Food energy requirements of the harp seal (Phoca groenlandica) population in the Barents and White Seas

The harp seal ( Phoca groenlandica ) population of the Barents and White Seas has probably decreased from about one million individuals to half this size the last few years. Energy requirements of the population have been estimated by use of the simulation model SEAERG. In this model the energy requirements of an individual seal from each age group is multiplied with the group size and summed to provide the requirements of the population. In addition to population size and age structure the total food and energy requirement is sensitive to individual activity levels as well as metabolic levels and other specified physiological functions. The interactions between the seal population and fisheries depends on the caloric density of the prey species which varies with season and location. Realistic simulations of interactions between seals and fisheries require more information about spatial and temporal variations in the prey selection of harp seals than is available today.
Present estimates indicate average maintenance requirements of about 13,600 and ll,150kcal/day for adult female and male harp seals respectively. The high value for the females is due to the costs of pregnancy and lactation. With a mean energy density of prey of 1500 kcal/kg, the corresponding food consumption is 9 kg/day for females and 7.4 kg/day for males.     

The ringed seal (Phoca hispida) spring diet in northwestern Spitsbergen, Svalbard

A total of 284 ringed seals (Phoca hispida) were sampled to determine their diet in the spring of 1981 and 1982. Few seals contained identifiable stomach contents. No significant age-or sex-related differences in choice of prey were found. It seems that in spring northwestern Spitsbergen ringed seals prey upon arctic cod (Boreogadus saida) , decapods and larger amphipods.? Diet, ringed seal, Svalbard .     

Growth, development and distribution of the euphausiids Thysanoessa raschi (M. Sars) and Thysanoessa inermis (Krøyer) in the southeastern Bering Sea

The distribution and abundance of the euphausiids Thysanoessa raschi and Thysanoessa inermis in the shelf waters of the southeastern Bering Sea were investigated during spring and summer of 1980 and 1981. Experiments were conducted during the study to describe the reproduction, growth and development of these species. T. inermis was the dominant euphausiid species observed over the outer shelf region; it began spawning in early April while T. raschi dominated the euphausiids over the middle shelf and began spawning in mid or late May. The seasonal progression in spawning followed the seasonal development of temperature; however, spawning did not begin earlier in 1981 which was a warmer year than 1980. Average egg production of T . raschi ranged from 3.4% to 3.8% dry body weight of the female per day during the first three days after capture. Secondary production estimates for T . raschi females ranged from 4.2% to 5.2% dry body weight per day in 1980 and 5.9% to 6.0% dry body weight per day in 1981. A sharp decline in the abundance of adolescent and adult euphausiids over the middle shelf during the spring bloom period when food appeared to be abundant suggests that predation by diving birds, pollack. Tanner crabs, whales and seals effectively controls the euphausiid population.     

Inuit spring hunting techniques and local knowledge of the ringed seal in Arctic Bay (Ikpiarjuk), Nunavut

Inuit hunting techniques used to catch ringed seals ( Phoca hispida ) were observed April-June 1993 on the land-fast ice of Admiralty Inlet, Nunavut, and adjoining fjords and bays. In addition, a survey of hunting techniques and knowledge of ringed seal biology and behaviour was conducted in the community of Arctic Bay (Ikpiarjuk), Nunavut, January-February 1994. A total of 246 seal structures were found in 31 days of hunting and 34 successful kills were observed. An experienced Inuk hunter found subnivean structures by sight, by walking on drifts and by probing snowdrifts with a harpoon ( unaaq ). Most structures were found using subtle visual cues. Breaking through the roof of a lair was the most common hunting technique observed in this study. Pups captured in this manner were subsequently used to lure the mother back into the breathing hole where she was harpooned. Ringed seals were also hunted by a number of other methods that have been described previously in the literature. Respondents in the hunter survey indicated that the ringed seal was the most important animal used by Arctic Bay Inuit. They also reported a variety of biological findings about ringed seals including: size differences among seals in different regions of the pack ice; that adult male ringed seals ( tiggak ) emitted a strong, mustelid-like odour from December until late May or early June. Hunters also reported that males were occasionally caught when coming to retrieve pups. All respondents reported seeing increasing frequencies of liver abnormalities in their ringed seal catches.     

Polar bear predation on ringed seals in the fast-ice of Hornsund, Svalbard

Polar bear hunting success on ringed seals in subnivean lairs and basking on the fast ice, was studied in Hornsund, Svalbard. A few bears were observed while actually hunting, but in most cases bear tracks were followed by snowmobile to determine the outcome of hunts. Seal carcasses were classified from size and tooth annuli as pups, juveniles or adults. A total of 62 subnivean structures were entered by bears, with six seals killed. One of ten charges on basking seals resulted in a kill. Success rates of bears in Hornsund arc compared with results of studies in Canada and Svalbard. OHunting success, polar bear, predation, ringed seal     

Oakes Bay 1: A Preliminary Reconstruction of a Labrador Inuit Seal Hunting Economy in the Context of Climate Change

Geografisk Tidsskrift—Danish Journal of Geography 110(2):245–259, 2010

This paper presents results of recent archaeological research at the site of Oakes Bay 1 (HeCg-08), on Dog Island, Labrador, dated from the late 17th to late 18th century. Analyses of faunal remains provide a means of reconstructing the site's subsistence economy. The site's inhabitants practiced a very consistent mode of hunting throughout this time period, depending heavily on adult ringed seals taken on the fast ice in winter and spring. Juvenile ringed seals, taken at the ice edge in the spring were a secondary resource. A lack of evidence for the hunting of harp seals in the fall and of ringed seal pups in late spring suggests that the site had a relatively short season of occupation. The consistent pattern of hunting through time suggests that the impacts of climatic variability on Inuit subsistence in the Nain region were relatively limited, moderated by their capacity for mobility on the sea ice rather than by whole scale changes in hunting practices and species choice. The Oakes Bay 1 site presents an example of a different subsistence economy than that seen at other recently examined sites in Labrador, suggesting that the impacts of the so-called Little Ice Age were not global or uniform.     

Going beyond hunger: Linking food supplies to global malnutrition

ABSTRACT

International food security and nutrition studies focus mainly on hunger rather than dietary diversity and the nutritional requirements essential for a productive life. The authors present a method that processes Food and Agriculture Organization food supply data into World Health Organization food groups to determine whether national food supply satisfies nutritional requirements for medium energy intake (i.e. c.2200 calories per day) rather than minimum energy intake. They employ a modified version of the International Food Policy Research Institute’s 2013 Global Hunger Index to group nations for comparison. The results show that most nations have a deficit in at least one of four required food groups. However, many developed Mediterranean nations with low levels of hunger display an adequate supply of all food groups. The positioning represents a successful model for managing the nutrition transition from plant-based diets to the consumption of animal protein, oils, fats, and sugars and other carbohydrates. Additionally, the results suggest that health risks associated with overweight and obesity may increase with societal development. Accordingly, the authors conclude that information on medium energy requirements should be combined with complementary socio-economic analysis to inform food and nutrition research and policy.     

Changes in the energy content of common species from Hornsund, Southwest Spitsbergen

During the period August 1981 to July 1982, samples of six species of Amphipoda common to Hornsund were collected, and a study of their energy value changes was carried out. Only slight fluctuations of energy values were observed throughout the year, and no distinct seasonal changes as in the case of boreal organisms. Individuals of greater body size exhibit higher energy values. The lowest energy values 10.93 kJ g⁻¹ d.w. (SD = 3.01) and highest ash contents 29.8% (SD = 7.6) were found in small Amphipoda (e.g. Ischyrocerus anguipes) , while species attaining greater body size were characterized by higher energy values and lower ash contents, for example Gammarellus homari 16.96 kJ g⁻¹d.w. (SD = 0.50), and 22.9% (SD = 3.3%) ash.     

中国食物供给能力分析

从中国各类型生态系统(农田、草地、水域) 的实际的食物生产能力出发,结合进出口产品中的食物部分,得出全国实际的食物供给能力,根据食物营养成分表中的转化率,将各类食物折算成人类生存所需的3 大营养成分(热量、蛋白质、脂肪) 的产量来表示,并利用ArcGIS 进行草地和农田食物供给的空间分析。以2004 年为例,中国实际食物供给能力为：热量1.601×10¹⁵ kcal,蛋白质6.163×10⁷ t,脂肪2.717×10⁷ t。其中,中国内陆生态系统实际可供给热量1.454×10¹⁵ kcal,蛋白质4.996×10⁷ t,脂肪2.074×10⁷ t,分别达到了陆地生态系统生产潜力的32.46%、38.33 %和41.12%,内陆生态系统食物供给还有较大的增长余地。在小康水平下,中国的食物热量、蛋白质、脂肪分别可以供养人口19.12 亿,20.84 亿和11.03 亿人,按照2010 年营养目标和2020 年全面小康目标,热量和蛋白质的供给已经较为充足,而脂肪的供给有所不足,今后需要注重油脂作物的种植和生产。结果还表明：中国的食物供给能力中,农田占据了绝大部分,不过比例有下降的趋势,从1998 年的84.66%,下降到2004 年的74.72%;草地和水域生态系统所提供的食物所占比例分别为4.83%~5.80%、6.02%~7.51%,波动较小;净进口食物所占比例逐年增长,1998 年仅为4.04%,2004 年增加到13.82%。通过平衡模型计算,在温饱、小康、富裕水平下,2004 年中国可以供养的人口分别为：15.34 亿,15.00 亿和14.11 亿,这表明,如果能够优化种植结构,合理配置植物性食物向动物性食物转化比例,均衡营养消费结构,中国实际食物供给较为充足。     

Ringed seal Phoca hispida fright behaviour caused by walrus Odobenus rosmarus

Other marine mammals tend to avoid walruses. The present paper describes two incidents of avoidance behaviour displayed by ringed seals in the presence of a walrus.     

Trichinella sp. in polar bears from Svalbard, in relation to hide length and age

DiaPhragma and masseter muscles from 376 polar bears ( Ursus maritimus ), 252 ringed seals ( Phoca hispida ), 84 bearded seals ( Erignathus barbatus ), and 77 arctic foxes ( Alopex lagopus ) from Svalbard were examined for Trichinella . Infection rates in polar bears varied between 23 and 58%, and between 3 and 67% in arctic fox- None of tne seals were infected. Trichinella in polar bears is probably transferred through cannibalism and scavenging upon polar bear carcasses. Infection rate in arctic fox was high when they preyed upon polar bear carcasses before polar bear hunting was prohibited in 1973. A low infection rate seems more natural when such prey is not available. No difference could be found in infection rate between male and female polar bears. There is only a slight increase in infection rate with age, as calculated from hide lengths, and many adult animals remain uninfected. Geographical isolation of polar bear populations may explain differences in Trichinella infection rates between bears from arctic America and arctic Europe. Possible explanations are that discrete polar bear populations have different food habits, or that they are exposed to different Trichinella strains.     

Foraging sexual segregation in a Mediterranean environment: Summer drought modulates sex-specific resource selection

A large body of studies have linked sexual segregation in dimorphic ungulates with differential resource selection and nutritional requirements of the sexes. However, detailed patterns of sexual dietary preferences have rarely been assessed as keystone mechanisms of sexual segregation. We compared diet and nutritional selection by 3 sex-age classes in the Iberian red deer (Cervus elaphus hispanicus Hilzheimer) across reproductive states and according to seasonal fluctuations in resource availability in a Mediterranean environment. Foraging segregation between sexes was found during rut when female/juvenile selection of shrubs was higher than that of males. Observed foraging patterns relate to a stronger selection of nitrogen, tannins and lignin by females and juveniles, and fibres by males. Our findings are associated to the Mediterranean climate, where rut and lactation concur with a shortage period, the particularly dry summer. Foraging segregation between sexes during the rut could be shaped by a conjunction of factors such as the low quality of resources and different fitness enhancement strategies. We highlight both the importance of including the dietary component and providing a temporal framework when documenting ungulate sexual segregation, and the interest of considering regional conditions when addressing management of ungulates with a wide distribution.     

中国第22和24次南极考察中山站越冬队员膳食调查

在南极中山站特殊环境下,膳食营养对人体的保护尤显重要。通过在中山站对第22和24次中国南极越冬队分别开展三次连续动态膳食调查,获取越冬队员的主要膳食模式,有针对性地提出改善膳食模式的建议,以保障越冬队员的健康。分别在2006年、2008年采用连续3—4天/次称重法对第22、24次中山站越冬队员进行三次膳食调查,计算平均每人每日能量及各种营养素摄入量,与《中国居民膳食营养素参考摄入量(Chinese DRIs)》进行对比分析、评价队员膳食营养状况。越冬队员平均能量摄入充足,符合中至重等体力劳动所需摄入量(2 700—3 200 kcal)。获得的17种营养素中,钙、维生素A、维生素C、微量元素硒的摄入量低于中国DRIs标准,钠摄入偏高,其余基本符合标准。烹调用油、食盐的摄入量超过中国营养学会建议的摄入量。脂肪、蛋白质提供的能量比(三大营养物质所提供的能量各占百分比)分别高于中国营养学会推荐的20%—30%、12%—14%,碳水化合物低于推荐的55%—65%。中山站越冬队员呈现高脂肪、高蛋白、低碳水化合物,烹调用油、食盐的摄入量过高,钠摄入偏高,以及维生素A、C和钙、硒摄入量过低的膳食结构。应调整脂肪、蛋白质、碳水化合物的摄入比例,调整烹调用油、钠盐的摄入量,补充维生素A、C和钙、硒。     

Availability of suitable land-fast ice and predation as factors limiting ringed seal populations, Phoca hispida, in Svalbard

We examined the stability of fast ice areas in western and northern Spitsbergen, the area north of Nordaustlandet, the bays and sounds of Hinlopen Stretet and the large area in the northern part of Storfjorden. NOAA satellite imagery from 1974 and 1988 and NOAA (AVHRR) imagery from 1980-87 were used to determine the dates of freeze-up and break-up. The number of days of fast ice present before the nominal birth date of ringed seal pups were computed for all major bays and fjords. Ice thickness was then computed from these data. Known prime breeding habitat in Svalbard is found in areas near glacier fronts in protected fjords and bays, where densities of birth lairs are 5.46 km⁻², corresponding to a ringed seal female density of 2.6 km⁻². Most of the ringed seal breeding habitat in Svalbard, however, consists of flat fjord ice where snow accumulation is rarely deep enough to permit birth lair construction. In these areas pups are often born in the open. Based on breathing hole densities, the density of adult females in the flat ice areas in the breeding period was estimated to 0.98 km⁻². A preliminary estimate is that approximately 19,500 pups could be born annually in the fast ice of Svalbard. Annual recruitment could be quite variable given the unpredictable nature of the fast ice areas and the high predation mortality on newborn pups. Discrepancies between our calculated ringed seal production and numbers of seals required to feed the large polar bear population in the area signal cause for management concern.     

Energy costs during incubation in Svalbard and Willow Ptarmigan hens

Studies of wild and captive Willow and Svalbard Ptarmigan hens have allowed us to estimate the daily energy cost during incubation. It was similar for the two species, varying between 70-85 kcal per day depending on number of eggs, nest insulation, ambient temperature, number of foraging periods and total time spent away from the nest. Daily energy cost during incubation was 15 - 20% above resting metabolic rate in non-incubating hens but only 45 - 55% of that in free-living non-incubating hens. Incubating hens reduced their energy expenditure through high nest attentiveness. A reduction in food intake during incubation led to loss in body weight.     

Feeding habits of harp and hooded seals in drift ice waters along the east coast of Greenland in summer and winter

Results of analyses of stomach and intestinal contents from hooded ( Cystophora cristata ) and harp ( Phoca groenlandica ) seals captured in the pack ice belt of the Greenland Sea in summer (July-August) in 2000 and winter (February-March) in 2001 revealed that the diet of both species were comprised of relatively few prey taxa. Pelagic amphipods of the genus Parathemisto , the squid Gonatus fabricii , polar cod ( Boreogadus saida ) and capelin ( Mallotus villosus ) constituted 63-99% of the observed diet biomass in both seal species, irrespective of sampling period, but their relative contribution to the diet varied both with species and sampling period/area. For hooded seals, G. fabricii and capelin were the dominant food items in winter 2001, but the summer 2000 diet comprised a mixture of this squid and polar cod. Parathemisto was most important for the harp seals during summer 2000; in winter 2001 the contribution from krill and capelin were comparable to that of Parathemisto . Multivariate analyses revealed differences in the intestinal contents of hooded and harp seals in areas where the two species' occurrence spatially overlapped. Different foraging depths of the two species may have contributed to the observed differences in diets.     

ALPINE AREAS IN THE COLORADO FRONT RANGE AS MONITORS OF CLIMATE CHANGE AND ECOSYSTEM RESPONSE*

ABSTRACT. The presence of a seasonal snowpack in alpine environments can amplify climate signals. A conceptual model is developed for the response of alpine ecosystems in temperate, midlatitude areas to changes in energy, chemicals, and water, based on a case study from Green Lakes Valley–Niwot Ridge, a headwater catchment in the Colorado Front Range. A linear regression shows the increase in annual precipitation of about 300 millimeters from 1951 to 1996 to be significant. Most of the precipitation increase has occurred since 1967. The annual deposition of inorganic nitrogen in wetfall at the Niwot Ridge National Atmospheric Deposition Program site roughly doubled between 1985–1988 and 1989–1992. Storage and release of strong acid anions, such as those from the seasonal snowpack in an ionic pulse, have resulted in episodic acidification of surface waters. These biochemical changes alter the quantity and quality of organic matter in high‐elevation catchments of the Rocky Mountains. Affecting the bottom of the food chain, the increase in nitrogen deposition may be partly responsible for the current decline of bighorn sheep in the Rocky Mountains.     

极端干旱区柽柳林地蒸散量及能量平衡分析

运用波文比-能量平衡法对极端干旱区柽柳林地的蒸散量及能量通量进行了连续的测定和估算,并对柽柳林地蒸散特点和能量平衡进行了分析和探讨。结果表明:柽柳林地的日平均蒸散量为1.6 mm/d,整个生长季的蒸散量为248.2 mm,蒸散量的季节变化系数为47%±3%。柽柳林地蒸散量的季节变化与土壤水分条件密切相关。柽柳林地蒸散量受气象因子和下垫面条件的影响和制约。在极端干旱区,感热通量消耗了绝大多数的能量,潜热通量在整个生长季只占很小的一部分,夜间,土壤储存的能量是大气能量的主要来源,而白天土壤是能量的主要汇源。     

Characteristics of land-atmosphere energy and turbulent fluxes over the plateau steppe in central Tibetan Plateau

The land-atmosphere energy and turbulence exchange is key to understanding land surface processes on the Tibetan Plateau(TP). Using observed data for Aug. 4 to Dec. 3, 2012 from the Bujiao observation point(BJ) of the Nagqu Plateau Climate and Environment Station(NPCE-BJ), different characteristics of the energy flux during the Asian summer monsoon(ASM) season and post-monsoon period were analyzed. This study outlines the impact of the ASM on energy fluxes in the central TP. It also demonstrates that the surface energy closure rate during the ASM season is higher than that of the post-monsoon period. Footprint modeling shows the distribution of data quality assessments(QA) and quality controls(QC) surrounding the observation point. The measured turbulent flux data at the NPCE-BJ site were highly representative of the target land-use type. The target surface contributed more to the fluxes under unstable conditions than under stable conditions. The main wind directions(180° and 210°) with the highest data density showed flux contributions reaching 100%, even under stable conditions. The lowest flux contributions were found in sectors with low data density, e.g., 90.4% in the 360° sector under stable conditions during the ASM season. Lastly, a surface energy water balance(SEWAB) model was used to gap-fill any absent or corrected turbulence data. The potential simulation error was also explored in this study. The Nash-Sutcliffe model efficiency coefficients(NSEs) of the observed fluxes with the SEWAB model runs were 0.78 for sensible heat flux and 0.63 for latent heat flux during the ASM season, but unrealistic values of-0.9 for latent heat flux during the post-monsoon period.     

苏州水网系列水质模型

为适应苏州水网水污染综合防治规划时进行水质预测的需要,本文提出苏州水网的非稳态系列水质模型,包括(1)网块水质模型,用于预测苏州网块水体水质年内(季节)变化;(2)分段水质模型,用于预测苏州城河逐段水质空间变化;(3)河网水质模型,用于预测苏州城河任一段面昼夜(逐时)水质变化。这些模型经过验证,获得满意的结果,并作了苏州水网的水质模拟和预测。