Phylogenetic relationships within Penaeoidea, particularly among taxa of Penaeidae, have long remained controversial. To expand mitogenomic resources for Penaeidae and evaluate the phylogenetic position of Atypopenaeus stenodactylus (Stimpson, 1860), we sequenced and annotated its complete mitochondrial genome and analyzed gene composition, codon usage, tRNA secondary structure, selective pressure, intraspecific mitogenomic variation and phylogenetic relationships. The mitogenome of A. stenodactylus is a typical closed circular double-stranded DNA molecule of 15,933 bp, containing 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes and one D-loop region, with a pronounced A + T bias. Among the 22 tRNAs, all except trnS1, which lacks the DHU arm, formed typical cloverleaf structures, although some showed limited local variation. All 13 PCGs had Ka/Ks values below 1, indicating overall purifying selection; nad6 showed the highest Ka/Ks value, whereas cox1 had the lowest. Comparative analysis of the three available A. stenodactylus mitogenomes, PV007824, PX672768 and PV434778, revealed conserved gene order and low sequence divergence, with variation mainly concentrated in the non-coding D-loop region. Phylogenetic analysis based on 13 PCGs placed A. stenodactylus within Penaeidae and showed close relationships with Metapenaeus, Alcockpenaeopsis, Batepenaeopsis and Trachypenaeus, although traditional Penaeidae monophyly was not recovered. After inclusion of the three conspecific mitogenomes, PV007824, PX672768 and PV434778 clustered together, further supporting the stability of the inferred phylogenetic position. Overall, this study enriches mitogenomic resources for Penaeidae and provides new molecular evidence for resolving phylogenetic relationships within Penaeoidea.

The efficacy of stock enhancement for conservation has long been limited by low survival rates of hatchery-reared fish after release. While environmental enrichment is a promising strategy to improve their ecological adaptability, the optimal practices for specific species remain poorly understood. This study investigated the effects of different levels of environmental complexity on the physiological and behavioral traits of juvenile rock bream (Oplegnathus fasciatus). Fish were reared in tanks with no structure, low-level structures, or high-level structures for four weeks, after which the growth performance, basal cortisol levels and exploratory behaviors were examined. Fish reared with low- and high-level structures had longer latencies to leave a shelter, and locomotor activity tended to decrease with increasing environmental complexity, suggesting enhanced caution and antipredator abilities in the fish. Contrary to expectations, the presence of the low- or high-level structures did not improve growth performance or reduce basal cortisol levels. Overall, these results indicate that increased environmental complexity potentially benefits antipredator behaviors in juvenile rock bream. However, further research is needed to refine this strategy and promote more ecologically adaptive phenotypes, thereby contributing to stocking success of this species.

In order to investigate the relationship between the growth characteristics of Rhopilema esculenta and surface water temperature during the rapid growth period in Hangzhou Bay, the authors conducted a survey of Rhopilema esculenta biology and environmental factors in Hangzhou Bay in June—July 2022. The results showed that: (1) The umbrella diameter of Rhopilema esculenta ranged from 45 to 650 mm, the average umbrella diameter was 327.55 mm; the body mass of Rhopilema esculenta ranged from 9 to 18 260 g, the average body mass was 2 748.21 g. (2) The relationship between umbrella diameter and body mass was given by W=1.578 5×10-5 UB3.120 8 (R2=0.975 4，n=1 601).(3) With the increase of date, the average umbrella diameter of Rhopilema esculenta increased from 104.33 mm to 361.20 mm and the average surface water temperature increased significantly from 21.69 ℃ to 27.94 ℃. (4) The average umbrella diameter and average surface temperature during the investigation period were fitted, and the relationship between them was as follows UB=6.07ST2-259.62ST+2 880.32 (R2=0.998 5). (5) After the opening of the fishery, the umbrella diameter of Rhopilema esculenta ranged from 115 to 650 mm with an average umbrella diameter of 391.96 mm; the body mass ranged from 40 to 18 260 g with an average body mass of 3857.60 g. The umbrella diameter and body mass of Rhopilema esculenta gradually increased with the date. This article studied the growth characteristics of Rhopilema esculenta and its relationship with surface water temperature during the rapid growth period in Hangzhou Bay, which can provide a reference basis for scientific mangement of Rhopilema esculenta fishing production during the summer fishing moratorium in Hangzhou Bay in the future.

Due to its red blood and unique taste, Barbatia virescens is considered a species of significant economic value in Chinese coastal cities. With the ever-growing global demand for seafood, human activities have severely damaged the habitat of B. virescens, leading to the degradation of natural resources and a dramatic decline in wild population numbers. To obtain more information on this species, genome survey sequencing was used. The genomic size of B. virescens was estimated to be 1.426 Gb, with a heterozygosity of 0.589

Group discrimination is a critical prerequisite for studying fish population dynamics, implementing effective fisheries management, and evaluating the outcomes of stock enhancement programs. However, research on group differentiation of Oplegnathus fasciatus (Kroyer, 1845), an economically important species in the East China Sea, remains limited across different geographical regions. We conducted a comparative analysis of trace element concentrations, including iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), chromium (Cr), cadmium (Cd), and mercury (Hg), as well as metalloid arsenic (As), in the muscle tissues of three distinct groups of O. fasciatus: the farmed group, the Yangtze River Estuary group, and the Zhongjieshan group. Trace elements were detected using inductively coupled plasma mass spectrometry. Group classification methods such as cluster analysis, stepwise discriminant analysis, and random forest were used to differentiate the groups based on these eight trace elements. Consequently, significant differences were observed in the concentrations of Fe, Cu, Zn, Cr, As, and Hg among the groups (p< 0.05), while differences in Mn and Cr were not statistically significant (p > 0.05). Discriminant analysis showed that cluster analysis effectively differentiated the farmed group from the Zhongjieshan group. Stepwise discriminant analysis achieved an overall accuracy of 85.1%, while the random forest model demonstrated an accuracy of 92.86%. These findings suggest that trace element concentrations could be applied to effectively distinguish among groups of O. fasciatus, with the random forest model outperforming traditional statistical methods to some extent. Our results are relevant to the activities of stock release and fisheries management.

Artificial enhancement and release activity is an important method in the restoration of fishery resources. In order to understand the possible genetic effect of hatchery-released populations on wild populations during the artificial enhancement and release activities of Sebastiscus marmoratus in Zhoushan waters, we utilized mitochondrial DNA control region sequences to examine the genetic diversity in four S. marmoratus populations, including one farmed population, one released population and two wild populations. A total of 68 haplotypes from 123 individuals were detected, including 3 shared haplotypes. Haplotype diversity ranged from 0.944 to 0.980, with a mean of 0.966. The nucleotide diversity ranged from 0.020 to 0.025, with a mean of 0.022. Analysis of Molecular Variance (AMOVA) indicated that the primary genetic variation occurs within populations and the index of genetic differentiation between populations (FST) among the four populations showed no differentiation. The results indicate that the current artificial enhancement and release has not impacted the S. marmoratus population in Zhoushan waters. Continued long-term monitoring is essential to protect the high-quality germplasm resources of S. marmoratus.

Live transportation is a critical component of fish farming and hatchery release. To optimize hatchery-release techniques and improve the survival rate of marbled rockfish (Sebastiscus marmoratus, Cuvier 1829) juveniles, the effects of varying transport durations (2, 4, 6, and 8 h) and densities (60, 90, 120, and 150 kg m−3) on the physiological indicators of the fish and water quality were investigated under controlled laboratory conditions. We found that as transport duration and density increased, water quality significantly deteriorated, with ammonia nitrogen levels rising and dissolved oxygen content and pH levels decreasing. Physiological indicators including levels of lactate, cortisol, and malondialdehyde and activities of superoxide dismutase, alkaline phosphatase, and glutamate oxaloacetate transaminase notably increased, indicating that the fish experienced heightened stress during transport. Additionally, the mortality rate of juveniles increased significantly with increasing density and transport duration. The high mortality rate might be associated with sustained elevated cortisol levels and liver damage. Our results are helpful for determining the optimal transport conditions for S. marmoratus juveniles and also provide valuable insights for improving transport techniques for other aquatic animal species.

As an important part of proliferation and discharge, crustaceans can effectively conserve and supplement fishery resources in natural waters. Based on the data of crustacean proliferation and release in Zhejiang Province from 2017 to 2021 and related literature, this paper systematically reviewed the annual variation trend of crustacean release type and quantity, release capital, and the spatial and quantitative distribution of release area and release specifications. The results show that: from 2017 to 2021, six species of crustacean proliferate in Zhejiang Province, including Penaeus japonicus, Portunus trituberculatus and Penaeus chinensis, etc.. A total of 5220, 455, 000 were released, and the investment was 33, 202, 000 yuan. Among them, the largest amount of release and investment was Japanese prawnaeus, the least amount of release was green crab, and the least amount of investment was Prawnaeus puerarii. The release area involved Wenzhou, Ningbo, Taizhou, Zhoushan and other cities, and the distribution of release was unbalanced between regions, and mainly concentrated in small and medium sizes. In this paper, some specific suggestions will be put forward on problems such as insufficient assessment of the effect of crustacean release species, poor release effect of some proliferating species, and few reserve species of crustacean release in the coastal waters of Zhejiang Province, so as to provide a basis for improving the scientific management of crustacean release species in the future.

To effectively distinguish natural and cultured populations of Oplegnathus fasciatus,we used both tradi-tional statistical analysis and neural network methods to compare six shape indices and twenty-one truss indices from otoliths of 174 randomly selected specimens(100 from a natural population and 74 from a cultured population).The results showed that among the six shape indices,ellipticity,roundness,and aspect ratio exhibited significant differences between the two populations.Twelve out of the twenty-one truss indices displayed significant differences.Results of discriminant analysis indicated that traditional statistical analysis and neural network methods achieved correct discrimination rates of 57.5％and 81.4％for shape indices,while for truss indices were 69.5％and 85.4％,respectively.These findings indicated that neural network technique is more effectively than traditional statistical method to distinguish natural and cultured populations of O.fasciatus.

海鳗等鳗鲡目鱼类是舟山群岛海域常见的近底层凶猛肉食性鱼类,研究鳗类的营养生态位可以了解其在舟山群岛海域生态系统中占据的营养层次.实验以舟山群岛海域的海鳗、前肛鳗、星康吉鳗、食蟹豆齿鳗和短吻吻鳗为对象,利用碳氮稳定同位素技术分析 5种鳗的营养生态位及种间食物关系.结果显示:①舟山群岛海域 5 种鳗的δ13C范围为-21.91‰～-14.97‰(平均值-17.03‰±1.14‰),δ15N范围为 9.56‰～15.13‰(平均值11.50‰±1.36‰).②非参数检验结果表明,不同物种间的碳氮稳定同位素比值之间均存在极显著差异;Pearson相关性分析表明,5 种鳗总体的δ13C、δ15N值与肛长相关性均不显著,除前肛鳗以外,其余 4 种鳗总体的δ13C值与肛长相关性不显著,δ15N值与肛长呈极显著正相关.③稳定同位素混合模型(SIAR)显示,鱼类、虾类和口足类是鳗类的主要食物来源.④海鳗与其他 4 种鳗的营养生态位均有重叠,说明它们之间的食源有一定程度的同质化,存在食物竞争;食蟹豆齿鳗和短吻吻鳗的校正核心生态位面积(SEAc)最大,说明二者食性泛化,其摄食类群主要取决于饵料生物的易得性;前肛鳗、星康吉鳗和短吻吻鳗之间不存在生态位重叠,说明其摄食种类有所分化,体现了同域分布近缘种的食性差异.本研究阐述了舟山群岛海域 5 种鳗的种间食物关系和进化共存机制,可为研究舟山群岛海域高营养级类群的食物网结构特征提供参考.

Since the 1980s, the main fishery resources in Zhejiang offshore have shown a declining trend. Therefore, since 2000, relevant units have continued to carry out artificial proliferation and release to repair fishery resources. Based on the statistical data of proliferation and release of Zhejiang offshore fish from 2017 to 2021, this paper compared the trends of release funds, release quantity and release species. It was concluded that 16 kinds of marine fish such as Larimichthys crocea, Acanthopagrus schlegelii, Nibea albiflora and Oplegnathus fasciatus were mainly released in 12 important proliferation and release sea areas of Zhejiang offshore from 2017 to 2021. The total investment in releasing funds was 112.859 million yuan, and a total of 467.998 million marine fish fry were released, of which 3.301 million yuan were marked fish and 488,000 fry were released. Investigation and literature reports show that stock enhancement plays a positive role in increasing the biological resources of marine fish in Zhejiang offshore, restoring the community structure of marine fish, protecting marine biodiversity, and promoting the development of marine fishery. Finally, according to the investigation and related literature, the author sorted out the problems existing in the proliferation and release and put forward relevant suggestions for improvement, in order to provide reference for the future scientific and standardized implementation of proliferation and release.

[Objective]To explore the anesthetic effect of eugenol on Sebastiscus marmoratus,and to provide reference for the tagged releasing technology of S.marmoratus.[Method]A total of 12 eugenol concentration groups of 10-180 mg/L were set up to observe the final anesthesia stage that the fish could reach at different concentrations,and the appropriate concentration range was preliminarily screened.The effective anesthesia concentration was further determined according to the anesthesia recovery time and recovery rate.On this basis,the comparative study of air exposure test was carried out.[Result]S.marmoratus could reach stage IV anesthesia within 3 min at a concentration of more than 30 mg/L,and no death and obvious stress response occurred within 5 min at a concentration of less than 80 mg/L.The suitable concentration range was 30-80 mg/L after preliminary screening.According to the commonly used effective anesthesia mass concentration selection criteria,combined with the resuscitation test,the effective anesthesia concentration of S.marmoratus was 40-50 mg/L.At this time,S.marmoratus could be anesthetized within 3 min,resuscitated within 7 min,and the survival rate was 100%after 15 min of anesthesia.All the S.marmoratus survived in the solution less than 150 mg/L for 5 min,and died in more than 5 min;In the air exposure test at a concentration of 40 mg/L,the average recovery time was the shortest at 15 min,and then the average recovery time gradually increased with the extension of air exposure time.Therefore,it is considered that S.marmoratus has recovered at 15 min in the air.In order to avoid the stress of the fish,the water-leaving test operation should be completed within 15 min.[Conclusion]The suitable anesthetic concentration of eugenol for the marker specification of S.marmoratus[body length(88.12±4.87)mm)]is 40-50 mg/L,and the operation of leaving water should be controlled within 15 min.If rapid anesthesia is required,50-150 mg/L can be selected,and the anesthesia time should be controlled within 5 min to avoid anesthesia death.

为探明浙江北部海域条石鲷标志放流回捕和移动分布情况,于2017-2018年采用挂牌标志开展条石鲷放流试验.依托标志回捕宣传册进行标志鱼有奖回捕,测量标志鱼体长、体质量,收集回捕日期、地点、方式等信息,整理分析相关数据.2次共放流标志条石鲷36482尾,共308尾回捕标志鱼被流刺网、垂钓、地笼和蟹笼捕获,回捕率为0.84％.流刺网回捕鱼数量占总回捕数量的比例为66.6％.通过对回捕信息的分析,发现回捕到的条石鲷均在岛礁附近,具有较强的恋礁习性.标志鱼最北移动到浪岗列岛,最南到宁波渔山列岛,放流附近海域占回捕总数量的85.4％.放流后30 d内标志条石鲷生长较慢,随后生长速度明显加快,75 d后,体长、体质量分别平均增长了59.2％和136.0％.

根据2016-2020年共5年春季(4月)的调查资料,对中街山列岛附近海域春季三疣梭子蟹资源的年间变化进行了研究.结果表明:中街山列岛附近海域春季的三疣梭子蟹群体以幼蟹为主;雌雄性比接近1:1;质量密度与尾数密度最大值均出现在2018年,而最小值均出现在2019年,其最大值分别是最小值的2.37倍与2.52倍,资源密度年间波动变化趋势明显;质量密度与尾数密度均和平均底温呈明显的二次曲线相关.

In natural environment, the existence of interactions of toxic mixtures could induce diverse biochemical pathways and consequently exert different toxicological responses in aquatic organisms. However, little information is available on the effects of combined xenobiotics on lower aquatic invertebrates. Here, we assessed the effects of cadmium (Cd, 0.31 mg/L) as well as the mixture of Cd (0.31 mg/L) and benzo(a)pyrene (Bap, 5 or 50 μg/L) on bioaccumulation, antioxidant, lipid peroxidation (LPO) and metallothionein (MT) responses in gills of thick shell mussel Mytilus coruscus. Upon exposed to single Cd, the metal bioaccumulation, antioxidant enzymes activities, LPO and MT level significantly increased in the gills, suggesting an apparent toxicity to mussels. The interaction of Cd + 5 μg/L Bap did not significantly alter these endpoints compared to single Cd. However, once the dose of Bap elevated to 50 μg/L, the induction of bioaccumulation, antioxidant system and LPO was even more pronounced while the induction of MT was remarkably inhibited, implying an accentuated toxicity. Collectively, the current results demonstrated that 0.31 mg/L Cd exposure resulted in severe toxicity to mussels despite of the induction of MT system to alleviate the metal toxicity. Once the Cd exposure combined with Bap, the lower dose of Bap could not change the Cd toxicity while the higher dose of Bap accentuated the toxicity by inhibiting metallothionein synthesis. These findings might provide some useful clues for elucidation the mechanism of the interaction of combined xenobiotics in molluscs.

三门湾是浙江省重点养殖海湾之一,沿岸海域环境污染和养殖业自身污染对浅海养殖业已造成严重威胁.本文根据2015-2016年对三门湾海域的环境质量调查结果,结合海洋环境功能区划对该海域环境质量现状进行了评价与分析;对海水的富营养化程度,沉积物中重金属的富集程度及潜在的生态危害效应进行综合分析.结果表明:(1)该海域水质除了无机氮、活性磷酸盐、pH和COD部分超标外,其他环境因子符合功能区相应的海水水质标准;(2)该海域沉积物的重金属含量均达标,底质环境状况良好;(3)三门湾海域各季节富营养化指数大于1,表明该海区富营养化程度较高;(4)各个季节潜在生态危害系数均远小于150,说明三门湾海域沉积物中重金属的潜在生态危害属于轻微危害范围.海水富营养化成因较为复杂,后续还需进行综合调查分析.

根据2018-2019年春季两个航次在舟山近海进行的浮游生物调查结果,对舟山近海的浮游动物群落结构(类群组成、优势种数量)年际变化进行了研究,利用典范对应分析(Canonical Correspondence Analysis,CCA)研究了两年春季浮游动物类群组成差异、优势种变化的原因,初步探讨了春季浮游动物群落结构动态变化的机制.结果表明:根据表层温度(Sea Surface Temperature,SST)、表层盐度(Sea Surface Salinity,SSS)的聚类分析,将该区域分为3个水团:杭州湾内水团(I区)、舟山本岛上升流水团II区)、舟山近海水团(III区).不同水团对浮游动物类群组成影响显著,引起2018年和2019年春季3个水团区差异的主要贡献种(贡献率>10％)均为中华哲水蚤,同一水团两年间年际差异的贡献种如下:I区为捷氏歪水蚤(56.91％)和真刺唇角水蚤(12.34％);II区为中华哲水蚤(72.64％)、 五角水母(13.35％);III区为中华哲水蚤(41.93％)、夜光虫(22.94％).CCA分析表明,第1 CCA轴(CCA1)和第2 CCA轴(CCA2)共解释了两年春季浮游动物优势种累计方差的46.14％ 和物种-环境累计方差的97.82％.CCA1主要反映了空间(近海水团和湾内水团)的差异.CCA2主要反映了2018年和2019年站位的年际差异.盐度是影响春季浮游动物群落结构空间差异的主要因素,而温度、叶绿素a浓度是春季浮游动物群落结构年际差异的主要因素.

为掌握重要鱼类索饵场仔稚鱼的生态分布,促进海洋渔业的发展,文章基于2011—2012年岱衢洋海域4个航次的定量采样,运用生态位宽度、生态位重叠和典范对应分析等方法,分析该海域仔稚鱼群落与海水环境因子的关系.研究结果表明:岱衢洋海域仔稚鱼的生态位宽度可分为广生态位、中生态位和窄生态位,其中广生态位种对资源环境的适应能力强且分布范围较广,而窄生态位种对资源环境的适应能力较弱且分布不均匀;生态位宽度与相对重要性指数呈极显著的正相关关系;仔稚鱼群落生态位重叠指数大于0.6的种对占总种对数的24.24％,生态位重叠程度较低;仔稚鱼分布存在明显的生态分化现象,仔稚鱼的生态位特征和生态习性受温度、盐度、悬浮物和叶绿素a等环境因子的影响较大.

The tagging experiments were conducted on large (average length of (10.3±0.6)cm)and small (average length of (6.8 ±0.5)cm)Nibea j aponica with three fish-tagging methods,i.e.H-bar tagging,coded wire tagging,and ventral sundering tagging. After a fortnight temporary rearing experiment,the result was as follows:all the three fish-tagging made no significant difference on the survival rate,and the success rate of tagging large group was evidently higher than that of tagging small group(p <0.05),but the success rate of H-bar tagging group was significantly lower than that of the other two groups(p <0.05).In addition to the liver to body weight ratio,different tagging methods significantly affected tagged fishes' primary growth indexes (p <0.01 ).Likewise,the forage conversion efficiency and the organ to body weight ratio were extremely influenced by the size of N .j aponica (p <0.01).The interaction between these two factors significantly affected the organ to body ratio (p <0.05),and extremely influenced the forage conversion efficiency and the liver to body weight ratio (p <0.01).Compared to the control group,the H-bar tagging group showed significant differences in various growth indexes(p <0.05),while the coded wire tagging group and ventral sundering tagging group only showed significant differences in the forage conversion efficiency and the organ to body weight ratio(p <0.05),respectively.Ac-cordingly,it is recommended that the ventral sundering tagging method is applicable for a short time tagging,and the coded wire tag-ging method has small effect on the growth of fish.As for N .j aponica ,when the body length is greater than 10.0 cm,it is suggested to adopt the H-bar tagging method in order to increase the recapturing rate.

According to the seine net survey data of fish larvae and juveniles from April to September in 2011, the index of species diversity, Cluster and MDS ordination analysis were used to analyze the spatio-temporal variations of species composition and diversity from the beach surf zone of Zhoushan archipelago. The results showed that 562 fish larvae and juveniles were collected in spring and summer, which belonged to 21 families and 37 species in total, the dominant species was Liza carinatus which comprised 20.82%, followed by Tridentiger trigonocephalus, Lateolabrax japonicus and Stolephorus chinensis which comprised 18.33%, 12.81% and 11.74% of the total number of individuals respectively. Cluster analysis showed that the community structure of fish larvae and juveniles in Zhoushan archipelago was relatively stable; Seasonal variation obviously, fish larvae and juveniles in July and August were the most similar, with the largest difference between April and September; Fish larvae and juveniles in Taohua island and Zhujiajian island were the most similar, with the largest difference between Xiushan island and Liuheng island.