为了解凡纳滨对虾(Litopenaeus vannamei)可能的微生物致病原因,通过对养殖水体环境细菌 16S rRNA基因进行高通量测序和生物信息学分析,研究比较了健康虾塘(HSP)、少量死虾塘(MinUH)和大量死虾塘(MajUH)水体细菌群落组成.结果表明,MajUH 氨氮、亚硝酸盐、细菌总数均显著高于其他组(P＜0.05),HSP细菌群落香农指数显著高于MajUH(P＜0.05).养殖水体中优势菌门为变形菌门、蓝藻门、放线菌门、拟杆菌门、绿菌门,其丰度在3 类虾塘中有很大差异,其中,蓝藻门在HSP、MinUH、MajUH的丰度分别为6.17%、5.94%、46.85%.对虾的大量死亡伴随着细菌群落的变化,RDA分析表明,细菌群落的分布主要由亚硝酸盐氮和氧化还原电位决定.通过文献检索和方差分析对HSP与MajUH进行比较后发现,当微生物群落多样性下降时,其对高pH的抑制和调控作用将会减弱,从而影响对虾健康状况.此外,研究还确定了 24个可区分健康和大量死亡虾塘主要细菌指示物,明确了水体细菌群落结构作为虾类健康状态指示指标的可行性.研究结果可为凡纳滨对虾养殖过程中的病害防治及新微生物资源开发提供基础数据.
为探究海水养殖条件下中华鲟(Acipenser sinensis)后备亲本的生理状况,对海水养殖 5 年的 13 尾中华鲟后备亲本的 28 项血液生化指标进行了测定.结果表明:中华鲟血液谷丙转氨酶(alanine aminotransferase,ALT)、谷草转氨酶(aspartate aminotransferase,AST)和总胆红素(total bilirubin,TBIL)含量分别为(1.48±0.93)U·L-1、(45.70±19.07)U·L-1 和(0.83±0.39)μmol·L-1,尿酸(uric acid,UA)和肌苷(creatinine,CR)浓度分别为(11.58±8.80)μmol·L-1 和(15.98±5.12)μmol·L-1;28 项血液生化指标中,葡萄糖(glucose,GLU)、甘油三酯(triglyceride,TG)、总胆固醇(total cholesterol,TC)、低密度脂蛋白(low density lipoprotein cholesterol,LDL-C)、白蛋白(albumin,ALB)、球蛋白(globulin,GLB)、白/球蛋白比(A/G)、总蛋白(total protein,TP)、CR、TBIL、AST、γ-谷胺酰基转移酶(gamma-glutamyltransferase,GGT)、胆碱酯酶(cholinesterase,CHE)、碱性磷酸酶(alkaline phosphatase,ALP)、乳酸脱氢酶(lactate dehydrogenase,LDH)等15 项指标变异系数小于 0.5;高密度脂蛋白(high density liptein cholesterol,HDL-C)、载脂蛋白 B(apolipoprotein B,APO-B)、总胆汁酸(total bile acid,TBA)、尿素氮(blood urea nitrogen BUN)、UA、直接胆红素(direct bilirubin,DBIL)、间接胆红素(indirect bilirubin,IBIL)、ALT、谷草/谷丙转氨酶比(AST/ALT)、α-羟丁酸脱氢酶(α-hydroxybutyrate dehydrogenase,α-HBDH)、肌酸激酶(creatine kinase,CK)、肌酸激酶同工酶(creatine kinase-MB,CK-MB)等 12 项指标变异系数在 0.5～1.0 之间;仅载脂蛋白 A1(apolipoprotein A1,APO-A1)的变异系数大于 1.0.与淡水养殖的中华鲟生化指标相比,海水养殖条件下的中华鲟血液的ALT、AST和TBIL活性有所降低,揭示其肝脏代谢可能产生了适应性变化;各项血液生化指标变异系数均较大,表明相同年龄不同个体之间血液生化指标的差异较大.研究结果可为海水养殖中华鲟的血液生化指标提供参考,并丰富海水养殖中华鲟血液生化的相关数据.
为提供更为准确的南太平洋黄鳍金枪鱼(Thunnus albacores)渔场预报信息,针对传统渔场分类问题中渔场和非渔场样本数据分布不均衡的问题,提出了一种基于自适应综合过采样(ADASYN)和Stacking集成的渔场分类模型——A-Stacking模型.利用2008-2019 年南太平洋黄鳍金枪鱼的渔业数据,结合时空因子、海洋环境因子共32 个特征要素(月份、经纬度、海平面异常、涡动能、叶绿素a浓度、叶绿素梯度、叶绿素距平、海表温度梯度、海表温度距平以及0～500 m水层的垂直温度和盐度)建立了南太平洋黄鳍金枪鱼渔场预报模型.为了验证模型的可靠性,将CART、Adaboost、GBDT、XGBoost、KNN、RF和Stacking模型对照.结果显示,A-Stacking模型具有更高的准确率、召回率、F1-score、G-mean和AUC值,且模型的ROC曲线和PR曲线能较好地包含其他模型,表明模型的分类效果更好.研究表明,A-Stacking集成模型对南太平洋黄鳍金枪鱼渔场的预报效果较好,能有效处理不均衡数据的渔场分类问题,可为今后的渔场预报方法提供参考.
为探讨铜驯化对高温胁迫下大黄鱼(Larimichthys crocea)氧化损伤和基因表达水平的影响,将体质量为(48.92±3.62)g的大黄鱼暴露在铜离子浓度为0 和 10μg·L-1 的水体中 14 d,再暴露在温度为 32℃的水体中24 h.结果显示,高温胁迫显著增加了大黄鱼肝脏中活性氧(ROS)和脂质过氧化物(LPO)含量(P＜0.05).铜驯化对常温下ROS和LPO含量不产生影响,而显著降低了高温胁迫下大黄鱼ROS 和LPO含量(P＜0.05),表明铜驯化缓解了高温胁迫对大黄鱼的氧化损伤.从高温胁迫组vs对照组、铜驯化组vs对照组和(铜驯化+高温胁迫)组vs高温胁迫组中分别筛选到 828 个、2 311 个和 1 084 个差异基因.GO和KEGG分析发现,差异基因主要富集在与TCA循环、氧化磷酸化、谷胱甘肽代谢、内质网蛋白加工、吞噬体和MAPK信号通路等相关功能上.聚类分析表明,高温胁迫下调了TCA循环、氧化磷酸化、谷胱甘肽代谢、吞噬体和MAPK信号等通路中的大部分基因表达,上调了内质网蛋白加工通路中的大部分基因表达,而铜驯化则对高温胁迫下大黄鱼的这些基因表达调控产生了拮抗效应,表明铜驯化通过改善有氧代谢、抗氧化、自噬和凋亡来提高大黄鱼的高温胁迫耐受性.研究结果可为深入研究铜污染物对大黄鱼高温胁迫耐受性的影响及其分子机制提供基础资料.
为研究下三横山岛养殖海域海-气界面CO2 交换通量及影响因素,从 2020 年 7 月开始,在该海域开展为期一年(4 次)的监测和分析,主要剖析其温度、盐度、pH、总碱度(TA)及水体中溶解无机碳(DIC)、溶解有机碳(DOC)、颗粒有机碳(POC)分布差异,估算下三横山岛养殖海域表层海水CO2 分压(pCO2)及海-气界面CO2 通量(FCO2)值,并分析pCO2 的影响因素,探讨下三横山岛该养殖海域海-气界面CO2 交换通量.结果表明,下三横山岛海域表层海水4 个季节的温度、盐度、pH、TA、DIC、DOC、POC的分布在季节上差异极显著(P＜0.01).下三横山岛海域pCO2 全年的变化范围为29.93～836.80 μatm,FCO2 值的变化范围为-45.67～216.50 mmol·(m2·d)-1.pCO2 与FCO2 值四季变化显著(P＜0.05),全年碳分布格局有较大差异,其中,仅春季为碳汇,碳汇强度为(-32.79±3.73)mmol·(m2·d)-1,夏、秋、冬季皆为碳源,碳源强度分别为(14.74±33.35)mmol·(m2·d)-1、(18.39±6.63)mmol·(m2·d)-1、(50.34±9.27)mmol·(m2·d)-1,其中,春、夏、秋季FCO2 最低值均出现在鱼类养殖区,最高值出现在贻贝养殖区.养殖区内的生物活动是影响下三横山岛海域表层海水pCO2 的重要因素.研究结果为下三横山岛多营养层级综合养殖的碳汇研究提供了前期数据及理论参考.
南极磷虾具有重要的商业价值且在南极食物网中处于极为关键的地位,为南极绝大多数动物重要的摄食对象,因此,了解影响磷虾丰度和繁殖的因素至关重要,其中寄生于磷虾体内的寄生虫往往被忽略.为充分了解南极磷虾寄生虫的类型、寄生形式及其对磷虾的潜在影响等,对南极磷虾中间寄生虫(法式海腰鞭毛虫Thalassomyces fagei)、体外寄生虫(吸管属纤毛虫Ephelota sp.)以及体内寄生虫(吸虫Trematode)的生命周期、寄生部位、感染特点等方面进行系统的总结和分析.结果显示,体外寄生虫往往需要适应磷虾频繁的蜕壳周期,高龄磷虾因蜕壳周期较长而致体外寄生虫附着和感染程度更高;中间寄生虫感染广泛且对磷虾具有多重危害,但其感染机制尚不明确;多主寄生的体内寄生虫对磷虾的危害较小,而单主寄生的簇虫和假丘类纤毛虫对磷虾危害性较大,其中吸虫的具体生命周期以及感染机制尚属未知.将来研究中,建议重点开展寄生虫与宿主之间的相互作用、感染机制、完整生命周期、寄生虫与磷虾体内细菌群落的关系以及磷虾性成熟度及年龄与寄生虫感染率和感染强度之间的关系等方面的工作.
为了解东黄海区域内日本鲭(Scomber japonicus)的资源动态,利用 1980-2019 年东黄海日本鲭渔业统计产量、机轮围网平均单位船组年产量(CPUE)和生物学测定数据,对该群体捕捞产量、资源量指数和群体结构之间的年代际变动关系进行了研究.结果表明:东黄海各年代日本鲭的平均产量以 20 世纪 80 年代最低,21 世纪 10 年代最高为42.39×104 t,随着年代的推移表现出持续增加的趋势,其中东海区持续增加,黄渤海区先增加后降低.机轮围网平均CPUE 前期在波动中上升,至 1999 年达到高峰值 3 776.00 t·单位船组-1,其后呈下降的趋势;20 世纪 80 年代为 1 954.60 t·单位船组-1,20 世纪 90 年代升高至2 839.80 t·单位船组-1,21 世纪00 年代又急剧降低至 1 701.10 t·单位船组-1,21 世纪 10 年代继续降低为 1 372.00 t·单位船组-1.日本鲭的平均叉长、平均体质量和优势叉长组均随年代的推移表现出持续减小的趋势:平均叉长从 1982 年的 337.15 mm 减小为2009 年的 309.67 mm,到 2019 年再继续减小至 265.90 mm;平均体质量从1982 年的 547.21 g减小为2009 年425.55 g,其后到2019 年又减小至226.40 g;优势叉长组从 1982 年的 320～360 mm减小为2009 年的290～330 mm,然后到2019 年继续减小至250～280 mm.20 世纪80-90 年代,机轮围网平均CPUE可以作为指示日本鲭捕捞产量变化的依据,但21 世纪以后已经不能作为判断日本鲭捕捞产量变化的依据.日本鲭捕捞产量维持在高位水平是捕捞强度的增加造成的,而非其自身资源量的增加所致.建议今后从科学层面建立日本鲭综合评价指数,合理评估资源量,在此基础上提出每年的最大可持续产量;渔业管理层面,建议在特定水域设立日本鲭种质资源保护区,同时制定针对日本鲭不同生长阶段的管理措施,尽快出台日本鲭总可捕量(total allowable catch,TAC)管理制度,达到资源可持续开发利用的目的.
为探究盐碱水养殖大规格中华绒螯蟹(Eriocheir sinensis)的品质参数,以山东东营滨海氯化物型盐碱水池塘养殖的大规格中华绒螯蟹为研究对象,探究其可食率、色泽、脂肪酸、游离氨基酸和矿物质元素等品质参数.结果表明,雌雄个体间可食率及肥满度指标均存在极显著差异(P＜0.01).雌性卵巢中水分含量极显著低于雄性性腺系统,而粗蛋白和粗脂肪含量则极显著高于雄性性腺系统(P＜0.01).雌体肝胰腺中二十二碳六烯酸DHA、花生四烯酸ARA、总高不饱和脂肪酸 ∑HUFA和总ω-3 多不饱和脂肪酸 ∑n-3 PUFA极显著低于雄体,卵巢中二十碳五烯酸EPA和ARA极显著低于雄体性腺系统(P＜0.01).雌性卵巢中 12 项游离氨基酸含量显著高于雄性性腺系统(P＜0.05).肝胰腺、性腺和肌肉组织中主要呈鲜味、甜味和苦味的氨基酸为谷氨酸Glu、丙氨酸Ala和精氨酸Arg.雌性卵巢中钠(Na)、钙(Ca)、锰(Mn)和总矿物质元素∑TME含量极显著低于雄性性腺系统(P＜0.01),钾(K)含量显著低于雄性性腺系统(P＜0.05),而镁(Mg)、铁(Fe)和锌(Zn)含量则极显著高于雄性性腺系统(P＜0.01).综上所述,氯化物型盐碱水养殖中华绒螯蟹雌雄个体各有优势,均是优质的人体营养物质来源.
为从分子水平分析九棘鲈属(Cephalopholis)鱼类物种分类关系,并验证细胞色素 C 氧化酶亚基 Ⅰ(COI)作为DNA条形码对九棘鲈属物种鉴定的有效性,采集了我国分布的 12 种九棘鲈属鱼类,利用PCR扩增及测序方法获得COI基因部分序列,结合GenBank下载的4 种九棘鲈COI基因进行分析,利用MEGA 7.0软件计算碱基信息与遗传距离,基于最大似然法和邻接法构建分子系统进化树.结果表明,16 种九棘鲈种内平均遗传距离为0.002,种间平均遗传距离为0.142,两者相差71 倍,表明COI基因可作为九棘鲈属鱼类分子鉴定的条形码基因.在分子系统进化上,16 种九棘鲈属鱼类聚为体色特征不同的 3 个类群,其中七带九棘鲈(C.igarashiensis)与卜氏九棘鲈(C.polleni)体色为多彩颜色,两者最先分化,位于进化树底部.其余的九棘鲈主要形成体色为红色与体色为褐色的类群,与形态学的分类结果一致.对于以往部分存在误鉴或同种异名分类争议的九棘鲈品种:青星九棘鲈(C.miniata)与半斑九棘鲈(C.hemistiktos)、橙点九棘鲈(C.aurantia)与黑边九棘鲈(C.spiloparaea),通过本研究构建的进化树枝长能清晰加以区分,并且两两之间的遗传距离也远大于0.020,揭示其各自应为独立的物种.研究结果可为九棘鲈属鱼类的分类及物种鉴定提供分子水平分类依据.
为探究青蛤(Cyclina sinensis)、菲律宾蛤仔(Ruditapes philippinarum)、等边浅蛤(Macridiscus aequilatera)、四角蛤蜊(Mactra veneriformis)的表观性状与出肉率的关系,对这4 种贝类随机抽样40～50 个进行解剖,测量壳长、体质量、软体质量、壳质量4 个性状参数,计算出肉率并进行正态检验,运用相关分析法和通径分析法对表观性状与出肉率的相关性进行研究.结果显示,菲律宾蛤仔、青蛤的壳长性状对出肉率总通径系数分别为0.391、0.394;建立的菲律宾蛤仔、四角蛤蜊、青蛤壳长和体质量对出肉率的回归方程的决定系数分别为0.414、0.119 和0.221.结果表明,运用表观性状来进行上述4 种贝类出肉率性状的选育存在可行性.
为研究海南省帚状江蓠(Gracilaria edulis)野生群体的种质资源、遗传多样性状况及红藻门物种间亲缘关系,采集海南省文昌和莺歌海潮间带的野生帚状江蓠,采用PCR扩增获得帚状江蓠质体 UPA基因片段(质体23S rRNA V区域)和线粒体COⅠ基因片段,分别对其进行序列比较及系统进化分析.结果表明,UPA基因片段T、C、A、G的含量分别为 26.2%、16.2%、30.3%、27.3%;COⅠ基因片段T、C、A、G的含量分别为39.2%、15.1%、27.6%、18.1%;UPA和COⅠ基因片段的A+T的平均含量分别为56.5%和 66.8%.UPA基因片段长度为370 bp,共检测出 1 种单倍型,无多态性位点;COⅠ基因片段长度为 664 bp,共检测出2 种单倍型,3 个多态性位点,均为简约信息位点.与UPA基因相比,COⅠ基因具有更高的变异度,更适合用于帚状江蓠遗传多样性的分析.基于UPA和COⅠ基因片段对帚状江蓠进行系统进化分析,两者结果一致,结合形态学分析表明,帚状江蓠应是江蓠属内独立的分支.
对一株海洋放线菌Streptomyces sp.MA12 进行次级代谢产物的研究和体外抗真菌活性测试,采用MCI中压柱色谱、硅胶柱色谱、Sephadex LH-20 凝胶柱色谱及半制备高效液相色谱(HPLC)等方法对发酵产物进行分离和纯化,综合运用质谱(MS)和核磁共振(NMR)等波谱学方法进行结构解析和鉴定.从放线菌Streptomyces sp.MA12 发酵产物中分离鉴定出3 种化合物,分别是trienomycin A(化合物 1)、trienomycin B(化合物2)和ansatrienin B(化合物3).抗菌活性测试发现,化合物 3 对 3 株白色念珠菌(标准敏感白色念珠菌SC5314,临床分离耐氟康唑白色念珠菌901,实验室基因编辑耐氟康唑白色念珠菌 816)有明显抑制作用,MIC值分别为4、8、4 μg·mL-1.从该海洋放线菌中发现了安莎三烯类化合物,并首次报道了其对氟康唑耐药真菌的抑制活性,研究结果丰富了海洋微生物的次级代谢产物种类,可为新型抗真菌药物的研发提供科学参考.
为补充长江口邻近海域沉积物中V、Cr、Co、Ni分布研究的历史基础数据,为后续相关研究提供数据对比和参考,对2011 年9 月长江口邻近海域28 个站位沉积物中重金属V、Cr、Co、Ni的分布特征、赋存形态、影响因素和潜在生态风险进行了分析.结果显示,沉积物中V、Cr、Co、Ni总含量在杭州湾北部(金山沿海)和舟山群岛附近(浙江省钱塘江入海口外)有两个明显的高值区.形态分析表明,各重金属主要以残渣态存在,其中V和Cr的活性形态远小于残渣态.各金属元素活性形态的高值区出现在北部近岸和南部外海,其在北部海域有随离岸距离的增加而显著降低的趋势,而在南部海域变化不明显,说明这些金属活性形态受陆源和海源共同影响.各金属的有机结合态和残渣态呈现出随离岸距离的增加而降低的趋势,表现为陆源属性;而碳酸盐和铁锰氧化物结合态在外海海域含量相对较高,表现为海源属性.V和Co的活性形态以碳酸盐结合态为主,易受酸碱度的影响;而Cr和Ni的活性形态以铁锰氧化物结合态为主,易受氧化还原条件的影响.富集因子评价结果表明,沉积物中各金属元素基本没有富集.次生相与原生相分布比值法评价可知,V、Cr为无污染,Ni为基本无污染,Co为轻度污染.
基于2016年和2020年浙江南部近海收集的71尾前肛鳗样品,通过测定碳氮稳定同位素比值计算其营养生态位指标,对比分析前肛鳗不同发育过程、不同季节及不同年份营养生态位的差异,探究营养生态位的变动规律及对资源的利用情况.结果表明:(1)2016年和2020年前肛鳗平均 δ13C值分别为(-15.19±0.31)‰、(-15.90±0.45)‰;平均 δ15N值分别为(12.42±0.45)‰、(12.92±0.25)‰;(2)单因素方差分析表明,2016年前肛鳗不同发育过程δ13C值差异不显著(P>0.05),δ15N值差异显著(P<0.05),不同季节间δ13 C值和δ15 N值均存在显著差异(P<0.05),而2020年前肛鳗不同发育过程δ13 C值和δ15 N值差异均不显著(P>0.05),不同季节间δ13C值存在显著差异(P<0.05),δ15N值差异不显著(P>0.05);(3)从个体发育来看,2016年前肛鳗有向高营养级饵料生物摄食的趋势,而2020年前肛鳗摄食特化现象不明显,但均随个体发育过程生态位宽幅逐渐减小,表明个体发育过程营养生态位会出现资源竞争共存分化现象;(4)种群营养多样性指标结果显示前肛鳗在秋、冬两季食物来源较春、夏两季更广泛,春季营养多元化程度与秋季相似,夏季营养多元化程度与冬季相似,各季节间营养生态位重叠较小,存在明显的时间分化现象;(5)2020年前肛鳗种群营养结构多样性指标相比2016年均出现不同程度的降低,两年的SEAc未发生重叠现象.由于种内种间的竞争压力,研究发现前肛鳗在个体发育过程及不同时间段都出现了营养生态位分化现象,从而达到维持物种共存、保持食物网结构稳态的目的.
Cumulative studies have shown that adequate lipid consumption is beneficial for improving the growth, protein efficiency ratio, and nitrogen and phosphorus retention of fish, as well as saving dietary protein and cost. Golden pompano Trachinotus ovatus, one of the promising candidates for intensive aquaculture in southern China with an annual production of around 240,000 tons, is a carnivorous marine fish. The dietary protein requirement of T. ovatus is relatively high at around 50%. Based on the essential fatty acids（EFA） requirement of T. ovatus[1.24-1.73% n-3 high unsaturated fatty acids（HUFA）, ratio of DHA to EPA about 1.4], the compound oil products（BO, consisting of fish, soybean, rapeseed and perilla oils with proper proportions） were developed by our group. In the previous studies, the growth promoting effects of compound oil and low fish meal diets（6 % fish meal） on Trachinotus ovatus was similar with control diets（fish oil and 20 % fish meal, prepared by small-scale production technology and culture conditions）. To further evaluate the large-scale application effect of compound oil products and low fish meal diets on the culture of Trachinotus ovatus, four isoproteic（48%） and isolipidic（11%） diets（D1-D4） were formulated by the large-scale production process in a local feed company. Based on the commercial feed of Trachinotus ovatus（containing 20% fish meal）, D1 contained 10% fish oil, D2 10% compound oil, D3 8% compound oil +4% fat powder. While diet D4 was low fish meal diet（containing 6.6% fish meal） with compound oil + fat powder. Each diet was fed to triplicate groups of Trachinotus ovatus juveniles（initial body weight about 64.75 g） in floating pond cages（2 m×2 m×1.5 m, 100 fish per cage） for 8 weeks. During the 8-week feeding trial, the water temperature was 26.5-32.5 ℃, salinity was 27-32 ‰. Fishes were fed to nearly satiation twice a day at 8∶00 and 16∶00. At the end of the feeding trial, all fishs were weighed after being fasted and anesthetized with 0.01% 2-phenoxyethanol. Six fishes per treatment were sampled for measuring body proximate composition, six fish were sampled for measuring muscle texture and the remaining six fish per treatment were sampled for collecting serum, liver, dorsal and ventral muscle. All samples were quickly frozen in liquid nitrogen and then stored at-80°C until analysis. The comparative analysis of growth performance, proximate composition of the whole body and muscle, serum biochemical parameters and hepatic antioxidant parameters, muscle fatty acid profiles, edible quality, and texture was studied among the four groups. The results showed that the final weight, weight gain rate（WGR）, specific growth rate（SGR）, daily intake rate（DFR）, condition factor（CF）, hepatosomatic index（HSI）, viscerosomatic index（VSI） and survival rate（SUR）, as well as proximate composition（moisture, crude fat, crude protein, crude ash） of all body displayed no significant difference among the four dietary groups（P＞0.05）. However, the feed coefficient（FC） of fish in diet D2 was lower than that of fish in the other three diets, and even significantly lower than that of fish in diet D1（P＜0.05）. Comparing to D1 and D2 groups, low serum glutamic oxalacetic transaminase（GOT） and glutamic-pyruvic transaminase（GPT） activities, and low density lipoprotein（LDL） levels were detected in D3 and D4 groups, and triglyceride（TG） level in D4 group was significantly lower（P＜0.05）. While serum high-density lipoprotein（HDL） and total cholesterol levels（T-CHO）, acid phosphatase（ACP） activities were comparable among four groups（P＞0.05）. In terms of hepatic antioxidant parameters, there was no statistic difference in hepatic total antioxidant capacity（T-AOC）, catalase（CAT）, superoxide dismutase（SOD） activities among the four groups（P＞0.05）, while low hepatic malondialdehyde（MDA） levels were observed in fish in diet D3 and D4. In terms of muscle nutrition, the crude protein and moisture content in the dorsal muscle of T. ovatus showed significant differences among four dietary groups（P＜0.05）. Specifically, the crude protein content of dorsal muscle was significantly higher in fish in D3 and D4 than that of D1 group（P＜0.05）. In addition, D2 group had lower dorsal muscle moisture content than the D1 group（P＜0.05）. while there was no difference in dorsal muscle moisture of fish among D1, D3 and D4 groups（P＞0.05）. The crude protein and moisture content of abdominal muscle showed no significant difference among four dietary groups（P＜0.05）, while crude lipid content in D4 group was significantly lower than that in D3 group（P＜0.05）. The fatty acid composition of dorsal and abdominal muscle of fish displayed parallel change pattern with the dietary fatty acid. Comparing to D1 group, the dorsal and abdominal muscle ARA, EPA, DPA DHA, HUFA and n-3 polyunsaturated fatty acid（PUFA） content of D2-D4 groups were significantly lower, while their monounsaturated fatty acid（MUFA） and n-6 PUFA content were significantly higher（P＜0.05）. High dorsal muscle saturated fatty acid（SFA） levels were detected in D1-D3 groups, while high abdominal muscle SFA levels were detected in D2 and D3 groups. Moreover, although the texture properties（tenderness, hardness, springiness, chewiness, gumminess, and cohesiveness） and edible quality（cooked meat rate and water holding capacity） of muscle showed no significant difference among four groups（P＞0.05）, numeric values of muscle texture in T. ovatus in D4 were higher than those in diet D1. These results indicate that compound oil and low-fish meal diets exhibit the same growth-promoting effect on Trachinotus ovatus as control diets（containing fish oil and 20 % fish meal）, and also is beneficial to improving hepatic health, muscle quality, which can be widely applied in the culture of T. ovatus. The results obtained here lay foundation for the application of high-efficiency and low fish meal diets in aquaculture.
There are a large number and a wide variety of bacteria in shrimp intestines, which play important roles in nutrient absorption, growth and development and disease defense. Intestinal bacteria are the main members of intestinal microorganisms, which have been found to be closely related to growth stage, individual size and health status of shrimp. Moreover, once the dynamic balance of intestinal flora of shrimp deviates from the normal and healthy range, the shrimp will exhibit metabolic abnormalities and tissue lesions, leading to the invasion of pathogenic microorganisms. With the continuous deepening of research, experts and scholars at home and abroad have begun to explore the unknown functions of shrimp intestinal microflora and made much progress in recent years, mainly involving growth and development, environmental stress, disease occurrence, feed nutrition, and water quality conditions. During the entire development process of shrimp, the structure of intestinal microflora undergoes significant changes. Intestinal microflora can be adjusted based on shrimp feed, feeding patterns, and nutrient requirements for growth and development, so the dynamic balance of symbiosis is more beneficial to both parties, thereby promoting shrimp growth. The abundance of Actinobacteria significantly increases with the extension of culture time of Litopenaeus vannamei, while α-Proteobacteria showes an opposite trend of change. γ-Proteobacteria is the dominant bacteria in healthy shrimp, accounting for 40% of L. vannamei and 90% of Penaeus monodon. During the early development stage of P. monodon, Proteobacteria dominates, but Actinomycetes becomes the dominant bacteria in the intestinal tract of adult shrimp. γ-and α-Proteobacteria and Flavobacteria are the dominant microflora of L. vannamei at different stages of early development. During the larval stage of L. vannamei, Vibrionaceae occupies an absolute advantage in the intestinal flora, but in juvenile and adult stages, Rhodobacteraceae gradually replaces Vibrionaceae as the dominant bacteria. In the early stage, the intestinal microflora of shrimp is variable, but in the later stage of development, it is relatively stable. In order to coexist with the host, the intestinal microflora of healthy shrimp regards pathogenic microorganisms as invasive species. Once the balance of intestinal flora changes significantly, harmful microorganisms will seize the opportunity to invade, leading to disease of host. There is a significant correlation between the intestinal microflora structure of shrimp and the outbreak of diseases. After an outbreak of disease, the normal activity of the intestinal microflora of L. vannamei is abnormal and presents a relatively disordered state. In recent years, experts and scholars have proposed the concept of microbiota-for-age Z scores（MAZ）, which is a time variant index of intestinal microflora based on the age of the host. MAZ is relatively stable in healthy shrimp, but once diseases occur, MAZ will decline sharply. Therefore, analysis of the structure of host intestinal microflora can assess the health level and susceptibility to pathogens. The core microflora of healthy shrimp is generally dominated by the orders Verrucomicrobiales and Alteromonadales, but during the outbreak of disease, the core microflora gradually shifts to a structure with the orders Rhodobacterales, Vibrionales, and Flavobacteria. There is a significant positive correlation between the immune status of shrimp and relative abundance of intestinal core flora. In order to make the dynamic balance of the intestinal flora and its symbiotic state with the host more conducive to adapting to changes in the external environment, the shrimp intestinal flora can be changed according to environmental conditions of water（ammonia nitrogen, water temperature, salinity, pH, etc.）. As an important ecological factor, salinity is crucial for the growth of cultured shrimp. The intestinal microflora of L. vannamei is closely related to the salinity of water. In highly saline water, multiple conditional pathogens in the intestinal tract increases, leading to a sharp decline in the health level of the shrimp. With the continuous changes of salinity, conditional pathogenic bacteria increase and beneficial bacteria decrease, indicating that continuous changes in salinity can lead to serious imbalance in the structure of intestinal flora and may lead to intestinal dysfunction. Research on the response mechanism of salinity stress to P. monodon has shown that the abundance of Vibrio in high salinity group is higher than that in low salinity group, while the abundance of Shewanella in low salinity group is higher than that in high salinity group. Based on the theory of coevolution, it can be inferred that the interaction between shrimp and its intestinal flora is formed through long-term coevolution, and this symbiotic mechanism can ensure the colonization and reproduction of intestinal bacteria. In other words, the evolution of shrimp intestinal microflora follows Darwin’s law of evolutionary dynamics, and shrimp host and their intestinal microflora must adapt to each other to survive. Establishing criteria for the intestinal microflora of healthy shrimp at different stages of development will help to assess the health level and development status of shrimp. The growth and development, phenotypic traits, and stress resistance characteristics of shrimp are closely related to the composition and structure of intestinal microflora. Therefore, establishing a relationship model between economic traits and intestinal microflora using bioinformatics, macrogenomics and molecular biology will be helpful in improving economic traits and productivity through optimizing the microflora structure. China is recognized as a major shrimp production and consumption country in the world, but there are many problems in China’s shrimp industry, such as frequent disease outbreaks, low feed utilization, and water environmental pollution. Intestinal microflora as a symbiotic partner of shrimp has become the focus of research on healthy shrimp farming. In the process of shrimp culture, it is necessary to rationally mix the nutritional components of the diet at different stages of development to fully utilize the beneficial functions of intestinal flora, thereby promoting intestinal health. Therefore, it is necessary to build a shrimp specific intestinal bacterial strain bank and develop shrimp specific probiotic preparations. In general, the beneficial function of intestinal microflora has been widely recognized, but precise microflora regulation technology is still in the initial stage. An in-depth understanding of the functional characteristics of intestinal flora can lay an important theoretical foundation for the healthy culture of shrimp and improve the production capacity and development and utilization of probiotics. This paper briefly describes the relationship between intestinal flora and growth and development, and disease occurrence. And the effects of feed nutrition and environmental stress on the intestinal flora of shrimp are further reviewed. Finally, this paper looks forward to the research and application trend of shrimp intestinal flora. The paper provides scientific basis for exploring the function of intestinal microbiota, improving shrimp intestinal nutritional health and developing new functional intestinal probiotics.
In order to understand the competitiveness and utilization status of major shrimps for habitat resources in Zhoushan sea area, this study analyzed shrimp data obtained from the bottom trawl survey of fishery resources conducted in April（spring） and October（autumn） 2018 in waters east of Zhoushan Islands. Niche width, niche overlap, cluster analysis, Pearson correlation test, Spearman rank correlation test, Ochiai index, Dice index and other measures were used to analyze the niche and interspecies relationship among major shrimp species. In this survey, shrimp species occurring in both two voyages were defined as major shrimp species. Pinkas index relative importance（IRI） was used to determine dominant species of major shrimps. Shrimps with IRI≥1 000 were defined as dominant species, and IRI＜100＜1000 were defined as important species. The results showed that: A total of 32 shrimp species were captured and identified, belonging to 21 genera and 10 families. The dominant species were Metapenaeopsis Barbata, Metapenaeopsis Dalei, Parapenaeopsis hardwickii and Solenocera crassicornis and their IRI were 2 547.26, 2 835.16, 4 507.25 and 1 753.93, respectively. A total of 19 shrimp species were found in both voyages. The top 3 shrimp species were Penaeus chinensis, Parapenaeopsis tenella and Penaeus harteni, with niche widths of 2.41, 2.38 and 2.25, respectively. Aegaeon rathbuni had the lowest niche width, which was 0.53.According to niche width cluster analysis, the main shrimp species could be divided into 3 groups: wide niche species（niche width value was between 2.00 and 2.50）, middle niche species（niche width value between 1.00 and 2.00） and narrow niche species（niche width value less than 1.00）. The similarity test was carried out by results of the cluster analysis. The results showed that R=0.943,P=0.001＜1%, indicating that the grouping results were reasonable. Main shrimp species niche overlap value ranged from 0 to 0.99, 11 shrimps with overlap value of 0, 6 higher than 0.90, The highest overlap value was 0.99, and the niche overlap value between Aegaeon rathbuni and Processa japonica was significantly different, indicating that there were differences in similarity degree of species in resource utilization.VR（variance ratio） method was used to calculate the overall correlation between the main shrimp species. VR value was 2.23＞1, indicating that there was a positive correlation between the main shrimp species. After analysis by Pearson correlation test and Spearman rank correlation test, the results of the two correlation tests were not completely equal, but both showed significant positive correlation among populations of main shrimps, which was consistent with the results of the overall correlation test.Ochiai index and Dice index were used to measure the degree of interspecific association of major shrimp species. 115 pairs with OI correlation index greater than 0.5, accounting for 67.3% of species logarithms, and 95 pairs with DI correlation index greater than 0.5, accounting for 55.6% of species logarithms. The species logarithms with both indices greater than 0.5 were far more than 50%. The overall results tended to be positively correlated, indicating strong interspecific association.The niche width of shrimp in the study area was segmented obviously. The high niche width was typical in Solenocera crassicornis and Parapenaeopsis tenella. Both Solenocera crassicornis and Parapenaeopsis tenella were dominant species, indicating that they were evenly distributed and had a large range of activities, and had strong ability to use resources and adapt to environment. The low niche width values might be related to the location of survey stations, the abundance and occurrence of species, and might also be closely related to marine environmental degradation.The results of this survey showed that there were great differences in the overlap value and degree among main shrimps. The niche width values of Solenocera crassicornis（2.41） and Parapenaeopsis tenella（2.38） were large and had a high degree of overlap with each other, indicating that these species pairs were similar in their ability to utilize habitat resources and occupied similar resource sites.In general, species with smaller niche width values also had smaller niche overlap values with other species, which might be due to their low utilization ability of habitat resources and relatively weak competition between species pairs. Meanwhile, among shrimps obtained in this survey, shrimps with narrow niche width did not necessarily have low overlap value with shrimps. For example, shrimps with the smallest niche width had high overlap value with other species, especially shrimps with Aegaeon rathbuni, which reached 0.99, it might be caused by the high station overlap rate between them.There was a significant positive correlation between the overall association（VR） of major shrimp species, which indicated that there was a phenomenon of interdependence among shrimp species and they had the same or similar needs for habitat resources. Meanwhile, the community structure in this area was stable and showed a positive succession trend. This might be due to the similarity of adaptation or utilization of non-restrictive factors in the habitat（water temperature, salinity, ocean current, etc.）, or to the strong association between the dominant species.Spearman rank correlation test was relatively higher than Pearson correlation test in significant and extremely significant logarithms of shrimp species. The reason may be that Pearson correlation test is a parameter test method, which requires that species must follow a continuous normal distribution, while shrimps in the sea area are distributed in clusters. Spearman rank correlation coefficient test is a non-parametric test method, and there is no requirement for the distribution form of penaeus. Therefore, Spearman rank correlation coefficient test has higher reliability and sensitivity.The results of this study showed that shrimp species pairs with significant and extremely significant positive correlation in correlation test also had larger niche width overlap value and stronger interspecies association. However, niche overlap and linkage analysis could not fully reveal the internal mechanism of the association between species in a community. In order to fully reflect the relationship between niche overlap and interspecific linkage, it is necessary to select appropriate measurement methods in subsequent investigations and comprehensively consider the changes of niche overlap in multiple dimensions.
Bottom-set gillnet has the characteristics of harvesting a variety of species, high economic benefits, high size-selectivity and poor species-selectivity. The hydrodynamic behavior of bottom-set gillnet under fishing operation are dynamically changed in response to combined effects of external forces from wave and current, and catch impact etc., which results in reduced fishing efficiency, fishing gear selectivity and security, and subsequently the remnant netting forms “ghost fishing”. The main internal factors affecting the fishing efficiency and selectivity of gillnet gear include mesh and twine size, working height of gillnet, twine material and hanging ratio, In addition, in the working process, due to the influence of external forces such as waves and streams and the interaction with fish behavior, the form and structure of gillnets change, fishing performance decreases, and selectivity changes. For the intention of further understanding the hydrodynamic behavior and geometry deformation under fishing operation, this study, on the basis of hydrodynamic experiment of polyethylene（PE） and nylon（PA） gillnets in the uniform current, investigated the effect of current velocity, solidity ratio and 90° turned mesh on the working height and shape characteristics of bottom-get gillnet, and developed the empirical formulas of deformation degree（k） of PE and PA gillnets. The results showed that the working height of gillnet was negatively correlated with the current velocity, and 96.5%, 69.3%, 43.9% and 29.9% of the initial height under the still water were achieved under current velocity of 0.2, 0.4, 0.6, 0.8 m·s -1 , respectively; hanging angle in the lower-half part of the gillnet increased with the current velocity.When V= 0 m·s -1 , the gillnet was stretched vertically in the water, the gillnet mesh was in the form of a high middle and low on both sides, the headline was inverted catenate-like. With the increase of current velocity, the gillnet gradually shifted backwards and downwards, the projection area of the gillnet in the Y-Z plane gradually became smaller, the projection area in the X-Y plane gradually increased, the projection area of the mesh in the Y-Z plane decreased, the curvature of the left and right side-rope got larger and larger, and more folds appeared with it. When the current velocity reached 0.8 m·s -1 , the lower part of the gillnet was close to the bottom surface of the tank. The twine material had little influence on the working height of gillnet, but had a significant impact on the expansion form of the bar. The height of the two kinds of twine materials（PE and PA） gillnets was almost the same under the same current velocity, but PA gillnets at different current velocities had a larger projection area in the X-Y plane, the overall form was more uniform, the lower part of the netting was not wrinkled, and the mesh was always maintained more uniform expansion. Under T0 and T90 assembly, the working height and uniformity of gillnets at different current velocities varied greatly. In still water and when V= 0.2 m·s -1 , the working height of T0 gillnet was significantly higher than that of T90 gillnet, and the M4 Z-axis coordinates of T0 gillnet tracer point were 5.1 cm and 9.0 cm higher than those of T90 gillnet, respectively, while the M3 Z-axis coordinates of the center point of T90 gillnet were 8.0 cm and 5.0 cm higher than those of T0 gillnet. When the current velocity increased, the projection area of T90 gillnet in the Y-Z plane was significantly larger, the working height of the netting was significantly higher than that of T0 gillnet, and the mesh expansion form was closer to the positive diamond, but at this time, the deformation degree of the lower half of the mesh of the two assembly methods was basically the same. The large solidity ratio not only leads to an increase in the current velocity and resistance through the mesh, but also sometimes changed the current state in the net, affecting the selectivity of fishing gear and quality of the catch. In this study, the form changes of PE and PA gillnets with different solidity ratios showed that under the four sets of current velocity conditions, the working height of gillnets of PE and PA materials was negatively correlated with the solidity ratio, the smaller the solidity ratio, the larger the working height of gillnet, the smaller the degree of deformation, the smaller the projection area of the netting in the X-Y plane, and the closer the mesh form to positive diamond expansion. Based on the influence of twine diameter, bar length, Reynolds number, on the resistance of the netting, the nonlinear fitting of different materials, solidity ratios and current velocities was obtained, and the expressions of deformation degree k of PE and PA materials were obtained, and according to the characteristics of the expression, the response surfaces of the specific current velocity, bar length and deformation degree k were obtained by response surface analysis method, and the calculated results were compared with the test results. The results showed that at a certain velocity, the longer the bar length, the smaller the twine diameter, and the greater the degree of the gillnet deformation. When the bar length was fixed, the degree of gillnet deformation k was negatively correlated with the current velocities and the twine diameter of netting; when the twine diameter was fixed, the smaller the current velocity, the larger the bar length, and the greater the degree of deformation k. In general, the calculated result was in good agreement with the test result, but the calculated result of the degree of deformation of PA gillnet at low current velocity(V=0.2 m·s -1 ) was quite different from the experimental test. To sum up, in the traditional gillnet operation, PA material twine is mostly selected, which is conducive to the full expansion of the netting in water. The solidity ratio is the key factor of whether the gillnet can maintain the ideal form in the current, the smaller the solidity ratio, the stronger the water crossing ability, the smaller the resistance in the horizontal direction, the higher the height of the gillnet, and the more the mesh tends to be positive diamond expansion.
Pelagic fishery is an important industry of the national economy. Due to the distance from land and port, the lack of effective means of observation and regulation is not conducive to the sustainable development of this industry. Automatic identification system（AIS） is an open data transmission system applied between ship and shore, and between ship and ship. The signals are sent and received in very high frequency（VHF） through transponders, and detailed information such as ship’s movement position is recorded using global positioning system（GPS） receivers, and important information such as ship’s position, speed, heading, ship’s name and call sign can be exchanged automatically. The initial purpose of AIS is to ensure the safety of ship navigation, which is a necessary navigation equipment for modern ships. The data generated by AIS has become an important data source for the study of pelagic fisheries because of its characteristics of wide coverage and high accuracy. This paper clarified the important role of AIS in pelagic fisheries by analyzing the characteristics of AIS data and its processing methods and the development and application of AIS technology at home and abroad. It explains how to extract and process AIS data effectively, including how to handle missing values and filter outliers and store them in an appropriate format, and finally how to apply the processed information to the field of pelagic fisheries through different algorithms and visualization processes. This paper focuses on three main application directions of AIS data in pelagic fisheries and the corresponding research methods. The identification of fishing vessel operation status and central fishing ground forecast are the most applied aspects in the field of pelagic fisheries, including the identification of fishing vessel operation status, calculation of fishing operation intensity, perception of fishing ground exploitation situation and dynamic changes by using the attribute features such as speed and heading in AIS trajectory data, which play an important role in the assessment of fishery resources and marine ecological protection. The monitoring of offshore fishing vessels and illegal fishing behavior is one of the most direct directions of AIS data application. AIS has great potential in monitoring unregulated fishing activities, and the larger and more perfect the amount of AIS data, the more accurate the monitoring of such activities. More and more scholars are exploring the application of AIS data in marine environmental protection and marine habitat management, which provides more tools to utilize and protect marine biodiversity. The application of AIS data is beneficial to improving the efficiency of marine habitat management, and also plays a role in monitoring overfishing in the high seas of pelagic fisheries. Then, we discusses the advantages and disadvantages of each method and its development prospects by comparing the research methods in different application directions. With the continuous progress of marine fisheries disciplines, modern statistics, artificial intelligence, machine learning and data mining and other disciplines and methods, the application models and research methods of AIS in fisheries science are becoming more and more diversified, promoting the progress and development of fisheries science, especially in fishing forecast technology and fishing vessel monitoring. However, there are certain problems and limitations of many methods and models in practical fisheries production applications. Therefore, we conclude with a summary of the important roles played by AIS data in pelagic fisheries applications and make a discussion of the shortcomings and deficiencies of related research methods. And a proposal for the optimization of AIS data applications in pelagic fisheries is presented, which is expected to provide a scientific basis for the sustainable development of pelagic fisheries. In the future, AIS may also solve more challenges including IUU monitoring and marine environmental protection to better serve the global marine fisheries.
Fishery non-drugs for aquaculture are important materials for production. Their quality is related to the sustainable development of aquaculture, as well as to the quality and safety of aquaculture products, food safety and ecological safety. In the long term, the Ministry of Agriculture and Rural Affairs has been paying great attention to the issue of aquaculture with input regulation, strictly adhering to the law for the production, operation and use of related products and other aspects of supervision and law enforcement. In order to evaluate the quality and safety of fishery non-drugs in the process of aquaculture, fishery non-drugs used in aquaculture in Shanghai area were studied in this paper.High resolution mass spectrometry screening technology was used to screen and analyze the hidden drug components of fishery non-drugs in aquaculture farms, fishery drug stores and network platforms in Shanghai, and to explore the harmfulness of pesticides and veterinary drugs in non-drugs fishery inputs to the quality and safety of aquatic products.From April 2020 to August 2020, a total of 300 fishery non-drug samples were collected in seven batches from various aquaculture farms and fishery pharmacies in Shanghai, and online platforms. According to the efficacy of their labels, the non-drugs collected for fishery use could be divided into 7 categories: water quality improver, sediment improver, antidote, micro-ecological agents, impurity removal, growth-promoter agent and pesticide. The results showed that among 300 fishery non-drugs samples, 189 unlabeled drug components were detected in 104 samples, including 15 drug components, and the total screening rate was 34.7%. According to the source of screened drug samples, the detection rate of samples collected from fishery pharmacy was the lowest, 22.5%, followed by aquaculture farms, 25.3%, and network platform was the highest, 72.6%, three times that of the other two sources. Through on-the-spot visits and investigations, it is found that when farmers buy non-fishery drugs from pharmacies, they need to register their real names online in the pharmacies, and the process of purchasing drugs is also connected with relevant administrative departments, the whole sales process has a good traceability, product quality assurance is relatively good. The network platform purchase is directly through channels like Taobao, which does not need to register the information. The convenience and lower cost makes online purchase more acceptable for purchasers. The unlabeled drug component added in these products was three times the quantity of formal pharmacy, leading to obviously better short-term use effect. Many farmers choose to buy online fishery non-drugs. However, the long-term use of such products leads to residues in aquatic products exceeding the maximum residue limit and causes pollution of aquaculture environment, further significantly resulting in other increased hazards. Therefore, the supervision of online platforms for the purchase of fishery non-drugs should be further strengthened and improved. According to properties of the detected drugs, there were 6 kinds of pesticides in the 15 kinds of drug components, including prometrazine, simetryne, simazine, carbendazim, trichlorfon and ethoxyquin; 8 kinds of veterinary drugs, including enrofloxacin, mequindox, erythromycin, gatifloxacin, florfenicol, sulfadiazine, ciprofloxacin and trimethoprim; and 1 kind of discontinued drug, pefloxacin. These stealthily added drugs had certain risks of excessive drug residues in aquaculture species and pollution of aquaculture environment. In terms of types of drugs screened out, a certain quantity of hidden drug components were screened out in different categories of non-fishery drugs, but there were great differences in the types of drugs screened out, among which the most hidden drugs were in water quality improvers. The main reason for adding multi-drugs was to highlight the efficacy of the products, such as bactericidal, insecticidal, antiviral effects and so on. Pesticides and veterinary drugs were screened out in different categories of fishery non-drugs, among which water quality improvers, substrate improvers and antidotes were screened out. Compared with other types of non-drugs for fishery use, the proportion of hidden pesticides screened out from the miscellaneous samples was the highest（45%）, and most of the screened pesticides were herbicides and insecticides, the utility model could enhance the impurity removal effect in non-drugs for fishery use. According to the types of drugs detected in the samples, of 104 samples containing hidden drugs, 57 screened out a single drug, 47 screened out 2 and more drugs, 25 screened out 3 and more drugs, 9 screened out 4 and more drugs, 3 screened out 5 and more drugs, and 2 screened out 6 drugs. 87.2% of the hidden drugs were 10-10 000 μg·kg -1 , of which 117（61.9%） were over 100 μg·kg -1 in 189 items. 10 000 μg·kg -1 or more accounted for 10.1%, and the highest content was 1 093 023 μg·kg -1 , which was close to the effective concentration labeled on common veterinary drug product. If farmers use these products, the unintentional drug residue will be caused in aquaculture. While the effective withdrawal period before the sale of aquatic products on the market can not be guaranteed. It will possibly cause the residue exceeding the MRL in farmed aquatic products, resulting in product failure. This shows that the source of fishery non-drugs and the type and content of hidden drugs is one of the main reasons for drug residues in aquaculture aquatic products. The long-term use of such products will not only lead to aquaculture drug resistance and other problems, thus increasing drug residues in aquatic products. Residues of veterinary drugs in aquatic products may cause human poisoning, allergies, increased drug resistance of pathogenic bacteria and even lead to deformity and cancer in serious cases, and do great harm to people’s health. Drug residues can also cause secondary pollution to aquaculture water body and sediment, and cause certain harm risks to the aquaculture ecological environment.
