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1.
Robert L. Pitman John W. Durban Michael Greenfelder Christophe Guinet Morton Jorgensen Paula A. Olson Jordi Plana Paul Tixier Jared R. Towers 《Polar Biology》2011,34(2):303-306
Studies have shown that killer whale (Orcinus orca) communities in high latitudes regularly comprise assemblages of sympatric ‘ecotypes’—forms that differ in morphology, behavior,
and prey preferences. Although they can appear superficially similar, recent genetic evidence suggests that breeding is assortative
among ecotypes within individual communities, and species-level divergences are inferred in some cases. Here, we provide information
on a recently recognized ‘type D’ killer whale based on photographs of a 1955 mass stranding in New Zealand and our own six
at-sea sightings since 2004. It is the most distinctive-looking form of killer whale that we know of, immediately recognizable
by its extremely small white eye patch. Its geographic range appears to be circumglobal in subantarctic waters between latitudes
40°S and 60°S. School sizes are relatively large (mean 17.6; range 9–35; n = 7), and although nothing is known about the type D diet, it is suspected to include fish because groups have been photographed
around longline vessels where they reportedly depredate Patagonian toothfish (Dissostichus eleginoides). 相似文献
2.
The underwater behaviour of 11 belugas or white whales was examined during summer using time-at-depth records relayed by
satellite-linked data-loggers. Simultaneous tracking information was obtained for each whale. Eight distinct dive profiles
were identified in submergences made to depths of >40 m. Four of these, together comprising 84% of these “deep” dives, were
of a square profile. They were characterised by a continuous descent to a particular depth (usually the sea bed), a “bottom
phase” at or near that depth, and a direct ascent to the surface. These dives are presumed to be made for benthic foraging.
Other, much less common, dive shapes were “V”-shaped, parabolic and trapezoidal. “Shallow” dives (15–40 m depth) were of a
variety of shapes, short duration and high average horizontal speeds. Many probably occurred during periods of directed travel.
This population of belugas treats most of the water column as dead space separating resources of oxygen and nutrition.
Received: 8 January 1998 / Accepted: 27 April 1998 相似文献
3.
The population size of Antarctic minke whales Balaenoptera bonaerensis has been changing simultaneously with profound changes in the physics, i.e., mesopredator habitat features, of the Southern
Ocean. Although the two trends may not be related, distinguishing among the factors responsible requires a better understanding
of minke whale habitat preferences. For the first time at a large geographic scale, i.e., between 140° E and 35° W, we use
data not constrained by vessels needing to avoid sea ice to model the habitat affinities of this pagophilic mesopredator.
Using Maxent, we modeled minke whale proximity to the Antarctic Shelf Break Front (ASBF) and the southern boundary of Antarctic
Circumpolar Current (sbACC), as well as association with sea ice, given that global climate change is altering the positions
or intensity of these features. We also included water depth and chlorophyll (proxy for productivity) as variables. Minke
whale presence data were gathered using strip and line census on 55 cruises on board icebreakers during late spring and summer,
1976–2005. The most important variable was distance to ASBF, followed by water depth and sea-ice concentration. That is, found
principally in waters south of the sbACC during summer, minke whales were most abundant near the outer edge of the continental
shelf (shallow depth), including areas heavily covered by sea ice. We propose that as the sbACC moves south and sea ice disappears,
as projected by global climate models, minke whale habitat will shrink, and likely intra- and inter-specific competition will
increase. 相似文献
4.
Mandy L. H. Cook René A. Varela Juli D. Goldstein Stephen D. McCulloch Gregory D. Bossart James J. Finneran Dorian Houser David A. Mann 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2006,192(5):489-495
Several mass strandings of beaked whales have recently been correlated with military exercises involving mid-frequency sonar highlighting unknowns regarding hearing sensitivity in these species. We report the hearing abilities of a stranded juvenile beaked whale (Mesoplodon europaeus) measured with auditory evoked potentials. The beaked whale’s modulation rate transfer function (MRTF) measured with a 40-kHz carrier showed responses up to an 1,800 Hz amplitude modulation (AM) rate. The MRTF was strongest at the 1,000 and 1,200 Hz AM rates. The envelope following response (EFR) input–output functions were non-linear. The beaked whale was most sensitive to high frequency signals between 40 and 80 kHz, but produced smaller evoked potentials to 5 kHz, the lowest frequency tested. The beaked whale hearing range and sensitivity are similar to other odontocetes that have been measured. 相似文献
5.
Boulder shores are common at all latitudes and dominate the intertidal and subtidal zones of sub-Antarctic coastlines. The
encrusting benthos of boulders was examined on similar shore types at four locations: Tierra del Fuego, East Falkland, West
Falkland and Bird Island (off South Georgia). Bird Island is unusual in experiencing high trampling and organic enrichment
from fur seals. The results were compared to a Patagonian site and a non-trampled South Georgia site (Husvik) and other sites
taken from the literature. Principal Component Analysis revealed South Atlantic/Southern Ocean encrusting faunas formed a
distinct cluster when compared to assemblages from elsewhere at similar latitudes. Bray Curtis cluster analysis of the South
Atlantic-Southern Ocean sites showed the major division was between Southern Ocean and South Atlantic Ocean sites, beyond
which there were three distinct clusters centred around Patagonia (Magellanic), the Falklands and Southern Ocean sites. The
organisation of competitive interactions between species was mostly determinate and transitive (essentially hierarchical).
The transitivity index scores were higher than most similar assemblages studied to date. The diversity of encrusting assemblages
ranged from Shannon Weaver H values of 2.38–0.77 (East Falkland and Bird Island, respectively) in the intertidal to 1.27–0.73 (Patagonia and South Georgia,
respectively) in the subtidal zone. Annual mortality (of bryozoan colonies) varied from 85–97% in the intertidal to 65–92%
in the subtidal, being higher in the Southern Ocean than South Atlantic sites, largely due to ice scour and wave action. The
Bird Island mortality values may be high even for a Southern Ocean site.
Accepted: 5 October 2000 相似文献
6.
Tibor Szép Anders Pape M?ller Steven Piper Rick Nuttall Zoltán D. Szabó Péter L. Pap 《Journal of Ornithology》2006,147(2):245-253
On the basis of correlation analyses between annual Normalised Difference Vegetation Index (NDVI) values in Africa and the
annual survival rate estimated for a breeding population of barn swallows Hirundo rustica from Denmark, we identified potential wintering and migration areas in South Africa during December–February and March–May,
when barn swallows commonly occur in South Africa. During December–February we identified potential wintering areas only in
the western part of South Africa, in the Karoo. Potential areas in the central and eastern parts of the country were only
identified during March–May. NDVI values in the Karoo during March–May explained most of the variance in annual adult survival
rate of the population. The high ratio of European ringed barn swallows among controlled individuals in the Karoo was similar
to the ratio that would be expected based on the number of ringed barn swallows and the population sizes of barn swallows
in north-western European breeding populations. The level of this ratio in the Karoo was higher than in any other locality
in the central and eastern parts of South Africa and Botswana, indicating that ringed birds from the eastern flyway are absent
to a much smaller extent than ringed birds from the western flyway. This approach shows that the NDVI and survival method
can focus ringing efforts to regions and areas that are likely to harbour specific breeding populations, thereby helping to
identify potential wintering and migration areas for breeding populations of migratory birds. 相似文献
7.
Two beaked whales identified as Sowerby's beaked whale (Mesoplodon bidens) were observed in sea state 0–1 on 16 July 1995 at 71°30′N 04°00′E in the Norwegian Sea. A number of morphological features,
such as dentition, were clearly seen during the encounter. The Sowerby's beaked whale's core distribution is in the North
Sea and the previous northernmost sighting was made at 63°06′N 00°41′E. According to the literature, the species has never
been recorded in the polar zone. The sighting in the Norwegian Sea suggests that the current data on the species distribution
is uncertain, and that its range may include the polar waters of the Norwegian Sea.
Received: 24 April 1996 / Accepted: 25 August 1996 相似文献
8.
Linda Wolfe 《Primates; journal of primatology》1979,20(4):525-534
This report contains detailed data on the sexual behavior of the 60 sexually mature females of the Arashiyama West troop of
Japanese macaques.
The study group was a natural troop transported intact in 1972 to a ranch in South Texas. Since transplantation, the monkeys
have been free to roam and feed within a 42.2 ha enclosure. Analysis of data collected on the 140 monkeys that composed the
troop during the 1973–74 and 1974–75 breeding seasons revealed: (1) Female-male mounting is an important aspect of Japanese
macaque sexual behavior; (2) All females had preferred partners and most avoided both heterosexual and homosexual interactions
with close kin; (3) Pubescent and adult females exhibit different patterns of sexual behavior; (4) Pubescent and adult females
were affected somewhat differently by the transportation from Japan to their current home in South Texas. These behavioral
patterns and their implications are discussed.
The study was partially supported by PHS Biomedical Science Grant 50-262-1112. 相似文献
9.
The stomach contents of four bowhead whales (Balaena mysticetus) harvested between 1994 and 2008 from the Canadian Arctic were examined to assess diet composition. Three samples were collected
from bowhead whales of the Eastern Canada–West Greenland (EC–WG) population and represent, according to our knowledge, the
first diet analysis from this bowhead whale stock. We also examined the stomach content of one bowhead whale from the Bering-Chukchi-Beaufort
(BCB) population hunted in 1996. All four whales had food in their stomachs and their diet varied from exclusively pelagic
(BCB whale), with Limnocalanus macrurus being the main prey, to epibenthic and benthic (EC–WG) with Mysis oculata playing an important role. These results indicate broad foraging spectrum of the bowhead whales and add to a basic knowledge
of their diet. 相似文献
10.
Arnason U Gullberg A Gretarsdottir S Ursing B Janke A 《Journal of molecular evolution》2000,50(6):569-578
Extant cetaceans are systematically divided into two suborders: Mysticeti (baleen whales) and Odontoceti (toothed whales).
In this study, we have sequenced the complete mitochondrial (mt) genome of an odontocete, the sperm whale (Physeter macrocephalus), and included it in phylogenetic analyses together with the previously sequenced complete mtDNAs of two mysticetes (the
fin and blue whales) and a number of other mammals, including five artiodactyls (the hippopotamus, cow, sheep, alpaca, and
pig). The most strongly supported cetartiodactyl relationship was: outgroup,((pig, alpaca),((cow, sheep),(hippopotamus,(sperm
whale,(baleen whales))))). As in previous analyses of complete mtDNAs, the sister-group relationship between the hippopotamus
and the whales received strong support, making both Artiodactyla and Suiformes (pigs, peccaries, and hippopotamuses) paraphyletic.
In addition, the analyses identified a sister-group relationship between Suina (the pig) and Tylopoda (the alpaca), although
this relationship was not strongly supported. The paleontological records of both mysticetes and odontocetes extend into the
Oligocene, suggesting that the mysticete and odontocete lineages diverged 32–34 million years before present (MYBP). Use of
this divergence date and the complete mtDNAs of the sperm whale and the two baleen whales allowed the establishment of a new
molecular reference, O/M-33, for dating other eutherian divergences. There was a general consistency between O/M-33 and the
two previously established eutherian references, A/C-60 and E/R-50. Cetacean (whale) origin, i.e., the divergence between
the hippopotamus and the cetaceans, was dated to ≈55 MYBP, while basal artiodactyl divergences were dated to ≥65 MYBP. Molecular
estimates of Tertiary eutherian divergences were consistent with the fossil record.
Received: 12 July 1999 / Accepted: 28 February 2000 相似文献
11.
Cory J. D. Matthews Sebasti��n P. Luque Stephen D. Petersen Russel D. Andrews Steven H. Ferguson 《Polar Biology》2011,34(7):1091-1096
Killer whales (Orcinus orca) occur in the eastern Canadian Arctic during the open-water season, but their seasonal movements in Arctic waters and overall
distribution are poorly understood. During August 2009, satellite transmitters were deployed onto two killer whales in Admiralty
Inlet, Baffin Island, Canada. A whale tracked for 90 days remained in Admiralty and Prince Regent Inlets from mid-August until
early October, when locations overlapped aggregations of marine mammal prey species. While in Admiralty and Prince Regent
Inlets, the whale traveled 96.1 ± 45.3 km day−1 (max 162.6 km day−1) and 120.1 ± 44.5 km day−1 (max 192.7 km day−1), respectively. Increasing ice cover in Prince Regent Inlet in late September and early October was avoided, and the whale
left the region prior to heavy ice formation. The whale traveled an average of 159.4 ± 44.8 km day−1 (max 252.0 km day−1) along the east coast of Baffin Island and into the open North Atlantic by mid-November, covering over 5,400 km in approximately
one month. This research marks the first time satellite telemetry has been used to study killer whale movements in the eastern
Canadian Arctic and documents long-distance movement rarely observed in this species. 相似文献
12.
Márcia H. Engel Nelson J. R. Fagundes Howard C. Rosenbaum Matthew S. Leslie Paulo H. Ott Renata Schmitt Eduardo Secchi Luciano Dalla Rosa Sandro Luis Bonatto 《Conservation Genetics》2008,9(5):1253-1262
In the Southwestern Atlantic Ocean, humpback whales migrate every winter to the Brazilian coast for breeding and calving in
the Abrolhos Bank. This breeding stock represents the remnants of a larger population heavily exploited during the beginning
of the 20th century. Despite its relevance to conservation efforts, the degree of current genetic variation and the migratory
relationship with Antarctic feeding areas for this population are still largely unknown. To examine these questions, we sequenced
∼400 bp of the mitochondrial DNA control region from samples taken off the Brazilian coast (n = 171) and near the Antarctic Peninsula (n = 77). The genetic variability of the Brazilian humpback whale breeding population was high and similar to that found in
other Southern Hemisphere breeding grounds. Phylogenetic analysis suggested the existence of a new mitochondrial clade that
exists at low frequency among Southern Hemisphere populations. Direct comparison between the Brazilian and the Colombia breeding
populations and the Antarctic Peninsula feeding population showed no genetic differentiation between this feeding region and
the Colombian breeding area or between feeding Areas I and II near the Antarctic Peninsula. In contrast, these populations
were genetically distinct from the Brazilian population. Two humpback whales sampled off South Georgia Islands, in the Scotia
Sea, shared identical haplotypes to whales from Brazil. Our results, supported by photo-identification and satellite telemetry
data, suggest that the main feeding area of the Southern Hemisphere humpback whale population is likely to be located near
the South Georgia/South Sandwich Islands area and not in the Antarctic Peninsula. 相似文献
13.
Intercropping of field crops in cotton for the management of purple nutsedge (Cyperus rotundus L.) 总被引:2,自引:0,他引:2
A 2-year field investigation was carried out during 2003–2004 to determine the effectiveness of intercropping single and double
rows of sorghum, soybean and sesame in a cotton crop on the suppression of purple nutsedge (Cyperus rotundus L.). Results revealed that all three intercrops were effective in inhibiting purple nutsedge density (70–96%) and dry matter
production (71–97%) during both years of experimentation. Control in the second year was more effective than in the first
year. The seed cotton yield was also depressed by the intercrops but its suppression (8–23%) was far less severe than that
of purple nutsedge and its loss was compensated by greater total economic returns. Intercropping of sorghum and sesame produced
greater than 20% net benefits (up to 60%) in comparison with the control (cotton alone). Soybean intercropping produced comparable
net benefits (95–103%). Sesame two rows intercrop treatment appeared the most profitable with net benefit of 51–59% with good
purple nutsedge control (73–92% density suppression, 77–95% dry weight suppression) during both years of experimentation. 相似文献
14.
Su-Ping Li Ryszard Ochyra Peng-Cheng Wu Rodney D. Seppelt Ming-Hong Cai Hai-Ying Wang Cheng-Sen Li 《Polar Biology》2009,32(10):1415-1425
Drepanocladus longifolius (Mitt.) Paris is recorded for the first time from King George Island, South Shetland Islands, in the maritime Antarctic.
It was collected in West Lake during the 23rd Chinese National Antarctic Research Expedition in 2006–2007. The moss was found
at a depth of 5–6 m attached to the bed of the lake. The stems of the moss are about 1–1.5 m in length. The moss exhibits
seasonal growth patterns, with shorter branch internodes, more widely spaced leaves and more branches in summer than in winter.
Most of the branches are initiated in summer. The annual shoot extension is about 3–6 cm, which implies that the plants must
be at least 15 years of age. The distribution of aquatic moss species and records in Antarctica is outlined and discussed
and the nomenclature of previous reports clarified. 相似文献
15.
The diet of Antarctic fur sealsArctocephalus gazella during the breeding season at South Georgia 总被引:1,自引:0,他引:1
The diet of lactating female Antarctic fur seals Arctocephalus gazella at South Georgia was investigated during the pup-rearing period (January/March) of 1991–1994. Antarctic krill Euphausia superba was the main prey item, occurring in 88% of all scats (n=497), whereas fish occurred in 47% and squid in 5% of all scats. There was considerable intra- and inter-annual variation
in the characteristics of krill taken by fur seals. The distribution of krill sizes taken suggests that fur seals are not
actively selecting particular sizes of krill and, therefore, that the krill in the diet reflects the krill available around
South Georgia. The absence of group 3 krill (44–48 mm in length) in the South Georgia area, as indicated by their absence
in the diet of seals, is suggested as a possible reason for low availability of krill and the subsequent reproductive failure
among krill predators. The frequency of occurrence of fish was much higher than in previous studies; the pattern of fish consumption
showed a consistent seasonal pattern in 3 of the 4 years studied. Of the total number of the myctophid Protomyctophum choriodon, the most numerous fish taxon, 98% were taken between early February and the middle of March. Champsocephalus gunnari and Lepidonotothen larseni agg., which both feed on krill, dominated the fish component of the diet outside this period and together constituted 94%
of the total estimated biomass of fish consumed. The intra- and inter-annual variability in the diet of Antarctic fur seals
emphasise the need for diet studies to be conducted during the entire pup-rearing periods of several years.
Received: 15 March 1995/Accepted: 13 May 1995 相似文献
16.
The diet of Cape petrel Daption capense was investigated at Laurie Island, South Orkney Islands (60°46′S, 44°42′W), Antarctica, in the period January–February 1996. Stomach contents of adults and regurgitate of chicks were sampled during
the post-hatching period. The analysis showed that during the whole sampling period Antarctic krill and fish represented the
predominant preys in terms of frequency of occurrence, forming nearly 35.8% and 64% by mass, respectively. The species Electrona antarctica was the most frequent fish prey. Amphipods were present in lower numbers and cephalopods were detected in the diet, but in
a very small proportion. Diet composition in terms of frequency of occurrence, mass and number is compared with results of
previous studies.
Received: 27 September 1996 / Accepted: 22 February 1997 相似文献
17.
During January/February 2006, we satellite-tracked two different ecotypes of killer whales (Orcinus orca) in McMurdo Sound, Ross Sea, Antarctica, using surface-mounted tags attached with sub-dermal darts. A single Type B whale
(pinniped prey specialist), tracked for 27 days, traveled an average net distance of 56.8 ± 32.8 km day−1, a maximum of 114 km day−1, and covered an estimated area of 49,351 km2. It spent several days near two large emperor penguin (Aptenodytes forsteri) colonies, a potential prey item for this form. By contrast, four Type C killer whales (fish prey specialists) tracked for
7–65 days, traveled an average net distance of 20 ± 8.3 km day−1, a maximum of 56 net km day−1, and covered an estimated area of only 5,223 km2. These movement patterns are consistent with those of killer whale ecotypes in the eastern North Pacific where mammal-eating
‘transients’ travel widely and are less predictable in their movements, and fish-eating ‘residents’ have a more localized
distribution and more predictable occurrence, at least during the summer months. 相似文献
18.
Inter-annual variability in the diet of Chinstrap penguins (Pygoscelis antarctica) at Laurie Island, South Orkney Islands was examined based on stomach contents of adults coming ashore during the 1997/1998–2001/2002 breeding seasons. Krill (Euphausia superba) dominated the diet either as frequency of occurrence (in 100% of samples), number (>99%), and percentage contribution in weight (>99.5%). Other prey items were minor but did vary between years. The contribution in weight of fish, amphipods and cephalopods ranged between 0.01–0.5, <0.01–0.14 and 0–0.03, respectively. Although minor components varied slightly along the years, the weight of stomach contents was significantly different. It was found that for a given weight the maximum observed percentage of undigested krill resulted negatively correlated with the stomach contents total weight. The proportion of whole krill observed in individual penguins, expressed as a fraction of the maximum corresponding to its weight was used to characterize the prevailing conditions in each season. 相似文献
19.
Skeletal remains of baleen whales killed during the onset of 20th century commercial whaling lie scattered across the shores and abandoned whaling stations of the subantarctic island of South Georgia. Here we report on genetic species identification of whale bones collected from South Georgia using standard historical DNA protocols. We amplified and sequenced short fragments of the mitochondrial DNA (mtDNA) control region from 281 available bone samples. Of these, 231 provided mtDNA sequences of sufficient quality and length (174–194 bp) for species identification: 158 bones were identified as humpback whale (Megaptera novaeangliae), 51 bones were identified as fin whale (Balaenoptera physalus), 18 bones were identified as blue whale (B. musculus), two bones were identified as sei whale (B. borealis), one bone was identified as a southern right whale (Eubalaena australis), and one bone was identified as a southern elephant seal (Mirounga leonina). The prominence of humpback, fin, and blue whale bones in the sample collection corresponds to the catch record of the early years of whaling on the island of South Georgia (pre‐1915), prior to the depletion of these populations. 相似文献
20.
The spring mesozooplankton community at South Georgia: a comparison of shelf and oceanic sites 总被引:3,自引:3,他引:0
Mesozooplankton (predominantly 200–2000 μm) were sampled at a shelf and an oceanic station close to South Georgia, South
Atlantic, during austral spring (October/November) 1997. Onshelf zooplankton biomass was extremely high at 10–16 g dry mass
m−2 (0–150 m), 70% comprising the small neritic clausocalaniid copepod Drepanopus forcipatus. Large calanoid species, principally Calanoides acutus and Rhincalanus gigas, contributed only 8–10%. At the oceanic station, biomass in the sampled water column (0–1000 m) was ∼6.5 g dry mass m−2 and 4–6 g dry mass m−2 in the top 200 m. Here, large calanoids composed 40–50% of the standing stock. Antarctic krill (Euphausia superba) occurred in low abundances at both stations. Vertical profiles obtained with a Longhurst Hardy Plankton Recorder indicated
that populations of C. acutus and R. gigas, which overwinter at depth, had completed their spring ascent and were resident in surface waters. Dry mass, carbon and lipid
values were lower than found in summer but were consistent with overwintered populations. Phytoplankton concentrations were
considerably higher at the oceanic station (2–3 mg chlorophyll a m−3) and increased over the time on station. In response to this, egg production of both large calanoid species and growth rates
of R. gigas approached those measured in summer. Onshelf phytoplankton concentrations were lower (<1 mg m−3), and low egg production rates suggested food limitation. Here phytoplankton rations equivalent to 6% zooplankton body C
would have been sufficient to clear primary production whereas at the oceanic station daily carbon fixation was broadly equivalent
to zooplankton carbon biomass.
Accepted: 25 April 1999 相似文献