东海外海远东拟沙丁鱼Sardinops melanostictus(Temminck et Schlegel)的年龄和生长的研究

本文样品系取自北纬32°00～35°30′、东经131°00以西海域的机轮围网渔获物。采用耳石作为年龄研究材料,叉长和耳石半径之间呈直线相关,叉长和体重之间呈曲线相关。耳石轮纹由透明带和不透明带交替排列而成,年轮界于两带之间。该鱼的生长可按Yon Bertalanffy的长度、重量生长方程求得。各龄鱼的平均叉长(mm)和体重(g)分别为:Ⅰ龄130.62mm和21.10g;Ⅱ龄176.34mm和54.76g; Ⅲ龄196.40mm和70.00g; Ⅳ龄215.98mm和93.23g; Ⅴ龄232.07mm和120.20g;Ⅵ龄243.00mm和141.00g;     

性成熟和个体大小对西北太平洋柔鱼耳石形态的影响

根据2007年7-10月我国鱿钓船在西北太平洋海域连续采集的柔鱼样本,以耳石最大宽度(MW)与其总长(TSL)之比作为耳石形态变化的指标,利用方差分析和最小显著差法分析了性成熟和个体大小对耳石形态的影响。结果表明,耳石的生长持续出现在柔鱼的整个生命周期,性成熟度为Ⅰ期与Ⅱ~Ⅴ期之间的个体,其耳石MW/TSL皆存在显著差异(P<0.05),而性成熟度为Ⅱ~Ⅴ期的个体,它们之间的MW/TSL无显著差异(P>0.05),说明性成熟度Ⅰ期后的个体,其耳石形态不随性成熟度的增加而变化;胴长为200~280 mm的4个胴长组,耳石MW/TSL大多与其它组存在显著差异(P<0.05),而个体大于280 mm的各组间,其耳石MW/TSL无显著差异(P>0.05),说明胴长大于280 mm后的个体,其耳石形态不随胴长的增大而变化。性成熟度Ⅰ期和胴长范围200~280 mm对耳石形态影响一致,这一时期与柔鱼开始进入亚北极海域(42~46°N)进行索饵洄游的时间相对应,柔鱼耳石的MW/TSL可以作为表征其性成熟和早期生长变化的有效指标。     

嘉陵江不同江段蛇(鱼句)耳石形态特征及差异

为研究蛇（鱼句）耳石的形态特征以及不同环境下的耳石形态差异,以蛇（鱼句）左侧微耳石和星耳石作为研究材料,利用传统形态法测量耳石的14个参数且将其转化为11个形状指标,并利用地标点法在星耳石上选取12个地标点,对2016年6—7月间采自嘉陵江上游、中游、下游的195尾蛇（鱼句）的耳石样本进行形态研究。结果显示,蛇（鱼句）微耳石呈肾形,3个江段微耳石形态无显著差异;蛇（鱼句）星耳石呈圆形、椭圆形,表面粗糙,脊突数少于20,翼叶较基叶发达,中央突不明显,主凹槽轮廓似水滴状。相对扭曲主成分分析将3个江段的蛇（鱼句）星耳石分为两种形态类型：Ⅰ型和Ⅱ型,其中Ⅰ型主要为嘉陵江上游江段蛇（鱼句）的耳石样本,Ⅱ型则包括嘉陵江中游和下游的蛇（鱼句）耳石样本。传统形态法和地标点法的综合结果表明,两种类型耳石形态差异主要表现在整体轮廓、脊突数,以及基叶、主凹槽和背侧距离等特征上,逐步判别分析对Ⅰ型和Ⅱ型星耳石的正判率达95.5%,区分效果较好。研究表明,嘉陵江不同江段蛇（鱼句）星耳石分为两种类型,且存在显著的形态差异;蛇（鱼句）星耳石的形态差异可能是对水温、流速等环境因子主动适应的结果,如在上游生活的蛇（鱼句）,其较细长且脊突较多的Ⅰ型星耳石能够较好地适应上游低温、多变的急流环境。     

性成熟和个体大小对智利外海茎柔鱼耳石生长的影响

根据2007-2008年智利外海茎柔鱼资源调查期间采集的样本,以耳石最大宽度MW与其总长TSL之比作为表征耳石生长的指标,利用方差分析研究性成熟和个体大小对耳石生长的影响。分析认为,雌性个体的耳石MW/TSL与性腺成熟度存在相关性,性成熟度Ⅰ级与Ⅲ级、Ⅱ级与Ⅲ级个体的耳石MW/TSL存在显著差异(P<0.05);而雄性个体的耳石MW/TSL与性腺成熟度无关。雌性个体的耳石MW/TSL与胴长也存在着相关性,胴长300～400mm的个体与500～600mm和600～700mm、胴长400～500mm与500～600mm和600-700mm的雌性个体,它们耳石MW/TSL差异显著(P<0.05),胴长为400～500mm至500～600mm的个体,其MW/TSL增加迅速,差异极显著(P<0.01)。胴长350～400mm与400～500mm、400～450mm与450～500mm的雄性个体,它们耳石MW/TSL也存在显著差异(P<0.05),胴长400～450mm时的MW/TSL值为最小。研究表明,性成熟和个体大小对智利外海茎柔鱼耳石的生长有影响,但雌雄个体有差别。     

西北太平洋秋刀鱼主要体征及繁殖特性研究

根据2014年6—7月和10—11月于西北太平洋公海两航次采集的秋刀鱼样本,分析其性别比例、体长和体质量组成、摄食等级,以探究其生长、性腺及繁殖特性。研究结果表明,随着月份的增大,秋刀鱼雌性比例逐渐降低,雄性占比升高;6、7月雌、雄样本优势体长组与体质量组范围均较10、11月小;体长和体质量关系中,秋刀鱼雌性生长系数为3.24,雄性为2.82;各月样本胃饱满度以1级为主,F检验表明,除0级外,4个月内各摄食等级间呈显著差异(P<0.01);秋刀鱼雌、雄样本性腺发育以Ⅱ期为主,各性腺等级间差异不显著(P>0.05),雌性性腺指数在Ⅱ、Ⅲ、Ⅳ期内大于雄性,Ⅴ、Ⅵ期内相反,逻辑斯蒂方程表明,秋刀鱼50%性成熟体长雌性为284.7 mm,雄性为267.4 mm;雌性秋刀鱼绝对繁殖力为1032～17 708粒/尾,平均值为(5522±3196)粒/尾,绝对繁殖力高的个体体长和体质量分别为280～320 mm、110～150 g。     

绿鳍马面魨年龄和生长的初步研究

1.体长与椎体之间的关系呈正紧密直线相关。其关系式为:L=7.046R 49.590 r=0.938 2.用第一个椎骨的椎体作为观察和测定年轮的材料。年轮在透射光线下界于透明带和不透明带之间。其特征可分为以下三种类型:(1)单带型,(2)双带型,(3)多带型。 3.根据椎体边缘相对生长量的周年测定结果,证实该年轮系一年形成一次,时间为12月份至翌年5、6月份,主要的形成期是4～6月份。 4. 绿鳍马面鲀各龄鱼的平均体长和体重为:Ⅰ龄鱼:119.5毫米,44.5克;Ⅱ龄鱼:159.9毫米,70.9克;Ⅲ龄鱼:194.8毫米,136.9克;Ⅳ龄鱼:215.2毫米,190.8克;Ⅴ龄鱼;229.2毫米,231.3克;Ⅵ龄鱼:245.9毫米,283.5克。 5.体长和体重之间呈指数函数关系。关系式:L=41.324·W~(0.315) 6.从现有的标样观察和分析,绿鳍马面鲀的最高寿命为X龄。年龄组成比较简单,以Ⅲ、Ⅳ龄组占优势,Ⅵ龄以上各组数量极少。     

基于4种形态学技术的裘氏鳄头冰鱼与南极小带腭鱼耳石外型比较研究

为研究多种形态学技术对南极冰鱼耳石的种群分类效果,利用裘氏鳄头冰鱼(Champsocephalus gunnari)和南极小带腭鱼(Cryodraco antarcticus)样本,对描述耳石的5种基础形态学参数进行分析并转换为7种形状指标,比较分析了两种冰鱼间的耳石形态学差异,再利用主成分分析、逐步判别分析法和随机森林法对两种耳石的77个傅里叶系数进行判别。结果表明,两种冰鱼的耳石参数和体长均有显著的相关性(P0.05),裘氏鳄头冰鱼的体长与部分耳石参数呈幂函数关系,而南极小带腭鱼耳石的长、高、面积、周长、质量与体长均呈对数关系。裘氏鳄头冰鱼较南极小带腭鱼耳石环率更低,即更趋近于圆,更为规则。传统的形态学测量方法无法区分两类耳石,主成分分析可较好地区分两种鱼类的耳石,而逐步判别分析和随机森林分析的判别率分别达到98.78%和91.67%。逐步判别分析在小样本分析中具有优势,随机森林分析则适用于大样本判别。     

北太平洋公海秋刀鱼渔场初步分析

根据2004年7~11月“中远渔1号”调查船北太平洋公海秋刀鱼渔场探捕调查的生产情况,对秋刀鱼渔场进行分析。结果发现:①秋刀鱼渔场可根据渔场位置分为北部渔场和南部渔场,北部渔场范围为44°~45°N、156°~158°E,南部渔场范围为41°~42°N、150°~151°E,南部渔场的分布范围小于北部渔场。②秋刀鱼的生产以11月份生产最好,平均日产量达22.7t,其中最高日产量为60.42t;8月份的秋刀鱼生产最差,平均日产量为2.95t,与2003年的12.05t反差较大,主要是由于受到渔场环境因子变化的影响,鱼发位置偏至俄罗斯专属经济区内的缘故。③秋刀鱼舷提网作业平均日放网次数达7.6次,最高1天放网次数达到16次,而最高网次产量为11.05t。④秋刀鱼渔获组成以中小型鱼为主,占80%以上,除7月份渔获中特大型秋刀鱼占有较大比例外,其余月份很少有特大级秋刀鱼。⑤在相近的渔场位置,秋刀鱼个体随着生产月份的推迟,鱼体呈变小的趋势。     

南海海域鸢乌贼中型群与微型群渔业生物学比较

根据2012年9—10月采集的780尾鸢乌贼样本,对比研究了中型群和微型群两个种群的渔业生物学特征,为南海海域鸢乌贼渔业资源的管理、保护等提供基础资料。按海洋调查规范测定样本的胴长、体质量、性腺指数和摄食指数等生物学指标,通过磨片测定耳石生长纹数。结果显示,中型群胴长范围79～266 mm,优势胴长为111～145 mm,平均胴长随纬度的变化不明显;微型群胴长范围56～118 mm,优势胴长为66～95 mm,平均胴长随纬度的升高略呈上升趋势。中型群体质量分布范围17.47～957.20 g,优势体质量为45.01～120.00 g;微型群体质量分布范围5.81～76.56 g,优势体质量为5.01～50.00 g;中型群和微型群平均体质量随纬度的升高均有上升的趋势。中型群和微型群两个群体雌性和雄性样本的胴长和体质量之间的关系均适合幂函数。中型群雌雄比例为0.80∶1,未成熟与成熟个体比例为1.12∶1;微型群雌雄比例为3∶1,未成熟与成熟个体比例为0.83∶1。中型群雌性的性腺指数为1.71,雄性为3.31;微型群雌性的性腺指数为4.07,雄性为4.11。中型群雌性的摄食指数为5.07,雄性为3.54;微型群雌性的摄食指数为1.89,雄性为2.75。中型群耳石日龄范围为30～135 d,微型群耳石日龄范围为44～81 d。根据样本捕捞日期,推测微型群和中型群的产卵高峰分别为7月和8月。南海海域鸢乌贼秋季样本中型群个体规格大于微型群个体,2个群体的性成熟和孵化存在错峰现象,微型群雌性性成熟和产卵略早于中型群的雌性。推断7°、14°和16°N海域是鸢乌贼群体在南海的摄食场。     

张家口坝上高背鲫鱼的年龄与生长

为研究张家口坝上高背鲫鱼的年龄与生长特征,以鳞片上的年轮为年龄鉴定依据,得出该鱼体长(L)与鳞长(B)呈直线正相关:L=28.647B+12.888(r2=0.968 1);并通过生物学测量得出该鱼体重(W)与体长(L)呈指数函数关系,表达式为:W=8×10-6 L3.299 2(r2=0.992 6);渔获物年龄组成为Ⅰ龄26.7%,Ⅱ龄26.7%,Ⅲ龄30.0%,Ⅳ龄13.3%,Ⅴ龄3.3%。渔获物体长范围为74.19～194.15mm,体重范围为14.05～306.00g,其中体长120～150mm的个体占多数(53.33%)。除Ⅲ龄鱼外,体长增长是逐渐较小的趋势,体重增长是逐渐较大的趋势。Ⅲ龄鱼体长、体重增长都最慢。     

西北太平洋秋刀鱼渔业探析

由于近海渔业资源的衰退和恶化,我国海洋渔业面临严峻的挑战。1985年我国远洋渔业开始起步,1989年发展了远洋鱿钓渔业,1993年首次进入西北太平洋从事柔鱼钓生产,经过艰难的创业和发展,到2002年我国远洋鱿钓船已发展到480多艘,成为我国渔业生产的支柱产业之一。但是,近几年来北太平洋总产量徘徊在9万t左右,另外,我国有80多条专业鱿钓船在西南大西洋作业,7～10月无生产。因此,尽快找到新的捕捞对象,提高经济效益,是当前发展远洋渔业的迫切任务。而栖息在亚洲和美洲沿岸太平洋热带和温带水域中的秋刀鱼,则以其具有一定的资源量、简单易行的捕捞方式以及广阔的销售前景,成为远洋鱿钓船队今后可供选择的捕捞对象之一。     

西北太平洋秋刀鱼舷提网捕捞技术

自2003年我国大陆成功开发了西北太平洋秋刀鱼渔场之后，秋刀鱼已逐步进入中国大陆市场。对于秋刀鱼捕捞技术，在历经刺网、围网等渔具后，现基本以舷提网捕捞作业为主。根据2004年6—10月大连“国际903”号生产调查船在西北太平洋海域进行探捕调查的生产情况，对秋刀鱼舷提网的捕捞技术，从渔捞设备至捕捞具体操作技术进行介绍。     

The parasite Ichthyophonus sp. in Pacific herring from the coastal NE Pacific

The protistan parasite Ichthyophonus occurred in populations of Pacific herring Clupea pallasii Valenciennes throughout coastal areas of the NE Pacific, ranging from Puget Sound, WA north to the Gulf of Alaska, AK. Infection prevalence in local Pacific herring stocks varied seasonally and annually, and a general pattern of increasing prevalence with host size and/or age persisted throughout the NE Pacific. An exception to this zoographic pattern occurred among a group of juvenile, age 1+ year Pacific herring from Cordova Harbor, AK in June 2010, which demonstrated an unusually high infection prevalence of 35%. Reasons for this anomaly were hypothesized to involve anthropogenic influences that resulted in locally elevated infection pressures. Interannual declines in infection prevalence from some populations (e.g. Lower Cook Inlet, AK; from 20–32% in 2007 to 0–3% during 2009–13) or from the largest size cohorts of other populations (e.g. Sitka Sound, AK; from 62.5% in 2007 to 19.6% in 2013) were likely a reflection of selective mortality among the infected cohorts. All available information for Ichthyophonus in the NE Pacific, including broad geographic range, low host specificity and presence in archived Pacific herring tissue samples dating to the 1980s, indicate a long‐standing host–pathogen relationship.     

Reproductive biology of female Pacific bluefin tuna Thunnus orientalis from south-western North Pacific Ocean

Pacific bluefin is a highly valuable pelagic species that inhabits a broad range in the North Pacific Ocean. The reproductive biology, especially for the spawning aggregation in the south-western North Pacific Ocean, is not well understood. Thus, a total of 119 paired ovary specimens were collected from the Taiwanese longline fleet during the 1999 fishing season (late April through June) to gain a better understanding of important reproductivity-related stock parameters associated with this species. The following conclusions were made: (i) condition factor decreased from late May to early June; (ii) the sex ratio might be 1∶1 for spawners; (iii) the gonadosomatic index stayed at a relatively high level and markedly increased from late May to early June; (iv) histological examination of oocytes indicated that all specimens were sexually mature; (v) spawning activity appeared to start in May and peak in late May to early June; (vi) batch fecundity incre ased with fork length; and (vii) preliminary estimates of spawning frequency between batches ranged 2–4.5 days based on analysis of postovulatory follicles.     

Patchiness structure and mortality of Pacific saury Cololabis saira larvae in the northwestern Pacific

Patchiness structure and mortality rates of Pacific saury Cololabis saira larvae were estimated in the frontal area of the Kuroshio Extension in spring 2000 and 2001. Drogued GPS buoys, which were used as Lagrangian reference points, were deployed to mark dense patches of saury larvae and a series of samplings was conducted using a neuston net around the buoys during the night over a period of several days. A total of 225 tows were conducted and 11 690 specimens were sampled during four buoy tracking. Despite the occurrence of water diffusion, patchiness density, distance between adjacent patches and patch size estimated by geostatistical analysis did not drastically change during the buoy tracking and these parameters were robust for the difference of variogram models and the threshold larval density defining patchiness. Such a stability of the patchiness allowed the estimation of larval mortality from the decrease of larval density for different size classes with respect to individual growth based on the samples taken repeatedly during the buoy tracking. Although low or negative values were obtained for the larvae right after hatching, probably due to continuous hatching, the estimates of mortality then increased and became stable in the range of 23–37% day⁻¹ with a small standard deviation until their knob length reached to 36 mm. In situ information on the patchiness structure and larval mortality provides crucial parameters for simulating the recruitment process of small pelagic fishes in high-resolution hydrodynamic models.     

Effects of the North Pacific Current on the productivity of 163 Pacific salmon stocks

Horizontal ocean transport can influence the dynamics of higher‐trophic‐level species in coastal ecosystems by altering either physical oceanographic conditions or the advection of food resources into coastal areas. In this study, we investigated whether variability in two North Pacific Current (NPC) indices was associated with changes in productivity of North American Pacific salmon stocks. Specifically, we used Bayesian hierarchical models to estimate the effects of the north‐south location of the NPC bifurcation (BI) and the NPC strength, indexed by the North Pacific Gyre Oscillation (NPGO), on the productivity of 163 pink, chum, and sockeye salmon stocks. We found that for salmon stocks located in Washington (WA) and British Columbia (BC), both the BI and NPGO had significant positive effects on productivity, indicating that a northward‐shifted bifurcation and a stronger NPC are associated with increased salmon productivity. For the WA and BC regions, the estimated NPGO effect was over two times larger than the BI effect for pink and chum salmon, whereas for sockeye salmon the BI effect was 2.4 times higher than the NPGO. In contrast to WA and BC stocks, we found weak effects of both horizontal ocean transport processes on the productivity of salmon stocks in Alaska. Our results indicated that horizontal transport pathways might strongly influence population dynamics of Pacific salmon in the southern part of their North American ranges, but not the northern part, suggesting that different environmental pathways may underlie changes in salmon productivity in northern and southern areas for the species under consideration.     

Feeding habits of Pacific pomfret Brama japonica inthe transition zone of the central North Pacific

ABSTRACT:   We examined the diets of three size groups of the Pacific pomfret Bramajaponica collected in April and May 2000 in the transition zoneof the central North Pacific. Amphipods, cephalopods and fish werethree of the most common prey groups of pomfret. Of the three size groups,small pomfret (11.0–19.9 cm standard length (SL))preyed mainly on amphipods and occasionally on cephalopods (mainlytransitional species Onychoteuthis borealijaponica ) and fish.(These prey amphipods and fish could not be identified to lowertaxonomic levels because they were too digested.) Medium and largepomfret (20.0–30.9 and 31.0–40.9 cm SL,respectively) preyed mainly on cephalopods (mainly O. borealijaponica ,but also on two subarctic species, namely Berryteuthis anonychus and Gonatopsisborealis ), suggesting that these cephalopod species ensure energyfor the northward migration of these two size groups in the transitionzone in the spring. The next most common prey for medium pomfretwas amphipods (mainly subtropical species Phronima sedentaria and Platyscelusovoides ), followed by fish (mainly Bathylagus sp.). However,in the case of large pomfret, fish (mainly Paralepididae sp. 'A')were the next most common prey, followed by amphipods (mainly P.sedentaria and P. ovoides ), indicating that the importanceof fish as prey increases with growth for medium and large pomfret.     

太平洋金枪鱼延绳钓渔业

本文主要介绍了最近几年太平洋金枪鱼延绳钓渔业的发展情况和太平洋沿岸国家金枪鱼延绳钓生产现状,重点叙说了太平洋金枪鱼延绳钓捕捞的几个主要种类的渔场分布、产量变化动态和发展趋势,为我国远洋渔业单位进行金枪鱼延绳钓开发提供参考。