scholarly journals Heart rates and abdominal temperatures of free-ranging South Georgian shags, Phalacrocorax georgianus

1997 ◽  
Vol 200 (4) ◽  
pp. 661-675 ◽  
Author(s):  
R M Bevan ◽  
I L Boyd ◽  
P J Butler ◽  
K Reid ◽  
A J Woakes ◽  
...  

The South Georgian shag (Phalacrocorax georgianus) shows a remarkable diving ability comparable to that of penguins, yet nothing is known of the physiology of these birds. In this study, heart rates and abdominal temperatures were recorded continuously in four free-ranging South Georgian shags using an implanted data-logger. A time­depth recorder was also attached to the back of the implanted birds to record their diving behaviour. The diving behaviour of the birds was essentially similar to that reported in other studies, with maximum dive durations for individual birds ranging between 140 and 287 s, and maximum depths between 35 and 101 m. The birds, while at the nest, had a heart rate of 104.0±13.1 beats min-1 (mean ± s.e.m.) and an abdominal temperature of 39.1±0.2 °C. During flights of 221±29 s, heart rate and abdominal temperature rose to 309.5±18.0 beats min-1 and 40.1±0.3 °C, respectively. The mean heart rate during diving, at 103.7±13.7 beats min-1, was not significantly different from the resting values, but the minimum heart rate during a dive was significantly lower at 64.8±5.8 beats min-1. The minimum heart rate during a dive was negatively correlated with both dive duration and dive depth. Abdominal temperature fell progressively during a diving bout, with a mean temperature at the end of a bout of 35.1±1.7 °C. The minimum heart rate during diving is at a sub-resting level, which suggests that the South Georgian shag responds to submersion with the 'classic' dive response of bradycardia and the associated peripheral vasoconstriction and utilisation of anaerobic metabolism. However, the reduction in abdominal temperature may reflect a reduction in the overall metabolic rate of the animal such that the bird can remain aerobic while submerged.

1999 ◽  
Vol 202 (9) ◽  
pp. 1115-1125 ◽  
Author(s):  
A.L. Southwood ◽  
R.D. Andrews ◽  
M.E. Lutcavage ◽  
F.V. Paladino ◽  
N.H. West ◽  
...  

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.


1997 ◽  
Vol 200 (15) ◽  
pp. 2083-2095 ◽  
Author(s):  
R D Andrews ◽  
D R Jones ◽  
J D Williams ◽  
P H Thorson ◽  
G W Oliver ◽  
...  

Heart rates of northern elephant seals diving at sea and during apnoea on land were monitored to test whether a cardiac response to submergence is an important factor in their ability to make repetitive, long-duration dives. Seven juvenile northern elephant seals were captured at Año Nuevo, CA, instrumented and translocated to release sites around Monterey Bay. Heart rate and dive depth were recorded using custom-designed data loggers and analogue tape monitors during the seals' return to Año Nuevo. Heart rates during apnoea and eupnoea were recorded from four of the seals after they hauled out on the beach. Diving patterns were very similar to those of naturally migrating juveniles. The heart rate response to apnoea at sea and on land was a prompt bradycardia, but only at sea was there an anticipatory tachycardia before breathing commenced. Heart rate at sea declined by 64% from the surface rate of 107 +/- 3 beats min-1 (mean +/- S.D.), while heart rate on land declined by 31% from the eupnoeic rate of 65 +/- 8 beats min-1. Diving heart rate was inversely related to dive duration in a non-linear fashion best described by a continuous, curvilinear model, while heart rate during apnoea on land was independent of the duration of apnoea. Occasionally, instantaneous heart rate fell as low as 3 beats min-1 during diving. Although bradycardia occurs in response to apnoea both at sea and on land, only at sea is heart rate apparently regulated to minimise eupnoeic time and to ration oxygen stores to ensure adequate supplies for the heart and brain not only as the dive progresses normally but also when a dive is abnormally extended.


2004 ◽  
Vol 82 (7) ◽  
pp. 1147-1156 ◽  
Author(s):  
J L Hicks ◽  
R J O'Hara Hines ◽  
J F Schreer ◽  
M O Hammill

Harbour seal (Phoca vitulina L., 1758) pups are aquatically active from birth and have been shown to develop increased cardiac control throughout the nursing period. In an attempt to quantify and compare these developmental changes, data previously collected on pups in the St. Lawrence River estuary, Quebec, Canada, were analyzed. Time–depth recorders and heart-rate recorders were employed on eight pups to obtain depth and heart-rate measurements simultaneously. Analyses involved partitioning the data into intervals of surface–dive–surface. These intervals were then allocated into nine consecutive segments: presurface, predive surface, descent, prebottom, bottom, postbottom, ascent, postdive surface, and postsurface. Mean heart rate for each segment was then correlated with the mean depth per segment and overall dive duration. With increasing dive depth, a decrease in heart-rate variability with age was observed. There was no apparent relationship between mean heart rate during the dive and overall dive duration. The proportion of time spent in the lower heart-rate mode was observed to increase with age during most phases of a dive. Relative changes in mean heart rate between consecutive dive segments indicated an initial decrease in mean heart rate prior to submersion and an increasing trend before surfacing. These findings indicate that harbour seal pups develop increased cardiac control prior to weaning and that anticipatory cardiac responses to diving and surfacing (bradycardia and tachycardia, respectively) may be evident.


2011 ◽  
Vol 89 (12) ◽  
pp. 1195-1205 ◽  
Author(s):  
Amélie A. Augé ◽  
B. Louise Chilvers ◽  
Lloyd S. Davis ◽  
Antoni B. Moore

Female New Zealand sea lions ( Phocarctos hookeri (Gray, 1844)) at the Auckland Islands (remnant populations) are the deepest and longest diving otariids. These remnant populations are found at the margin of the historical range of the species. We hypothesized that diving behaviours of animals in the core of their historical range is less extreme owing to a better marine habitat. All female New Zealand sea lions (n = 13, aged 2–14 years) born on the Otago Peninsula (initial recolonising population) were equipped with time–depth recorders during April and May 2008, 2009, and 2010. The mean dive depth was 20.2 ± 24.5 m and mean dive duration was 1.8 ± 1.1 min, some of the lowest values reported for otariids. Otago female New Zealand sea lions did not exhibit two distinct diving specialisations as reported at the Auckland Islands. Otago adult females exceeded calculated aerobic dive limits in 7.1% of dives compared with 68.7% at the Auckland Islands. The contrasting differences in diving behaviour between Otago and the Auckland Islands suggest that Otago represents a better marine habitat for New Zealand sea lions, with food easily accessible to animals of all ages.


1988 ◽  
Vol 66 (2) ◽  
pp. 446-458 ◽  
Author(s):  
Burney J. Le Boeuf ◽  
Daniel P. Costa ◽  
Anthony C. Huntley ◽  
Steven D. Feldkamp

The free-ranging dive pattern of seven adult female northern elephant seals (Mirounga angustirostris) was obtained with time–depth recorders during the first 14 – 27 days at sea following lactation. The instruments were recovered and mass gain at sea determined when the animals returned to the rookery at Año Nuevo, California, to molt. The seals gained a mean of 76.5 ± 13.9 kg during a mean of 72.6 ± 5.0 days at sea. The mean dive rate was 2.7 ± 0.2 dives/h and diving was virtually continuous during the entire period at sea. Mean dive duration was 19.2 ± 4.3 min with the longest submersion lasting 48 min. Mean surface interval between dives was 2.8 ± 0.5 min, so that only 14.4% of the recorded time at sea was spent on the surface. Surface intervals did not vary with the duration of preceding or succeeding dives. Modal dive depth for each female was between 350 and 650 m. The maximum dive depth was estimated at 894 m, a depth record for pinnipeds. The deep, nearly continuous dive pattern of female northern elephant seals differs from the dive pattern of other pinnipeds and appears to serve in foraging, energy conservation, and predator avoidance.


1998 ◽  
Vol 66 (2) ◽  
pp. 383-387 ◽  
Author(s):  
M. Khalid ◽  
W. Haresign ◽  
D. G. Bradley

AbstractThis study consisted of two experiments. In experiment 1, stress responses of sheep which were restrained either in a laparoscopy cradle or a roll-over cradle were compared. The results of this experiment indicated that restraint in roll-over cradle is less (P < 0·05) stressful than that in a laparoscopy cradle when assessed in terms of the elevation and duration of both the mean heart rate and plasma cortisol responses. Experiment 2 compared the stress responses of sheep subjected to restraint in a laparoscopy cradle, restraint in a laparoscopy cradle with intrauterine artificial insemination (AI) by laparoscopy, minimal restraint with cervical AI or restraint in a roll-over cradle plus foot-trimming. All treatments resulted in significant elevations in both heart rate and plasma cortisol concentrations (F < 0·001). The peak heart rate was significantly (P < 0·05) higher in ewes subjected to cervical AI than in those subjected to intrauterine insemination, with other treatments intermediate. The peak cortisol response did not differ among different treatments. The duration over which both the mean heart rate and -plasma cortisol concentrations remained significantly elevated above pre-treatment concentrations did not differ among treatment groups. The results of this study suggest that while restraint using a laparoscopy cradle is more stressful than that using a rollover cradle, the stress inflicted by intrauterine insemination by laparoscopy itself is no greater than that due to restraint using the laparoscopy cradle alone, cervical AI or the management practice offoot-trimming using a rollover cradle.


1994 ◽  
Vol 267 (5) ◽  
pp. E642-E647
Author(s):  
G. B. Pidgeon ◽  
A. M. Richards ◽  
M. G. Nicholls ◽  
R. R. Bailey ◽  
K. L. Lynn ◽  
...  

To assess the effects of ouabain on pressor and vasoactive hormone responsiveness, 10 healthy volunteers were pretreated with ouabain (0.5 mg i.v. 42 and 18 h before study) or placebo before pressor challenge with angiotensin II (ANG II; 2, 4, and 8 ng.kg-1.min-1 for 30 min/dose) and norepinephrine (NE; 5, 15, and 45 ng.kg-1.min-1 for 15 min/dose). There were no differences at baseline between the two study days regarding mean arterial pressure (MAP) or heart rate. Baseline pulse pressure, however, was significantly greater after ouabain (47 +/- 3 vs. 41 +/- 1 mmHg; P < 0.05). The mean maximum increments in MAP during ANG II and NE infusions were 17.5 +/- 1.1 and 10.5 +/- 1.3 (SE) mmHg, respectively, after ouabain and 19.2 +/- 1.3 and 10.4 +/- 1.5 mmHg after placebo (not significant). The mean heart rate was lower during both infusion periods on the ouabain study day compared with control (P < 0.05). Baseline plasma levels of ANG II, aldosterone, plasma renin activity, atrial and brain natriuretic peptide, guanosine 3',5'-cyclic monophosphate, NE, and epinephrine and achieved levels during the two infusions were similar on the two study days. We conclude that short-term ouabain administration does not alter pressor responsiveness or plasma levels of vasoactive hormones in healthy volunteers.


1998 ◽  
Vol 85 (5) ◽  
pp. 1974-1981 ◽  
Author(s):  
R. D. Andrews

Few commercial products are available for investigators who wish to monitor multiple physiological and behavioral variables in unrestrained subjects. When telemetry is not practical, e.g., in studies of at-sea diving physiology, one of the only options is to design and build a custom data-logging instrument. This paper describes how a data logger was developed for the successful long-term monitoring of dive depth, swim speed, heart rate, water temperature, and multiple body temperatures from free-ranging northern elephant seals. The task was facilitated by using a commercially available single-board computer designed specifically for portable multichannel data acquisition and, where possible, off-the-shelf sensors/transducers available with integrated signal-conditioning circuits. A smaller data logger for monitoring the electrocardiogram, body temperature, and dive behavior of double-crested cormorants is also described to illustrate the flexibility and simplicity of this approach. Although it is customized for diving animals, with incorporation of the appropriate sensors the basic design should be applicable to studies of comparative, environmental, or exercise physiology involving most medium-to-large animals, including humans.


Author(s):  
G.F. Stegmann

Anaesthesia of 2 five-year-old femaleAfrican elephants (Loxodonta africana) was required for dental surgery. The animals were each premedicated with 120 mg of azaperone 60 min before transportation to the hospital. Before offloading, 1 mg etorphine was administered intramuscularly (i.m.) to each elephant to facilitate walking them to the equine induction / recovery room. For induction, 2 mg etorphine was administered i.m. to each animal. Induction was complete within 6 min. Surgical anaesthesia was induced with halothane-in-oxygen after intubation of the trunk. During surgery the mean heart rate was 61 and 45 beats / min respectively. Systolic blood pressures increased to 27.5 and 25.6 kPa respectively, and were treated with intravenous azaperone. Blood pressure decreased thereafter to a mean systolic pressure of 18.1 and 19.8 kPa, respectively. Rectal temperature was 35.6 and 33.9 oC at the onset of surgery, and decreased to 35.3 and 33.5 oC, respectively, at the end of anaesthesia. Etorphine anaesthesia was reversed with 5mg diprenorphine at the completion of 90 min of surgery.


1995 ◽  
Vol 52 (5) ◽  
pp. 1064-1073 ◽  
Author(s):  
Andrew J. Westgate ◽  
Andrew J. Head ◽  
Per Berggren ◽  
Heather N. Koopman ◽  
David E. Gaskin

The diving behaviour of seven free-ranging harbour porpoises (Phocoena phocoena) was examined using time–depth recorders. In total, 8167 individual dives were recorded over 254 h. The longest period of data collection from an individual was 106.1 h. Mean dive depths and durations ranged from 14 ± 16 to 41 ± 32 m, and from 44 ± 37 to 103 ± 67 s, respectively. The maximum recorded dive depth and duration was 226 m and 321 s. This performance may not represent the maximum capacity of harbour porpoises but rather the maximum depth of the study area. Individual dives had similar rates of descent and ascent, which ranged from 1.1 ± 0.6 to 2.3 ± 1.4 m/s, and from 0.9 ± 0.6 to 2.1 ± 1.4 m/s, respectively. Two porpoises with monitoring periods >2 days demonstrated a diel pattern in their diving, making fewer, but deeper dives at night. Comparison of the diving behaviour of harbour porpoises with data on the depth of 140 porpoises entanglements in groundfish gill nets in the Bay of Fundy showed these seven porpoises made between 22 and 70% of dives to depths (range 20–130 m) where the majority of entanglements were reported.


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