南极半岛南极磷虾栖息地适应性研究

南极磷虾(Euphausia superba)作为南极生态系统中的关键物种,其时空分布研究对发展磷虾渔业和理解南大洋生态系统均有重要的作用,相关研究有利于磷虾种群的资源评估以及中心渔场的探测。本文利用海表温度（Sea Surface Temperature,SST）、海面高度（Sea Surface Height,SSH）、海表面叶绿素（Sea surface chlorophyll,SSC）、海冰面积覆盖(Sea Ice Coverage,SIC）等环境因子,分别采用神经网络拟合和一元非线性拟合方法,并结合最小值法、最大值法、连乘法、算术平均法、几何平均法、加权算术平均法等构建了磷虾栖息适宜指数 (Habitat Suitability Index,HSI) 模型。结果表明,神经网络模型预报结果更符合磷虾实际栖息分布情况,而一元非线性拟合预测结果较为连续。最大值法和最小值法计算结果差异较大,容易引进较大的误差。连乘法的预测效果较好,算术平均法、几何平均法和加权算术平均法的预测结果相似,且较为稳定。     

Interannual variability of the South Georgia marine ecosystem: biological and physical sources of variation in the abundance of krill

Interannual variability is a characteristic feature of the Southern Ocean ecosystem, yet the relative roles of biological and physical processes in generating these fluctuations are unknown. There is now extensive evidence that there are years when there is a very low abundance of Antarctic krill ( Euphausia superba ) in the South Georgia area, and that this variation affects much of the ecosystem, with the most obvious impacts on survival and breeding success of some of the major predators on krill. The open nature of the South Georgia ecosystem means this variability has large-scale relevance, but even though there are unique time series of data available, information on some key processes is limited. Fluctuations in year-class success in parts, or all, of the krill population across the Scotia Sea can generate large changes in the available biomass. The ocean transport pathways maintain the large-scale ecosystem structure by moving krill over large distances to areas where they are available to predator colonies. This large-scale physical system shows strong spatial and temporal coherence in the patterns of the interannual and subdecadal variability. This physical variability affects both the population dynamics of krill and the transport pathways, emphasizing that both the causes and the consequences of events at South Georgia are part of much larger-scale processes.     

高真空脱溶工艺对南极磷虾油品质影响

为评估高真空脱溶技术对南极磷虾油品质的影响,该研究测定正己烷残留量、虾青素含量、色泽、氧化稳定性、脂肪酸组成,以及动脉粥样硬化指数（atherosclerosis index,AI）和血栓形成指数（thrombogenic index,TI）等多项指标,对脱溶工艺效果进行全面评估。结果表明,在50 ℃处理50 min、60 ℃处理30 min或70 ℃处理15 min的条件下,南极磷虾油中的正己烷残留量显著降至20 mg/kg以下,符合《食品安全国家标准 食用油：GB/T 2716-2018》对溶剂残留量的限定。脱溶工艺保护了虾青素含量,确保其质量分数维持在30 mg/kg以上,满足《农业农村部水产行业标准 磷虾油：SC/T 3506-2020》对磷虾油合格品的规定。脱溶处理后的磷虾油在色泽、氧化稳定性、脂肪酸组成以及AI和TI等关键指标上展现出良好的稳定性,未见显著变化（P > 0.05）。高真空脱溶工艺有效去除了溶剂残留,同时完好保留了磷虾油的理化特性和营养价值,为油脂工业高效、环保的脱溶解决方案的提出提供参考。     

南极磷虾粉替代鱼粉对圆斑星鲽幼鱼生长性能、血清和肝脏生化指标及血清非特异性免疫指标的影响

本试验旨在探究南极磷虾粉替代鱼粉对圆斑星鲽幼鱼生长性能、血清和肝脏生化指标及血清非特异性免疫指标的影响。以鱼粉和玉米蛋白粉为蛋白质源,高筋粉为糖源,鱼油、豆油和磷脂为脂肪源配制基础饲料。以南极磷虾粉分别替代基础饲料中0(对照)、10%、20%、30%、40%、50%的鱼粉,配制6种等氮等脂的试验饲料(分别记为R0、R10、R20、R30、R40和R50),饲喂初始体重为(38.16±0.11)g的圆斑星鲽幼鱼50 d,每种饲料设3个重复,每个重复投喂30尾鱼。结果表明:1)R30、R40组圆斑星鲽幼鱼的增重率和饲料效率较高,显著高于其他各组(P0.05);R50组的死亡率显著高于其他各组(P0.05)。南极磷虾粉替代鱼粉水平对圆斑星鲽幼鱼的肝体比和脏体比没有产生显著影响(P0.05)。2)R10和R30组的血清总蛋白含量显著高于其他各组(P0.05);与对照组相比,南极磷虾粉替代10%~30%的鱼粉对圆斑星鲽幼鱼血清中谷草转氨酶和谷丙转氨酶以及肝脏中谷氨酸脱氢酶活性无显著影响(P0.05)。R40、R50组血清中谷草转氨酶和谷丙转氨酶活性与对照组相比显著升高(P0.05),R40组肝脏中谷草转氨酶活性较之对照组显著降低(P0.05),且R50组肝脏中谷丙转氨酶活性显著低于其他各组(P0.05)。3)与对照组相比,南极磷虾粉替代10%~30%的鱼粉可显著提高圆斑星鲽幼鱼血清中溶菌酶、碱性磷酸酶的活性(P0.05)。综合来看,南极磷虾粉替代10%~30%的鱼粉可以提高圆斑星鲽幼鱼的生长性能和非特异性免疫力,并对鱼体的肝脏功能和蛋白质代谢无不利影响。     

船舶摇摆和工艺参数对南极磷虾挤压脱壳效果的影响

为了探究风浪造成的船只摇摆和工艺参数设置对南极磷虾挤压脱壳加工效果的影响,该文测量记录了不同横摇和纵摇状态下脱壳加工的得肉率和虾壳残留,分析了不同条件下脱壳滚轴长度区域的脱壳完成率。结果表明:船舶摇摆会对脱壳加工得肉率与虾壳残留率造成影响,但差异均不显著(P0.05),在纵摇7?和横摇5?时虾壳残留率分别达到1.07%和1.64%。船舶的摇摆对脱壳完成率有一定影响,随着摇摆幅度的增加,同一区域内脱壳完成率呈下降趋势。增加滚轴的长度能有效防止由于摇摆幅度增加而造成脱壳完成率降低的问题,当滚轴长度为1 200 mm时,脱壳完成率大于95%。放置时间对脱壳效果的影响较大(P0.05),放置2 h后的磷虾在区域Ⅳ的脱壳完成率降低至94%,虾壳残留率也相应增多。研究结果可为南极磷虾脱壳设备的应用和产业化提供参考。     

Protein from Northern krill (Thysanoessa inermis), Antarctic krill (Euphausia superba) and the Arctic amphipod (Themisto libellula) can partially replace fish meal in diets to Atlantic salmon (Salmo salar) without affecting product quality

The main objective of the present study was to evaluate the effect of using three different crustacean meals (Tysanoessa inermis, Euphausia superba, Themisto libellula) on product quality of Atlantic salmon (Salmo salar L.). In order to do this, a total of six iso‐protein, iso‐lipid and iso‐carotenoid diets were prepared. Two experimental diet series were prepared. In the first series, a control feed (K0) was compared with diets where 20%, 40% and 60% of the fish meal protein were replaced with protein from Northern krill T. inermis (K20, K40 and K60, respectively). In the second series, control feed (K0) was compared with diets where 40% of the dietary protein was replaced by protein from T. inermis (K40), Antarctic krill E. superba (AK40) and the Arctic amphipod T. libellula (AMP40). The salmon groups were fed the various diets for 160 days and the average weight of the fish increased from 410 g to around 1500 g. Fish given diets containing krill displayed a general better growth compared with the ones given pure fish meal diet. Replacing fish meal protein with protein from the crustacean sources had, in general, only minor effects on the flesh quality measured both by technical and sensory methods. However, some significant effects were noted. Postmortem muscle pH was generally lower (P < 0.05), for K20, K40, AMP40 in fish fed crustacean diets compared with those receiving the control diet. Increasing the replacement level of non‐fish meal protein from Northern krill (K20, K60) significantly reduced the rigor contraction. Fish given K20 had a slightly firmer meat texture, measured as resistance to post‐rigor compression, especially when compared with K60 (P < 0.05). Fish from the K20 and AMP40 groups had a deeper red flesh coloration [both light reflection (A*‐value and chroma) and flesh astaxanthin concentration] than fish fed K0 and higher inclusions of krill meal. The groups with the highest astaxanthin flesh content also showed the best growth and had the highest feed intake. Finally, a sensory panel analysis differed slightly from the technical measurements in that K0, rather than K20 was given the highest score for hardness and colour. In comparison with K0, AK40 got the lowest salty taste and hardness scores from the panellists relative to the control fish (P < 0.05). Despite minor effects on the present quality measures, it is concluded that meal from three different crustacean species can successfully replace fish meal up to 60% with Northern krill, and 40% of Antarctic krill and amphipod meal of dietary proteins.     

南极磷虾产业发展最新动向

在全球渔业资源衰退,大多数海洋渔业品种被过度捕捞的大背景下,南极磷虾巨大的资源量越来越引人关注。本文对近年来南极磷虾捕捞产量的变动情况和南极磷虾产业的发展现状与趋势进行了分析论述。随着南极磷虾捕捞产量的快速增长、加工技术日趋完善、新产品开发应用力度加大和市场的不断拓展,人们对南极磷虾产业的发展前景充满期望。     

南极磷虾冻藏温度下的品质变化及其货架期分析

以出肉率及化学变化(pH、TVB-N、TBARS、Ca² -ATPase活性)为指标,结合感官评价,探讨了南极磷虾冻藏温度下(-8、-18和-28 ℃)的品质变化及货架期。实验结果显示,南极磷虾感官评分与冻藏时间和冻藏温度均有显著的相关性(r=0.982和0.981),-8 ℃条件下20 d后南极磷虾感官不可接受,-18和-28 ℃条件下南极磷虾分别在75和120 d时感官不可接受;出肉率与冻藏时间有显著的相关性(r=0.953),在-8、-18和-28 ℃条件下南极磷虾出肉率在货架期终点分别达到31.62%、31.21%、34.52%;pH与冻藏时间和冻藏温度相关性不明显,不适宜用作反映南极磷虾冻藏条件下的品质指标,但随时间的延长pH仍呈增长趋势,在货架期终点3种冻藏温度下南极磷虾pH分别达到7.94、7.99、7.84;TVB-N和TBARS分别与冻藏时间有显著相关性(r=0.944和0.935),但TVB-N只与-8 ℃条件下的温度有显著相关性,TBARS只与-18和-28 ℃冻藏温度有显著相关性,在货架期终点时(感官不能接受)3种冻藏温度下南极磷虾TVB-N和TBARS分别为21.43、20.49、19.74 mg/100 g和0.88、0.78、0.66 mg MA/kg,均低于腐败水平阈值;Ca² -ATPase活性下降显著,与冻藏时间呈显著相关性(r=-0.929)。南极磷虾感官指标、出肉率、TVB-N、TBARS、Ca² -ATPase活性均在冻藏期间有明显变化,且与冻藏时间有明显的相关性,可以考虑用作反映冻藏条件下南极磷虾品质变化指标。因此,综合各项指标并结合感官评价,可以判断实验过程中3种冻藏温度下南极磷虾货架期终点分别为20、75、120 d。     

Southern Ocean iron fertilization by baleen whales and Antarctic krill

Iron is the limiting micronutrient in the Southern Ocean and experiments have demonstrated that addition of soluble iron to surface waters results in phytoplankton blooms, particularly by large diatoms. Antarctic krill (Euphausia superba) eat diatoms and recycle iron in surface waters when feeding. Baleen whales eat krill, and, historically, defecation by baleen whales could have been a major mechanism for recycling iron, if whale faeces contain significant quantities of iron. We analysed the iron content in 27 samples of faeces from four species of baleen whale. Faecal iron content (145.9 ± 133.7 mg kg^?1) is approximately ten million times that of Antarctic seawater, suggesting that it could act as a fertilizer. Furthermore, we analysed the iron content of seven krill species and of muscle tissue of two species of baleen whales; all samples had high iron levels. Using these figures, together with recent estimates of the range and biomass of krill, we calculate that the Antarctic krill population contains ～24% of the total iron in the surface waters in its range. Thus, krill can act as a long‐term reservoir of iron in Antarctic surface waters, by storing the iron in their body tissue. Pre‐exploitation populations of whales and krill must have stored larger quantities of iron and would have also recycled more iron in surface waters, enhancing overall ocean productivity through a positive feedback loop. Thus, allowing the great whales to recover might actually increase Southern Ocean productivity through enhancing iron levels in the surface layer.