scholarly journals Distance Estimation in Reproduction Tasks in a Harbor Seal (Phoca vitulina)

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 938
Author(s):  
Eric Maaß ◽  
Frederike D. Hanke
Keyword(s):  
Visual Information ◽  
Path Integration ◽  
Visual Cues ◽  
Distance Estimation ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Experimental Paradigm ◽  
Feeding Grounds ◽  
Specific Distance

Harbor seals commute between haul-out places and feeding grounds close to the shore or in the open ocean, which is considered a low structured environment, at first sight not providing many cues for orientation/navigation. Nevertheless, seals are well-oriented. For returning to a specific location, seals may use both external and internal cues to, for example, perform path integration requiring the integration of distances traveled and angles steered. We herein assessed the seal’s ability to estimate distances, previously swum or unknown, in reproduction tasks. Reproduction tasks refer to an experimental paradigm in which the experimental animal is required to swim a specific distance first and subsequently reproduce this distance, with visual cues present or absent. The seal was able to estimate and then reproduce distances (0.5–18.5 m) with the smallest error below 10% of the actual distance, and its precision was higher with distances repeatedly swum compared to its performance with unfamiliar distances. In the absence of visual cues, the seal’s performance slightly dropped; however, it was still able to perform the task with an error of 21%. In conclusion, distance estimation may help seals to navigate precisely towards their goals, even if, for example, visual information is not available.

Hormonal changes and enforced diving in the harbor seal Phoca vitulina. II. Plasma catecholamines

1982 ◽  
Vol 242 (5) ◽  
pp. R528-R532 ◽  
Author(s):  
A. J. Hance ◽  
E. D. Robin ◽  
J. B. Halter ◽  
N. Lewiston ◽  
D. A. Robin ◽  
...  
Keyword(s):  
Recovery Period ◽  
Control Period ◽  
Plasma Catecholamines ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Hormonal Changes ◽  
Inotropic Effects ◽  
Arterial Constriction

Plasma epinephrine and norepinephrine concentrations were measured in five harbor seals, Phoca vitulina, during a control period, during a 6-min dive, and during a 30-min postdiving recovery period. Measurements were performed with and without prior glucose administration. Control epinephrine concentrations [189 +/- 118 (SD) pg/ml] and norepinephrine concentrations (340 +/- 191 pg/ml) were similar to resting values in humans. During diving there are dramatic increases in both epinephrine and norepinephrine concentrations, which returned to control values by 30 min of the postdiving recovery period. A similar pattern was found after glucose infusion. The increased catecholamines were not the primary mechanism responsible for arterial constriction during the dive. Persistent diving bradycardia suggests obliteration of the chronotropic effects of catecholamines during the dive. An unchanged stroke volume suggests obliteration of the inotropic effects of catecholamines during the dive. Catecholamines do not appear to be involved in postdiving hyperglycemia and hyperglucogenemia. Neither the regulatory role of increased catecholamines nor the physiological function of increased catecholamines was apparent from the studies. However, dramatic increases in plasma catecholamines during diving appear to be an important component of the hormonal response to prolonged diving in aquatic mammals.

scholarly journals Morphological characteristics of harbor seal (Phoca vitulina) whiskers and their use in dietary reconstruction using stable isotope ratios

2018 ◽  
Vol 96 (11) ◽  
pp. 1255-1263 ◽  
Author(s):  
Justin Smith ◽  
Shawna Karpovich ◽  
Greg A. Breed ◽  
Diane M. O’Brien
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Whisker Growth ◽  
Morphological Characteristics ◽  
Isotope Ratios ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Dietary Reconstruction ◽  
Whisker Morphology

We investigated whether inferences about harbor seal (Phoca vitulina Linnaeus, 1758) whisker shed status and growth rates based on whisker morphology could improve dietary time series from whisker isotopic profiles. We identified morphometric characteristics of Alaskan harbor seal whiskers, including a smooth root section (SRS) and a bumpy section. The SRS was longer for spring versus fall-collected whiskers and matched the length of fully grown, shed whiskers. Thus, SRS length can differentiate whisker shed and growth status, and we used it to determine the sequence of whisker shedding by cohort in summer-captured harbor seals. The mean interbump length (IBL) correlated with whisker length, potentially providing a proxy for whisker growth rate. We compared carbon isotope ratios (expressed as δ13C values) along the three longest whiskers from 10 harbor seals, using two approaches for converting whisker position to date: (1) a standard growth rate constant based on captive studies and (2) individually adjusted growth rates based on whisker morphology. Intraindividual patterns of whisker δ13C values became more synchronous when expressed by deposition date rather than by position; however, adjusting growth rates based on IBL did not improve synchrony further. These findings suggest that whisker morphology can contribute whisker growth rate and shedding information for dietary reconstruction.

scholarly journals Both visual and idiothetic cues contribute to head direction cell stability during navigation along complex routes

2011 ◽  
Vol 105 (6) ◽  
pp. 2989-3001 ◽  
Author(s):  
Ryan M. Yoder ◽  
Benjamin J. Clark ◽  
Joel E. Brown ◽  
Mignon V. Lamia ◽  
Stephane Valerio ◽  
...  
Keyword(s):  
Visual Information ◽  
Path Integration ◽  
Visual Cues ◽  
Cell Activity ◽  
Neural Representation ◽  
Head Direction ◽  
Motion Cues ◽  
Cell Stability ◽  
Self Motion ◽  
The Relationship

Successful navigation requires a constantly updated neural representation of directional heading, which is conveyed by head direction (HD) cells. The HD signal is predominantly controlled by visual landmarks, but when familiar landmarks are unavailable, self-motion cues are able to control the HD signal via path integration. Previous studies of the relationship between HD cell activity and path integration have been limited to two or more arenas located in the same room, a drawback for interpretation because the same visual cues may have been perceptible across arenas. To address this issue, we tested the relationship between HD cell activity and path integration by recording HD cells while rats navigated within a 14-unit T-maze and in a multiroom maze that consisted of unique arenas that were located in different rooms but connected by a passageway. In the 14-unit T-maze, the HD signal remained relatively stable between the start and goal boxes, with the preferred firing directions usually shifting <45° during maze traversal. In the multiroom maze in light, the preferred firing directions also remained relatively constant between rooms, but with greater variability than in the 14-unit maze. In darkness, HD cell preferred firing directions showed marginally more variability between rooms than in the lighted condition. Overall, the results indicate that self-motion cues are capable of maintaining the HD cell signal in the absence of familiar visual cues, although there are limits to its accuracy. In addition, visual information, even when unfamiliar, can increase the precision of directional perception.

Influence of storms and maternal size on mother–pup separations and fostering in the harbor seal, Phoca vitulina

1992 ◽  
Vol 70 (8) ◽  
pp. 1640-1644 ◽  
Author(s):  
Daryl J. Boness ◽  
Don Bowen ◽  
Sara J. Iverson ◽  
Olav T. Oftedal
Keyword(s):  
Surface Current ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Frequency Of Occurrence ◽  
Lactation Period ◽  
Maternal Size ◽  
Proximate Causes ◽  
Previous Location

Fostering behavior has been documented in a large number of mammals and birds, but its frequency of occurrence and proximate causes are poorly understood in most species. Ten percent of a sample of 76 paint-marked female harbor seals (Phoca vitulina) fostered pups for some portion of the lactation period. Fostering appears to be associated with females having lost their own pup. In a subsample of 30 pairs that were followed closely, 3 of 16 females that lost their pups fostered, but none of 14 females that maintained continuous association with their pups throughout lactation did so. Smaller, and presumably younger, females were significantly more likely to become separated from their pups than were larger, and presumably older, females (73 vs. 33%). A high proportion (68%) of 35 separations observed occurred during the same day as, or within 1 day following, a storm. In 7 of 8 instances where we relocated pups after they were separated from their mothers during a storm, we found them in the direction of the surface current, 4.9 km from their previous location, on average. These data suggest that storms were the primary cause of separation of harbor seal mothers from their pups, and that younger mothers may be more likely to become separated from their pups. As fostering only occurs after a mother has lost her pup, we suggest that fostering, too, may be more likely among younger females.

Adaptations to diving in the harbor seal— gas exchange and ventilatory response to CO2

1963 ◽  
Vol 205 (6) ◽  
pp. 1175-1177 ◽  
Author(s):  
Eugene D. Robin ◽  
H. Victor Murdaugh ◽  
William Pyron ◽  
Edgar Weiss ◽  
Peter Soteres
Keyword(s):  
Gas Exchange ◽  
Ventilatory Response ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Pulmonary Gas Exchange ◽  
Respiratory Center ◽  
Harbor Seals ◽  
Response Curves ◽  
Ventilatory Response To Co2

Pulmonary gas exchange and the ventilatory response to CO2 were measured in six female harbor seals, Phoca vitulina. Mean Paco2 (48 ± 6 mm Hg) is higher in the seal and mean Pao2 (88 ± 9 mm Hg) is lower than the corresponding value in man. The seal shows a depressed ventilatory response to CO2 both in terms of slope and intercept of CO2 response curves. The depressed respiratory center sensitivity to CO2 presumably is an adaptative mechanism permitting prolonged diving in this species.

Pulmonary circulation of the harbor seal

1978 ◽  
Vol 45 (5) ◽  
pp. 718-727 ◽  
Author(s):  
E. E. Sinnett ◽  
G. L. Kooyman ◽  
E. A. Wahrenbrock
Keyword(s):  
Cardiac Output ◽  
Atmospheric Pressure ◽  
Pulmonary Blood Flow ◽  
Pulmonary Arterial Pressure ◽  
Ambient Pressure ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Right Atrial ◽  
Harbor Seals ◽  
Pulmonary Arterial

Cardiac output (Q) and pulmonary arterial pressure (Ppa) were measured under various conditions in four harbor seals (Phoca vitulina) weighing 35--52 kg. In seals anesthetized with halothane, Q averaged 3.47 l/min; in awake resting seals, Q averaged 11.5 l/min; and during surface dives (i.e., at atmospheric pressure) Q averaged 1.99 l/min. Stroke volume was one-third and two-thirds of the awake resting value during anesthesia and diving, respectively. Systolic Ppa was usually 40--50 Torr in anesthetized and awake resting seals, but was about 10 Torr lower during both surface and compression (i.e., elevated ambient pressure) dives. Diastolic Ppa was constant and high during anesthesia and quite variable in awake resting seals. During both surface and compression dives the diastolic Ppa often fell to the same level as right atrial pressure. We conclude that Q and Ppa are high in awake resting seals and that pulmonary blood flow may cease between beats during diving.

Clear diel patterns in breeding calls of harbor seals (Phoca vitulina) at Hornby Island, British Columbia, Canada

2018 ◽  
Vol 96 (11) ◽  
pp. 1236-1243
Author(s):  
Katrina Nikolich ◽  
Héloïse Frouin-Mouy ◽  
Alejandro Acevedo-Gutiérrez
Keyword(s):  
British Columbia ◽  
Foraging Behavior ◽  
Breeding Season ◽  
Light Level ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Female Behavior ◽  
Nocturnal Foraging ◽  
Male Calling

During the breeding season, male harbor seals (Phoca vitulina Linnaeus, 1758) produce underwater calls for sexual advertisement. The daily and seasonal timing of these calls is influenced by female availability (i.e., tidal haul-out patterns, foraging behavior, and oestrus cycle). Therefore, temporal patterns of male calling can provide clues about patterns of female behavior. We collected underwater recordings during the 2014 breeding season at Hornby Island, British Columbia, Canada, and examined the relationships of light level, progression of breeding season, and tide relative to call presence or absence and calling rate. Calls were 15 times more likely to occur at night than during the day. Nocturnal peaks in calling rate have been observed in other harbor seal populations and have been attributed to tidal haul-out patterns and nocturnal foraging of females. In this study, tide level did not have a significant effect on calling rate, and female foraging behavior was not monitored. One acoustic observation of mammal-eating killer whale (Orcinus orca (Linnaeus, 1758)) calls was followed by 48 h of decreased calling rate. We infer that predation risk influences the temporal pattern of male calling at this location and suggest further study to support this hypothesis.

Asymmetrical male-mediated gene flow between harbor seal (Phoca vitulina) populations in Alaska

2009 ◽  
Vol 87 (6) ◽  
pp. 498-507 ◽  
Author(s):  
J. K. Herreman ◽  
G. M. Blundell ◽  
D. B. McDonald ◽  
M. Ben-David
Keyword(s):  
Gene Flow ◽  
Gulf Of Alaska ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Southeast Alaska ◽  
Glacial Ice ◽  
Migration Rates ◽  
Glacier Bay ◽  
High Gene

Harbor seals ( Phoca vitulina richardii (Gray, 1864)) in Alaska are currently treated as three distinct management stocks. Previous genetic analyses using mitochondrial DNA suggested that these stocks are differentiated genetically. We studied populations in Glacier Bay (GB; Southeast Alaska Stock), where harbor seals are declining, and Prince William Sound (PWS; Gulf of Alaska Stock), where the population has recently stabilized. Using six pairs of hypervariable microsatellite primers, we determined that these populations are a single panmictic unit with estimated migration rates of 22 animals/generation (PWS to GB) and 63 animals/generation (GB to PWS). The asymmetrical gene flow between GB and PWS is likely driven in part by a recent increase in competitors and predators of seals in GB. In contrast with males, emigration of females from PWS to GB (8.3 seals/generation) is higher than emigration of females from GB to PWS (3.3 seals/generation), likely because females use glacial ice as pupping habitat. Despite the high gene flow, the number of migrants per year (0.02% of the Gulf of Alaska population) is likely too low to influence the demographics of harbor seals in PWS, and the two populations may best be managed as separate stocks.

Heart rate during breath-holding and diving in the unrestrained harbor seal (Phoca vitulina richardi)

1973 ◽  
Vol 51 (7) ◽  
pp. 671-680 ◽  
Author(s):  
David R. Jones ◽  
H. Dean Fisher ◽  
Susan McTaggart ◽  
Nigel H. West
Keyword(s):  
Heart Rate ◽  
Associative Learning ◽  
Heart Rate Response ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Breath Holding ◽  
Harbor Seals ◽  
Breathing Rate ◽  
Complex Phenomenon

Heart rate and breathing movements have been monitored in three unrestrained harbor seals. On voluntary submergence heart rate fell markedly in all seals, and after 2–3 s submergence stabilized at about 40–50% of the predive level. Heart rate increased before the animals broke surface at the end of the dive and, when breathing began again, a postdive tachycardia was observed. Two of the three seals frequently showed anticipation of the dive as judged from their heart-rate response. Heart rate during feeding dives was generally more variable; in fact one seal exhibited no bradycardia in 20% of its feeding dives, although another seal showed a significantly greater bradycardia than was seen in routine dives. When breathing rate was low (less than five breaths min−1) respiratory variations in the heart rate occurred, although the onset of bradycardia was much more rapid during diving than during breath-holding. Because of the flexibility of the response it is concluded that the generation of diving bradycardia in the seal is a complex phenomenon which, aside from any responses set in train by peripheral receptors, must also involve some form of associative learning.

Growth rates of vibrissae of harbor seals (Phoca vitulina) and Steller sea lions (Eumetopias jubatus)

2001 ◽  
Vol 79 (6) ◽  
pp. 1053-1061 ◽  
Author(s):  
Amy C Hirons ◽  
Donald M Schell ◽  
David J St. Aubin
Keyword(s):  
Growth Rates ◽  
Isotope Analysis ◽  
Harbor Seal ◽  
Phoca Vitulina ◽  
Harbor Seals ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Active Growth ◽  
Sea Lions ◽  
Two Peaks

Growth rates of vibrissae (whiskers), which act as a temporal record of feeding in harbor seals (Phoca vitulina) and Steller sea lions (Eumetopias jubatus), were estimated using 13C- and 15N-labeled glycine followed by stable-isotope analysis. The labeled glycine was incorporated into keratin and served as a temporal marker for growth-rate calculation. One captive harbor seal received two doses 147 days apart, while a second seal received one dose; vibrissae were analyzed after 86 and 154 days. The peak positions indicated that growth began in the fall, continued into spring, but ceased in June, with active growth rates of 0.33 mm/day. Two adult captive Steller sea lions each received two labeled doses during a 308-day period. After 427 days vibrissae in both sea lions showed two peaks corresponding to the markers; growth rates were calculated as 0.05–0.07 mm/day. Growth rates in captive juvenile and wild adult Steller sea lions, 0.10–0.17 mm/day, supported the assumption that major isotopic oscillations in vibrissae of wild sea lions were annual. The multiyear records imply that Steller sea lions retain their vibrissae; harbor seal vibrissae, in contrast, have periods of rapid growth and appear to be shed, at least in part, annually.

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