“发展碳汇渔业科技 服务国家双碳战略”学术研讨会在山东荣成召开

正本刊讯9月7日～8日,"发展碳汇渔业科技、服务国家双碳战略"学术研讨会以"线下+线上同步直播"形式在山东省荣成市举行,与会专家集中研讨了碳汇渔业作用机制、计量方法、标准体系及支撑碳中和科学途径。研讨会由农业农村部渔业渔政管理局指导,中国水产科学研究院主办,中国水产科学研究院黄海水产研究所和海洋试点国家实验室海洋渔业功能实验室承办。     

内陆渔业生态系统的碳循环特征及碳汇机制

渔业是水体生态系统中惟一可控的有效增汇产业, 碳汇渔业是水体生态系统中惟一的“碳汇产业”。为了更好地把握内陆渔业生态系统碳循环及碳汇机制的特征, 目前的重点研究应包括内陆渔业水域生态环境(包括自然水域和池塘)中碳循环的规律, 碳赋存形态的归转, 各类水产品生物对碳汇的贡献途径和份额以及相应的计量体系和评价模型等; 同时, 希望合理地估算及测定内陆渔业水体、水–气界面间CO2通量, 把握内陆渔业水域生态系统碳源/碳汇的动态, 进而构建内陆渔业水域生态系统的环境碳/生物碳/碳通量时空变化的信息库。     

海洋牧场渔业碳汇研究进展

海洋通过“溶解度泵”和“生物泵”完成碳汇过程，且具有碳固存容量大、储存时间长的显著优势，可有效缓解CO2排放产生的温室效应，在应对全球气候变化中发挥着不可替代的作用。渔业是人类利用海洋的基础生产活动，对近海碳循环过程具有重要的影响，渔业碳汇是海洋碳汇不可或缺的组成部分。海洋牧场作为一种以水域栖息地修复、水生生物资源养护为主旨的新型渔业模式，通过增殖水生生物资源量，提升生物固碳量，实现渔业对海洋碳汇的扩增。本文针对我国对海洋牧场的界定，梳理了国内外对海洋牧场关键碳汇因子固碳机理及其过程和潜能等方面的研究现状，浅析了海草床、牡蛎礁等典型海洋牧场生态系统在近海碳汇扩增中的重要作用。建议在海洋牧场固碳机理与碳循环过程、海洋牧场碳汇扩增技术和海洋牧场碳汇计量方法等方面开展重点研究，以期为渔业绿色发展，扩增海洋碳汇和服务“双碳”战略提供科学参考。     

海洋浮游植物与渔业碳汇计量

探讨了海洋浮游植物与渔业碳汇的关系,重点介绍了其与渔业碳汇计量相关的参数:浮游植物初级生产力、碳生物量、比生长率和比摄食率,对于每种参数简要介绍其原理及常用方法。本质上,渔业碳汇是浮游植物碳汇过程的一个重要分支,其碳汇测算等同于生态系统中关于浮游植物颗粒态有机碳通量的测算。     

贝藻类碳汇功能及其在海洋牧场建设中的应用模式初探

资源管理型渔业是未来海洋渔业发展的主要方向,海洋牧场是资源管理型渔业的主要方式之一。海洋牧场建设与碳汇渔业相结合是一种全新的水生生物养护形式,以贝类养殖和藻类栽培为载体的海洋牧场建设具有广泛的应用前景。本文分析了当前中国海洋牧场建设的形式,同时对贝藻类碳汇功能及其在海洋牧场建设中的重要性进行了论述,并结合浅海海域实际条件提出建设海洋牧场合理规划建议。     

关于在台州市加快发展碳汇渔业的思考

生物固碳具有操作成本低、易施行的特点,且可以达到间接减排的效果,是目前应对气候变暖最经济、最现实、最有效的手段。分析综述了碳汇渔业的概念、机理和固碳能力,阐述了在台州市加快发展碳汇渔业的重要意义,提出了加快发展碳汇渔业的路径选择和政策建议。     

渔业碳汇与碳汇渔业定义及其相关问题的辨析

本文基于联合国政府间气候变化专门委员会(IPCC)关于碳汇和碳源的解释和水生植物固碳特点,对2010年提出的渔业碳汇和碳汇渔业的定义进行修订,强调了渔业碳汇功能和增汇的基本表达方式和水生植物在渔业碳汇中的重要作用,进一步解释了通过水生藻类养殖、滤食性贝类和鱼类等养殖、渔业生物群体捕捞和增殖等渔业生产活动促进水生生物“移出和储存”CO2等温室气体的过程和机制。分析了贝类养殖在不需要投放饵料的前提下,通过滤食浮游植物及有机碎屑等颗粒有机物大量使用水体中CO2的过程及机制,从能量收支层面论述了使用碳、移出碳、储存碳和释放碳4个碳库的特征及其数量关系,进而证实贝类养殖提升了水域生态系统碳汇能力,是碳汇而不是碳源。贝藻养殖碳汇评估结果表明,随着海水养殖生产持续发展,近20年我国近海贝藻养殖碳汇有较大幅度的增加,总碳汇量从2001年394万t增加到2020年659万t,其中近三年(2018—2020)平均总碳汇量为648万t (相当于每年义务造林87万hm2);净碳汇量从2001年255万t增加到2020年430万t,近三年(2018—2020)平均净碳汇量为422万t (相当于每年义务造林56万hm2)。最后,提出了健康持续、深入发展碳汇渔业的相关建议。     

我国海洋渔业的中间组织行为研究

从世界范围来看,渔业中间组织的建立对于海洋渔业的发展起到了重要的推动作用,研究渔业中间组织对于我国海洋渔业的发展具有重要作用。文章探讨海洋渔业中间组织的无核心、单核心以及多核心三种基本组织形式及其内容,并在借鉴日本渔业协同组合建立和运作形式的基础上,分析我国海洋渔业中间组织在组织、运作、政府管理等方面存在的问题,提出加大授权力度、提高综合服务能力等发展建议。     

贵贵州地区碳汇渔业潜力研究

我国是当今世界水产品产量最高的国家，渔业呈现地区发展不平衡、不充分的格局，内陆地区渔业发展水平总体上远低于沿海地区。在当前“碳达峰”和“碳中和”双碳战略背景下，渔业迎来了前所未有的机遇和挑战尤其是对于内陆淡水渔业，碳汇渔业将成为未来的一个重要发展方向。该文主要根据《中国水产统计资料》和《中国渔业统计年鉴》，以贵州省为例，结合贵州地区近年来的渔业发展现状，估算了贵州省近五年(2016—2020年)的渔业碳汇强度，分析了贵州地区发展碳汇渔业的潜力。渔业碳汇强度估算结果显示，2016—2020年贵州省渔业碳移出量在1.4 t到1.7 t之间，平均碳移出量为1.5 t。贵州省渔业发展相对落后，水产品捕捞产量和养殖产量均远低于全国平均水平，但贵州省近年来大力推广稻渔综合种养和湖库养殖等生态渔业模式，到2020年稻田养殖和湖库养殖面积分别占全省水产养植总面积的74.2%和19.2%，二者产量达到全省总产量的一半以上，远高于全国平均水平。稻渔综合种养和湖库养殖等生态渔业成为贵州省水产养殖业的重要养殖模式，未来这类具备碳汇功能的生态渔业规模将会进一步扩大，是贵州地区扭转渔业养殖模式和渔业经济增长方式的机遇，对碳汇渔业的全面推广和渔业的可持续发展具有重要指导意义。     

辽宁省海洋渔业环境监督监测站

辽宁省海洋渔业环境监督监测站位于大连市黑石礁，始建于1986年，当年入全国渔业环境监测网，为网站成员。担负辽宁省近岸海域渔业水域的环境监测、污染事故的调查鉴定及监督监测、珍稀水生物种生态环境的监测、水生生物毒物残留的监测、海岸工程建设项目对渔业环境影响的评估以及赤潮预报监测等多项任务。2004年6月1日经国家认证认可监督管理委员会批准为计量认证合格单位。目前可开展的检测项目有，海洋水文与气象、海水环境、海洋沉积物环境、海洋生物质量等，包括海洋中无机氮、活性磷酸盐、化学耗氧量、重金属、有机物、石油类、海洋生物、微生物等52个项目的检测与分析，还可开展多种生物实验及其病理、毒理的检测分析。建站以来，承担了多项国家、部局的渔业环境评价、赤潮预报、渔业生态等方面的研究项目。     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.     

Cardiac,ventilatory and metabolic responses of two ecologically dissimilar species of fish to waterborne cyanide

Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8–9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths followed by a sudden respiratory arrest. The bullheads exhibited hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were much greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, possibly due to a greater fuel supply. Overall, the trout responded to cyanide in a manner similar to that produced by environmental hypoxia whereas the bullheads experienced a gustatory stimulus which masked the hypoxia-like response.     

An overview of stress physiology of fish transport: changes in water quality as a function of transport duration

This study brings an integrated analysis about the relationship between water deterioration and its physiological consequences in live fish transport. The analysis was focused on the transport water and its deterioration, and physiological challenges imposed on the fish. Usual commercial handling procedures employed to mitigate fish stress during transport were discussed. Future topics of research for the establishment of safer fish transport protocols were proposed. Transport was classified into short (≤8 h) or long transport (>8 h). The main issue in short transports should be the prevention of water pH reduction, while in long transports it is the increase in ammonia. Plasma cortisol is the most employed marker for stress and is acutely elevated upon short episodes of transport, but remains elevated even in long‐transport events. Plasma glucose is perhaps a better marker for handling stress. Plasma lactate, pH, osmolality CO₂ and ions should be more often evaluated. Plasma Na⁺ and Cl^‐ are very useful markers of acidosis, due to their respective exchange for H⁺ and , for acid–base regulation. The establishment of species‐specific transport protocols should be preceded by such combined analyses of water and physiological parameters.     

Are hatchery‐reared abalone naïve of predators? Comparing the behaviours of wild and hatchery‐reared northern abalone,Haliotis kamtschatkana (Jonas, 1845)

Abalone populations have declined worldwide, generating interest in enhancement using hatchery‐reared individuals. In many cases, such restoration efforts have met with limited success due to high predator‐induced mortality rates. Furthermore, the mortality rates of outplanted hatchery abalone are often considerably higher than for wild individuals. This study uses northern abalone (Haliotis kamtschatkana) as a case study to determine whether hatchery‐reared abalone behave differently than their wild counterparts. In the field, outplanted hatchery‐reared abalone were significantly less responsive than wild abalone, in terms of number of abalone responding and intensity of response, to nearby movement and to physical contact with an inert probe. Also, when encountering a cue to which all abalone responded (a seastar predator), hatchery‐reared individuals remained subdued. Anti‐predator behavioural deficits in hatchery‐reared abalone were more pronounced in 4‐year‐old individuals than in 1‐year‐old individuals, suggesting an influence of either age or amount of time spent in the hatchery environment. These behavioural differences are expected to increase the vulnerability of hatchery‐reared abalone to predators, and are likely a major cause of their elevated predator‐induced mortality when outplanted.     

Effects of cadmium on the kinetics of calcium uptake in developing tilapia larvae, Oreochromis mossambicus

The toxic effects of Cd²⁺ on Ca²⁺ influx kinetics in developing tilapia (Oreochromis mossambicus) larvae were evaluated. Addition of 20 µg l^-1 of Cd²⁺ to the environment of 0 and 3 day-old larvae competitively inhibited the Ca²⁺ uptake within 4h resulting in a great increase in K_m values for Ca²⁺ influx (19.3 and 17.4 fold, respectively) as compared with their respective controls. Consequently, the actual Ca²⁺ influx of larvae in solutions of 0.2 mM Ca²⁺ are suppressed by 32–45%. Also, 3 day-old larvae were more sensitive to internally accumulated Cd²⁺ than 0 day-old larvae. Although the Ca²⁺ influx in 0 and 3 day-old larvae may be restored to the levels of their respective controls with 24h of being transferred to a 20 µg l^-1 Cd²⁺ solution, total body Ca²⁺ content was significantly reduced in 3 day-old larvae. Increased Ca²⁺ uptake efficiency ensures sufficient Ca²⁺ for normal growth. However, rapid increase in Ca²⁺ influx after hatching also leads to higher Cd²⁺ uptake. Exposure to Cd²⁺ will lead to a drop in body Ca²⁺ content resulting in retardation of larval growth. Therefore, we conclude that if Ca²⁺ uptake is interfered with at this critical stage of development, larvae will not be able to maintain normal levels of body Ca²⁺ and will show signs of Cd²⁺ poisoning.     

Migratory dynamics of stream-spawning longnose gar (Lepisosteus osseus)

Abstract– Literature evidence suggests that lake-dwelling longnose gar (Lepisosteus osseus) enter tributary streams to spawn, Until the present study, the dynamics of this breeding migration had never been investigated quantitatively. During the summers of 1991 and 1992, longnose gar were captured as they entered Weaubleau Creek, Missouri, a tributary of Harry S. Truman Reservoir. The in-stream spawning migration began in early April and ended in late May, and was positively correlated with stream flow and water level, and negatively correlated with water temperature. In-stream residence times ranged from 15 to 94 days, with males exhibiting longer residence times than females. Once in-stream, longnose gar travelled as far as 10 km upstream and occupied certain pools at greater relative frequencies. Although the reason for this preferential utilization is not completely understood, it may relate to pool depth and riffle proximity. Longnose gar disperse from the spawning stream great distances, with gar captured in Weaubleau Creek being recaptured up to 48 km away. This information should provide fisheries biologists the means to consider the reproductive ecology of this species in their conservation and management decisions.     

Nutritional regulation of hepatocyte fatty acid desaturation and polyunsaturated fatty acid composition in zebrafish (Danio rerio) and tilapia (Oreochromis niloticus)

The desaturation and elongation of [1-¹⁴C]18:3n-3 was investigated in hepatocytes of the tropical warm freshwater species, zebrafish (Danio rerio) and Nile tilapia (Oreochromis niloticus). The hepatocyte fatty acid desaturation/elongation pathway was assayed before and after the fish were fed two experimental diets, a control diet containing fish oil (FO) and a diet containing vegetable oil (VO; a blend of olive, linseed and high oleic acid sunflower oils) for 10 weeks. The VO diet was formulated to provide 1% each of 18:2n-6 and 18:3n-3, and so satisfy the possible EFA requirements of zebrafish and tilapia. At the end of the dietary trial, the lipid and fatty acid composition was determined in whole zebrafish, and liver, white muscle and brain of tilapia. Both zebrafish and tilapia expressed a hepatocyte fatty acid desaturation/elongation pattern consistent with them being freshwater and planktonivorous fish. The data also showed that hepatic fatty acid desaturation/elongation was nutritionally regulated with the activities being higher in fish fed the VO diet compared to fish fed the FO diet. In zebrafish, the main effect of the VO diet was increased fatty acid Δ6 desaturase activity resulting in the production of significantly more 18:4n-3 compared to fish fed the FO diet. In tilapia, all activities in the pathway were greater in fish fed the VO diet resulting in increased amounts of all fatty acids in the pathway, but primarily eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3). However, the fatty acid compositional data indicated that despite increased activity, desaturation of 18:3n-3 was insufficient to maintain tissue proportions of EPA and DHA in fish fed the VO diet at the same level as in fish fed the FO diet. Practically, these results indicate that manipulation of tilapia diets in commercial culture in response to the declining global fish oil market would have important consequences for fish fatty acid composition and the health of consumers. Scientifically, zebrafish and tilapia, both the subject of active genome mapping projects, could be useful models for studies of lipid and fatty acid metabolism at a molecular biological and genetic level. This revised version was published online in August 2006 with corrections to the Cover Date.     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg^?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg^?1 protein) than essential amino acids (425.82 ± 9.15 g kg^?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.