内壳在头足类年龄与生长研究中的应用进展

年龄与生长是渔业基础生物学研究的重要内容。体长频度法估算头足类的年龄并不可靠,而利用硬组织来研究头足类的年龄和生长是最为有效的方法之一。内壳作为头足类少数硬组织之一受到国内外学者的广泛关注。本文从内壳的提取、保存、制备、观察,生长纹的特征,生长纹周期性以及日龄鉴定等方面综述了其在头足类年龄和生长方面的研究进展。分析认为,柔鱼类内壳因其生长早期的生长纹不清晰而无法用来鉴定其整个生活史的年龄;乌贼类内壳因其生长受环境尤其水温的影响显著,因此并不适合用作年龄鉴定的材料;而章鱼类内壳在其年龄和生长研究中应用前景最广泛。今后的研究希望能够在年龄鉴定基础上,开展内壳时间序列上的微量元素与稳定同位素研究,为进一步分析头足类的种群结构、摄食生态、栖息环境以及生活史等内容提供基础资料。     

南极鱼类年龄与生长研究进展

南极鱼类生长相对缓慢,独特的生物学特性使其年龄鉴定较其他海区鱼类更为困难。但考虑到鱼类年龄鉴定是开展渔业资源评估的基础,因此过去一些年来,硬质部位,如鳞片、鳍条(棘)、脊椎骨以及耳石等仍成为南极鱼类的主要鉴龄材料。本文对南极鱼类年龄鉴定的方法和材料进行了总结回顾,将年龄鉴定的方法和材料进行比较,分析各自优缺点。结果显示:(1)对于具鳞的南极鱼类,因鳞片在鱼类生长过程中存在重吸收现象,因而利用鳞片及鳍条(棘)单独鉴龄所得出的结果通常小于耳石的鉴龄结果,缺乏精确性;(2)南极鱼类生活跨度较大,高龄鱼体长频次分布严重重叠,以致无法准确判断其年龄结构;(3)耳石重量法易受到特殊个体影响而误判年龄;(4)因鳍条易损坏,脊椎骨采集较为困难,且许多南极鱼类无鳞,目前大多数南极鱼类使用耳石鉴定年龄,其也成为目前最为精准的南极鱼类鉴龄方法,但同时利用鳞片和耳石重量等对鉴定结果进行验证;(5)南极鱼类尚存在无统一的鉴龄标准、人为主观性较强以及缺乏早期生活史研究等不足之处;(6)为了研究南极鱼类早期生活史,耳石微化学及微结构等方法将被广泛利用。     

利用胃磨鉴定三疣梭子蟹年龄初探

三疣梭子蟹(Portunus trituberculatus)是中国重要的经济物种,对其进行年龄鉴定有利于其种群资源的评估和管理。该研究对三疣梭子蟹的胃磨进行制片处理,初步探讨了胃磨鉴龄的可行性。三疣梭子蟹胃磨由5个部分(前幽门骨、外幽门骨、尾贲门骨、轭贲门骨和翼贲门骨)组成,依据前人研究结果选取外幽门骨和尾贲门骨进行切片观察。结果显示,三疣梭子蟹胃磨微结构由4个部分(蜡质层、外角质层、钙化层和膜层)组成,用于年龄鉴定的生长纹主要存在于钙化层中。利用7个生长方程拟合三疣梭子蟹生物学数据与生长纹数目的关系,结合赤池信息量准则(AIC)得出甲长与甲宽呈线性函数关系、甲宽与体质量呈幂函数关系;体质量与胃磨生长纹数目的关系适用于Gompertz模型,甲长、甲宽与胃磨生长纹数目的关系则更适用于v-B生长模型。即胃磨生长纹可以作为甲壳类年龄鉴定的材料,但由于实验样本偏小型化,后续需要延长时间跨度进一步验证。     

闽南—台湾浅滩二长棘鲷年龄和生长研究

本文根据闽南一台湾浅滩1019尾二长棘鲷年龄和生长的周年资料，阐明年轮特征及其形成时期、生长发育阶段和参数，并探讨种群结构的资源特点。其鳞片可作为年龄鉴定依据，从鳞片边缘增长率和体长分布频率，表明年轮每年形成一次，3—4月为年轮主要形成时期。逆算体长不存在Rosa Lee现象，各年龄组平均体长的实测值，以定差法所求得的生长参数为最佳值。衰老拐点(相当于Ⅳ龄组)正处于成鱼强壮期转入老年鱼生长衰老期。拖网周年渔获中0龄组最多，Ⅰ龄组次之。应严格限制拖捕当年生的0龄组幼鱼。     

长鳍吻(鱼句)年龄和生长的研究

对443尾长鳍吻鮈标本作了年龄和生长研究。用鳞片鉴定年龄并退算鱼的生长.得出体长与鳞径、体长与体重的相关式及生长方程。体重生长拐点在2.2龄。限制捕捞3龄以下个体,有利于资源增殖.     

鱼类年龄鉴定研究概况

鱼类年龄鉴定是渔业资源评估的基础内容,经过长时间的发展,众多的方法被应用到这一领域。综述了目前应用较广泛的一些年龄鉴定方法,包括硬组织鉴定法和长度分析法两大部分方法,并分析了它们的优点和缺点。目前,鱼类年龄鉴定工作中存在的主要问题有:鉴定方法的精确度不高;鉴定方法多数较冗繁,耗时耗力;鱼类年龄鉴定未经标准化。有鉴于此,有必要对各种鉴定方法进行校验。介绍了几种常用的年龄校验方法,并对其进行了分析。     

南湾水库鳙鱼的生长及其资源评估

南湾水库的鳙鱼的平均年龄为3龄,南湾水库鳙鱼体长与体重的关系呈幂指数关系,关系式为W=0.0413L2.8472(R2=0.9422)。应用VonBertalanffy生长方程拟合其生长规律,体长与体重的生长不等速,其主要生物学参数为:L∞=87.6cm,W∞=28.5kg,体长的k=0.2443、t0=0.26778;体重的k=0.141、t0=-0.137,拐点年龄ti=7.5龄,拐点体重为8.05kg。回捕率37.5%,自然死亡率27.0%,其它死亡率33.3%。南湾水库鳙鱼的适宜开捕年龄为3 龄,平均体重约3947g。适当减小起捕规格,提高捕捞强度,可增加鲢鳙鱼的产量和效益。     

青岛胶州湾铠平鲉年龄、生长和种群繁殖力

针对2013年和2014年采自青岛胶州湾的209尾铠平鲉(Sebastes hubbsi)样本开展了年龄、生长和种群繁殖力研究。耳石轮纹结构的年龄鉴定结果显示,铠平鲉的年龄分布范围为1~+~7~+龄,2~+~4~+龄为优势年龄组(77.5%)。体长与体重呈幂函数关系:W=8×10~(-5) L~(2.797)(R~2=0.861)。Von Bertalanffy体长生长方程为L_t=131.4×[1-e~(-0.269(t+2.697))],体重生长方程为W_t=63.6×[1-~(e-0.269(t+2.697))]~(2.797)。其生长过程可分为3个阶段:(1)1~+~3~+龄为快速生长期;(2)3~+~6~+龄为成熟稳定期;(3)6~+龄以后为高龄衰老期。所采样本的性比(2.12︰1)明显偏离1︰1(P0.05),雌性个体样本数在各体长段均高于雄性个体。性腺指数(GSI)和肝脏指数(HSI)变化趋势相反,肝脏可能为其性腺发育提供物质基础和能量来源。绝对怀卵量波动于482~6166粒,平均值为3266粒;相对体长怀卵量显著低于卵生鱼类,表明卵胎生鱼类体内胚胎发育、孵化的护卵方式可能使其以较少的怀卵量即可维持种的延续。结合拐点年龄对应的拐点体重及50%性成熟体长,建议以体长80 mm、体重20 g作为铠平鲉的开捕标准,以维护青岛胶州湾铠平鲉资源的可持续利用。     

内蒙古西湖鲤的生物学特性

对西湖鲤的年龄、生长、食性、繁殖等进行分析.西湖鲤体长与体重关系式为W=0.0589L~(2.791)。4龄以前生长较快.提高鱼产量的措施一是合理捕捞,只捕3~ 龄以上的鲤;二是加强资源增殖保护.     

三道河水库大眼鳜的年龄和生长

依据大眼鳜鳞片上的疏密切割等特征鉴定年龄。渔获个体以Ⅱ龄鱼为主占８６％。鳞长与体长关系Ｌ＝１２１３２６Ｓ１０５０８。体长与体重关系Ｗ＝１２３８×１０－２Ｌ３１９８９。体长、体重与年龄的关系适用ＶｏｎＢｅｒｔａｌａｕｆｙ生长方程拟合：Ｌｔ＝Ｌ∞（１－ｅ－０５０８３（ｔ－０３９９））；Ｗｔ＝Ｗ∞（１－ｅ－０５０８３（ｔ－０３９９）３１９８９。拐点年龄为２５６ａ，与生长指标陡然下跌年龄和性成熟年龄基本一致。为了资源的持续利用应限捕体重５３０ｇ、相应体长２８３ｃｍ以下个体     

Evidence for systemic age underestimation in shark and ray ageing studies

Numerous studies have now demonstrated that the most common method of ageing sharks and rays, counting growth zones on calcified structures, can underestimate true age. I reviewed bomb carbon dating (n = 15) and fluorochrome chemical marking (n = 44) age validation studies to investigate the frequency and magnitude of this phenomenon. Age was likely to have been underestimated in nine of 29 genera and 30% of the 53 populations studied, including 50% of those validated using bomb carbon dating. Length and age were strongly significant predictors of occurrence, with age typically underestimated in larger and older individuals. These characteristics suggest age underestimation is likely a systemic issue associated with the current methods and structures used for ageing. Where detected using bomb carbon dating, growth zones were reliable up to 88% of asymptotic length (L_∞) and 41% of maximum age (A_Max). The maximum magnitude of age underestimation, Δ_Max, ranged from five to 34 years, averaging 18 years across species. Current perceptions of shark and ray life histories are informed to a large extent by growth studies that assume calcified ageing structures are valid throughout life. The widespread age underestimation documented here shows this assumption is frequently violated, with potentially important consequences for conservation and management. In addition to leading to an underestimation of longevity, the apparent loss of population age‐structure associated with it may unexpectedly bias growth and mortality parameters. Awareness of these biases is essential given shark and ray population assessments often rely exclusively on life history parameters derived from ageing studies.     

Classifying tagging experiments for commercial fisheries into three fundamental types based on design,data requirements and estimable population parameters

Mark–recapture experiments have the potential to provide direct estimates of fundamental parameters required for fishery stock assessment and provision of subsequent management advice in fisheries. The literature on mark–recapture experiments is enormous, with a variety of different experimental designs and estimation models; thus, it can be difficult to grasp the primary features of different approaches, the inter‐relationship among them and their potential utility in different situations. Here, we present an overview of the tagging experimental designs that are appropriate for use in commercial fishery situations. We suggest that most mark–recapture experiments in a large‐scale fishery context can be classified into one of three basic types – Petersen, tag‐attrition or Brownie – based on the fundamental design employed for releases and recaptures. The release and recapture strategy (e.g. the number of release events, whether the size of the sample examined for recaptured tags is known) determines which parameters can be estimated and from where the information for estimating them arises. We conclude that an integrated Brownie and Petersen approach is the most powerful of the different approaches in terms of the range of parameters that can be estimated without underlying assumptions or constraints on parameters. Such an approach can provide direct estimates of fishing mortality, natural mortality and population size, which are the main population dynamics parameters that traditional fishery stock assessments attempt to estimate.     

乌江思林水电站库区鱼类增殖放流效果初步研究

为探究乌江思林水电站鱼类增殖放流效果,2013年和2014年对思林(沙沱)鱼类增殖放流站放流的中华倒刺鲃(Barbodes sinensis)和白甲鱼(Varicorhinus simus)部分个体进行了荧光标记,共标记放流1.98万尾中华倒刺鲃和4.56万尾白甲鱼,并在2014年与2015年进行了2个周期的回捕调查。结果显示,回捕调查捕获鱼类12种,共计2687尾;其中,中华倒刺鲃和白甲鱼的渔获物占比分别为1.60%和0.71%,未见荧光标记个体。通过走访调查,收集到标记中华倒刺鲃7尾(2014年6尾,2015年1尾)、白甲鱼7尾(2014年4尾,2015年3尾),回捕率分别为0.013%~0.049%和0.009%~0.030%,回捕地点共7个,距离放流地点226~24 105 m。研究表明,思林(沙沱)鱼类增殖放流站的增殖放流活动可对中华倒刺鲃、白甲鱼等起到一定增殖效果。为取得更好的增殖放流效果,建议调整放流方法、放流地点、加强渔政管理和宣传教育。     

Performance of rainbow trout, Salmo gairdneri Richardson, in a put-and-take fishery, and influence of anglers' behaviour on catchability

Abstract. Stock, catch and fishing effort statistics for a 12·5-ha lowland pul-and-lake trout fishery have been used to compute the ‘catchability’ of rainbow trout, Salmo gairdneri Richardson, during the fishing seasons 1980–1983. Seasonal trends in the fishes’ susceptibility to capture by fly-fishing are apparent but there was no indication that, in this fishery, newly stocked fish were more vulnerable than the longer-term residents. This consistency of recapture rates of rainbow trout, relative to the population available, is a function both of the fish's behaviour and that of the anglers themselves, and it is suggested that for management purposes the latter must be taken into account. In the fishery studied rainbow trout grew well at fish densities below 60 kg ha^?1, but even with overall recapture levels exceeding 80% the yield of the fishery was less than the weight of fish stocked. The selection of strains of rainbow trout which satisfy the requirements of sport fisheries is discussed.     

The eel fishery in Lough Neagh,Northern Ireland – an example of sustainable management?

Abstract  Lough Neagh produces over 500 t of grown eel annually and employs 300 people fishing yellow and silver eel. Glass eel are transported upstream and stocked into the Lough. Since glass eel returns crashed in the 1980s, additional glass eel seed has been purchased from other fisheries. The fishery now faces ecological, social and economic pressures. Prices for the product have fallen; recruitment to the fishery has declined, and seed has decreased in availability and increased in price. Fishers are less inclined to take up the hard work required to make a living fishing eel and the fisher population is ageing. The European Commission has recognised the decline of eel and proposed emergency measures, which may further affect the viability of the fishery. The sustainability of the fishery is examined, based on the relationship between glass eel input and grown eel outputs over a period of 45 years, set against increasing environmental, socio-economic, and natural resource pressures. Spawning escapement of silver eel is estimated by mark–recapture experiments.     

Single spaghetti tagging as a high-retention marking method for Japanese common sea cucumber <Emphasis Type="Italic">Apostichopus japonicus</Emphasis>

Populations of sea cucumbers, including the Japanese common sea cucumber Apostichopus japonicus, have been seriously depleted worldwide due to overfishing. Mark–recapture study is an efficient means of collecting ecological data. However, the use of such a method in sea cucumbers is difficult because they lack hard tissues in the body wall. Here we tested the viability of various tagging methods on A. japonicus. First, we applied conventional tags using four different methods [single spaghetti (T-bar) tagging, double spaghetti tagging, ribbon tagging, and Atkins tagging] to ten individuals per method in aquaria for 14 days. Of the methods used, single spaghetti tagging had the highest retention rate. Then we examined the retention rate of single spaghetti tags on ten individual sea cucumbers for up to approximately 6 months in rearing conditions. The single spaghetti tagging method showed a retention rate of 100% over at least 7 days, and 50% of the tags remained embedded after 56 days. The longest duration of tag retention was 174 days, at which time the experiment was terminated. These results indicate that single spaghetti tagging is reliable for both short- and longer-term studies, making it a useful tool for ecological and conservation studies in sea cucumbers.     

鱼类自然死亡系数评估研究进展

自然死亡系数是渔业资源评估中不可或缺的重要参数,其准确度直接决定了资源评估结果的可靠性,进而影响渔业管理策略的制定。本文从生活史参数、标志回捕和年龄结构3个方面列举了国内外自然死亡系数的常用评估方法,讨论了相关方法的优缺点及影响因素,并以犬齿牙鲆(Paralichthys dentatus)和中国近海鱼类为例对比分析不同模型的计算结果。在此基础上,着重介绍了Pauly经验公式在中国近海主要经济鱼类自然死亡系数评估中的应用进展及存在问题。根据渔业资源调查和研究数据现状,认为现阶段使用Pauly经验公式评估中国近海经济鱼类自然死亡系数具有积极作用。     

Conservation of spawning time between years in lumpfish Cyclopterus lumpus and potential impacts from the temporal distribution of fishing effort

Lumpfish, Cyclopterus lumpus L., has an extended ovary development period and a relatively long spawning season. It therefore seems unlikely that individuals spawning later in the season would be able to recover from spawning and develop their gonads in time to spawn during the early part of the season the following year. The hypothesis that individuals spawning early or late in a spawning season would spawn early or late the following year was tested using fish tagged in Iceland between 2008 and 2017. The tagging date and recapture date the following year were positively correlated with an average of 356 days at large (DAL). Fish sampled from the fishery indicate that tagging/recapture date gives an indication of spawning time. From this, it was concluded that spawning time in the current year can be used to predict spawning time the following year. As fishing effort was greatest at the end of April/beginning of May, it seems likely that fish that come to spawn at this time will be subject to a higher fishing mortality. Therefore, they will be less likely to spawn successfully than fish spawning earlier or later in the year. If spawning time is under genetic control, then this could have consequences for the spawning phenology of lumpfish.     

Evaluation of ageing accuracy with complementary non‐lethal methods for slow‐growing,northern populations of shoal bass

In the upper Chattahoochee River basin, where some populations of shoal bass, Micropterus cataractae Williams & Burgess, are imperilled, age and growth data are lacking. Age and growth of shoal bass in this basin were assessed with non‐lethal means using scales and mark–recapture. Mark–recapture data allowed for estimation of accuracy and determination of effects of any scale‐based inaccuracies on growth models. Scale‐based age estimates were accurate for 57% of the samples, and errors of 1 to 3 years included equal numbers of over‐ and underestimates of age. von Bertalanffy growth models based on scale ages were similar to those based on mark–recapture ages for ages 3–8 but noticeably divergent for younger and older fish. Scales provided estimates of longevity up to 12 years of age, and growth models produced from mark–recapture suggest scale ages underestimated age, especially for older fish. These populations of shoal bass live longer and grow slower than other populations, suggesting regional management strategies may be needed.