ASC) and pepsin-solubilized collagen (PSC) were prepared from the waste freshwater carp fish scales. The results of SDS-PAGE showed that purified collagens were composed of at least two different chains which were in accordance with the type I collagen with α chain composition of (α1)2α2. Compared with the carp fish ordinary muscle type I collagen , porcine dermis type I collagen and other seawater fish collagens, freshwater carp fish scales collagen contained relative high half-cystine (Cys-s), but lower denaturation temperature(Td) than the porcine dermis type I collagen. These collagens had evident absorption at 230 nm by UV-Vis spectra. The spectrum X-ray diffraction showed that the collagen remained single-helix and tri-helix configuration with the minimum values of the repeat spacings (d) of about 4.48 ? and 11.87 ?. Therefore, to make more effective use of limited-resources, carp fish scales can be a potential resource for the extraction of type I collagen or gelatin.展开更多
基金partially supported by National Key R&D Program (No. 2016YFC 1401900)the National Natural Science Foundation of China (Nos. 61379127, 61379128, 61572448)+1 种基金the Fundamental Research Funds for the Central Universities (No. 201713016)Qingdao National Laboratory for Marine Science and Technology Open Research Project (No. QNLM2016ORP 0405)
文摘Vessel Monitoring System(VMS) provides a new opportunity for quantified fishing research. Many approaches have been proposed to recognize fishing activities with VMS trajectories based on the types of fishing vessels. However, one research problem is still calling for solutions, how to identify the fishing vessel type based on only VMS trajectories. This problem is important because it requires the fishing vessel type as a preliminary to recognize fishing activities from VMS trajectories. This paper proposes fishing vessel type identification scheme(FVID) based only on VMS trajectories. FVID exploits feature engineering and machine learning schemes of XGBoost as its two key blocks and classifies fishing vessels into nine types. The dataset contains all the fishing vessel trajectories in the East China Sea in March 2017, including 10031 pre-registered fishing vessels and 1350 unregistered vessels of unknown types. In order to verify type identification accuracy, we first conduct a 4-fold cross-validation on the trajectories of registered fishing vessels. The classification accuracy is 95.42%. We then apply FVID to the unregistered fishing vessels to identify their types. After classifying the unregistered fishing vessel types, their fishing activities are further recognized based upon their types. At last, we calculate and compare the fishing density distribution in the East China Sea before and after applying the unregistered fishing vessels, confirming the importance of type identification of unregistered fishing vessels.
文摘Vibrio anguillarum, an important bacterial fish pathogen, expresses a variety of virulence factors contributing to its ability to cause vibriosis in fish. Many virulence factors of this pathogen remain however unknown. For example, a type IV pilus system was previously reported to be potentially involved in the virulence of this bacterium but no experimental evidence was reported yet. In this study, complete genome sequencing of V. anguillarum strain VIB15, shown to be highly virulent towards sea bass (Dicen- trarchus labrax L.) larvae, revealed the presence of a PilA pilin. A V. anguillarum VIB15 pilA mutant was constructed and the pathogenicity of this mutant was assessed in a gnotobiotic sea bass system developed for virulence screening. Our results suggest that the V. anguillarum pilA gene is not crucial for virulence towards sea bass larvae. Possibly, another type IV pilus system identified in V. anguillarum, showing homology to the mannose-sensitive hemagglutinin pilin of Vibrio cholerae, may complement the pilA mutation. Alternatively, the type IV pilus system has a role in infection of juvenile or adult fish, rather than in the larval phase. As such, further research is required to unravel the potential role of type IV pili in V. anguillarum virulence.
文摘Acid-soluble collagen (ASC) and pepsin-solubilized collagen (PSC) were prepared from the waste freshwater carp fish scales. The results of SDS-PAGE showed that purified collagens were composed of at least two different chains which were in accordance with the type I collagen with α chain composition of (α1)2α2. Compared with the carp fish ordinary muscle type I collagen , porcine dermis type I collagen and other seawater fish collagens, freshwater carp fish scales collagen contained relative high half-cystine (Cys-s), but lower denaturation temperature(Td) than the porcine dermis type I collagen. These collagens had evident absorption at 230 nm by UV-Vis spectra. The spectrum X-ray diffraction showed that the collagen remained single-helix and tri-helix configuration with the minimum values of the repeat spacings (d) of about 4.48 ? and 11.87 ?. Therefore, to make more effective use of limited-resources, carp fish scales can be a potential resource for the extraction of type I collagen or gelatin.
文摘为解析长江口洄游性、海洋性与河口性三类仔稚鱼生境分布的环境驱动因子,根据2022年9月(夏季)、2023年4月(春季)长江口仔稚鱼采样数据,采用最大熵(Maximum entropy,MaxEnt)模型分析凤鲚(Coilia mystus,洄游性)、鳀(Engraulis japonicus,海洋性)和香䲗(Callionymus olidus,河口性)的生境分布特征及其环境驱动机制。结果表明,长江口南支的海表面温度、pH、营养盐高于北支,而北支的海表面盐度、叶绿素高于南支;MaxEnt模型对这3种仔稚鱼生境分布具有较强的预测能力[曲线下面积(Area under the curve,AUC)>0.8],且春季略优于夏季;影响凤鲚和香䲗春、夏季生境分布的关键因子均为海表面溶解氧(相对贡献率分别为80.8%、86.6%和39.8%、30.2%),而鳀为海表面盐度(分别为44.0%和79.0%)。不同生态类型仔稚鱼的生境特征及其关键环境因子存在显著差异,导致其早期生活史阶段的补充过程对环境变化的响应呈现种间特异性。因此,长江口仔稚鱼资源的保护需针对不同生态类型鱼类的生物学特性及栖息地需求,制定差异化的保护策略。
