Population structure of bigeye tuna (Thunnus obesus) in the Indian Ocean inferred from mitochondrial DNA

Population structure of bigeye tuna (Thunnus obesus) in the Indian Ocean, Western Pacific Ocean and Eastern Atlantic Ocean were investigated using mitochondrial (mt) DNA sequence data. A total of 380 specimens were sampled from four regions in the Indian Ocean (Cocos Islands, Southeastern Indian Ocean, Southwestern Indian Ocean and Seychelles), and one region each from the Atlantic (Guinea) and the Western Pacific Oceans, respectively. The reconstructed neighbor-joining phylogeny based on the first hypervariable region (HVR-1) of the mitochondrial control region sequence data showed that haplotypes from the Indian and the Western Pacific Oceans could be grouped into two clades (Clades I and III), whereas in the Atlantic Ocean, two divergent clades (Clades I and II) coexisted. A single stock of bigeye tuna in the Indian Ocean was supported by hierarchical AMOVA tests and pairwise Φ_ST analyses. Clade I was the dominant population in the Indian and the Western Pacific Oceans which consisted of more than 96% of the specimens and Clade II was a specific group exclusively restricted to the Atlantic Ocean which made up 77% of its specimens. A new minor Clade, Clade III was discovered in the Indian and the Western Pacific Ocean. Overall, these analyses indicated that bigeye tuna of the Indian Ocean constituted a single panmictic population.     

Effects of local scale perturbations in the Atlantic bluefin tuna (Thunnus thynnus L.) trap fishery of Sardinia (W. Mediterranean)

Time series (1825–1973) of the Atlantic bluefin tuna, Thunnus thynnus, landings from the trap fishery of Sardinia (W. Mediterranean) were analyzed to identify (i) patterns of catch variability in the historical traps of Isola Piana, Portoscuso and Porto Paglia, and (ii) effects of three local environmental variables: Mining, Run-off and Sea Surface Temperature.We applied different time series analysis techniques: auto-correlation functions, spectral analysis and Dynamic Factor Analysis (DFA). Moreover, an asymmetrical design using a Before/After and Control/Impact location approach was used to test the perturbations due to mining processes that have characterized the fishery area.A sharp decreasing trend of Porto Paglia trap landings beginning in 1880, coincided with mechanized mining. This result was confirmed by the ANOVAs contrasting Before vs. After (P < 0.01) and Controls vs. Impact location (P < 0.01).We found a slight cyclical behaviour in the same time series. Spectral analysis highlighted that pattern synchronized with the Run-off cycles with periods corresponding to 7 years. We hypothesized that the effect of Run-off from watershed mine tailing dams creates a pulsing boundary ‘reflective’ effect for tuna migration schools on the in-shore trap of Porto Paglia, resulting in a periodic oscillation of captures.We have identified (i) a reversal of trends in captures between Portoscuso and Isola Piana traps and (ii) significant differences of the monthly distribution of capture events and timing of landings (P < 0.01) with a higher proportion now in May, rather than in June as in the past. We assume there is a relationship with climatic changes because warmer waters can induce precocity in gonad maturation. DFA did not show any significant differences among environmental factors and landings probably because the cyclical component in Run-off is masked. We emphasize the importance of Mediterranean traditional traps as ‘sentinels’ of the homing reproductive behaviour of bluefin tuna and we argue the case for a plan to link the remaining traps in a common monitoring network.     

南海—北印度洋SST变化趋势及周期分析

利用来自NOAA的SST（海袁温度）资料,计算了近半个世纪以来（1950～2009年）南海—北印度洋SST的整体变化特征,主要计算了整体变化趋势、变化趋势的区域性差异、季节性差异、变化周期.结果表明,近半个世纪以来,南海—北印度洋大部分海域的SST表现出显著的逐年线性递增趋势,其中北印度洋的递增趋势强于南海,印度洋赤道中东部海域的递增趋势尤为明显,可达0.014℃/a以上;南海—北印度洋海域的SST以0.011 5℃/a的速度显著性逐年线性递增,在夏季的递增趋势强于冬季,冬季和夏季分别以0.010 6、0.012 2℃/a的速度显著性逐年线性递增;该海域的SST具有显著的2.4 ～2.9、3.1 ～5.7年的显著性变化周期,以及40年以上的长周期震荡.     

北大西洋大青鲨年龄和生长研究

2010年10月~2011年3月金枪鱼延绳钓船在北大西洋西部水域(48° ~ 52°N/15° ~ 34°W , 3° ~ 15°N/34° ~ 40°W)兼捕524尾大青鲨(雄性328尾,雌性196尾),本文根据从中随机采集的51尾雄性(104~254 cm FL))和52尾雌性(135~211 cm FL)大青鲨椎骨样本进行年龄鉴定和生长研究。结果表明：叉长和脊椎骨半径的关系式为FL=192.8VR0.837 (n=117,R2=0.90);通过10%硝酸钴染色法观察脊椎骨轮纹,雄性的年龄范围为2~9龄,雌性为3~7龄;平均百分比误差指数(IAPE)为6.33%,精确度较高;采用实测的年龄-叉长数据估算雄性大青鲨年龄,逆算的年龄-叉长数据描述雌性大青鲨生长;von Bertalanffy生长参数为: L∞=330.4cm FL, k=0.15yr-1, t0=-0.64yr (雄性); L∞=295.7cm FL, k=0.14yr-1,t0=-0.62yr (雌性);雌雄寿命分别为21yr 和20yr。     

全国海洋水产类高校学报被引计量指标的统计与分析

期刊被引计量指标，包括总被引频次、影响因子、即年指标、他引率和被引半衰期等5项计量指标。这些指标主要显示该期刊被读者使用和重视的程度，以及在科学交流中的地位和作用，是评价期刊质量高低的重要依据和客观标准。为了全面、准确、公正、客观地评价和利用全国海洋水产类高校学报，对其被引计量指标中最重要的前3项分别进行统计与分析的结果表明，提高学报的被引计量指标应采取以下措施：(1)努力提高编辑质量：(2)加强组约稿工作；(3)加快编辑流程，尽快缩短出版时滞；(4)重视并增加交叉学科论文的发表。     

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。     

热带太平洋雌性黄鳍金枪鱼繁殖生物学研究

黄鳍金枪鱼(Thunnus albacores)是3个热带金枪鱼鱼种之一,也是我国远洋金枪鱼渔业的主要捕捞对象之一。本研究根据我国金枪鱼渔业观察员在热带太平洋海域(14°1'S-11°41'N,158°43'E-128°24'W)采集的229尾雌性黄鳍金枪鱼样本,基于组织切片法对其繁殖生物学特征进行研究。结果表明:成熟度以Ⅰ、Ⅱ期为主,性成熟个体占样品总数的36.7%;运用Logistic模型拟合的性成熟比率(P)与叉长(L_F)关系曲线(成熟度曲线)方程为P=1/1+e~([-0.072(LF-138.13)]),对应的50%性成熟叉长为138.13 cm;在南半球,纬度越高,性成熟比率和性腺成熟指数越高。东太平洋和中西太平洋(以150°W为界)黄鳍金枪鱼群体的成熟度表现出区域性差异,东太平洋群体的成熟进程比中西部快,且产卵活动存在季节性差异。东太平洋和中西太平洋群体成熟度的性腺成熟指数变化规律相似。比较肉眼观测法和组织切片法,发现肉眼观测法对Ⅱ、Ⅴ期的判断准确率较高,对Ⅰ、Ⅳ期的判断准确率低。     

Organs development,gene expression and health of Atlantic salmon (Salmo salar L.) fed genetically modified soybeans compared to the near‐isogenic non‐modified parental line

The present experiment was conducted to study the possible effects of genetically modified (GM), full‐fat soybean meal (FFSBM) from Round‐up Ready^® soybeans compared to its parental, and closest near‐isogenic, non‐modified (nGM) soybean variety, added at moderate (150 g kg^?1) and high (300 g kg^?1) inclusion levels. The fish showed a high specific growth rate (SGR 1.27–1.52), and nearly doubled their body weight (BW), with final weights varying from 1009 to 1110 g. Increased levels of dietary FFSBM, independent of the soy being GM or not, significantly decreased mean values of SGR, thermal growth rate, condition factor, final BW, liver somatic index, lipid efficiency ratio, apparent digestibility coefficients (ADC) of protein and gross energy, liver lipid content and plasma cholesterol, and significantly increased ADC of starch and muscle fatty acid levels of 18:3n‐3, 20:4n‐6, 20:5n‐3 and total n‐3. Increasing dietary GM FFSBM significantly increased feed conversion ratio, and significantly decreased protein efficiency ratio, ADC of lipid and dry matter and plasma triacylglycerol (TAG) levels. Spleen somatic index was significantly larger in fish groups fed GM FFSBM compared to groups fed nGM FFSBM, which might indicate a possible immune response exerted by the GM soybeans. Mean normalized expression of heat shock protein 70 mRNA in distal intestine was significantly up‐regulated while normalized expression of catalase in liver was down‐regulated, in fish fed FFSBM compared to fish fed FM. In conclusion, substituting moderate to high levels of GM Round‐up Ready^® FFSBM in diets for Atlantic salmon and compared to the closest near‐isogenic counterpart available, resulted in many effects independent of the soy being GM or not, but with the notable exceptions of enlarged spleen and lowered plasma TAG.     

Mitigating fur seal interactions: relocation from Tasmanian aquaculture farms

• 1. At Tasmanian salmon aquaculture farms, fur seals were trapped and relocated to reduce interactions with stock, operations and equipment. From 1990 to 2005, 4517 relocations of 1124 seals were undertaken, peaking at 1203 relocations in 2003.
• 2. Of the relocations, 56% were recaptured seals. Most seals had less than 10 captures (46%), with 3% trapped more than 20 times.
• 3. Relocations were mostly seasonal, occurring in the austral winter and spring with a peak in August.
• 4. Seal recapture intervals were highly variable, ranging from days to years. Within the same year, recapture intervals per seal ranged from 4 to 258 days, mean 36 days.
• 5. Australian fur seals were trapped more frequently than New Zealand fur seals. The first trapped New Zealand fur seal was identified in 2000.
• 6. Relocation provides short‐term relief from seal interactions but does not mitigate the interaction problem in the longer term.
• 7. The core of the seal interaction problem is the current inability to exclude seals from pens and fish stock. Salmon farms are providing a predictable, accessible food source for seals.

Copyright © 2008 John Wiley & Sons, Ltd.