Modeling the egg and larval transport pathways of the Antarctic toothfish (Dissostichus mawsoni) in the East Antarctic region: New insights into successful transport connections

The Antarctic toothfish (Dissostichus mawsoni) is an important fishery species widely distributed in the Southern Ocean, especially in areas covered by sea ice. Understanding fish distributions and life cycles, including the transport and survival of eggs and larvae, is essential for the assessment and sustainable management of the fishery. However, owing to difficulties with in situ winter observations, information on the early life stages of D. mawsoni is lacking. Here, we investigated the transport pathways of fish eggs and larvae through a particle tracking study, using satellite-derived ocean surface velocities in the East Antarctic region, which includes important D. mawsoni habitats and exploratory fisheries. Our results indicate that particles released from continental slopes are more likely to be successfully transported to suitable settlement grounds than those released from the BANZARE Bank (the southern region of the Kerguelen Plateau), which is situated further north and has been hypothesized to be a potential spawning ground for D. mawsoni. This study demonstrates successful source–settlement connections in relation to ocean recirculation and suggests important settlement regions for D. mawsoni larvae in the East Antarctic region.     

Necessary elements of precautionary management: implications for the Antarctic toothfish

We review the precautionary approach to fisheries management, propose a framework that will allow a systematic assessment of insufficient precaution and provide an illustration using an Antarctic fishery. For a single‐species fishery, our framework includes five attributes: (1) limit reference points that recognize gaps in our understanding of the dynamics of the species; (2) accurate measures of population size; (3) ability to detect population changes quickly enough to arrest unwanted declines; (4) adequate understanding of ecosystem dynamics to avoid adverse indirect effects; and (5) assessment of the first four elements by a sufficiently impartial group of scientists. We argue that one or more of these elements frequently fail to be present in the management of many fisheries. Structural uncertainties, which characterize almost all fisheries models, call for higher limit points than those commonly used. A detailed look into the five elements and associated uncertainties is presented for the fishery on the Antarctic toothfish in the Ross Sea (FAO/CCAMLR Area 88.1, 88.2), for which management was recently described as ‘highly precautionary’. In spite of having features that make the Ross Sea fishery ideal for the application of the precautionary approach, gaps in our knowledge and failure to acknowledge these gaps mean that current regulation falls short of being sufficiently precautionary. We propose some possible remedies.     

鳞头犬牙南极鱼LeptinB基因在抵御低温应激中的作用

为了探究瘦素基因(LeptinB, LepB)在斑马鱼肝脏细胞系(ZFL)低温应激中的作用,本研究根据鳞头犬牙南极鱼(Dissostichus mawsoni) LepB基因(DM-LepB)编码的氨基酸序列,克隆到构建的pTOL2-actin-EGFP质粒中(启动子为斑马鱼的β-actin)。选取EcoRⅠ和BamHⅠ为限制酶,设计构建了pTOL2-LepB+HIS-EGFP表达载体,并转染至ZFL细胞中。选择致死温度10 ℃进行实验,采用流式细胞术检测了低温胁迫下细胞的存活率,使用增强型CCK-8试剂盒检测了低温条件下细胞的生长增殖情况,使用荧光探针DHE检测了细胞活性氧(ROS)含量。结果显示,LepB基因的过表达能有效减少细胞ROS的产生,减轻细胞凋亡以应对低温胁迫。分析还显示,DM-LepB的过表达也有利于维持低温刺激下的胞内ATP水平与线粒体状态,有效减轻低温刺激对细胞的凋亡和坏死作用,对细胞冷应激起到保护作用。采用油红O染色和甘油三酯(TG)实验检测发现,DM-LepB基因能减缓低温刺激时细胞脂质的消耗,较多的脂质保留可减弱低温刺激对细胞的伤害,使得细胞能更好地抵抗低温损害。研究结果为揭示南极鱼类的低温适应分子机制提供了基础资料。     

鳞头犬牙南极鱼atp6v0c基因在HeLa细胞中抗寒功能的研究

为探求南极鱼ATP酶类在低温适应下的作用,从鳞头犬牙南极鱼Dissostichus mawsoni的c DNA文库中克隆atp6v0c基因(dmatp6v0c),并转染到He La细胞中,通过流式细胞仪检测细胞在低温胁迫下(10℃)的死亡率,获得了dmatp6v0c基因的全部编码序列,其长度为462 bp,并将其插入到真核表达载体pc DNA3.1(-)上用于体外表达。结果表明,与对照组相比,在低温胁迫下,过表达dmatp6v0c基因的He La细胞死亡率从(19.23±1.87)%显著降低到(8.13±0.04)%(P0.05)。研究表明,在低温胁迫下dmatp6v0c基因过表达能显著降低He La细胞的死亡率,试验结果可为dmatp6v0c基因作为鱼类耐寒育种的候选基因提供理论依据。