为客观地揭示世界大洋性鱿钓渔业的研究态势及研究热点,促进我国大洋性鱿钓渔业的可持续发展,基于Web of Science核心合集数据,利用文献计量学方法,对其文献的增长趋势及期刊分布进行分析,并基于作者和机构合作网络、关键词共现的知识...为客观地揭示世界大洋性鱿钓渔业的研究态势及研究热点,促进我国大洋性鱿钓渔业的可持续发展,基于Web of Science核心合集数据,利用文献计量学方法,对其文献的增长趋势及期刊分布进行分析,并基于作者和机构合作网络、关键词共现的知识图谱及突变检测等方法,探究世界大洋性鱿钓渔业的研究热点及其研究前沿,结果表明:研究文献总体上呈递增趋势,且文献的科研影响力及国际关注度非常高;作者、机构间均形成了频繁而稳定的合作关系,作者合作方面形成了以陈新军、陈勇等作者为核心及以RODHOUSE等为核心的两大作者合作群,机构合作方面分别以上海海洋大学和英国南极调查局为核心的机构间建立了广泛的合作关系;海洋淡水生物学、渔业、海洋学和生态学等为世界大洋性鱿钓渔业的优势学科领域。当前世界大洋性鱿钓渔业的研究前沿有4个方向:(1)开展重要大洋性经济鱿鱼种类的基础生物学和生态学研究;(2)研究大洋性鱿鱼资源评估及其资源对全球气候和环境变化的响应机理;(3)结合海洋遥感信息研究渔业栖息地及跨学科交叉融合;(4)开展基于生态系统的大洋性鱿钓渔业资源综合管理研究。展开更多
A survey was conducted in the equatorial area of Indian Ocean for a better understanding of the dynamics of hook depth distribution of pelagic longline fishery. We determined the relationship between hook depth and ve...A survey was conducted in the equatorial area of Indian Ocean for a better understanding of the dynamics of hook depth distribution of pelagic longline fishery. We determined the relationship between hook depth and vertical shear of current coefficieney, wind speed, hook position code, sine of wind angle, sine of angle of attack and weight of messenger weight. We identified the hook depth models by the analysis of covariance with a general linear model. The results showed that the wind effect on the hook depth can be ignored from October to November in the survey area; the surface current effect on the hook depth can be ignored; the equato- rial undercurrent is the key factor for the hook depth in Indian Ocean; and there is a negative correlation between the hook depth and vertical shear of current and angle of attack. It was also found that the deeper the hook was set, the higher hook depth shoaling was. The proposed model improves the accuracy of the prediction of hook depth, which can be used to estimate the vertical distribution of pelagic fish in water column.展开更多
The Tonle Sap Lake is home to three types of communities： land-based, water-based and land-water based communities, whose livelihoods are dependent on Lake＇s resources. This paper examines how fishing communities in...The Tonle Sap Lake is home to three types of communities： land-based, water-based and land-water based communities, whose livelihoods are dependent on Lake＇s resources. This paper examines how fishing communities in the Tonic Sap Lake make their living in the context of declined resources, increased competition between fishers, the resources politics and the increased trades around the Lake. The paper concludes that in the old day, communities around the lake were related to one another through bartering rice and fish. However, at present, as resources declining, these communities compete over resources, and in doing so, they build relationship and connection with powerful elites including officials, fish traders and the fishing operators, who could protect them in fishing. As a consequence, fishers are trapped in the webs of vicious cycle of poverty, conflicts, corruption and patronage system and exploited and sucked in these webs.展开更多
Evaluation of spatial-temporal variability of species composition and diversity in oceanic ecosystems is not easy because it is usually difficult to obtain sufficient data quantifying such variability.In this study,we...Evaluation of spatial-temporal variability of species composition and diversity in oceanic ecosystems is not easy because it is usually difficult to obtain sufficient data quantifying such variability.In this study,we examined pelagic species diversity indicators,species richness,Shannon-Wiener index of diversity and Hurlbert's species evenness,for fish assemblages from two areas(north and south) in the North Pacific Ocean(2°±12°N,178°E±165°W) during May±July 2008.The assemblages were based on data collected by an onboard scientific observer during a commercial longline fishing trip.The species richness and Shannon-Wiener diversity index of fish assemblages in the northern area were slightly higher than those in the southern area,although these differences were not significant(t test,P.0.05).Non-parametric multidimensional scaling and analysis of similarities indicated that there were significant differences in fish assemblages between the two areas(P,0.01).展开更多
In the Middle Ages, as in other historical past periods, there was a double perception of the value of water. On the one hand, water was considered as an indispensable necessity for human life and, on the other, it ac...In the Middle Ages, as in other historical past periods, there was a double perception of the value of water. On the one hand, water was considered as an indispensable necessity for human life and, on the other, it acquired a symbolic value, whose manifestations are equally palpable. As an example, there can be brought up the setting up of public fountains in the towns of late Middle Ages. They were essential not only for the daily water provision for the citizens but also meant to honor and pomp the city. Similar double meaning can be also found in the functioning of the medieval fisheries as their economic activity guaranteed food supply and even managed to acquire religious and symbolic implications in the Christian society.展开更多
Reproductive biology of L. mormyrus was studied using monthly samples totaling 224 fish obtained from AI-Haneah fishing site, eastern Libya Mediterranean Sea. Lengths of the examined fish ranged between 11.5 cm and 23...Reproductive biology of L. mormyrus was studied using monthly samples totaling 224 fish obtained from AI-Haneah fishing site, eastern Libya Mediterranean Sea. Lengths of the examined fish ranged between 11.5 cm and 23.4 cm. Corresponding weights were 24.5 g and 160.8 g. The minimum values of the condition factors, KF and Kc, were 1.38 and 1.21 at the average fish length of 12.4 cm. These values increased with increases in length until they reached maximum values of 1.59 and 1.41 at the length of 22.1 cm. The high values of KF and Kc, Gonado-Somatic Index and oocyte diameter maintained during May, June, July, and August and the monthly changes in gonadal condition, indicated that summer was the breeding season of L. mormyrus. The oocyte diameter ranged between 379± 25.3 μ and 1,511 ± 143.3μ （n = 76） with an average of 895 ± 111.3 μ. The sex ratio was in favor of females during all months of the study. The overall sex ratio was 1 ： 1.52. Length at first maturity, Ls0, for L. mormyrus was found to be 14.15 cm for males and 14.45 for females. Overall average of absolute fecundity was 4,342±557 egg per fish （n = 45）. The overall average of relative fecundity was 234± 181 egg per cm. Absolute fecundity increased with increasing fish length.展开更多
Although the majority of studies on mate choice focus on female mate choice, there is growing recognition of the role of male mate choice too. Male mate choice is tightly linked to 2 other phenomena： female competiti...Although the majority of studies on mate choice focus on female mate choice, there is growing recognition of the role of male mate choice too. Male mate choice is tightly linked to 2 other phenomena： female competition for males and ornamentation in females. In the current article, I review the existing literature on this in a group of fishes, Poeciliidae. In this group, male mate choice appears to be based on differences in female quality, especially female size, which is a proxy for fecundity. Some males also have to choose between heterospecific and conspecific females in the unusual mating system of the Amazon molly. In this case, they typically show a preference for conspecific females. Whereas male mate choice is relatively well documented for this family, female ornamentation and female competition are not.展开更多
文摘为客观地揭示世界大洋性鱿钓渔业的研究态势及研究热点,促进我国大洋性鱿钓渔业的可持续发展,基于Web of Science核心合集数据,利用文献计量学方法,对其文献的增长趋势及期刊分布进行分析,并基于作者和机构合作网络、关键词共现的知识图谱及突变检测等方法,探究世界大洋性鱿钓渔业的研究热点及其研究前沿,结果表明:研究文献总体上呈递增趋势,且文献的科研影响力及国际关注度非常高;作者、机构间均形成了频繁而稳定的合作关系,作者合作方面形成了以陈新军、陈勇等作者为核心及以RODHOUSE等为核心的两大作者合作群,机构合作方面分别以上海海洋大学和英国南极调查局为核心的机构间建立了广泛的合作关系;海洋淡水生物学、渔业、海洋学和生态学等为世界大洋性鱿钓渔业的优势学科领域。当前世界大洋性鱿钓渔业的研究前沿有4个方向:(1)开展重要大洋性经济鱿鱼种类的基础生物学和生态学研究;(2)研究大洋性鱿鱼资源评估及其资源对全球气候和环境变化的响应机理;(3)结合海洋遥感信息研究渔业栖息地及跨学科交叉融合;(4)开展基于生态系统的大洋性鱿钓渔业资源综合管理研究。
基金funded by Ministry of Agriculture of China under Project of Fishery Exploration in High Seasin 2006 (No. Z06-43)the National High Technology Research and Development Program of China (No. 2012AA092302)+1 种基金Specialized research fund for the doctoral program of higher education (No. 20113104110004)Shanghai Municipal Education Commission Innovation Project (No. 12ZZ168)
文摘A survey was conducted in the equatorial area of Indian Ocean for a better understanding of the dynamics of hook depth distribution of pelagic longline fishery. We determined the relationship between hook depth and vertical shear of current coefficieney, wind speed, hook position code, sine of wind angle, sine of angle of attack and weight of messenger weight. We identified the hook depth models by the analysis of covariance with a general linear model. The results showed that the wind effect on the hook depth can be ignored from October to November in the survey area; the surface current effect on the hook depth can be ignored; the equato- rial undercurrent is the key factor for the hook depth in Indian Ocean; and there is a negative correlation between the hook depth and vertical shear of current and angle of attack. It was also found that the deeper the hook was set, the higher hook depth shoaling was. The proposed model improves the accuracy of the prediction of hook depth, which can be used to estimate the vertical distribution of pelagic fish in water column.
文摘The Tonle Sap Lake is home to three types of communities： land-based, water-based and land-water based communities, whose livelihoods are dependent on Lake＇s resources. This paper examines how fishing communities in the Tonic Sap Lake make their living in the context of declined resources, increased competition between fishers, the resources politics and the increased trades around the Lake. The paper concludes that in the old day, communities around the lake were related to one another through bartering rice and fish. However, at present, as resources declining, these communities compete over resources, and in doing so, they build relationship and connection with powerful elites including officials, fish traders and the fishing operators, who could protect them in fishing. As a consequence, fishers are trapped in the webs of vicious cycle of poverty, conflicts, corruption and patronage system and exploited and sucked in these webs.
基金Supported by the China National Fishery Observer Programthe Shanghai Leading Academic Discipline Project (No. S30702)
文摘Evaluation of spatial-temporal variability of species composition and diversity in oceanic ecosystems is not easy because it is usually difficult to obtain sufficient data quantifying such variability.In this study,we examined pelagic species diversity indicators,species richness,Shannon-Wiener index of diversity and Hurlbert's species evenness,for fish assemblages from two areas(north and south) in the North Pacific Ocean(2°±12°N,178°E±165°W) during May±July 2008.The assemblages were based on data collected by an onboard scientific observer during a commercial longline fishing trip.The species richness and Shannon-Wiener diversity index of fish assemblages in the northern area were slightly higher than those in the southern area,although these differences were not significant(t test,P.0.05).Non-parametric multidimensional scaling and analysis of similarities indicated that there were significant differences in fish assemblages between the two areas(P,0.01).
文摘In the Middle Ages, as in other historical past periods, there was a double perception of the value of water. On the one hand, water was considered as an indispensable necessity for human life and, on the other, it acquired a symbolic value, whose manifestations are equally palpable. As an example, there can be brought up the setting up of public fountains in the towns of late Middle Ages. They were essential not only for the daily water provision for the citizens but also meant to honor and pomp the city. Similar double meaning can be also found in the functioning of the medieval fisheries as their economic activity guaranteed food supply and even managed to acquire religious and symbolic implications in the Christian society.
文摘Reproductive biology of L. mormyrus was studied using monthly samples totaling 224 fish obtained from AI-Haneah fishing site, eastern Libya Mediterranean Sea. Lengths of the examined fish ranged between 11.5 cm and 23.4 cm. Corresponding weights were 24.5 g and 160.8 g. The minimum values of the condition factors, KF and Kc, were 1.38 and 1.21 at the average fish length of 12.4 cm. These values increased with increases in length until they reached maximum values of 1.59 and 1.41 at the length of 22.1 cm. The high values of KF and Kc, Gonado-Somatic Index and oocyte diameter maintained during May, June, July, and August and the monthly changes in gonadal condition, indicated that summer was the breeding season of L. mormyrus. The oocyte diameter ranged between 379± 25.3 μ and 1,511 ± 143.3μ （n = 76） with an average of 895 ± 111.3 μ. The sex ratio was in favor of females during all months of the study. The overall sex ratio was 1 ： 1.52. Length at first maturity, Ls0, for L. mormyrus was found to be 14.15 cm for males and 14.45 for females. Overall average of absolute fecundity was 4,342±557 egg per fish （n = 45）. The overall average of relative fecundity was 234± 181 egg per cm. Absolute fecundity increased with increasing fish length.
文摘Although the majority of studies on mate choice focus on female mate choice, there is growing recognition of the role of male mate choice too. Male mate choice is tightly linked to 2 other phenomena： female competition for males and ornamentation in females. In the current article, I review the existing literature on this in a group of fishes, Poeciliidae. In this group, male mate choice appears to be based on differences in female quality, especially female size, which is a proxy for fecundity. Some males also have to choose between heterospecific and conspecific females in the unusual mating system of the Amazon molly. In this case, they typically show a preference for conspecific females. Whereas male mate choice is relatively well documented for this family, female ornamentation and female competition are not.
