区域渔业管理组织中的鲨鱼养护管理问题研究

镰状真鲨属大型中上层鲨鱼,是东太平洋地区金枪鱼延绳钓和围网兼捕渔获最多的鲨鱼种类,近年来资源衰退严重,被世界自然保护联盟 (IUCN)评估为易危物种,并列入《濒危物种国际贸易公约》 (CITES)附录 II。开展鱼类年龄与生长研究,是评估其资源状况的基础,可为制定有效的物种保护政策提供理论依据。以东太平洋金枪鱼延绳钓兼捕记录的802尾 (雌性 316尾,雄性 486尾)镰状真鲨为研究对象,实验随机采集67尾 (雌性 35 尾,雄性 32 尾)脊椎骨样本,通过切片法和草酸铵结晶紫染色法鉴定年龄,建立最适生长模型。结果显示,延绳钓兼捕的东太平洋镰状真鲨以全长160~220 cm,年龄9~15龄个体为主,雌、雄最大观测全长分别为222.58和233.47 cm,最大年龄分别为18龄和17龄,雌、雄逆推全长的最适生长模型均为Logistic模型,其中雌性 相似文献   

甲壳类年龄鉴定方法研究进展

甲壳类特有的蜕壳现象,使其能够记录年龄信息的外骨骼周期性消失,因此甲壳类的年龄鉴定一直未得到较好的解决。年龄鉴定是评估甲壳类渔业资源的基础,鉴定甲壳类年龄的方法主要有饲养法、标记重捕法、体长频度法、脂褐素分析法、放射性同位素分析法和硬组织生长纹分析法。饲养法、标记重捕法和放射性同位素分析法较准确,然而由饲养法得到的数据不适用于实际野生环境,放射性同位素分析法花费较高,因此,这两种方法都存在较大的局限性。应用最广泛的标记重捕法和体长频度法也存在不足之处。相对于体长频度鉴龄技术而言,脂褐素分析法优势明显,但是对劳动强度和技术要求高。硬组织生长纹分析法是最近几年出现的鉴龄技术,也存在人为主观性较强等不足。本文对甲壳类年龄鉴定的方法进行了总结回顾,将不同鉴定方法进行比较,分析优缺点,以期为开展甲壳类资源评估与管理提供基础。     

东太平洋镰状真鲨年龄与生长

镰状真鲨属大型中上层鲨鱼，是东太平洋地区金枪鱼延绳钓和围网兼捕渔获最多的鲨鱼种类，近年来资源衰退严重，被世界自然保护联盟(IUCN)评估为易危物种，并列入《濒危物种国际贸易公约》(CITES)附录II。开展鱼类年龄与生长研究，是评估其资源状况的基础，可为制定有效的物种保护政策提供理论依据。以东太平洋金枪鱼延绳钓兼捕记录的802尾(雌性316尾，雄性486尾)镰状真鲨为研究对象，实验随机采集67尾(雌性35尾，雄性32尾)脊椎骨样本，通过切片法和草酸铵结晶紫染色法鉴定年龄，建立最适生长模型。结果显示，延绳钓兼捕的东太平洋镰状真鲨以全长160～220 cm，年龄9～15龄个体为主，雌、雄最大观测全长分别为222.58和233.47 cm，最大年龄分别为18龄和17龄，雌、雄逆推全长的最适生长模型均为Logistic模型，其中雌性■雄性■，雌、雄个体50%性成熟年龄t50分别为(13.50±0.43)和(13.42±0.46)龄，50%性成熟全长L50分别为(207.60±2.43)和(200.67±3.60) cm。     

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。     

基于生活史特征的数据有限条件下渔业资源评估方法比较

渔业资源评估是开展渔业资源管理,维系渔业可持续发展的基础工作。传统的渔业资源评估方法需要统计产量、资源丰度指数甚至年龄结构等大量数据,由于调查经费和数据的缺乏,全球仅1%的鱼种进行过系统性的资源评估。近年来,在数据有限(data-limited)条件下如何开展资源评估已日益成为学术界的关注热点。本文将基于生活史特征的评估方法分为仅需要生活史参数,需要产量数据和生活史参数,需要产量数据、生活史参数及体长或年龄数据等3大类,分别从方法、数据要求、输出结果及局限性进行了系统回顾分析,提供了关于生活史特征参数的常见估算方法,并就其中两种模型对北大西洋大青鲨(Prionace glauca)的可持续渔获量进行了初步评估与比较。最后,对数据缺乏模型的使用及模型在中国近海渔业资源评估中的运用提出了建议。     

利用耳石鉴定头足类年龄与生长研究进展

年龄和生长是头足类生物学研究的重点内容,利用耳石轮纹鉴定其年龄、分析其生长特性是一种可靠而有效的方法。耳石经提取、研磨、抛光后制备成切片,对切片观察面轮纹进行计数可得到日龄。研磨平面的选择是头足类耳石制片的最关键步骤,通常选择纵截面研磨。轮纹计数时,一般选择轮纹相对比较清晰的背区计数。适合头足类的生长模型有线性、指数、幂函数、逻辑斯谛、Gompertz和Von Bertalanffy等多种。分析认为,同一种头足类在不同生长阶段以及不同种群间,其年龄组成、生长率以及适合的生长模型往往不同,因此,建议应先对研究对象进行不同产卵季节或地理种群的划分,然后根据不同种群分别研究其生长并建立生长模型。     

渔业科技前沿

加拿大:科学家发现鉴定龙虾年龄的方法新不伦瑞克大学(UNB)的科学家们发现了测定龙虾年龄的方法。Raouf Kilada及其同事表示,龙虾身上的一些标记可以用来测算年龄。该研究成果发表在《加拿大水产与水生科学》杂志上。一些海洋动物,如鲨鱼的骨头上存在生长轮,扇贝和蛤类在其壳上也存在着生长轮。但是,到目前为止,甲壳类动物由于缺乏永久性的     

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。     

北太平洋长鳍金枪鱼年龄与生长初步研究

北太平洋长鳍金枪鱼(Thunnus alalunga)是金枪鱼渔业的主要捕捞对象之一,其资源的养护和管理日益受到各方关注,鱼类年龄鉴定是渔业资源研究的重要内容之一。根据2013~2014年北太平洋长鳍金枪鱼探捕所采集的227个脊椎骨样本,用不同的染色方法分成4组进行年龄的鉴定,选用线性模型、指数模型和幂指数模型对叉长和脊椎骨半径进行拟合,最后选出结果最好的鉴定组和拟合模型,通过年龄鉴定估算长鳍金枪鱼的Von Bertalanffy生长方程。研究结果表明,北太平洋长鳍金枪鱼的叉长范围为52~104 cm,优势叉长组为81~90 cm,占总数的83.1%;年龄组成以5、6龄较多,占样本总数的80.86%。最终得到北太平洋长鳍金枪鱼生长方程为:Lt=109.180 2[1-e~(-0.258 783(t-1.991 28))],t_(tp)=2.25。     

Multimodel approaches in shark and ray growth studies: strengths,weaknesses and the future

Multimodel frameworks are common in contemporary elasmobranch growth literature. These techniques offer a proposed improvement over individual growth functions by incorporating additional candidate models with alternative characteristics. Sigmoid functions (e.g. Gompertz and logistic) are a popular alternative to the commonly used von Bertalanffy growth function (VBGF) as they are hypothesized to better suit certain taxa based on body shape (such as batoids) or reproductive mode (such as egg‐layers). However, this hypothesis has never been tested. This study examined 74 elasmobranch multimodel growth studies by comparing the growth curves of their respective candidate models. Hypotheses regarding model performances were rejected as the VBGF was equally likely to fit best for all taxa and reproductive modes. Subsequently, no individual model was suited to be used a priori. Differences between candidate model fits were greatest at age zero with Gompertz and logistic functions providing estimates that were 15% and 23% larger on average than the VBGF, respectively. However, length‐at‐age estimates of the different models became negligible at older ages. Differences between candidate models were mostly small (≤5%), and the multimodel framework only marginally affected length‐at‐age estimates. However, there were cases where some candidate models provided inappropriate fits that contrasted considerably to the best fitting model. In some of these instances, a single‐model framework could have yielded biologically unrealistic growth estimates. Therefore, no study could pre‐empt whether or not it required a multimodel framework. A framework was subsequently recommended to maximize the accuracy of model fits for elasmobranch length‐at‐age estimates using multimodel approaches.     

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.     

滇池鲤4种年龄鉴定材料的比较

为确定鉴定滇池鲤（Cyprinus carpio）年龄的适宜材料,对4种年龄鉴定材料（耳石、鳞片、胸鳍条和鳃盖骨）的形态和年轮标志进行了描述,并对这4种钙化组织鉴定鲤年龄的一致性进行了探讨。2013年5、6、8-11月以及2014年3-7月,使用拖网采集云南滇池鲤584尾,体长范围7.5~50.5 cm,体重范围17.2~3 211.3 g。其中耳石采集于584尾样本,鳃盖骨和鳞片分别采集于276尾样本,胸鳍条采集于274尾样本。微耳石磨片轮纹清晰,在反射光下呈明暗相间的条纹,年龄标志明显。同一鉴定者2次年龄读数的吻合率,微耳石磨片轮最高（88.0%),鳞片次之(84.1%),胸鳍条和鳃盖骨则分别为73.7%和72.1%。2次读龄的平均误差百分比,微耳石磨片和鳞片较小,分别为2.6%和2.9%;胸鳍条和鳃盖骨较高,分别为4.7%和5.9%。以微耳石磨片年龄读数为基准,鳞片年龄读数与其吻合率最高(77.5%),平均变异系数最低(6.14%);鳃盖骨和胸鳍条与其吻合率分别为61.9%和56.2%,平均变异系数均超过12%。综合分析认为,耳石是滇池鲤年龄鉴定的最佳材料,鉴定4龄以下个体年龄时可使用鳞片,鳃盖骨和胸鳍条则不适于滇池鲤的年龄鉴定。     

Growth standards for nine North American fish species

Abstract  Standard methods for comparing population characteristics within and among fish populations greatly enhance communications among fisheries scientists, improve the efficiency of data analysis, and provide insight that helps guide management actions. Although standard methods are available for comparing some fish population characteristics (e.g. length structure, body condition), similar methods are lacking for comparing growth. The purpose of this study was to provide standards (i.e. percentiles and a standard growth model) for nine ecologically and recreationally important fish species. Percentile distributions of mean back-calculated length at age were estimated using data obtained from the published literature and from data solicited from state and federal agencies throughout North America. Percentiles of growth were estimated for bluegill, Lepomis macrochirus Rafinesque, common carp, Cyprinus carpio Linnaeus, flathead catfish, Pylodictis olivaris (Rafinesque), largemouth bass, Micropterus salmoides (Lacepède), sauger, Sander canadensis (Griffith & Smith), smallmouth bass, Micropterus dolomieu Lacepède, white bass, Morone chrysops (Rafinesque) and yellow perch, Perca flavescens (Mitchill). Standard growth models (i.e. von Bertalanffy models) were developed for these species and for channel catfish, Ictalurus punctatus (Rafinesque). These results provide tools that will help scientists compare growth of fishes across North America.     

Difficulties associated with modeling growth in the Atlantic angel shark (Squatina dumeril)

Several methods were used in an attempt to develop an age and growth model for the Atlantic angel shark (Squatina dumeril). Band counts from vertebral sections, which were fit to the traditional von Bertalanffy growth equation, the Gompertz growth equation, and the two-parameter von Bertalanffy growth equation, did not produce realistic parameter estimates. Additionally, a length-based Bayesian model was applied to fishery-independent length–frequency data, and a full Bayesian model was fitted to length-at-age data to estimate parameters for von Bertalanffy growth equation. Both the length-based and full Bayesian models failed to converge; the length–frequency data showed high bimodality unrelated to season, year, or other factors, and band counts were not predictable by length. Vertebral band counts were not valid for ageing Atlantic angel sharks, and length-based methods, which require normally distributed length–frequencies, were not appropriate for this data set. This study represents the first attempt at modeling age and growth for this species and provides research guidelines for future research initiatives.     

Growth rates of rainbow smelt in Lake Champlain: effects of density and diet

Stritzel Thomson JL, Parrish DL, Parker‐Stetter SL, Rudstam LG, Sullivan PJ. Growth rates of rainbow smelt in Lake Champlain: effects of density and diet. Ecology of Freshwater Fish 2010. © 2010 John Wiley & Sons A/S Abstract – We estimated the densities of rainbow smelt (Osmerus mordax) using hydroacoustics and obtained specimens for diet analysis and groundtruthed acoustics data from mid‐water trawl sampling in four areas of Lake Champlain, USA–Canada. Densities of rainbow smelt cohorts alternated during the 2‐year study; age‐0 rainbow smelt were very abundant in 2001 (up to 6 fish per m²) and age‐1 and older were abundant (up to 1.2 fish per m²) in 2002. Growth rates and densities varied among areas and years. We used model selection on eight area–year‐specific variables to investigate biologically plausible predictors of rainbow smelt growth rates. The best supported model of growth rates of age‐0 smelt indicated a negative relationship with age‐0 density, likely associated with intraspecific competition for zooplankton. The next best‐fit model had age‐1 density as a predictor of age‐0 growth. The best supported models (N = 4) of growth rates of age‐1 fish indicated a positive relationship with availability of age‐0 smelt and resulting levels of cannibalism. Other plausible models were contained variants of these parameters. Cannibalistic rainbow smelt consumed younger conspecifics that were up to 53% of their length. Prediction of population dynamics for rainbow smelt requires an understanding of the relationship between density and growth as age‐0 fish outgrow their main predators (adult smelt) by autumn in years with fast growth rates, but not in years with slow growth rates.     

On the age and growth of bogue,Boops boops (L.), from the Portuguese coast

Abstract Between 1984 and 1990, a total of 4892 bogues, Boops boops (L.) were caught in Peniche and 4352 in Algarve, with the total length varying from 6 to 40 cm. Age determination was carried out using direct reading and back-calculation on the otoliths. Von Bertalanffy growth equations, based on mean lengths per age group, were established for both samples and using both methods. Applying the Hotelling T² test to the growth parameters of those equations, it was concluded that there were no significant differences between them. This conclusion allowed the validation of the two methods employed, and the combination of the data from Peniche and Algarve into one single age-length key from which a growth equation for the Portuguese coast was calculated and described as: L_t = 45.918 {1-exp [-0.124 (t + 2.628)]}.     

Growth and mortality of prairie stream fishes: relations with fish community and instream habitat characteristics

Abstract – Few studies have been conducted to describe the age structure, growth rates and mortality of fishes in small stream ecosystems. The purpose of this study was therefore to determine age structure, growth rates and mortality (i.e., total annual mortality and, age-specific mortality) of central stonerollers Campostoma anomalum , creek chubs Semotilus atromaculatus , red shiners Cyprinella lutrensis and green sunfish Lepomis cyanellus from 13 streams on Fort Riley Military Reservation, Kansas, using incremental growth analysis. Further, we were interested in determining the influence of fish community and instream habitat characteristics on growth rates. The age structure of central stonerollers, creek chubs, and red shiners was dominated by young individuals (i.e., less than age 2); however, over 60% of the green sunfish were age 2 to age 4. Mean total annual mortality was >60% for cyprinids and averaged approximately 44% for green sunfish. The age-specific mortality of central stonerollers and red shiners was generally less than 45% between age 0 and 1 and increased to over 85% for fishes greater than age 1. Fish community characteristics (e.g., catch per unit effort of trophic guilds) and chemical habitat (e.g., total phosphorous) were not related to growth rates ( P >0.05). Growth of central stonerollers was not significantly correlated with physical habitat ( P >0.05). However, the growth increments of creek chubs, red shiners, and green sunfish were related to the amount of woody debris (e.g., total woody debris, log complex habitat; r >0.60; P ≤0.05). The results of this study provide important information on the population dynamic rate functions of cyprinid and green sunfish populations in small prairie streams. Furthermore, these data suggest that woody debris is important habitat influencing growth of stream fishes. ^Note     

A new concept related to growth coefficient

ABSTRACT: Although the notion of growth coefficient is important in growth analysis, its meaning is not necessarily pointed out clearly, at least analytically. The present paper, based on the von Bertalanffy model, gives an extended quantity of it and investigates its properties for logistic and Gompertz models. It is age dependent and converges to the coefficient of age in the models, growth coefficient in the traditional sense. The graphs of the quantity and the length show similarity for the logistic model, but not for the Gompertz model, although they show the same type of fluctuation. Moreover, the analysis indicates that the newly defined quantity has a property suitable to be called a growth density of the growth of length. Our discussion also shows the importance of the notion of growth remainder.