中国气候与环境演变评估(I): 中国气候与环境变化及未来趋势

头足类是重要的渔业资源之一,其渔业生物学特性极易受到海洋环境变化的影响。气候系统中的能量主要储存载体是海洋。近年来频发的气候变化事件引发海洋环境因子变动,直接或间接地改变了头足类的渔业生物学特性,对头足类的渔业生产造成影响。为此,本文归纳和总结了气候变化对头足类繁殖、年龄生长与早期生活史等3个方面的影响,并提出了展望。结果表明,气候变化事件的发生极易影响头足类动物的渔业生物学特性,海洋环境因子中的温度和初级生产力变动为主要影响因素。目前,相关研究对象多为柔鱼科和枪乌贼科等经济种类,选用的海洋环境因子也多为海洋环境温度,今后应结合其他海洋环境数据研究气候变化事件对其他种类的影响。本文旨为研究气候变化事件对头足类渔业生物学特性的影响提供理论依据,为近年来气候变化事件频发下头足类渔业的可持续发展提供科学指导。

     

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。     

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。     

头足类角质颚研究进展Ⅰ——形态、结构与生长

头足类通常为一年生种类,是典型的短周期生命物种。鉴于其特殊的生活史特点,及其在海洋生态系统中占据的重要地位,各国学者越来越关注头足类的基础生物学。角质颚作为重要的硬组织之一,具有形态相对稳定且不易腐蚀等特点,近些年来对其内部结构组成和微结构的研究越来越多,其几丁质结构和黑色素沉着的变化也得到很大的关注。本文基于前人对角质颚在形态、生化结构和年龄生长方面的研究进行回顾,并对近几十年来的研究方向展开分析。结果认为,角质颚的研究方向应该从定性到定量分析开始转变,并且要更加关注角质颚形状变化与其生化结构和生长等规律性变化之间的关系。     

鱼类早期生活史研究与其进展

鱼类早期生活史的研究，主要涉及卵和仔鱼发育，仔鱼最佳饲养条件、饵料密度、营养、生长、临界期、饥饿、捕食、环境耐力和毒性反应等和渔业密切相关的诸因子，是鱼类自然资源繁殖保护和养殖业苗种培育的基础。近二、三十年来，鱼类早期生活史研究已成为水产科学的一个崭新领域，在国际上受到广泛重视并迅速发展。国际海洋开发理事会(ICES)曾三次举行鱼类早期生活史学术讨论会，     

珠江卷口鱼年龄生长、食性和繁殖的研究

本文报道了珠江卷口鱼的年龄生长、食住和繁殖方面的研究结果。通过分析确定:卷口鱼的年龄级由I—IV龄鱼组成,各龄鱼分别占渔获物总量的42.21％、38.21％、19.21％和0.38％。用统计学方法,计算出卷口鱼体长与鳞长的相关式为:L=8 43.30R(r=0.9956);体长与体重的相关式为:W=8.226×10~(-3)L~(3.374)(Γ=0.9654)。对卷口鱼各种食物的组成、季节变化及出现率作了分析探讨。卷口鱼个体绝对怀卵量波动于7878—48880粒之间,平均22250.7粒。绝对怀卵量与体长和体重的相关式为:R=4.5419L~(3.6208)和R=40.88W 1209. 文中对卷口鱼的资源繁殖保护,网具使用和合理捕捞规格等问题进行了讨论。     

长江口凤鲚繁殖群体年龄与生长研究

为了探究凤鲚繁殖群体年龄与生长之间的关系,于2018年5月、6月和7月以及2019年5月在长江口水域采集凤鲚(Coilia mystus)繁殖群体,从渔获物中获得样品194尾,研究了其年龄结构和生长特性。结果显示,年龄结构为1～3龄,其中1、2龄为优势群体,占样品总数的82.48%。体长范围为69～192 mm,体质量范围为1.5～30.3 g,平均体长(128.87±25.26) mm,平均体质量(9.90±6.61) g。体长与体质量关系式中参数a为2×10^-6,参数b为3.17。体长和体质量生长方程中渐进体长L_∞和渐进体质量W_∞分别为212.33 mm和48.22 g,生长系数k为0.43,理论生长起点年龄t₀为-0.88。长江口凤鲚雄性个体趋向于匀速生长(b=2.87),而雌性个体为异速生长(b=3.31)。体质量生长曲线拐点年龄为1.81龄,拐点年龄对应的体长和体质量分别为145.44 mm和14.52 g。与之前的研究结果相比,近年来长江口凤鲚拐点年龄和渐进体长均有所增大,表明其小型化趋...     

鸭绿江上游花羔红点鲑的年龄_生长_食性和繁殖的研究

花羔红点鲑的鳞片年累特征为疏密一切割混合型。体长和体重关系密切,属均匀性生长类型。主要以水生昆虫为食,对食物有明显的选择性;主要摄食季节为夏秋两季,但可终年摄食。雌雄鱼几乎２＋龄达到性成熟,产卵期为１０￣１１月,绝对繁殖力为２８０￣５００粒,每年产一次卵,属秋季产卵类型。产卵场底质为石砾,水深５０￣７０ｃｍ,水流速度１．５￣２．０ｍ／ｓ,水温一般为５￣８℃。     

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。     

Effects of early life mass mortality events on fish populations

Mass mortality events are ubiquitous in nature and can be caused by, for example, diseases, extreme weather and human perturbations such as contamination. Despite being prevalent and rising globally, how mass mortality in early life causes population-level effects such as reduced total population biomass, is not fully explored. In particular for fish, mass mortality affecting early life may be dampened by compensatory density-dependent processes. However, due to large variations in year-class strength, potentially caused by density-independent variability in survival, the impact at the population level may be high in certain years. We quantify population-level impacts at two levels of mass mortality (50% and 99% additional mortality) during early life across 40 fish species using age-structured population dynamics models. The findings from these species-specific models are further supported by an analysis of detailed stock-specific models for three of the species. We find that population impacts are highly variable between years and species. Short-lived species that exhibit a low degree of compensatory density dependence and high interannual variation in survival experience the strongest impacts at the population level. These quantitative and general relationships allow predicting the range of potential impacts of mass mortality events on species based on their life history. This is critical considering that the frequency and severity of mass mortality events are increasing worldwide.     

Sex-specific growth pattern during early life history in masu salmon, Oncorhynchus masou

Abstract –  To examine whether or not sex-specific growth occurs in fry of masu salmon Oncorhynchus masou , 90 half-sibling fry chosen from three different classes of egg size (small, medium and large) and emergence time (period from fertilisation to first feeding; early, middle and late) were raised in a tank for 60 days. In all four replications, male fry grew faster than females. The difference in growth between sexes was greater among siblings hatched from larger eggs. Fast-growing, young male masu salmon show a precocious form that tends to mature without migrating to sea. Slower growing males tend to show the anadromous form, which is only shown in females. Sex-specific life histories may influence the sex-specific growth patterns during early life history.     

鲨鱼类年龄和生长特性的研究进展

鲨鱼是海洋生态系统的重要生物类群。鲨鱼的年龄与生长作为基础的生活史特征,是资源评估所需的关键种群信息。鲨鱼的年龄与生长研究需要解决样本的选择与处理、年龄鉴定的方法和校正、生长模型的运用和参数估计等基本问题,否则难以得到可靠的结果。总结分析了两大类年龄鉴定方法及3种年龄校正技术的优缺点和应用局限性,比较分析了各种生长模型的应用差别,并对常见大洋性鲨鱼的生长参数进行了总结。研究认为,第一背鳍上部的脊椎骨是鲨鱼年龄鉴定的最佳硬质,硬质的处理需要借助化学方法,以提高轮纹清晰度;对年龄鉴定的校正是避免或减少系统误差的关键,校正方法的选择需要考虑鱼种的寿命;生长曲线的拟合需要选择多种备选模型,建议通过AIC信息准则筛选最优模型,为鲨鱼年龄与生长的进一步研究提供方法和技术上的参考,也可以为有关种类的资源评估提供生长参数。     

东太平洋茎柔鱼生活史研究进展

茎柔鱼广泛分布于东太平洋,其资源量在秘鲁海域最为丰富,是中国鱿钓渔业最为重要的目标种类之一。而且,作为捕食者和被捕食者,茎柔鱼位于食物链的中间环节,在海洋生态系统中具有重要地位。本文回顾了有关茎柔鱼的种群结构、日龄与生长、繁殖习性、摄食生态学以及洄游路径的研究,全面归纳和总结了茎柔鱼的生物学特性以及相关研究的发展趋势和最新研究进展,提出了目前研究所存在的问题和需要努力的方向。此外,通过对已有研究结果的分析和总结,绘制了茎柔鱼在东太平洋的洄游路线,为茎柔鱼资源的合理开发、利用及科学管理提供依据。     

The cost of early maturation on growth, body condition and somatic lipid content in a lake pumpkinseed (Lepomis gibbosus) population

We investigated the implications of early maturation in a central Ontario population of pumpkinseed (Lepomis gibbosus) by comparing the growth trajectory, body condition, lipid to body weight ratio and past growth history of mature and immature females through the 1992 growing season. Pumpkinseeds were sampled from Beloporine Lake from May 28 to July 24 and on November 20, just prior to freeze-up of the lake. Prior growth history and length at age were determined by backcalculation from scale annuli. Nearly all females age 3 and older had matured in 1992, so we focused on age 2 females (22% mature). Females that matured at age 2 were significantly larger at the end of their first year of life than those that did not mature at age 2, although there was no significant difference between groups in the prior year's growth rate. The mature age 2 females were significantly larger than immatures, at the beginning and end of their third growing season, but not during the June 2 - July 19 breeding season. The condition factor of mature females was higher than that of immature females on all but one collection date. However, the mean somatic lipid-to-body weight ratio was higher in immature females on all sample dates and significantly higher over the grwing season. We conclude that the costs of early maturation include lack of length and weight gain during the breeding season, and loss of stored lipid. The latter may be associated with increased overwinter mortality.     

Feeding rhythm and growth of the tongue sole, Cynoglossus semilaevis Günther, during its early life stages

The feeding rhythm and growth characteristics of the early life stages of the tongue sole, Cynoglossus semilaevis Günther, were studied. Larvae began to prey on rotifers about 2–3 days after hatching at 23°C. About 12 days after hatching, larvae had grown to 8–9 mm in total length and were able to prey on Artemia larvae. As the larvae grew, they showed an increasing feeding capacity and a distinct feeding rhythm. Feeding intensity for day‐6 larvae was highest at 12:00 and 18:00 hours, about 2–3 h after the maximum feeding incidence. The highest levels of feeding intensity for day‐16 larvae occurred between 09:00 and 18:00 hours. By day 26, when the larvae had metamorphosed, feeding capacity had again increased considerably and, in contrast to the earlier stages, feeding intensity peaked at 18:00 and 24:00 hours concurrently with feeding incidence. Thus, tongue sole were found to have different feeding rhythms in the pre‐ and post‐metamorphosis stages, with the highest feeding activity in the daytime during the larval planktonic stage, and at night during the juvenile benthic stage. The estimated maximum daily feeding rates were 65%, 40% and 11% of body weight on days 6, 16 (larvae) and 26 (juveniles) respectively. Size variation increased markedly with development.     

褐藻羊栖菜繁殖生物学特征和生活史流程的补充研究

以温州市洞头区人工养殖羊栖菜和野生羊栖菜为研究样本,详细描述了羊栖菜成熟孢子体有性生殖,假根与侧生枝无性生殖的繁殖生物学特征和生活史流程。详细记录了羊栖菜卵、精子和受精卵的减数分裂和有丝分裂过程,假根、茎(主茎和侧生茎)、叶(气囊)和生殖托(雌托和雄托)等4类器官生长、发育和分化过程,胚、幼孢子体和成熟孢子体形态结构特征。在此基础上对现有羊栖菜繁殖生物学特征及生活史流程进行了补充和修正,增加了羊栖菜侧生枝无性生殖和羊栖菜幼孢子体期有性生殖的相关内容,并重新绘制了羊栖菜生活史流程图。该研究结果将为开展羊栖菜养殖生态学研究,深层次解析羊栖菜生殖节律、种群繁衍与环境关系奠定基础。     

Spawning success and early life history of longnose suckers in Great Lakes tributaries

Fish eggs and larvae are often subject to very high mortality, and variation in early life survival can be important for population dynamics. Although longnose suckers (Catostomus catostomus) are widespread in northern North America, little is known about their early life history. We examined fecundity and early larval survivorship during sucker spawning events in three small Lake Michigan tributaries. Although egg deposition varied 25% among spawning events, estimated larval export to the lake varied over 25,000‐fold from around 1000 to 26 million. Based on variation in environmental conditions across years, it appears that spring flow and temperature may be important determinants of egg survival to larval outmigration. Larval age data suggest that most individuals that survived to outmigration hatched during a 2‐day period despite adult spawning across at least 10 days. Most larvae spent <2 weeks in the stream and emigrated around the time of transition from endogenous to exogenous feeding before substantial growth occurred. In two of three cases, larvae drifted exclusively at night; however, high drift rates occurred during both day and night in the case where larvae were very abundant, suggesting density‐dependent drift behaviour. Our results indicate that survival in tributary streams from egg deposition to larval export is highly variable in longnose suckers. These large differences in early life survival may translate into variability in recruitment, thereby influencing population structure and dynamics.