Hydrological and water cycle processes of inland river basins in the arid region of Northwest China

The increasing shortage in water resources is a key factor affecting sustainable socio-economic development in the arid region of Northwest China(ARNC). Water shortages also affect the stability of the region's oasis ecosystem. This paper summarizes the hydrological processes and water cycle of inland river basins in the ARNC, focusing on the following aspects: the spatial-temporal features of water resources(including air water vapor resources, runoff, and glacial meltwater) and their driving forces; the characteristics of streamflow composition in the inland river basins; the characteristics and main controlling factors of baseflow in the inland rivers; and anticipated future changes in hydrological processes and water resources. The results indicate that:(1) although the runoff in most inland rivers in the ARNC showed a significant increasing trend, both the glaciated area and glacial ice reserves have been reduced in the mountains;(2) snow melt and glacier melt are extremely important hydrological processes in the ARNC, especially in the Kunlun and Tianshan mountains;(3) baseflow in the inland rivers of the ARNC is the result of climate change and human activities, with the main driving factors being the reduction in forest area and the over-exploitation and utilization of groundwater in the river basins; and(4) the contradictions among water resources, ecology and economy will further increase in the future. The findings of this study might also help strengthen the ecological, economic and social sustainable development in the study region.     

北部湾二长棘犁齿鲷的时空分布特征

二长棘犁齿鲷(Evynnis cardinalis)作为北部湾主要经济鱼类之一,长久以来受过度捕捞的影响,其资源量发生较大波动,将对渔业生产和种群结构有较大影响。文章根据2014年~2015年近海渔业资源调查资料,应用生物量和个体数单位捕捞努力量渔获量(CPUE)综合分析该鱼种资源的季节变化和空间分布。结果表明该鱼种广泛分布于北部湾中国管辖海域内,四季的出现率均在86%以上。生物量和个体数CPUE有明显的季节变化,均表现为最高值在夏季(平均值分别为7.3 kg·h~(-1)和240.83尾·h~(-1)),而冬季最低(平均值分别为1.76 kg·h~(-1)和21.94尾·h~(-1))。从空间分布看,生物量和个体数CPUE高值区主要分布于北部湾20°N以北海域,而低值区则处于海南岛西部海域。近年来在该海域实施的资源养护措施已取得初步成效,相比于20世纪90年代,二长棘犁齿鲷的资源量有所恢复。但二长棘犁齿鲷生物学特征分析结果表明,体长200 mm或体质量80 g以上的群体比重总体偏低,种群低龄化和小型化问题仍较为严峻,需采取新的管理措施(增大最小网目和开捕体长),以降低捕捞强度,改善种群结构。     

船载摇摆胁迫对斑石鲷血液生化指标的影响研究

为了探索鱼类在船载摇摆条件下的应激响应和适应性,为深远海大型养殖平台养殖工艺设计与模式构建提供基础数据和理论依据,利用机械摇摆台模拟船载工况,研究了不同摇摆周期和时间条件下斑石鲷的血液生化指标变化情况。结果表明:(1)短时间摇摆条件下(5 min),摇摆周期10 s组的斑石鲷与空白组无显著性差异;摇摆周期5 s组的斑石鲷血清葡萄糖显著降低、皮质醇和肾上腺素指标显著升高、肌糖原和肝糖原无显著差异。(2)长时间摇摆条件下(60 min),摇摆周期5 s组和10 s组之间斑石鲷无显著性差异。但是,与空白组相比,血清葡萄糖指标均显著降低,皮质醇和肾上腺素指标也均显著升高,肌糖原和肝糖原指标无显著差异。(3)水质变化情况显示,摇摆60 min对于水温、盐度、pH、溶解氧、氨氮等的影响不显著。根据试验结果认为,短期小幅摇摆对斑石鲷不会造成较大影响,而大幅度剧烈摇摆会引起斑石鲷一定程度的应激反应。     

河北沿海焦氏舌鳎资源现状分析

焦氏舌鳎过去利用价值较低,但随着渔业捕捞能力的增强,渔业资源衰退的问题日益突出,焦氏舌鳎的生态优势逐步显现。通过对河北省沿岸焦氏舌鳎近年资源状况进行研究,发现近两年其生态优势度有所提升,群体组成存在小型化、低龄化的特点,就此提出了渔业资源养护相关建议。     

我国渔药剂型使用现状及其在渔药安全使用技术中的价值

从渔药安全使用的角度,对我国渔药剂型的现状和存在的问题进行了分析。通过总结渔药剂型在提高生物利用度、降低毒副作用、延长作用时间和提高稳定性等方面的作用,阐述了渔药剂型在降低水产品药物残留风险方面的潜在应用价值,期望为我国渔药剂型在渔药安全使用中提供参考。     

内陆河水资源合理利用的优化分配方法

依据内陆河流域不同区域在水资源条件、气候条件、经济发展水平及水资源利用途径等方面的差异性，以及时序上水资源的利用规律，提出了旨在合理利用水资源，改善生态环境的水资源优化分配方法。通过在黑河流域的实例应用，论证了该方法的有效性。     

渔场鱼量模型的建立

微分方程的平衡点可分为稳定和不稳定两种。当轻轻扰动平衡点时，系统状态就会剧烈变化。若新的状态决不会回到原平衡点，此点就是不稳定的；相反，如果一个系统在稳定平衡点附近受到干扰，它总是企图回到平衡点，那么此点就是稳定的。用这一数学工具可以解决诸如渔场鱼量等一系列实际问题。     

基于水质-声音-视觉融合的循环水养殖鱼类摄食强度识别

在工厂化循环水养殖中，准确识别鱼类摄食强度是实现精准投喂的前提和关键。水质、视觉、声音等单模态数据均可用于评估摄食强度，但单一模态往往具有片面性，难以完全反映全局特征，存在识别精度低、可移植性差等问题。多模态方法通过融合不同模态的特征，可为摄食强度量化提供新的手段。基于此，为融合鱼类摄食中的“水质-声音-视觉”信息，实现高精度的鱼类摄食强度量化，该研究在多模态Transformer（multimodal transformer，MulT）的基础上，提出一种多模态融合的鱼类摄食强度识别算法Fish-MulT。首先，从输入的水质、声音和视觉数据中提取特征向量；其次，利用多模态转移模块（multimodal transfer module，MMTM）对输入的特征向量进行融合，得到3种融合向量；然后对融合向量添加自适应权重并相加，得到融合模态；最后，利用融合模态将MulT算法中各模态分支的跨模态Transformer（cross-modal transformer）从2个优化为1个。试验结果表明，与MulT算法相比，本文算法的鱼类摄食强度识别准确率由93.30%提高到95.36%，参数量减少38%。与水质、声音和视觉单模态相比，准确率分别提高68.56%、21.65%和3.61%。可用于制定精准投喂策略，并为开发智能投喂系统提供技术支持。     

Effects of Sowing Methods on Upland Rice in Lowland Rice-Vegetable Sequence in Inland Valley

Triple cropping in the inland valleys of southwestern Nigeria is technically possible but the third crop between the main crop and vegetables has poor establishment due to soil saturation. Identification of appropriate sowing methods is required in this niche. A field experiment was conducted at the University of Agriculture, Abeokuta, Nigeria in 2007/2008 and 2008/2009 cropping seasons to evaluate the effect of sowing methods on the performance of upland rice （Oryza spp.） in a lowland rice-vegetable sequence. The first, second, and third crops in the sequence were planted in May, September and December, respectively. Two upland rice varieties, namely New Rice for Africa 1 （NERICA 1） and ITA 150 constituted the main plot treatments while the subplot treatments were sowing methods. The mean grain yield of lowland rice for two years was 7.74 t ha^-1. The fluted pumpkin had a fresh leaf weight of 14.78 t ha^-1. The grain yields of the two upland rice varieties （1.81 and 1.85 t ha^-1） and sowing methods which ranged between 1.63 and 2.05 t ha^-1 were similar in both cropping seasons. However, the interaction of variety by sowing methods had a significant effect on grain yield. Transplanting and pre-germinated broadcast had the highest grain yield for NERICA 1 while dry broad cast and pre-germinated dibbled had the highest in ITA 150. Hence, the productivity of triple cropping in the inland valley was enhanced by sowing methods.     

Long-term trends in the competitive shore fishery along the KwaZulu-Natal coast,South Africa

Twenty-four years (1977–2000) of competitive shore angling catch and effort data from the KwaZulu-Natal Coastal Anglers Union for the province of KwaZulu-Natal were analysed. Of a minimum of 117 species recorded, the most commonly caught species were dusky shark (Carcharhinus obscurus) (26%), milk shark (Rhizoprionodon acutus) (18%) and shad (Pomatomus saltatrix) (10%). By weight, the top species were dusky shark (34%) and diamond ray (Gymnura natalensis) (19%). All the above species showed considerable inter-annual variation in their respective contributions to annual catch. Probably as a result of changes in fishing patterns, dusky shark and milk shark showed a general decline in percentage contribution to catch over the period, while contributions of lesser guitarfish (Rhinobatos annulatus), giant guitarfish (Rhynchobatus djiddensis), diamond ray (Gymnura natalensis) and brown ray (Himantura gerrardi) increased. Mean overall annual cpue by number and weight showed a non-significant increase over the period, while each of the investigated species showed a constant trend in mean annual weight. There were high proportions of juveniles in the catches of dusky shark (100%), dusky kob (92%) and giant guitarfish (78%). Improvements made to the structure of shore angling competitions and the overall contribution of competition angling to resource management in South Africa is discussed.