鱼笼诱捕鱼类的渔具结构与渔法特点

1996—1997年,我们设计了几种不同形状、不同尺寸的鱼笼,在东山、漳浦两地进行鱼笼诱捕鱼类的一系列海上生产试验。本文主要介绍这几种鱼笼的结构及该种作业在生产上的渔法特点。     

萤光拖网推广试验的研究报告

本文报道了1996—1997年萤光拖网推广试验的结果,比较和分析了不同光周期下,萤光网的作业效率变化及其对不同渔获类型的捕获效应关系。试验表明,太阳光、月光和天气变化都对萤光网的作用效率产生影响,这种影响因渔获类型的不同表现各个相同,并伴随昼夜交替而发生变化。萤光网对各类型渔获的最有利捕捞时间,大多在黄昏至夜间的低照度下;萤光网对不同捕捞对象有不同的效应,具有种间差异大,并与其生态类群存在密切联系的特点。本试验研究结果,符合于海洋动物视觉功能的特征,也符合于海洋动物生态类群的一般规律。     

Daily ration of Japanese Spanish mackerel Scomberomorus niphonius larvae

SUMMARY: Diel successive samplings of Japanese Spanish mackerel Scomberomorus niphonius larvae were conducted throughout 24 h both in the sea and in captivity in order to estimate their daily ration. Using the Elliott and Persson model, the instantaneous gastric evacuation rate was estimated from the depletion of stomach contents (% dry bodyweight) with time during the night for wild fish (3.0–11.5 mm standard length) and from starvation experiments for reared fish (8, 10, and 15 days after hatching (DAH)). Japanese Spanish mackerel is a daylight feeder and exhibited piscivorous habits from first feeding both in the sea and in captivity. Feeding activity peaked at dusk. The estimated daily ration for wild larvae were 111.1 and 127.2% in 1996 and 1997, respectively; and those for reared larvae ranged from 90.6 to 111.7% of dry bodyweight. Based on the estimated value of daily rations for reared fish, the total number of newly hatched red sea bream Pagrus major larvae preyed by a Japanese Spanish mackerel from first feeding (5 DAH) to beginning of juvenile stage (20 DAH) in captivity was calculated to be 1139–1404.     

Conservation of Aquatic Biodiversity in China

本文探讨了中国目前水生生物多样性的状况。人类活动已对水生物的生存环境造成严重影响 ,面对生物多样性的丧失 ,我们应设法保护它。本文在保护水生生物多样性方面提出了一个新的观点 ,从保护流域生态环境入手以保护水生生物多样性     

Exotic vs. native plant dominance over 20 years of old-field succession on set-aside farmland in Argentina

Exotic plants are major constituents of species pools in modern landscapes. Managing succession for restoration of degraded ecosystems thus requires an understanding of novel trajectories unfolding in mixed, native/exotic plant assemblages. We examined trends in native and exotic species abundance over 20 years of old-field succession on set-aside farmland in the Inland Pampa, Argentina. Changes in plant cover and species richness were annually monitored on adjacent permanent plots established in different years (1978-1989). Both native and exotic species occurred in early, mid and late successional stages, exhibiting similar life-form replacement patterns, from annual forbs, through annual to perennial grasses. Exotic plant richness declined with plot age. Yet, four exotic grasses remained dominant through succession (50-70% cover), with plots initiated in later years showing increased exotic cover. While native perennial grasses occurred from the onset of succession, increasing from 5 to 12 spp/plot, they only showed transient peaks below 30% cover. Cluster analysis of 113 plot-year samples identified alternative community states for early, mid and late successional stages, which were connected by a complex network of interweaving dynamic pathways. Depending on the plot, vegetation dynamics comprised directional temporal trajectories as well as nondirectional pathways, and arrested community states dominated by exotic grasses. Our results illustrate the overwhelming role of exotic species in modern old-field succession, and their potential to hinder recovery of native communities on former agricultural land. Community states with novel, native/exotic plant mixtures could be managed to deliver specific ecosystem services (e.g. forage production, carbon sequestration). However, meeting conservation goals may require active restoration measures, including exotic plant removals and native grass seeding.     

舟山市渔村转型现状及对策研究

分析了渔村转型过程中存在的问题,并在新农村建设的基础上结合渔村自身的特点提出适宜的解决措施,进一步推进新渔村的建设.     

卷柏属(Selaginella)管状分子的研究

[目的]研究卷柏管状分子的类型和特点。[方法]用扫描电子显微镜对经离析法处理的4种卷柏属植物的茎进行观察。[结果]中华卷柏和蔓出卷柏中具有管胞,其中蔓出卷柏中还可见梯状穿孔的管状分子,推测可能为导管;圆枝卷柏、垫状卷柏仅观察到导管,有梯状穿孔以及网状-梯状混合型穿孔2种类型。这4种卷柏中,圆枝卷柏和垫状卷柏的管状分子最为进化,蔓出卷柏次之,中华卷柏最原始。垫状卷柏、蔓出卷柏和中华卷柏的管状分子类型为首次报道。卷柏管状分子类型的不同可能与其生境有关。[结论]该研究为验证同形叶和异形叶类型卷柏管状分子的差别以及探讨卷柏管状分子的演化问题奠定了基础。     

The value of bushmeat and other wild foods to rural households living in extreme poverty in Democratic Republic of Congo

We examine the relationship between poverty and the use of wild foods, namely bushmeat, fish and wild plants, within a Congolese agricultural community. A sample of 121 households were monitored over a 16-month period, using a combination of participatory and quantitative survey techniques, to assess their wealth and their production, consumption and market sales of wild foods. Households varied in wealth but all could be considered subject to extreme poverty (income below US$1 per capita per day). Our analyses indicate that wild foods play a small role in household consumption but a major role in household income. Hence, over 90% of both bushmeat and fish production is sold at market. In addition, the value of wild foods increases in the “lean season” when agricultural production is low. We also find that the poorest households in this community are unable to capitalise on the most valuable wild foods, bushmeat and fish, as a source of food or cash income. We use an entitlements framework to explain the factors that determine such wealth-related variation between households, indicating that household use of wild foods is determined more by social and economic constraints than by resource abundance in this community. Nevertheless, our findings show that overall the small-scale commercialisation of wild foods provides a vital source of income for rural households living in extreme poverty.     

Mass mortality of common eiders (Somateria mollissima) in the Dutch Wadden Sea, winter 1999/2000: starvation in a commercially exploited wetland of international importance

Mass mortality of common eiders (Somateria mollissima) was observed in winter 1999/2000 in the Dutch Wadden Sea. Approximately 21,000 common eiders died. Dissected birds were severely emaciated and 94% were infected with the acanthocephalan parasite Profilicollis botulus. Green shore crabs (Carcinus maenas), intermediate hosts of the parasite, were slightly more ‘available’ than in other years, but parasite infections in the eiders were close to normal. Few eiders were oiled (5%), there were no toxicological, bacteriological, or virological explanations for the observed mortality.In the Wadden Sea, a wetland of international importance, mussel (Mytilus edulis) cultures occur in sublittoral areas, while mechanical cockle (Cerastoderma edule) fisheries are licensed annually after evaluation of available resources. The wintering eiders in 1999/2000 required c. 3.1 million kg ash-free dry mass, while information on mussel and cockle stocks (irrespective of accessibility and profitability) suggested a resource 4.7× the requirement of common eiders only. Food shortage is suggested to have caused the observed mortality, involving both principal (mussels and cockles) and secondary (Spisula) prey.Winter census reports showed shifts in wintering distribution of common eiders in the 1990s, indicating the utilisation of Spisula in the North Sea in poor food years in the Wadden Sea. Following particularly intense fisheries in summer 1999, attempts to feed on Spisula in winter 1999/2000 failed. It is hypothesised that overfishing of mussels and cockles in the Wadden Sea in the early 1990s resulted in structurally reduced food resources, contractions of the foraging area of common eiders, and increased use of secondary prey in the North Sea.     

调节安对棉花各器官亚显微结构的影响

 调节安（1.1-Dimethylmorpholinium chloride）是一种新型植物生长调节剂，经连续3年试验示范证明，用调节安浸种和叶面喷施能使植株叶片变绿增厚、生长稳健、蕾大、花大、降低脱落率、提高成铃率，具有明显的增产效果。沿着植株对水分和营养的吸收、运输、光合产物的制造、运输和贮藏途径，用扫描电镜观察各器官的关键部位（根、叶、叶柄、蕾柄、花丝等）细胞亚显微结构的变化特征是：有关输导组织变得更加发达，营养贮藏细胞内含物增多，叶片表面气孔密度大大提高，栅栏组织增厚、变密。这些结构变化是调节安增进植株各个器官功能的结构依据。