Population dynamics of Calanus chilensis in the Chilean Eastern Boundary Humboldt Current

A study of the population dynamics of Calanus chilensis was carried out in the coastal area of the Mejillones Peninsula (23°S), which is an upwelling site in the Eastern Boundary Humboldt Current. Information was derived from time-series sampling (15 day interval) at three stations, and from two broad-scale cruises: under active upwelling, and under 1997/1998 El Niño conditions. Calanus chilensis showed continuous reproduction throughout the year. In the study area, upwelling takes place intermittently year-round, suggesting that Calanus production is not limited by food. Advection played an important role in structuring the spatial distribution of Calanus , both during upwelling and under El Niño conditions. Population losses from upwelling and offshore transport may be compensated by rapid turnover rates of cohorts, growing at temperature-dependent rates and hence allowing population recovery, even in abnormally warm waters during El Niño conditions.     

Environmental effects on forage and longline fishery performance for albacore (Thunnus alalunga) in the American Samoa Exclusive Economic Zone

The South Equatorial Counter Current (SECC) strongly influences the American Samoa Exclusive Economic Zone (EEZ) and changes strength on a seasonal and ENSO cycle. A strong SECC is associated with a predominantly anticyclonic eddy field as well as increased micronekton biomass and catch-per-unit-effort (CPUE) for albacore tuna, the economically important target species of the local longline fishery. A strong SECC carries chlorophyll a -rich waters from upwelling regions at the north coast of New Guinea towards the EEZ, most likely resulting in the observed increase in micronekton biomass, forage for albacore. Relatively stable anticyclonic eddies show a further increase in micronekton biomass, apparently advected from neighboring SECC waters. The presence of forage presumably concentrates albacore, thus resulting in the observed increase in CPUE. High shear regions of neither anticyclonic nor cyclonic eddies correlate with increased micronekton biomass. Areas characterized by South Equatorial Current (SEC) waters correspond to areas with the lowest micronekton biomass and the highest number of aggregative structures, which are most likely small pelagic fish shoals. Micronekton composition in SEC waters differs from that in the SECC. During El Niños, the seasonal signals at the north shore of New Guinea and in the SECC are exceptionally strong and correspond to higher albacore CPUE in the EEZ. My results suggest that the strength of upwelling and the resulting increase in chlorophyll a at New Guinea, as well as the Southern Oscillation Index, could be used to predict the performance of the local longline fishery for albacore tuna in the American Samoa EEZ.     

改善E1级刨花板预压性能的研究

针对E1级刨花板生产过程中出现板坯铺装时散坯的问题进行了研究。结果表明,在一定范围内,提高树脂粘度、面粉用量和固化剂用量,可以提高胶粘剂初粘性,使刨花板预压性能得到一定程度的改善,但效果有限。调胶时加入聚乙烯醇能显著改善预压性能。当所用树脂粘度为0.17Pa.s、固化剂用量1.9％、面粉用量4％时,再添加0.5％聚乙烯醇,就可以使得刨花板铺装过程中没有散坯问题,具有很好的预压性能。     

逸人·逸笔·逸气——论倪瓒诗画创作风格的互通

倪瓒身处元末，散尽家财，隐迹山水，交游甚广，以写诗、作画以自娱。倪瓒之画，不求形似，简笔率略而成，自得天真逸趣，形成简远空疏之境。倪瓒之诗，不事雕琢，遇事感兴，得乎性情之正，有冲淡萧散之风。作为画家兼诗人，倪瓒打破了画与诗两种不同艺术形式之间的壁垒，实现了其诗画艺术风格的互通。     

厄尔尼诺事件对西北太平洋柔鱼种群动态的影响

为了解西北太平洋柔鱼资源量变动与气候变化如厄尔尼诺事件等的关系，实验假设尼诺指数 (oceanic Ni?o index，ONI)影响柔鱼种群动态参数内禀自然增长率 (intrinsic rate of growth, r)和最大环境容纳量 (carrying capacity, K)并分别建立4种剩余产量模型 (SP、E_r-EDSP、E_K-EDSP、E_r- E_K-EDSP)探索厄尔尼诺事件影响下西北太平洋柔鱼的种群资源状态变化趋势。结果发现, E_r-EDSP、E_K-EDSP、E_r-E_K-EDSP等3个加入气候因子模型的偏差信息准则 (deviance information criterion，DIC)值小于传统剩余产量模型的DIC值，其中E_r-E_K-EDSP模型DIC值最小，模型精度最高，估计的最大可持续产量 (maximum sustainable yield，MSY)为39.26×10⁴ t。1994—2017年，北太平洋柔鱼的捕捞死亡率 (F_t) 低于目标死亡率 (F_tar)和MSY水平下的捕捞死亡率 (F_MSY)，2017年种群资源量小于MSY水平资源量 (B_MSY)。研究表明，西北太平洋柔鱼种群资源可能正处于过度捕捞阶段。该研究结果可为西北太平洋柔鱼的可持续开发提供建议。