The reproductive behavior and energetics of male gray seals ( Halichoerus grypus ) breeding on a land-fast ice substrate

The grey seal (Halichoerus grypus) is a sexually dimorphic polygynous phocid that breeds in a synchronous fashion, within populations, on both sides of the North Atlantic Ocean. This study was designed to examine factors that may influence maternal behaviour and energy investment of females breeding on land-fast ice. The study was conducted on the ice around Amet Island, Nova Scotia, during the breeding seasons of 1992, 1993, and 1994. Scan sampling and ad libitum observation techniques were used to record behaviour. Mass transfer from mothers to pups was determined using serial mass records for pairs. Rate of pup mass gain was 2.5 ± 0.6 kg/day and pup mass at weaning 50.0 ± 7.3 kg. The duration of lactation was 15.2 ± 1.6 days. Maternal mass at parturition was 210.6 ± 23.8 kg and female mass loss during the lactation period was 75.0 ± 16.0 kg. This mass loss represented 35.7 ± 6.1% of their parturition mass. Efficiency of mass transfer was 0.52 ± 0.12. Breeding habitat influenced maternal behaviour. Compared with land-breeding grey seals, ice-breeding females had an intensified nursing period, during which females transferred a similar amount of energy to their pups over a shorter time frame. Additionally, females on land-fast ice gave birth more synchronously than is the case in land-breeding colonies. Date of parturition within the breeding season had some influence on female behaviour; females giving birth late in the season were more active than females breeding earlier. The behaviour of males may play a role in determining the optimum time for birthing. Adult males spent more time engaged in agonistic behaviours late in the breeding season and the resultant disruption of adjacent females may serve as a selective force maintaining birthing synchrony. These influences also apply in land-breeding situations and are not likely to contribute to the contraction of the nursing period and the more synchronous breeding observed among females on ice. The more condensed lactation and birthing periods are likely a response to the higher risk of premature separation on the ice.

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Nasal heat and water exchange in gray seals

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1987.253.6.r883 ◽

1987 ◽

Vol 253 (6) ◽

pp. R883-R889 ◽

Cited By ~ 8

Author(s):

L. P. Folkow ◽

A. S. Blix

Keyword(s):

Water Exchange ◽

Ambient Air ◽

Minute Volume ◽

Halichoerus Grypus ◽

Evaporative Water ◽

Air Temperatures ◽

Respiratory Heat Loss ◽

Average Maximum ◽

Lower Critical Temperature ◽

Gray Seals

Metabolic rate (MR), expired air temperature (Tex), respiratory frequency (f), respiratory minute volume (V), and skin (Ts) and body (Tb) temperatures were recorded in three gray seals (Halichoerus grypus) at ambient air temperatures (Ta) between -40 and +20 degrees C. At Ta within the thermoneutral zone, MR averaged 3.7 W.kg-0.75, while mean V was 0.26 1.min-1.kg-0.75. At Ta below -11 degrees C [apparent lower critical temperature (Tlc)], both MR and V increased linearly with decreasing Ta. Average maximum MR (9.6 W.kg-0.75) and V (0.57 1.min-1.kg-0.75) were both recorded at Ta of -40 degrees C. Tex decreased with decreasing Ta to an average minimum value of 8 degrees C at Ta of -30 degrees C. The highest Tex recorded was 32 degrees C at Ta of +20 degrees C. At Ta of -20 degrees C, both total respiratory heat loss, with one exception, and respiratory evaporative water loss reached their lowest values. At this Ta, 66% of the heat and 80% of the water added to the inspired air were regained on expiration. We suggest that nasal heat exchange may be of considerable importance for thermal and water balance in many pinnipeds.

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Seasonal variability and individual consistency in gray seal (Halichoerus grypus) isotopic niches

Canadian Journal of Zoology ◽

10.1139/cjz-2019-0032 ◽

2019 ◽

Vol 97 (11) ◽

pp. 1071-1077

Author(s):

K.M. Hernandez ◽

A.L. Bogomolni ◽

J.H. Moxley ◽

G.T. Waring ◽

R.A. DiGiovanni ◽

...

Keyword(s):

United States ◽

Seasonal Variability ◽

Foraging Ecology ◽

Population Level ◽

The United States ◽

Halichoerus Grypus ◽

Dietary Specialization ◽

Gray Seal ◽

Individual Consistency ◽

Gray Seals

Although it is often assumed that individuals in generalist populations are equivalent, recent research indicates that individual dietary specialization can be common in marine predators. Gray seals (Halichoerus grypus (Fabricius, 1791)) were considered locally extinct in United States waters by 1958 but have since recolonized the region. Although considered generalists, less is known about gray seal foraging ecology in the United States. To address this, we used carbon and nitrogen stable isotope analyses to investigate the foraging niches of adult gray seals in Massachusetts, USA. We examined skin, fur, and blood components to investigate seasonal variability and individual consistency in foraging niches, and serially sampled vibrissae to quantify the degree of individual foraging specialization in this population. Our results suggest that seals shift from coastal foraging habitats before molt to offshore habitats after molt, with a coincident shift from higher to lower trophic-level prey. Adult gray seals also exhibited individual consistency in foraging niches independent of population-level shifts and reflect a generalist population composed of individual foraging specialists. These findings serve as a baseline for subsequent research on gray seals in United States waters that could help to determine the mechanisms which promote individual specialization in this population.

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Adaptive hormone changes in harp seals, Phoca groenlandica, and gray seals, Halichoerus grypus, during the postnatal period

General and Comparative Endocrinology ◽

10.1016/0016-6480(80)90006-4 ◽

1980 ◽

Vol 40 (4) ◽

pp. 434-445 ◽

Cited By ~ 37

Author(s):

F.Rainer Engelhardt ◽

Janet M. Ferguson

Keyword(s):

Postnatal Period ◽

Halichoerus Grypus ◽

Phoca Groenlandica ◽

Gray Seals

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SERUM BIOCHEMICAL AND HEMATOLOGIC REFERENCE INTERVALS FOR WEANLING NORTHWEST ATLANTIC GRAY SEALS (HALICHOERUS GRYPUS)

Journal of Zoo and Wildlife Medicine ◽

10.1638/2019-0086 ◽

2020 ◽

Vol 51 (1) ◽

pp. 228

Author(s):

David D. R. Krucik ◽

Barbara Mangold ◽

Wendy Puryear ◽

Mandy Keogh ◽

Andrea Bogomolni ◽

...

Keyword(s):

Reference Intervals ◽

Halichoerus Grypus ◽

Northwest Atlantic ◽

Serum Biochemical ◽

Gray Seals

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The behavior of adult gray seals (Halichoerus grypus) in the early stages of the breeding season

Canadian Journal of Zoology ◽

10.1139/z69-049 ◽

1969 ◽

Vol 47 (2) ◽

pp. 229-233 ◽

Cited By ~ 7

Author(s):

Austin W. Cameron

Keyword(s):

Nova Scotia ◽

Breeding Season ◽

Mass Movement ◽

Territorial Behavior ◽

Halichoerus Grypus ◽

Breeding Area ◽

Early Stages ◽

Gray Seals

A 4-week period, December 18, 1967, to January 16, 1968, was spent studying a colony of gray seals on the Basque Islands, Nova Scotia. Before hauling out on the breeding islands, the seals congregate on exposed reefs nearby, where they remain for several weeks. Once invasion of the breeding area begins there is a mass movement and the entire herd beaches within the space of a week. The first seal observed to haul out was a cow which whelped within 24 hours. The bulls take up stations almost immediately whereas the cows wander aimlessly over the breeding area until they have whelped. The spot at which the pup is born seems to determine the cow's station. For several days after the pup is born, the cow remains with it constantly; thereafter she goes to sea at regular intervals. For the first week to 10 days after beaching, the bulls exhibit no territorial behavior and it is possible the boundaries are not established until later. The resident bulls appeared to ignore each other and no fighting was observed.

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