The point of no return and pectoral angle of Japanese anchovy(Engraulis japonicus) larvae during growth and starvation

At a temperature of 23.0~24.8℃,the mixed feeding of Japanese anchovy larvae was initiated 24 h before the yolk-sac was exhausted.The point of no return(PNR) was reached on the 6th day after hatching.On the 4th day after hatching,the pectoral angle appeared in both fed and unfed anchovy larvae although it was more evident and sharper in the starved and the PNR stage larvae than in the fed ones.According to observations of larvae collected in the sea,the pectoral angles were evident not only in the larvae of 3.62~7.44 mm in standard length,but also in the larvae of 2.70 mm in standard length with remnants of yolk.The pectoral angles became diffuse when the larvae reached 7.84 mm and vanished at 9.86 mm.The pectoral angle cannot be used as a criterion to distinguish healthy from starving larvae.     

乌苏里拟鲿的不可逆点、窒息点及其对5种常见渔药的敏感性研究

通过实验生态学方法,研究了乌苏里拟鲿(Pseudobagrus ussuriensis)的初次摄食率、不可逆点、窒息点以及对5种常见渔药的敏感性.结果表明:水温22～23℃条件下,乌苏里拟鲿第7日龄初次摄食率达到最高值100%,仔鱼不可逆点(PNR)发生在孵化后第13天;窒息点与水温呈正相关性性(R=0.9093,P<...     

Ecological understanding for fishery management: Condition and growth of anchovy late larvae during different seasons in the Northwestern Mediterranean

The fishery of the European anchovy Engraulis encrasicolus in the Mediterranean needs several ecological approaches to be properly managed. As such, several surveys were carried out to study the ecology of larvae and juveniles of this species, which reproduces during the warmest period of the year (May through September) in the Gulf of Lions. In particular, we studied the late larvae (15 mm total length until metamorphosis), especially as other authors have focused on larvae below that size. Unexpectedly, we also collected anchovy late larvae during the December 2007 survey, whose range in size corresponded to a later spawning period than previously reported. Differences in the nutritional condition of these larvae were assessed by comparing indices of lipid composition and estimating growth rates from otolith measurements to provide information on the probability of survival between the two groups. The analysis of fatty acids, used as tracers of trophic relationships, indicates that these larvae fed mainly on zooplankton. Nutritional conditions of summer and late autumn larvae were very similar. In contrast, growth rates were higher for August larvae, probably due to the different temperatures in the two seasons. Our results are especially relevant in an ecological context where the increasing mean water temperatures in the Western Mediterranean could favor the extension of the anchovy spawning period up to late-Autumn months.     

海岸带土地利用格局演化及多情景开发模拟¬——以宁波市为例

海岸带土地在高强度开发下变化显著,明确其演化规律和驱动因子,为优化土地利用结构和合理利用海岸带资源提供重要依据。基于1990－2020年7期土地利用数据,利用土地利用强度指数、地理探测器模型等方法,分析宁波市海岸带土地利用格局演变特征及驱动因子;同时利用CA-Markov模型对2025年和2030年宁波市海岸带土地利用格局进行模拟。结果表明：（1）宁波市海岸带土地利用类型主要为林地和耕地,土地利用格局演化明显,其中耕地面积不断减少,林地、草地、水域和未利用地面积发生小幅度动荡,建设用地面积快速增长。（2）宁波市海岸带土地利用强度不断增加,研究区北部增长趋势明显,而南部增长速度缓慢。（3）地形和坡度是影响宁波市海岸带土地利用变化的主要自然因素,但影响程度不断减弱;GDP密度和人口密度是主要社会经济影响因素,影响强度逐渐增强;因子间交互作用类型主要为双因子增强和非线性增强,社会经济因子与自然因素中的海拔和坡度交互作用最为强烈。（4）未来宁波市海岸带土地利用变化剧烈区域将集中于杭州湾南岸、象山县东北部和宁海县南部,生态保护情景能最大程度保持土地利用结构稳定,有效缓解人地矛盾。     

From unjust uneconomic growth to sustainable fisheries in Newfoundland: The true costs of closing the inshore fishery for groundfish

Neoliberal economic and social policies during the last 65 years have placed a premium on continuous economic growth. Concern among ecological economists and other critics that economic growth results in loss of natural capital and ecosystem services led to introduction of the concept of “uneconomic growth,” defined as “growth of the macro economy that costs us more than it is worth” (Daly and Farley, Ecological economics principles and applications. Washington: Island Press; 2004). This paper proposes the concept of “unjust uneconomic growth” to pinpoint the additional costs of policies that promote uneconomic growth to the neglect of other considerations and uses the case of Newfoundland and Labrador fisheries policies since 1992 to document it. Newfoundland and Labrador fisheries experienced uneconomic growth in the 1980s leading to the collapse of ground fish stocks. The policies enacted since 1993 based on economic growth goals have failed to solve the ecological-social crisis and entailed additional costs to small-scale fisheries.     

Geographical distribution and age composition of Euphausia superba larvae (Crustacea：Euphausiacea) in the South Shetland Islands region and southern Scotia Sea in relation to environmental conditions

Spatial distribution patterns of the different life stages of Euphausia superba in the region of the South Shet- land Islands and southern Scotia Sea （Antarctica） were assessed based on scientific survey data collected in lanuary and February of 2010. Adults, eggs, nauplii, metanauplii, calyptopis I-Ill, and furcilia I-II were found in the investigation. The abundance of larvae averaged 1 172.8 ind./mz, with calyptopis I and II as the dominant stages. Habitat occupancy patterns varied among Euphausia superba at different stages, and three sub-regions were identified by cluster analysis. The degree of larval development increased from west to east. Larvae were not observed north of the South Shetland Islands. Calyptopis I was predominant in the water between Elephant Island and the South Orkney Islands, which featured no thermocline. Older stages, including calyptopis II and III and furcilia I and II, were common in north and northeast of the South Orkney Islands, which were characterized by high temperature and high chlorophyll concentration. Distri- bution and abundance of the early life stages of E. superba were associated with specific environmental con- ditions. According to Biota-Environment matching （BIOENV）, the distributions of E. superba larvae were correlated with a combination of temperature at the surface and 200 m, and 0-100 m integrated chlorophyll a concentration.