Reproductive potential in parkland- and arctic-nesting populations of mallards and pintails (Anatidae)

1977 ◽  
Vol 55 (8) ◽  
pp. 1242-1251 ◽  
Author(s):  
B. K. Calverley ◽  
D. A. Boag
Keyword(s):  
Clutch Size ◽  
Anas Platyrhynchos ◽  
Reproductive Potential ◽  
Ovarian Follicles ◽  
The Arctic ◽  
Energy Costs ◽  
The Status ◽  
Mackenzie River

We estimated the reproductive potential of mallards (Anas platyrhynchos) and pintails (A. acuta) nesting in the parklands of Alberta and the delta of the Mackenzie River, N.W.T., by recording the number of laying females and the potential clutch size, based on the status of ovarian follicles, in samples of each species collected at the two latitudes. A larger proportion of the ducks collected in the parklands were laying and their potential clutch sizes were larger than in the arctic. Thus, both species exhibited a greater reproductive potential in the parklands than in the arctic. The reasons for these differences are discussed in relation to energy costs to ducks breeding at the two latitudes.

The Status of the School Shark Fishery in South-Eastern Australian Waters

1959 ◽  
Vol 10 (2) ◽  
pp. 150 ◽  
Author(s):  
AM Olsen
Keyword(s):  
Maximum Yield ◽  
Reproductive Potential ◽  
South Australia ◽  
Slow Growth Rate ◽  
South Eastern ◽  
Pregnant Females ◽  
The Status ◽  
History Of ◽  
Annual Total ◽  
The Mean

The maximum yield of the school shark fishery in south-eastern Australian waters was 4.09 million lb in 1949. The catch has fluctuated since then about a declining trend to 3.18 million lb in 1956. In 1944, 7.3 hooks were required to catch a shark of mean weight 14.7 lb. In 1956 the number of hooks required was almost doubled: 13.6 hooks were needed to catch sharks of mean weight 13.7 lb; the catch per hook dropped from 2.01 to 0.99 lb. Whereas the catch per boat-month remained relatively stable at 4765 lb for 1944 and 4643 for 1956, the number of hooks used per boat-month increased from 2366 to 4668 hooks in 12 years. Throughout this period the mean weight of sharks in eastern Bass Strait remained fairly steady (11-13 lb) whereas there was a drop of 3 lb from a mean weight of 17-20 lb in the predominantly mature portion of the stock in western Bass Strait. Fishermen in South Australia have reported a comparable drop in the mean weight of sharks in their catches. During the period 1941-46 there was unrestricted inshore fishing of juveniles and pregnant females with a consequent severe drop in the inshore population. The subsequent decline in the annual total catch is believed to be due not only to a too intensive offshore fishery but also to the resultant reduced recruitment and depressed reproductive potential caused by the earlier destruction of juveniles and pregnant females. In the data presented in this paper there is evidence that the school shark fishery, which is operating on a single stock of sharks with a slow growth rate, a late sexual maturity, and a low fecundity, shows trends which are suggestive of depletion. Because similar trends in the soupfin shark fishery of California and in the dogfish fishery of British Columbia were followed by depletion, it has been inferred that regulations to protect the vulnerable phases of the life history of the school shark of Australia may be required. Measures for conservation are discussed.

scholarly journals Engineering Properties of Sea Ice

1977 ◽  
Vol 19 (81) ◽  
pp. 499-531 ◽  
Author(s):  
J. Schwarz ◽  
W. F. Weeks
Keyword(s):  
Sea Ice ◽  
Physical Properties ◽  
Field Studies ◽  
Engineering Properties ◽  
The Arctic ◽  
Electromagnetic Properties ◽  
Future Research ◽  
Human Society ◽  
Continental Shelves ◽  
The Status

AbstractAs the continental shelves of the Arctic become important as source areas for the oil and minerals required by human society, sea ice becomes an increasing challenge to engineers. The present paper starts with a consideration of the different fields of engineering which require information on sea ice with the tasks ranging from the design of ice-breaking ships to Arctic drilling platforms and man-made ice islands. Then the structure of sea ice is described as it influences the observed variations in physical properties. Next the status of our knowledge of the physical properties important to engineering is reviewed. Properties discussed include mechanical properties (compressive, tensile, shear and flexural strengths; dynamic and static elastic moduli; Poisson’s ratio), friction and adhesion, thermal properties (specific and latent heats, thermal conductivity and diffusivity, density) and finally electromagnetic properties (dielectric permittivity and loss, resistivity). Particular attention is given to parameters such as temperature, strain-rate, brine volume, and loading direction as they affect property variations. Gaps, contradictions in the data, and inadequacies in testing techniques are pointed out. Finally suggestions are made for future research, especially for more basic laboratory studies designed to provide the data base upon which further theoretical developments as well as field studies can be built.

The current status of aquatic biological resources and their habitat cross-border section in the Dnieper river within the Smolensk region Russian Federation and the Republic of Belarus

2021 ◽  
pp. 8-21
Author(s):  
Alexey Ivanovich Nikitenko ◽  
Dmitry Vladimirovich Goryachev ◽  
Vladimir Gennadlevich Kostousov ◽  
Georgy Prokofievich Prischepov ◽  
Viktor Kazimirovich Rizevsky ◽  
...  
Keyword(s):  
Size Structure ◽  
Reproductive Potential ◽  
Current Status ◽  
Commercial Fishing ◽  
Biological Resources ◽  
The Status ◽  
The Republic ◽  
Share Value ◽  
Made In ◽  
Russian Section

The study presents materials on the status of aquatic biological resources and their habitat in the Dnieper River within the territory of the Russian and the Belarus. In the recent period, there has been hardly any complex fishery research in the upper reach of the river within the boundaries of the Smolensk Region due to the lack of commercial fishing; the same can be applied to the reach of the river within the Vitebsk Region in Belarus. The collection of materials and scientific and research accounting network surveys for monitoring the state of aquatic bioresources were carried out on the Dnieper River as part of the research in 2019 according to a preplanned grid of stations. When fishing for scientific research purposes, 20 net-stops of smooth frame nets were made in the Russian section, and 9 net-stops were made in the Belarusian section. In the Russian section of the Dnieper River, the species composition was 16 species of fish, and in the Belarusian section — 22 species. The main catch in the Russian section is roach 29% and chub 20%, in the Belarusian section bream — from 3 to 46%, roach — from 19 to 63% and gustera — from 1.8 to 33%, in a slightly smaller number of river perch (on average up to 10%). The share value of roach and guster tends to decrease from the upper to the lower areas, bream-on the contrary to increase, the value of perch is approximately equal in all areas. In the size structure of the caught fish species, there is a dynamic with a good reproductive potential.

scholarly journals A 50 % increase in the mass of terrestrial particles delivered by the Mackenzie River into the Beaufort Sea (Canadian Arctic Ocean) over the last 10 years

2015 ◽  
Vol 12 (11) ◽  
pp. 3551-3565 ◽  
Author(s):  
D. Doxaran ◽  
E. Devred ◽  
M. Babin
Keyword(s):  
Organic Carbon ◽  
Arctic Ocean ◽  
Suspended Solids ◽  
Beaufort Sea ◽  
Freshwater Discharge ◽  
The Arctic ◽  
Field Observations ◽  
The Arctic Ocean ◽  
Arctic Rivers ◽  
Mackenzie River

Abstract. Global warming has a significant impact on the regional scale on the Arctic Ocean and surrounding coastal zones (i.e., Alaska, Canada, Greenland, Norway and Russia). The recent increase in air temperature has resulted in increased precipitation along the drainage basins of Arctic rivers. It has also directly impacted land and seawater temperatures with the consequence of melting permafrost and sea ice. An increase in freshwater discharge by main Arctic rivers has been clearly identified in time series of field observations. The freshwater discharge of the Mackenzie River has increased by 25% since 2003. This may have increased the mobilization and transport of various dissolved and particulate substances, including organic carbon, as well as their export to the ocean. The release from land to the ocean of such organic material, which has been sequestered in a frozen state since the Last Glacial Maximum, may significantly impact the Arctic Ocean carbon cycle as well as marine ecosystems. In this study we use 11 years of ocean color satellite data and field observations collected in 2009 to estimate the mass of terrestrial suspended solids and particulate organic carbon delivered by the Mackenzie River into the Beaufort Sea (Arctic Ocean). Our results show that during the summer period, the concentration of suspended solids at the river mouth, in the delta zone and in the river plume has increased by 46, 71 and 33%, respectively, since 2003. Combined with the variations observed in the freshwater discharge, this corresponds to a more than 50% increase in the particulate (terrestrial suspended particles and organic carbon) export from the Mackenzie River into the Beaufort Sea.

Increasing discharge from the Mackenzie River system to the Arctic Ocean

2016 ◽  
Vol 31 (1) ◽  
pp. 150-160 ◽  
Author(s):  
Stewart B. Rood ◽  
Sobadini Kaluthota ◽  
Laurens J. Philipsen ◽  
Neil J. Rood ◽  
Karen P. Zanewich
Keyword(s):  
Arctic Ocean ◽  
River System ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Mackenzie River

Human Rights and the Arctic

2009 ◽  
Vol 1 (1) ◽  
pp. 233-243
Author(s):  
Gudmundur Alfredsson
Keyword(s):  
Human Rights ◽  
Indigenous Peoples ◽  
The Arctic ◽  
International Human Rights Law ◽  
Human Rights Law ◽  
Independent State ◽  
The Status ◽  
Recent Developments ◽  
The Many ◽  
The Right

Abstract This article surveys some of the many international human rights law issues that come up in connection with the Arctic, such as the rights of indigenous peoples and the formulation of these rights in a draft Nordic Sami Convention. The focus, however, is on recent developments concerning the status of Greenland as a result of an agreement concluded in 2008 between the Danish and Greenlandic authorities. This agreement foresees not only a significant increase in self-government but also opens the door for the Greenlandic people to create an independent State through the exercise of the right to external self-determination as a matter of political decolonisation of an overseas colonial territory.

Can the Arctic Council and the Northern Forum find common ground?

Polar Record ◽  
2002 ◽  
Vol 38 (207) ◽  
pp. 289-296 ◽  
Author(s):  
Oran R. Young
Keyword(s):  
Indigenous Peoples ◽  
Common Ground ◽  
Bureaucratic Politics ◽  
The Arctic ◽  
Arctic Council ◽  
Global Issues ◽  
The Status ◽  
The Cold War ◽  
The Voice ◽  
Two Bodies

AbstractThe Arctic Environmental Protection Strategy (the forerunner of the Arctic Council) and the Northern Forum are both products of the sea change in Arctic politics occurring in the wake of the end of the Cold War. Both are soft law arrangements and both are lightly institutionalized. Yet these similarities have not provided a basis for collaboration between the Arctic Council (AC) and the Northern Forum (NF). For the most part, the two bodies have behaved like ships passing in the night. This article seeks to explain this lack of collaboration and to evaluate future prospects in this realm. The lack of collaboration is attributable in part to a number of sources of tension or fault lines, including issues relating to core-periphery relations, the concerns of indigenous peoples, divergent constituencies, the Russian connection, and bureaucratic politics and the complexities of political leadership. In part, it stems from ambiguities about the status of the AC and the NF combined with restrictions on the roles these bodies can play. There is little prospect of combining the two bodies into a more comprehensive Arctic regime. But there are opportunities to devise a realistic division of labor and to develop useful coordination mechanisms. The AC, for example, is the appropriate vehicle for efforts to strengthen the voice of the Arctic regarding global issues; the NF is well-suited to dealing with matters of community viability. Ultimately, the two bodies might consider creating a joint working group on sustainable development or organizing occasional joint meetings of the AC's Senior Arctic Officials and the NF's Executive Committee.

Reproductive characteristics of the Pyrenean high-mountain lizards: Iberolacerta aranica (Arribas, 1993), I. aurelioi (Arribas, 1994) and I. bonnali (Lantz, 1927)

2005 ◽  
Vol 55 (2) ◽  
pp. 163-190 ◽  
Author(s):  
Pedro Galán ◽  
Oscar Arribas
Keyword(s):  
Clutch Size ◽  
Reproductive Cycle ◽  
Reproductive Potential ◽  
Activity Cycle ◽  
Field Studies ◽  
Climatic Conditions ◽  
Distribution Area ◽  
High Mountain ◽  
Time Data ◽  
Reproductive Characteristics

AbstractThe three lacertid lizards species of the Iberolacerta genus, which have recently been described or recognised as different species, are reptiles that live strictly at the highest altitudes in Europe, from elevations of near 1900 up to more than 3000 m a.s.l. in the Pyrenees (Spain, Andorra, France). In this paper, the reproductive cycle and reproductive characteristics of these species are described for the first time. Data were obtained from field studies carried out in different high-mountain Pyrenean locations from 1989–2002. In addition we also conducted hatching studies in laboratory. Due to the harsh climatic conditions in the high mountains the activity cycle of these species is very short, just over 4 months, from mid-May to late September or beginning of October. This affects their reproductive cycle (i.e., only one annual egg-clutch is produced), as well as other reproductive characteristics, as the existence of a very advanced embryonic development at oviposition, which is interpreted as an advanced stage in the tendency towards viviparity, and diverse life history characteristics as a very little annual growth which greatly delays sexual maturity to 4 years in males and 4–5 years in females. Clutch size correlates significantly with female snout-vent length (SVL) in all three species. The average clutch size is 2.53 eggs in I. aurelioi (the smallest species), 3.03 in I. bonnali and 3.44 in I. aranica (the biggest species). Notwithstanding the differences in egg number the three species have a similar egg volume. The incubation period in the laboratory is very short with an average of 30–36 days among the species. The low reproductive potential observed in these three species and revealed in this paper is a strongly threatening factor which, together with their extremely reduced distribution area, endangers these endemic, rare and very threatened species.

Clairvoyants and mediums search for Franklin

Polar Record ◽  
2003 ◽  
Vol 39 (1) ◽  
pp. 1-18 ◽  
Author(s):  
W. Gillies Ross
Keyword(s):  
The Other ◽  
The Arctic ◽  
Other Hand ◽  
The Status

The search for Sir John Franklin (1847–59) coincided with a growing interest in mesmerism and modern spiritualism in Britain. Several clairvoyants, claiming to ‘see’ Franklin's ships and crews in the Arctic, made statements about the status and location of the overdue expedition, and at least three mediums described communications with Franklin’s spirit. Although the Admiralty provided assistance to Dr Haddock, the mesmerist of Emma, the Bolton clairvoyant, they did not take any action on the basis of her statements, probably because the various accounts were contradictory and could not be verified, and because the Admiralty Lords were sceptical of paranormal phenomena. Lady Franklin, on the other hand, visited clairvoyants and altered the plans for her search expeditions under Forsyth and Kennedy on the basis of a revelation. Recently, an American medium has described more than two dozen conversations with the spirits of Sir John and Lady Franklin.

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