scholarly journals Expansion of sandhill cranes (Grus canadensis) in east Asia during the non-breeding period

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7545 ◽  
Author(s):  
Linqiang Gao ◽  
Chunrong Mi ◽  
Yumin Guo
Keyword(s):  
East Asia ◽  
Breeding Period ◽  
Northeast Russia ◽  
Grus Canadensis ◽  
The Past ◽  
Occurrence Data ◽  
Past Half Century ◽  
The Status ◽  
Sandhill Cranes ◽  
Past Half

Aim Historically, the distribution of Sandhill Cranes included much of North America and extending in summer into northeast Russia. In recent years, observations of sandhill cranes in Asia during the non-breeding period have been frequently reported. However, the distribution and abundance of sandhill cranes during the non-breeding period in Asia have rarely been summarized and studied. Our study aimed to analyze the status of sandhill cranes that have spread south into East Asia during the non-breeding period and to assess the possible impacts of their potential spread. Methods Based on opportunistic data collected in the field and occurrence data collected online over the past half century, we used Geographic Information System to visualize the spatial distribution changes and regression analysis to analyze and visualize the changes in the amount of individuals over time. Results In the last 50 years, the distribution of sandhill cranes during the non-breeding season in Asia spanned 31 degrees in longitude to the west and 15 degrees in latitude to the south. Their distribution in Asia has expanded to 17 provinces and municipalities in China, Japan and South Korea. The amount of cranes in the non-breeding period in Asia increased significantly from 1963 to 2017. According to the historical records in East Asia, sandhill cranes were mixed with five other species of crane groups. Main conclusions These results indicate that the range and amount of sandhill cranes have expanded. Sandhill cranes were mixed with five other crane species, which indicate their adaptability to a range of habitat types and food resources. The implications of these trends in sandhill cranes in East Asia for this and other crane species warrants further research.

scholarly journals IS IT POSSIBLE TO SAVE THE AZOV BELUGA?

Fisheries ◽  
2020 ◽  
Vol 2020 (3) ◽  
pp. 71-75
Author(s):  
Sergey Podushka
Keyword(s):  
Huso Huso ◽  
Brood Stock ◽  
Half Century ◽  
The Past ◽  
Past Half Century ◽  
The Status ◽  
Past Half

The Azov beluga Huso huso maeoticus has the status of a subspecies. This is one of the most threatened and problematic species of the Russian ichthyofauna. Despite the measures taken to protect this subspecies, the situation has only worsened over the past half-century. Some authors already consider the Azov Beluga to be extinct. Brood stock of the beluga raised at the Don Sturgeon Plant, where the first females began to mature in 2018, lets us hope for the possibility of saving the Azov subspecies. Presumably the herd consists of both Azov and Caspian belugas, as well as hybrids between them. The issue of their identification is being discussed. A plan to preserve a clean line of the Azov Beluga is proposed.

scholarly journals A meta-analysis of the status of ICES fish stocks during the past half century

2007 ◽  
Vol 64 (4) ◽  
pp. 707-713 ◽  
Author(s):  
Henrik Sparholt ◽  
Mette Bertelsen ◽  
Hans Lassen
Keyword(s):  
Time Series ◽  
Meta Analysis ◽  
Fishing Mortality ◽  
Fish Stocks ◽  
Half Century ◽  
The Past ◽  
Past Half Century ◽  
The Status ◽  
1960S And 1970S ◽  
Past Half

Abstract Sparholt, H., Bertelsen, M., and Lassen, H. 2007. A meta-analysis of the status of ICES fish stocks during the past half century. – ICES Journal of Marine Science, 64: 707–713. Based on a meta-analysis of time-series of stock size, recruitment, and fishing mortality, the general status of fish stocks within the ICES Area (i.e. the Northeast Atlantic) is evaluated. The analysis is based on data for 34 (7 pelagic, 27 demersal) commercial stocks. The stocks were selected based on the quality of the data and the length of the time-series. The analysis indicates that most pelagic stocks recovered to sustainable levels with high productivity after several had collapsed in the 1960s and 1970s. In contrast, most demersal stocks have continued to decline over the past half century and are now recruitment-overfished. By reducing fishing mortality on demersal stocks on average by half and building up the stocks by a factor of about two, management could be brought in line with international agreements. If recruitment-overfishing is avoided for all demersal stocks and discarding is minimized, their yield might be almost doubled over the current yield. Among the major management initiatives during the past half century, only the closure of the pelagic fisheries in the mid-1970s can be clearly identified in the time-series as having had a direct effect on stock status.

EDITORIAL: Migration and competitiveness: Japan and the United States

2013 ◽  
Vol 10 (2) ◽  
pp. 115-124
Author(s):  
Philip L. Martin
Keyword(s):  
United States ◽  
The United States ◽  
Variable Cost ◽  
Fixed Cost ◽  
Special Issue ◽  
Science And Engineering ◽  
The Past ◽  
Past Half Century ◽  
Key Sectors ◽  
Past Half

Japan and the United States, the world’s largest economies for most of the past half century, have very different immigration policies. Japan is the G7 economy most closed to immigrants, while the United States is the large economy most open to immigrants. Both Japan and the United States are debating how immigrants are and can con-tribute to the competitiveness of their economies in the 21st centuries. The papers in this special issue review the employment of and impacts of immigrants in some of the key sectors of the Japanese and US economies, including agriculture, health care, science and engineering, and construction and manufacturing. For example, in Japanese agriculture migrant trainees are a fixed cost to farmers during the three years they are in Japan, while US farmers who hire mostly unauthorized migrants hire and lay off workers as needed, making labour a variable cost.

Reframing the Sciences of the Long Eighteenth Century

2020 ◽  
Vol 50 (1-2) ◽  
pp. 58-66
Author(s):  
Giuliano Pancaldi
Keyword(s):  
Eighteenth Century ◽  
History Of Science ◽  
Science Policy ◽  
Special Issue ◽  
Half Century ◽  
The Past ◽  
Past Half Century ◽  
History Of ◽  
Long Eighteenth Century ◽  
Past Half

Here I survey a sample of the essays and reviews on the sciences of the long eighteenth century published in this journal since it was founded in 1969. The connecting thread is some historiographic reflections on the role that disciplines—in both the sciences we study and the fields we practice—have played in the development of the history of science over the past half century. I argue that, as far as disciplines are concerned, we now find ourselves a bit closer to a situation described in our studies of the long eighteenth century than we were fifty years ago. This should both favor our understanding of that period and, hopefully, make the historical studies that explore it more relevant to present-day developments and science policy. This essay is part of a special issue entitled “Looking Backward, Looking Forward: HSNS at 50,” edited by Erika Lorraine Milam.

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