scholarly journals Variation of annual apparent survival and detection rates with age, year and individual identity in male Weddell seals ( Leptonychotes weddellii ) from long‐term mark‐recapture data

2019 ◽  
Vol 62 (1) ◽  
pp. 134-150
Author(s):  
Jamie L. Brusa ◽  
Jay J. Rotella ◽  
Robert A. Garrott ◽  
J. Terrill Paterson ◽  
William A. Link
Keyword(s):  
Individual Identity ◽  
Apparent Survival ◽  
Leptonychotes Weddellii ◽  
Mark Recapture ◽  
Detection Rates ◽  
Weddell Seals

Preweaning mortality of Weddell seal pups

1996 ◽  
Vol 74 (9) ◽  
pp. 1775-1778 ◽  
Author(s):  
Jason F. Schreer ◽  
Kelly K. Hastings ◽  
J. Ward Testa
Keyword(s):  
Mortality Rates ◽  
Weddell Seal ◽  
Leptonychotes Weddellii ◽  
Mark Recapture ◽  
Mcmurdo Sound ◽  
Weddell Seals ◽  
Ice Surface ◽  
Open Populations ◽  
Significant Mortality

We examined mortality prior to weaning of Weddell seal pups (Leptonychotes weddellii), using resighting data collected from 1984 to 1993 on the annual ice of McMurdo Sound, Antarctica. Mortality rates were estimated using counts of dead pups found on the surface and mark–recapture techniques. The standard Jolly–Seber model for open populations fit the recapture data best and corresponded well to the known biology of these animals. Yearly mortality rates estimated by mark–recapture techniques ranged from 6 to 22%, with a mean across years of 13%. These values are twice as high as those previously reported for Weddell seals and those calculated from counts of dead pups in this study. This suggests that there is significant unseen mortality due either to undiscovered fatalities on the ice surface or to significant mortality occurring in the water.

Possible food caching and defence in the Weddell seal: observations from McMurdo Sound, Antarctica

2005 ◽  
Vol 17 (1) ◽  
pp. 71-72 ◽  
Author(s):  
S.L. KIM ◽  
K. CONLAN ◽  
D.P. MALONE ◽  
C.V. LEWIS
Keyword(s):  
Shallow Water ◽  
Benthic Communities ◽  
Weddell Seal ◽  
Leptonychotes Weddellii ◽  
Mcmurdo Sound ◽  
Weddell Seals ◽  
Food Caching ◽  
The Common ◽  
Made In

On the basis of observations of Weddell seals (Leptonychotes weddellii Lesson) made in the course of studying shallow-water benthic communities in McMurdo Sound, Antarctica, we suggest that caching and/or defence of uneaten food may be a strategy practiced by this animal. Such a phenomenon is uncommon but taxonomically widespread among vertebrates. Depending on circumstances, it is termed hoarding, caching, or storage and may be short- or long-term, include defence of the resource, or have other variable expressions, with the common threads being deferred consumption and deterrence of consumption by others (Vanderwall 1990). Many vertebrate taxa exhibit hoarding behaviour, including rodents (e.g. Sciuridae), carnivores (e.g. Canidae, Felinidae) and birds (e.g. Corvidae, Picidae). No form of food caching, to our knowledge, has ever been reported in a wild pinniped.

scholarly journals Predictors of Occult Paroxysmal Atrial Fibrillation in Cryptogenic Strokes Detected by Long-Term Noninvasive Cardiac Monitoring

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Archit Bhatt ◽  
Arshad Majid ◽  
Anmar Razak ◽  
Mounzer Kassab ◽  
Syed Hussain ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Paroxysmal Atrial Fibrillation ◽  
Cryptogenic Stroke ◽  
Cardiac Monitoring ◽  
High Signal ◽  
Detection Rates ◽  
Non Invasive ◽  
Patient Reported ◽  
Premature Beats

Background and Purpose. Paroxysmal Atrial fibrillation/Flutter (PAF) detection rates in cryptogenic strokes have been variable. We sought to determine the percentage of patients with cryptogenic stroke who had PAF on prolonged non-invasive cardiac monitoring.Methods and Results. Sixty-two consecutive patients with stroke and TIA in a single center with a mean age of 61 (+/− 14) years were analyzed. PAF was detected in 15 (24%) patients. Only one patient reported symptoms of shortness of breath during the episode of PAF while on monitoring, and 71 (97%) of these 73 episodes were asymptomatic. A regression analysis revealed that the presence of PVCs (ventricular premature beats) lasting more than 2 minutes (OR 6.3, 95% CI, 1.11–18.92;P=.042) and strokes (high signal on Diffusion Weighted Imaging) (OR 4.3, 95% CI, 5–36.3;P=.041) predicted PAF. Patients with multiple DWI signals were more likely than solitary signals to have PAF (OR 11.1, 95% CI, 2.5–48.5,P<.01).Conclusion. Occult PAF is common in cryptogenic strokes, and is often asymptomatic. Our data suggests that up to one in five patients with suspected cryptogenic strokes and TIAs have PAF, especially if they have PVCs and multiple high DWI signals on MRI.

Calling depth and time and frequency attributes of harp (Pagophilus groenlandicus) and Weddell (Leptonychotes weddellii) seal underwater vocalizations

2005 ◽  
Vol 83 (11) ◽  
pp. 1438-1452 ◽  
Author(s):  
Hilary B Moors ◽  
John M Terhune
Keyword(s):  
Light Condition ◽  
Weddell Seal ◽  
Harp Seal ◽  
Vertical Array ◽  
Vocal Cords ◽  
Leptonychotes Weddellii ◽  
Call Duration ◽  
Weddell Seals ◽  
Pagophilus Groenlandicus ◽  
Breeding Seasons

Harp seal (Pagophilus groenlandicus (Erxleben, 1777)) daytime calling depth during the breeding season and Weddell seal (Leptonychotes weddellii (Lesson, 1826)) daytime and nighttime calling depth during the winter and breeding seasons were investigated using a small vertical array with hydrophones placed at depths of 10 and 60 m. Rough calling depth estimates (<35 m, ~35 m, >35 m) and more accurate point depth estimates (±5–10 m in most cases) were obtained. Significantly more calls were produced at depths ≤35 m for both species. The point depth estimates indicated that the calls occurred most frequently at depths >10 m; 60% of harp seal calls and 71% of Weddell seal calls occurred at depths between 10 and 35 m. The seals called predominately within areas of the water column where light would likely penetrate, but still avoided sea-ice interference to some extent. The vocalizations did not change over depth with respect to call type, the number of elements within a call, or total call duration, or with respect to season and light condition for Weddell seals. Frequency (kHz) of calls also did not change with depth, suggesting that harp and Weddell seals control the pitch of their vocalizations with the vocal cords of the larynx.

scholarly journals Arenavirus infection correlates with lower survival of its natural rodent host in a long-term capture-mark-recapture study

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Joachim Mariën ◽  
Vincent Sluydts ◽  
Benny Borremans ◽  
Sophie Gryseels ◽  
Bram Vanden Broecke ◽  
...  
Keyword(s):  
Rodent Host ◽  
Mark Recapture ◽  
Lower Survival

Establishing A Mark-Recapture Program For Dugongs In Moreton Bay, South-East Queensland

2002 ◽  
Vol 24 (1) ◽  
pp. 51 ◽  
Author(s):  
JM Lanyon ◽  
HL Sneath ◽  
JM Kirkwood ◽  
RW Slade
Keyword(s):  
Mating Strategies ◽  
Clear Water ◽  
Urban Centre ◽  
Mark Recapture ◽  
Moreton Bay ◽  
Yield Information ◽  
Faecal Samples ◽  
Capture Method ◽  
And Gender

This paper reports the commencement of the first mark-recapture program for a dugong (Dugong dugon) population. Moreton Bay, south-east Queensland supported a D. dugon population of more than 800 individuals in 1996 and is close to an urban centre, Brisbane. Several features of this population make a mark-recapture program feasible: a large resident population concentrated over a small and predictable area, a relatively clear water habitat, animals regularly exposed to boating traffic, and an efficient capture method. Fifty-four D. dugon were captured using the ?rodeo? method and tagged. Tags applied included a long-term dorsal PIT tag, a titanium turtle tag, fluke notch and temporary paint stick mark. For each D. dugon, body length, anal girth and gender were recorded. D. dugon were biopsied for genetic (microsatellite) analysis. Faecal samples were obtained for reproductive hormone assays. This program has the potential to yield information on trends in population size and distribution, population dynamics, mating strategies, social structure and general health of the population. This is the first season of a long-term project.

scholarly journals Long-term monitoring of margays (Leopardus wiedii): Implications for understanding low detection rates

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247536
Author(s):  
Bart J. Harmsen ◽  
Nicola Saville ◽  
Rebecca J. Foster
Keyword(s):  
Detection Rate ◽  
Camera Trap ◽  
Wide Distribution ◽  
Camera Traps ◽  
Detection Rates ◽  
Terrestrial Mammals ◽  
Exclusive Territories ◽  
Carnivore Species ◽  
Density Population

Population assessments of wide-ranging, cryptic, terrestrial mammals rely on camera trap surveys. While camera trapping is a powerful method of detecting presence, it is difficult distinguishing rarity from low detection rate. The margay (Leopardus wiedii) is an example of a species considered rare based on its low detection rates across its range. Although margays have a wide distribution, detection rates with camera traps are universally low; consequently, the species is listed as Near Threatened. Our 12-year camera trap study of margays in protected broadleaf forest in Belize suggests that while margays have low detection rate, they do not seem to be rare, rather that they are difficult to detect with camera traps. We detected a maximum of 187 individuals, all with few or no recaptures over the years (mean = 2.0 captures/individual ± SD 2.1), with two-thirds of individuals detected only once. The few individuals that were recaptured across years exhibited long tenures up to 9 years and were at least 10 years old at their final detection. We detected multiple individuals of both sexes at the same locations during the same survey, suggesting overlapping ranges with non-exclusive territories, providing further evidence of a high-density population. By studying the sparse annual datasets across multiple years, we found evidence of an abundant margay population in the forest of the Cockscomb Basin, which might have been deemed low density and rare, if studied in the short term. We encourage more long-term camera trap studies to assess population status of semi-arboreal carnivore species that have hitherto been considered rare based on low detection rates.

scholarly journals Assessing Summer Pond and Lake Inlet Use by Gray Treefrogs (Hyla versicolor/chrysoscelis complex) Using PVC Pipe Traps in Northwest Missouri

2020 ◽  
Vol 48 (2020) ◽  
pp. 17-21
Author(s):  
J. D. McGhee
Keyword(s):  
Sex Ratio ◽  
Hyla Versicolor ◽  
Monitoring Methods ◽  
Contingency Table Analysis ◽  
Detection Rates ◽  
Sampling Locations ◽  
Table Analysis ◽  
Pvc Pipe ◽  
Gray Treefrog

Abstract The widespread decline in amphibian populations highlights the need for establishing rigorous monitoring methods for long-term population studies. In an attempt to launch a long-term monitoring study for a Gray Treefrog complex (Hyla versicolor LeConte /chrysoscelis Cope, hereafter treefrog) population in northwest Missouri, I tested the use of PVC pipe traps in a system of ponds and inlets along a lakeside habitat for three years. For each pond (3) and inlet (2), I established an array of 16 pipes so as to compare differences in use between pipe location, ponds and inlets, and sex ratio between sites. Pipes were checked twice a week during the summer for the presence of treefrogs. Treefrog usage of pipes between ponds and inlets were compared using a contingency table analysis, while an ANOVA was used to assess differences in sex ratios between sites (α = 0.05). A single inlet was used by treefrogs more heavily than the other ponds or inlet (G = 13.61, df = 3, P = 0.0035), however, I found no differences in terms of pipe location within a pond or inlet. Mean sex ratio between water bodies varied but did not significantly differ. There appears to be little effect in terms of pipe placement within our 50 m buffer from the water's edge, but unique habitat effects at sampling locations may significantly affect detection rates or usage.

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