西南大西洋阿根廷滑柔鱼作业渔场特征

基于2006年1—7月中国鱿钓船在西南大西洋捕获阿根廷滑柔鱼的生产数据及卫星反演的海流、海水表层温度和叶绿素a浓度等海洋环境资料,综合分析了阿根廷滑柔鱼的作业渔场、产量及环境特点.结果表明：西南大西洋存在2个主要的阿根廷滑柔鱼渔场,南部中心位置在60°30′ W、45°30′ S,北部中心位置在58°00′ W、42°00′ S,1—7月,作业渔场由南向北移动;不同月份阿根廷滑柔鱼产量的差异较大,其中,1—4月产量较高,最高产量出现在3月,5月之后,其产量逐渐减少;阿根廷滑柔鱼渔场与福克兰寒流流经路径有关,北部渔场位于福克兰寒流的主流上,平均流速为28～60 cm·s^-1,南部渔场在寒流的西边界处,且其西部伴有一小尺度反气旋涡,平均流速在5～32 cm·s^-1;阿根廷滑柔鱼渔场的适宜海洋表层温度在7 ℃～15 ℃,最适宜温度约12 ℃,适宜的海水叶绿素a浓度在0.4～1.5 mg·m^-3,最适宜浓度在0.9～1.2 mg·m^-3,且海水叶绿素a浓度与捕捞量呈显著正相关关系（P<0.05）.     

西北太平洋柔鱼栖息地环境因子分析及其对资源丰度的影响

柔鱼(Ommastrephes bartramii)是西北太平洋海域重要的经济头足类,短生命周期的生活史特征决定其资源丰度易受海洋环境变化影响。根据1998—2010年我国鱿钓船生产统计资料和环境资料,包括海表温度(SST)和叶绿素浓度(Chl-a)数据,结合Nio 3.4区海表温距平值(SSTA),分析了SST和Chl-a浓度的季节和年际变化特征,并分别探讨了SST和Chl-a浓度距平值与Nio 3.4区SSTA及柔鱼资源丰度之间的关系。结果表明,产卵场海域Chl-a浓度冬季高夏季低,SST则夏季高冬季低;育肥场Chl-a和SST均呈夏季高冬季低变化,但6—12月份Chl-a浓度波动明显。产卵场和育肥场SST及Chl-a浓度年际变化明显。同时研究发现,厄尔尼诺、拉尼娜和正常年份时Nio 3.4区SSTA对柔鱼产卵场和育肥场环境的调控机制不同:拉尼娜和正常年份产卵场和育肥场温度上升,叶绿素浓度变化幅度小,有利于资源量补充,产量较高;厄尔尼诺年份温度和叶绿素均降低,尤其育肥场叶绿素浓度,对资源量产生不利影响,产量锐减。研究利用多元线性回归分别建立了基于温度和叶绿素的柔鱼资源丰度的预测模型,两者均能很好的预测柔鱼资源丰度(P0.05),但基于叶绿素的预测模型优于温度模型。     

西南大西洋阿根廷滑柔鱼耳石元素组成

耳石微量元素越来越广泛地被用于头足类群体划分、洄游史等领域的研究。根据我国鱿钓船2007、2008和2010年在西南大西洋生产期间采集的阿根廷滑柔鱼样本,利用激光剥蚀电感等离子质谱法(Laser ablation inductively coupled plasma mass spectrometry,LA-ICP-MS)按不同群体、不同性别和不同生长阶段,分析了33枚阿根廷滑柔鱼耳石的元素组成及分布特性。结果表明,阿根廷滑柔鱼耳石主要由56种元素组成,含量最多的前10种元素分别为钙Ca、锶Sr、钠Na、磷P、钾K、铁Fe、镁Mg、钡Ba、硼B、镓Ga。方差分析表明(ANOVA),不同性别间Ca、Sr、Na、P、K、Fe、Mg、Ba、B、Ga都不存在显著性差异(P0.05)。冬季孵化群和秋季孵化群间耳石的Sr、Na、Mg、Ba和B存在显著性差异(P0.05),Ca、P、K、Fe和Ga则不存在显著性差异(P0.05)。耳石的核心区、后核心区、暗区和外围区等不同部位间的Na、Ba和Ga不存在显著性差异(P0.05),Ca、Sr、P、K、Fe、Mg和B则存在显著性差异(P0.05)。研究表明,Sr和Mg含量及其分布特性最适合用于研究阿根廷滑柔鱼的群体划分、洄游史等渔业生态学特性。     

西南大西洋阿根廷滑柔鱼生物学年间比较

将2007年2—5月、2008年3—5月、2010年1—3月我国鱿钓船在西南大西洋公海海域采集的阿根廷滑柔鱼样本,比较其不同年间的生物学特性。结果表明,渔获物雌雄比为1.14—1.50:1;3a雌性个体的胴长(体重)分别为188—346mm(110—856g)、200—364mm(145—950g)、124—276mm(72—425g),雄性个体的胴长(体重)为178—298mm(102—703g)、193—314mm(145—680g)、104—335mm(70—374g)。2010年渔获个体明显比2007和2008年小。各年间及雌、雄个体间的体重与胴长关系均存在差异(P<0.001),渔获物中年间性成熟组成差异明显,此外各年3月份渔获个体也存在显著差异。雌、雄个体的胴长平均生长率分别为0.53—1.07 mm/d、0.47—0.68 mm/d,相对生长率分别为0.24—0.41%d-1、0.23—0.33%d-1;雌、雄个体的体重平均生长率在1.70—5.25 g/d、1.64—4.59 g/d,相对生长率分别为0.92—1.37%d-1、0.86—1.40%d-1。渔汛期间,胴长、体重与时间的关系均符合指数生长曲线,但生长指数年间差异明显。综合分析认为:2007年渔获物基本上为南巴塔哥尼亚种群;2008年以南巴塔哥尼亚种群为主,但也有少量较小个体的夏季产卵种群;2010年则以夏季产卵种群为主,并有少量的南巴塔哥尼亚种群。     

西南大西洋阿根廷滑柔鱼雄性个体的有效繁殖力特性研究

对西南大西洋阿根廷滑柔鱼(Illex argentinus)雄性个体的有效繁殖力特性, 以及有效繁殖力与个体生长发育关系进行了研究。结果表明, 阿根廷滑柔鱼雄性个体的胴长、体重的生物学最小型分别为207.79 mm和162.55 g; 个体有效繁殖力为(374±280.33)条精荚, 胴长相对有效繁殖力为(179.18±117.66)条/mm; 精荚的平均长度为(21.57±4.17) mm, 是胴长的(10.22±1.82)%。随着性腺发育, 个体有效繁殖力和精荚长度均增长显著(P<0.05), 前者在功能性成熟期达到最大值, 为(811±181.34)条精荚; 后者在繁殖产卵期达到最大值, 为(23.89±3.87) mm。同时, 个体有效繁殖力和精荚长度均与胴长、体重呈显著的线性函数关系(P<0.05)。回归拟合数据集比较分析和多元线性回归分析显示, 个体有效繁殖力与胴长、体重之间的线性关系不存在显著性差异(P>0.05), 但是体重对个体有效繁殖力的影响更为显著(P<0.001); 精荚长度与胴长、体重之间的线性关系存在显著性差异(P<0.001), 并且胴长、体重两者对精荚长度具有一致的影响效应(P<0.001)。以上结果表明, 阿根廷滑柔鱼雄性个体随着性腺发育持续产生并存储精荚, 精荚长度也随之显著增加, 并且与个体大小密切相关。     

基于贝叶斯Schaefer模型的阿根廷滑柔鱼资源评估与管理

利用基于贝叶斯统计方法的Schaefer模型对西南大西洋阿根廷滑柔鱼资源量进行评估,并对评估结果进行风险分析.结果表明:正态分布方案和基准方案两个模型参数的预测值及估算的生物学参考点接近,但均大于对数正态分布方案.3种方案下,2001-2010年的捕捞死亡率都远低于限制参考点F0.1,2001-2010年的渔获量也小于最大可持续产量(MSY),表明西南大西洋阿根廷滑柔鱼资源目前处于良好开发状况,没有遭受过度捕捞.决策分析表明,在相同的收获率情况下,对数正态分布方案得到的2025年资源量最低、资源崩溃的概率最大.3种方案下2025年渔获量最大时的收获率均为0.6,但是若将管理策略定为收获率0.6,则2025年以后资源量存在一定风险,因此较为保守的管理策略应将收获率控制在0.4左右,渔获量在55万t左右.     

阿根廷滑柔鱼年间生长及体征变化

阿根廷滑柔鱼(Illex argentinus)的生长发育及体征变化,可表征其能量积累和生殖投入方面的生活史策略,并随之影响繁殖成效和资源补充量。为此,研究根据2012—2014年在西南大西洋索饵育肥场采集的阿根廷滑柔鱼样本,采用残差指标分析方法和广义线性混合效应模型,分析了阿根廷滑柔鱼个体的体质量-胴长关系和体征变化的差异性。结果显示,阿根廷滑柔鱼样本的总体雌雄比例为1.25﹕1;雌性和雄性个体体型均以2014年的为最大,分别为(271.7±28.3)和(244.7±17.3) mm; 2012年和2013年样本的胴长差异性不显著,前者雌性和雄性胴长分别为(207.9±31.0)和(201.1±28.9) mm,后者雌性和雄性胴长分别为(213.6±18.0)和(203.5±19.0) mm。每个年份雌性和雄性个体的体质量与胴长呈显著的幂函数关系,且每个年份幂函数关系式的b值与匀速生长b=3存在差异。雌性和雄性个体体征的年间差异明显,同年度不同月份之间的体征亦存在显著差异(2012年雌性除外)。雌性和雄性个体的体征与胴长密切相关,胴长×月份作用对不同月份个体体征的影响效应具有一致性,...     

中小尺度下西北太平洋柔鱼资源丰度的空间变异

西北太平洋柔鱼是我国最重要的远洋捕捞对象之一,掌握其资源分布在空间上的分布特征将可为资源的可持续开发和利用提供基础。本文采用2011年8-10月我国在北太平洋150?-160?E、38?-48?N海域的柔鱼生产统计数据,以单船日产量(CPUE)为资源丰度指标,分经纬度10′?10′、20′?20′、30′?30′、40′?40′、50′?50′、60′?60′和70′?70′等7个尺度,利用地统计学方法对柔鱼资源丰度的空间分布特征进行了分析,探讨柔鱼资源丰度的空间变异特性。结果显示,8-10月柔鱼资源丰度均以指数模型拟合产生的空间自相关异质性程度最好;小尺度下(10′?10′、20′?20′、30′?30′)柔鱼资源丰度空间结构表现出中等水平及其以上的空间自相关变异程度,中尺度下(40′?40′、50′?50′、60′?60′和70′?70′)则相对比较低,基本上为弱空间自相关变异程度;柔鱼资源丰度空间结构显示有各向异性,8月和9月的方向角分别为西北-东南走向和东北-西南走向,10月受柔鱼性成熟开始南向洄游以及海洋环境的影响,其方向角变化较大。此外,论文对柔鱼资源丰度的适宜尺度作了进一步探讨,综合分析认为CPUE空间变异的研究应以小尺度为适宜,其中30′?30′最为稳定。论文结合柔鱼的栖息环境等,分析了它们对资源丰度时空变异及其特征的影响。     

阿根廷滑柔鱼两个群体间耳石和角质颚的形态差异

头足类硬组织具有稳定的形态特征、良好的信息储存以及抗腐蚀性等特点。根据2007年2—5月和2010年1—3月我国鱿钓船采集的阿根廷滑柔鱼样品,提取出625对耳石和787对角质颚,测量耳石10个形态数据和角质颚12个形态数据,通过除以胴长(Mantle Length,ML)校正后,对南巴塔哥尼亚群体(South Patagonic Stock,SPS)和布宜诺斯艾利斯-巴塔哥尼亚群体(Bonaerensis-Northpatagonic Stock,BNS)形态差异进行分析,并建立不同群体的判别函数。结果表明,BNS群体耳石和角质颚外形参数雌性大于雄性,而SPS群体则为雄性大于雌性。均数差异性检验认为,同一群体不同性别的耳石总长(Total StatolithLength,TSL)、最大宽度(Maximum Width,MW)、侧区长(Lateral Dome Length,LDL)、翼区长(Wing Length,WL)、翼区宽(WingWidth,WW)存在显著差异(P<0.05),同性别不同群体的MW、背侧区长(Dorsal Lateral Length,DLL)、吻侧区长(RostrumLateral Length,RLL)和WW存在显著差异(P<0.05)。而同一群体不同性别间角质颚的上头盖长(Upper Hood length,UHL)、上脊突长(Upper Crest length,UCL)、上喙长(Upper Rostrum length,URL)、上喙宽(Upper rostrum width,URW)、上侧壁长(UpperLateral wall length,ULWL)、下喙长(Lower Rostrum length,LRL)存在显著差异(P<0.01),同一性别不同群体角质颚的下头盖长(Lower Hood length,LHL)、下脊突长(Lower crest length,LCL)、LRL、下喙宽(Lower Rostrum width,LRW)、下侧壁长(LowerLateral wall length,LLWL)、下翼长(Lower Wing length,LWL)存在显著差异(P<0.01)。耳石形态参数经主成分分析,认为BNS群体雌雄的主成分因子主要集中在TSL/ML、DLL/ML、RW/ML和MW/ML,SPS群体主要集中于TSL/ML、RW/ML、WW/ML和DDL/ML;角质颚形态参数经主成分分析,认为BNS群体主成分因子主要集中在UHL/ML、UCL/ML、ULWL/ML和LRW/ML,SPS群体主要集中在UHL/ML、UCL/ML、ULWL/ML、URL/ML、LWL/ML和LRL/ML。利用角质颚和耳石对两群体样本分性别建立了判别函数,判别正确率均高于60%,所划分群体在部分形态指标上差异明显,具有一定的可信度。今后应加强样本采集个体大小和时间跨度,以更好的分析其群体变化规律。     

基于GLBM模型的中国大陆阿根廷滑柔鱼鱿钓渔业CPUE标准化

西南大西洋阿根廷滑柔鱼既是西南大西洋生态系统中的重要种类,也是鱿钓渔业的重要捕捞对像.单位捕捞努力量渔获量(CPUE)是表示渔业资源状况及其丰度的常用指标.根据2000-2010年中国大陆鱿钓船在西南大西洋的生产统计数据和海洋卫星遥感获得的海洋环境数据(表温,表温水平梯度,海面高度,叶绿素浓度),利用基于贝叶斯的广义线性模型(GLBM),分未加入固定交互选项、加入固定交互选项和加入随机交互选项3种情况对中国大陆西南大西洋阿根廷滑柔鱼鱿钓渔业的CPUE进行标准化.根据偏差信息准则(DIC)值最小来确定最佳贝叶斯模型.结果表明,包含纬度、海表温度、表温水平梯度、海面高度、月×纬度、月×经度及年×纬度变量且加入随机交互项的GLBM模型为最适.标准化后的CPUE较名义CPUE小,年间变化平缓.与广义线性模型(GLM)和广义加性模型(GAM)标准化的CPUE比较,GLBM模型更能反映其资源丰度的真实水平.研究认为,2001-2010年间经GLBM模型标准化后的CPUE呈现逐年下降的趋势.     

Sex‐specific reproductive investment of summer spawners of Illex argentinus in the southwest Atlantic

Energy investment in reproduction and somatic growth was investigated for summer spawners of the Argentinean shortfin squid Illex argentinus in the southwest Atlantic Ocean. Sampled squids were examined for morphometry and intensity of feeding behavior associated with reproductive maturation. Residuals generated from length‐weight relationships were analyzed to determine patterns of energy allocation between somatic and reproductive growth. Both females and males showed similar rates of increase for eviscerated body mass and digestive gland mass relative to mantle length, but the rate of increase for total reproductive organ weight relative to mantle length in females was three times that of males. For females, condition of somatic tissues deteriorated until the mature stage, but somatic condition improved after the onset of maturity. In males, there was no correlation between somatic condition and phases of reproductive maturity. Reproductive investment decreased as sexual maturation progressed for both females and males, with the lowest investment occurring at the functionally mature stage. Residual analysis indicated that female reproductive development was at the expense of body muscle growth during the immature and maturing stages, but energy invested in reproduction after onset of maturity was probably met by food intake. However, in males both reproductive maturation and somatic growth proceeded concurrently so that energy allocated to reproduction was related to food intake throughout the process of maturation. For both males and females, there was little evidence of trade‐offs between the digestive gland and reproductive growth, as no significant correlation was found between dorsal mantle length‐digestive gland weight residuals. The role of the digestive gland as an energy reserve for gonadal growth should be reconsidered. Additionally, feeding intensity by both males and females decreased after the onset of sexual maturity, but feeding never stopped completely, even during spawning.     

Diversity and abundance of glycosyl hydrolase family 5 in the North Atlantic Ocean

The diversity and abundance of glycosyl hydrolase family 5 (GH5) were studied in the North Atlantic Ocean. This family was chosen because of the large number of available sequences from cultured bacteria, the variety of substrates it targets, and the high number of similar sequences in the Sargasso Sea environmental genome database. Three clone libraries of a GH5 subcluster were constructed from the Mid-Atlantic Bight and the eastern and western North Atlantic Ocean. The two North Atlantic Ocean libraries did not differ from each other but both were significantly less diverse than the Mid-Atlantic Bight library. The abundance of GH5 genes estimated by quantitative PCR was positively correlated with chlorophyll concentrations in the eastern part of a transect from Fort Pierce, Florida, to the Azores and in a depth profile, suggesting that the supply of labile organic material selects for GH5-bearing bacteria in these waters. However, the data suggest that only <1% of all bacteria harbor the GH5 subcluster. These and other data suggest that the hydrolysis of polysaccharides requires complicated multi-enzyme systems.     

Purification, characterization and molecular cloning of tyrosinase from the cephalopod mollusk, Illex argentinus.

Tyrosinase (monophenol, L-DOPA:oxygen oxidoreductase) was isolated from the ink of the squid, Illex argentinus. Squid tyrosinase, termed ST94, was found to occur as a covalently linked homodimeric protein with a molecular mass of 140.2 kDa containing two copper atoms per a subunit. The tyrosinase activity of ST94 was enhanced by proteolysis with trypsin to form a protein, termed ST94t, with a molecular mass of 127.6 kDa. The amino acid sequence of the subunit was deduced from N-terminal amino acid sequencing and cDNA cloning, indicating that the subunit of ST94 is synthesized as a premature protein with 625 amino acid residues and an 18-residue signal sequence region is eliminated to form the mature subunit comprised of 607 amino acid residues with a deduced molecular mass of 68,993 Da. ST94 was revealed to contain two putative copper-binding sites per a subunit, that showed sequence similarities with those of hemocyanins from mollusks, tyrosinases from microorganisms and vertebrates and the hypothetical tyrosinase-related protein of Caenorhabditis elegans. The squid tyrosinase was shown to catalyze the oxidation of monophenols as well as o-diphenols and to exhibit temperature-dependency of o-diphenolase activity like a psychrophilic enzyme.     

Meso- and bathypelagic distribution and abundance of chaetognaths in the Atlantic sector of the Southern Ocean

We conducted multinet sampling during winter and summer in the Southern Ocean (Atlantic sector) to investigate the effect of water mass, season and water depth on abundance and species composition of meso- and bathypelagic chaetognaths. Eukrohnia hamata (mean 115 ind. 1,000 m⁻³) and Sagitta marri (mean 51 ind. 1,000 m⁻³) were dominant, complemented by E. bathypelagica (mean 19 ind. 1,000 m⁻³) and E. bathyantarctica (mean 19 ind. 1,000 m⁻³) below 1,000 m. A further six species were identified, among them the rare bathypelagic species Heterokrohnia fragilis and the subtropical Eukrohnia macroneura that is new to the Antarctic. Water depth and season were the principal determinants of abundance and species composition patterns, indicating vertical seasonal migration and vertical segregation of species. The life cycles of E. hamata and S. marri were studied additionally. Their maturity stages were vertically segregated and prolonged reproductive periods are suggested for both species.     

Occurrence and abundance of three larval codlet species (Bregmacerotidae, Teleostei) in the Southwest Atlantic Ocean (12–22°S)

There are still only a few studies related to Bregmacerotidae larvae in Brazil, although these larvae are frequently collected in oceanic ichthyoplankton samples. Thus this study analyzes the occurrence and abundance of Bregmaceros larvae along the Brazilian central coast and describes larval characteristics. During three oceanographic cruises samples were collected between the Real River (12°S) and the São Tomé Cape (22°S). Oblique hauls were conducted from a maximum depth of 200 m, using bongo nets of 330‐ and 500‐μm mesh size. Among the 951 bregmacerotids collected, three species were identified corresponding to 89%Bregmaceros atlanticus, 8%Bregmaceros cantori and 3%Bregmaceros n. sp. B. atlanticus was widely distributed along the study area and was more frequent in stations situated beyond the 200‐m isobath; this species was more abundant during the winter, showing a peak of density between Vitória and the São Tomé Cape (355 larvae per 10 m²). Bregmaceros cantori densities were very similar during the three cruises; the highest value (25.6 larvae per 10 m²) was recorded during the winter and higher concentrations were observed in neritic stations along the 200‐m isobath. Bregmaceros n. sp. was rare in collections made during the three cruises; it was concentrated along the Bahia coast (12–18°S), and was more frequent in stations situated in the oceanic region. Bregmaceros atlanticus varying from 2.0 to 6.0 mm and Bregmaceros n. sp. larvae varying from 3.0 to 6.0 mm were present in all cruises, indicating that they spawn year‐round. Bregmaceros cantori did not show a distribution pattern among the different length classes, probably associated with the fact that this species has a coastal distribution.     

Primary structure of the basic nuclear protein from spermatozoa of the mollusk Illex argentinus and its comparison with the structure of sperm proteins in other animals

The spermatic protein of chromatin I2 of squid Illex argentinus was separated by HPLC into two components I2-1 and I2-2. Amino acid sequences of the major portion of protein I2-1 (52 residues) and the N-terminal sequence of protein I2-2 (21 residues) were determined. Arginines in protein I2-1 are arranged in clusters typical of protamines; the first cluster is in the N-terminus, the longest heterogeneous basic cluster is in the central part of the protein chain, the C-terminal part of the molecule contains two clusters of three hydroxyamino acids each. The N-terminal sequences of illexins I2-1 and I2-2 (1-14 residues) are highly homologous. Homologous regions were found in illexin I2-1, tunnin of tuna fish and avian gallin thus defining the notion of proteins of an intermediate type from mollusc spermatozoa chromatin exemplified by the squid protamine-like protein.