Physiological effects on dive patterns and foraging strategies in yearling Weddell seals (Leptonychotes weddellii)

1997 ◽  
Vol 75 (11) ◽  
pp. 1796-1810 ◽  
Author(s):  
Jennifer M. Burns ◽  
Michael A. Castellini ◽  
Jason F. Schreer
Keyword(s):  
Stepwise Regression ◽  
Dive Depth ◽  
Foraging Strategies ◽  
Diving Behavior ◽  
Physiological Effects ◽  
Morphometric Measurements ◽  
Leptonychotes Weddellii ◽  
Weddell Seals ◽  
The Mean ◽  
The Relationship

Fifteen yearling Weddell seals (Leptonychotes weddellii) were captured, measured, weighed, bled, equipped with time–depth recorders, and released to determine if diving behavior was related to physical condition. Upon recovery of the time–depth recorders, dives were classified into four types based on shape, using cluster analysis. Based on maximum depth, two groups were further subdivided, for a total of seven types. The mean and maximal dive depth, duration, and frequency were determined for each yearling for all dive types combined and for each type separately. Stepwise regression and ANOVA techniques were used to test the relationship between diving behavior and physiological and morphometric measurements. In general, half of the variation in the pooled diving behavior could be explained by body-size differences. Larger yearlings made longer and shallower dives than smaller yearlings. Dive patterns suggested that large yearlings foraged primarily on small shallow-water prey items, while small yearlings concentrated on energy-dense deep-water prey. However, the interpretation of diving behavior, foraging locations, and diet that resulted from separating individuals and dive types was very different from that based on average diving behavior. This argues against ignoring variation among individuals and using only average diving behavior when describing marine mammal dive patterns.

Foraging energetics and diving behavior of lactating New Zealand sea lions, Phocarctos hookeri

2000 ◽  
Vol 203 (23) ◽  
pp. 3655-3665 ◽  
Author(s):  
D.P. Costa ◽  
N.J. Gales
Keyword(s):  
New Zealand ◽  
Metabolic Rate ◽  
Dive Depth ◽  
Diving Behavior ◽  
Metabolic Rates ◽  
Sea Lion ◽  
Water Turnover ◽  
Sea Lions ◽  
The Mean ◽  
Phocarctos Hookeri

The New Zealand sea lion, Phocarctos hookeri, is the deepest- and longest-diving sea lion. We were interested in whether the diving ability of this animal was related to changes in its at-sea and diving metabolic rates. We measured the metabolic rate, water turnover and diving behavior of 12 lactating New Zealand sea lions at Sandy Bay, Enderby Island, Auckland Islands Group, New Zealand (50 degrees 30′S, 166 degrees 17′E), during January and February 1997 when their pups were between 1 and 2 months old. Metabolic rate (rate of CO(2) production) and water turnover were measured using the (18)O doubly-labeled water technique, and diving behavior was measured with time/depth recorders (TDRs). Mean total body water was 66.0+/−1.1 % (mean +/− s.d.) and mean rate of CO(2) production was 0. 835+/−0.114 ml g(−)(1)h(−)(1), which provides an estimated mass-specific field metabolic rate (FMR) of 5.47+/−0.75 W kg(−)(1). After correction for time on shore, the at-sea FMR was estimated to be 6.65+/−1.09 W kg(−)(1), a value 5.8 times the predicted standard metabolic rate of a terrestrial animal of equal size. The mean maximum dive depth was 353+/−164 m, with a mean diving depth of 124+/−36 m. The mean maximum dive duration was 8.3+/−1.7 min, with an average duration of 3.4+/−0.6 min. The deepest, 550 m, and longest, 11.5 min, dives were made by the largest animal (155 kg). Our results indicate that the deep and long-duration diving ability of New Zealand sea lions is not due to a decreased diving metabolic rate. Individual sea lions that performed deeper dives had lower FMRs, which may result from the use of energetically efficient burst-and-glide locomotion. There are differences in the foraging patterns of deep and shallow divers that may reflect differences in surface swimming, time spent on the surface and/or diet. Our data indicate that, although New Zealand sea lions have increased their O(2) storage capacity, they do not, or cannot, significantly reduce their at-sea metabolic rates and are therefore likely to be operating near their physiological maximum.

The development of diving behavior in juvenile Weddell seals: pushing physiological limits in order to survive

1999 ◽  
Vol 77 (5) ◽  
pp. 737-747 ◽  
Author(s):  
Jennifer M Burns
Keyword(s):  
Blood Chemistry ◽  
Weddell Seal ◽  
Dive Duration ◽  
Foraging Strategies ◽  
Foraging Efficiency ◽  
Diving Behavior ◽  
Weddell Seals ◽  
Physiological Limits ◽  
Behavioral Constraints ◽  
Absolute Energy

In juvenile phocids, the successful transition from nursing to independent foraging is contingent upon the development of adequate diving skills within the limited time between weaning and the depletion of body reserves. Yet, because juvenile seals are unable to remain submerged for as long as adults, owing to their smaller size, higher metabolic rates, and lowered oxygen stores, their behavioral options are likely constrained. To determine how such limitations might influence foraging strategies, we studied the development of diving behavior and physiology in Weddell seal (Leptonychotes weddellii) juveniles, using a combination of time-depth recorders, satellite-linked dive recorders, and morphological and physiological measurements (mass and blood chemistry). Time-depth recorder data indicated that the average depth, duration, and frequency of dives made by pups increased rapidly in the period from birth through weaning, but slowed soon thereafter. While preweaning increases in these parameters were correlated with seal age, postweaning increases in dive capacity were gradual and were probably the result of slower changes in mass and body composition. In weaned pups and yearlings, dive frequency and time underwater increased with age and (or) mass. Despite their smaller size and lower absolute energy requirements, the amount of time juveniles spent in the water was similar to that spent by adults. However, because juveniles were unable to remain submerged as long as adults and because most foraging dives were deep, juveniles were unable to spend an equivalent amount of time at the foraging depths. This difference was evident even though juveniles dove much closer to their anaerobic threshold than did adults. These findings support the hypothesis that the foraging efficiency of younger seals is reduced relative to that of adults, owing to physiological and morphological constraints on aerobic dive duration, and suggests that low juvenile survival might result from behavioral constraints.

Over-winter movements and diving behavior of female Weddell seals (Leptonychotes weddellii) in the southwestern Ross Sea, Antarctica

1994 ◽  
Vol 72 (10) ◽  
pp. 1700-1710 ◽  
Author(s):  
J. Ward Testa
Keyword(s):  
Ross Sea ◽  
Diving Behavior ◽  
Winter Period ◽  
Pleuragramma Antarcticum ◽  
Long Distance ◽  
Leptonychotes Weddellii ◽  
Mcmurdo Sound ◽  
Weddell Seals ◽  
Pack Ice ◽  
Fast Ice

The movements and diving behavior of 18 adult female Weddell seals (Leptonychotes weddellii) were determined by satellite telemetry during the over-winter period in 1990 and 1991. Nine seals provided diving and movement data for 8 – 9 months. Seals that normally bred in the eastern part of McMurdo Sound spent most of the winter in the middle and northern parts of McMurdo Sound before the annual shore-fast ice had formed in those areas, or in the pack ice 0–50 km north of the sound and Ross Island. This is a greater use of pack ice, as opposed to shore-fast ice, in winter than was previously believed. Some long-distance movements (one over 1500 km in total) to the middle and northwestern parts of the Ross Sea also occurred. Although highly variable within and between individuals, dives indicative of foraging were primarily to mid-water regions (100 – 350 m) in both years, and were similar to those that have been observed in spring and summer, when Pleuragramma antarcticum is the primary prey of Weddell seals in McMurdo Sound.

Use of Emetics and Anesthesia for Dietary Assessment of Weddell Seals

1988 ◽  
Vol 15 (4) ◽  
pp. 423 ◽  
Author(s):  
NJ Gales ◽  
NJ Gales ◽  
HR Burton ◽  
HR Burton
Keyword(s):  
Body Weight ◽  
Standard Length ◽  
Induction Time ◽  
Dietary Assessment ◽  
Post Mortem ◽  
Weddell Seals ◽  
Induction Dose ◽  
Ketamine Hydrochloride ◽  
The Mean ◽  
The Relationship

One female and 19 male Weddell seals, Leptonychotes weddellii, were injected with the emetic apomorphine hydrochloride. Fourteen of these were immobilised with combinations of ketamine hydrochloride and diazepam before the emetic was injected. One seal was administered the emetic tincture of ipecac while immobilised. The mean induction dose of ketamine hydrochloride was 7.99 � 1.99 mg kg-1 (mean�SD) and that of diazepam was 0.05 � 0.01 mg kg-1. The mean induction time was 23.07 � 17.63 min and the mean duration of immobilisation was 127.00 � 20.72 min. Six of the 22 seals apomorphine hydrochloride vomited and the seal given tincture of ipecac did not vomit. The mean dose of apomorphine hydrochloride that produced vomiting in immobilised animals was 0.18 � 0.10 mg kg-1 and the mean dose of apomorphine hydrochloride that produced vomiting in non-immobilised animals was 0.22 � 0.15 mg kg-1. Three seals died after drug administration during the study. Post-mortem examinations were conducted on these animals and nothing abnormal was found. Seals were weighed on 15 occasions (weight range, 137-402 kg) and the relationship between standard length (L, in centimetres) and body weight (W, in kilograms) was found to be: W=3.66L- 489.30. Food comprising five species of fish, two cephalopods and one gastropod were identified. Nematodes and gastroliths were present in most vomit samples. Centrally acting emetics and dissociative anaesthesia were both found to have limitations for use in Weddell seals.

Heart rates and diving behavior of leatherback sea turtles in the eastern pacific ocean

1999 ◽  
Vol 202 (9) ◽  
pp. 1115-1125 ◽  
Author(s):  
A.L. Southwood ◽  
R.D. Andrews ◽  
M.E. Lutcavage ◽  
F.V. Paladino ◽  
N.H. West ◽  
...  
Keyword(s):  
Heart Rate ◽  
Sea Turtles ◽  
Dive Depth ◽  
Dive Duration ◽  
Diving Behavior ◽  
Leatherback Turtles ◽  
Heart Rates ◽  
The Mean ◽  
Leatherback Sea Turtles ◽  
Mean Heart Rate

Heart rates and diving behavior of leatherback sea turtles (Dermochelys coriacea) were monitored at sea during the internesting interval. Instruments that recorded the electrocardiogram and the depth and duration of dives were deployed on six female leatherback turtles as they laid eggs at Playa Grande, Costa Rica. Turtles dived continually for the majority of the internesting interval and spent 57–68 % of the time at sea submerged. Mean dive depth was 19+/−1 m (mean +/− s.d.) and the mean dive duration was 7.4+/−0.6 min. Heart rate declined immediately upon submergence and continued to fall during descent. All turtles showed an increase in heart rate before surfacing. The mean heart rate during dives of 17.4+/−0.9 beats min-1 (mean +/− s.d.) was significantly lower than the mean heart rate at the surface of 24.9+/−1.3 beats min-1 (P<0.05). Instantaneous heart rates as low as 1.05 beats min-1 were recorded during a 34 min dive. The mean heart rate over the entire dive cycle (dive + succeeding surface interval; 19.4+/−1.3 beats min-1) was more similar to the heart rate during diving than to the heart rate at the surface. Although dive and surface heart rates were significantly different from each other, heart rates during diving were 70 % of heart rates at the surface, showing that leatherback turtles do not experience a dramatic bradycardia during routine diving.

Multi-Center Calibration of the Second Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149R

1991 ◽  
Vol 65 (03) ◽  
pp. 263-267 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Reference Material ◽  
Standard Error ◽  
Standard Errors ◽  
Sensitivity Index ◽  
Long Term Stability ◽  
Significant Bias ◽  
The Mean ◽  
The Relationship ◽  
International Sensitivity Index

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.

Evaluation of the Efficacy of ST2 and NT-proBNP in the Diagnosis and Prediction of Short- Term Prognosis in Heart Failure with Reduced Ejection Fraction

2017 ◽  
Vol 9 (04) ◽  
Author(s):  
Shivananda B Nayak ◽  
Dharindra Sawh ◽  
Brandon Scott ◽  
Vestra Sears ◽  
Kareshma Seebalack ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ejection Fraction ◽  
Cardiac Biomarkers ◽  
Double Blind Study ◽  
Short Term ◽  
Double Blind ◽  
Reduced Ejection Fraction ◽  
The Mean ◽  
Design And Methods ◽  
The Relationship

Purpose: i) To determine the relationship between the cardiac biomarkers ST2 and NT-proBNP with ejection fraction (EF) in heart failure (HF) patients. ii) Assess whether a superiority existed between the aforementioned cardiac markers in diagnosing the HF with reduced EF. iii) Determine the efficacy of both biomarkers in predicting a 30-day cardiovascular event and rehospitalization in patients with HF with reduced EF iv) To assess the influence of age, gender, BMI, anaemia and renal failure on the ST2 and NT-proBNP levels. Design and Methods: A prospective double-blind study was conducted to obtain data from a sample of 64 cardiology patients. A blood sample was collected to test for ST2 and NT-proBNP. An echocardiogram (to obtain EF value), electrocardiogram and questionnaire were also obtained. Results: Of the 64 patients enrolled, 59.4% of the population had an EF less than 40%. At the end of the 30- day period, 7 patients were warded, 37 were not warded, one died and 17 were non respondent. Both biomarkers were efficacious at diagnosing HF with a reduced EF. However, neither of them were efficacious in predicting 30-day rehospitalization. The mean NT-proBNP values being: not rehospitalized (2114.7486) and 30 day rehospitalization (1008.42860) and the mean ST2 values being: not rehospitalized (336.1975), and 30-day rehospitalization. (281.9657). Conclusion: Neither ST2 or NT-proBNP was efficacious in predicting the short- term prognosis in HF with reduced EF. Both however were successful at confirming the diagnosis of HF in HF patients with reduced EF.

scholarly journals Correlation between fundus autofluorescence and visual function in patients with cone-rod dystrophy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Satoru Kanda ◽  
Takumi Hara ◽  
Ryosuke Fujino ◽  
Keiko Azuma ◽  
Hirotsugu Soga ◽  
...  
Keyword(s):  
Visual Field ◽  
Significant Relationship ◽  
Fundus Autofluorescence ◽  
Univariate Analysis ◽  
Retrospective Chart Review ◽  
Mean Deviation ◽  
Wide Field ◽  
The Mean ◽  
The Relationship ◽  
Field Imaging

AbstractThis study aimed to investigate the relationship between autofluorescence (AF) signal measured with ultra-wide field imaging and visual functions in patients with cone-rod dystrophy (CORD). A retrospective chart review was performed for CORD patients. We performed the visual field test and fundus autofluorescence (FAF) measurement and visualized retinal structures with optical coherence tomography (OCT) on the same day. Using binarised FAF images, we identified a low FAF area ratio (LFAR: low FAF/30°). Relationships between age and logMAR visual acuity (VA), central retinal thickness (CRT), central choroidal thickness (CCT), mean deviation (MD) value, and LFAR were investigated. Thirty-seven eyes of 21 CORD patients (8 men and 13 women) were enrolled. The mean patient age was 49.8 years. LogMAR VA and MD were 0.52 ± 0.47 and − 17.91 ± 10.59 dB, respectively. There was a significant relationship between logMAR VA and MD (p = 0.001). LogMAR VA significantly correlated with CRT (p = 0.006) but not with other parameters. Conversely, univariate analysis suggested a significant relationship between MD and LFAR (p = 0.001). In the multivariate analysis, LFAR was significantly associated with MD (p = 0.002). In conclusion, it is useful to measure the low FAF area in patients with CORD. The AF measurement reflects the visual field deterioration but not VA in CORD.

scholarly journals An exploration of the relationship between recruitment communication and foraging in stingless bees

2021 ◽  
Author(s):  
Robbie I’Anson Price ◽  
Francisca Segers ◽  
Amelia Berger ◽  
Fabio S Nascimento ◽  
Christoph Grüter
Keyword(s):  
Stingless Bees ◽  
Sugar Content ◽  
Social Information ◽  
Food Resources ◽  
Food Sources ◽  
Foraging Strategies ◽  
High Quality ◽  
Recruitment Communication ◽  
Eusocial Bees ◽  
The Relationship

Abstract Social information is widely used in the animal kingdom and can be highly adaptive. In social insects, foragers can use social information to find food, avoid danger or choose a new nest site. Copying others allows individuals to obtain information without having to sample the environment. When foragers communicate information they will often only advertise high quality food sources, thereby filtering out less adaptive information. Stingless bees, a large pantropical group of highly eusocial bees, face intense inter- and intra-specific competition for limited resources, yet display disparate foraging strategies. Within the same environment there are species that communicate the location of food resources to nest-mates and species that do not. Our current understanding of why some species communicate foraging sites while others do not is limited. Studying freely foraging colonies of several co-existing stingless bee species in Brazil, we investigated if recruitment to specific food locations is linked to (1) the sugar content of forage, (2) the duration of foraging trips and (3) the variation in activity of a colony from one day to another and the variation in activity in a species over a day. We found that, contrary to our expectations, species with recruitment communication did not return with higher quality forage than species that do not recruit nestmates. Furthermore, foragers from recruiting species did not have shorter foraging trip durations than those from weakly-recruiting species. Given the intense inter- and intraspecific competition for resources in these environments, it may be that recruiting species favour food resources that can be monopolised by the colony rather than food sources that offer high-quality rewards.

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