scholarly journals Tracking young of the year gray seals Halichoerus grypus to estimate fishery encounter risk

2021 ◽  
Author(s):  
K Murray ◽  
J Hatch ◽  
RA DiGiovanni Jr ◽  
E Josephson
Keyword(s):  
Halichoerus Grypus ◽  
Young Of The Year ◽  
Gray Seals

scholarly journals Assessing the disturbance potential of small unoccupied aircraft systems (UAS) on gray seals (Halichoerus grypus) at breeding colonies in Nova Scotia, Canada

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4467 ◽  
Author(s):  
Lauren Arona ◽  
Julian Dale ◽  
Susan G. Heaslip ◽  
Michael O. Hammill ◽  
David W. Johnston
Keyword(s):  
Image Analysis ◽  
Nova Scotia ◽  
Acoustic Properties ◽  
Matched Pair ◽  
Short Term ◽  
Gray Seal ◽  
Aircraft Systems ◽  
Sequential Image ◽  
Young Of The Year ◽  
Gray Seals

The use of small unoccupied aircraft systems (UAS) for ecological studies and wildlife population assessments is increasing. These methods can provide significant benefits in terms of costs and reductions in human risk, but little is known if UAS-based approaches cause disturbance of animals during operations. To address this knowledge gap, we conducted a series of UAS flights at gray seal breeding colonies on Hay and Saddle Islands in Nova Scotia, Canada. Using a small fixed-wing UAS, we assessed both immediate and short-term effects of surveys using sequential image analysis and between-flight seal counts in ten, 50 m2 random quadrats at each colony. Counts of adult gray seals and young-of-the-year animals between first and second flights revealed no changes in abundance in quadrats (matched pair t-test p > 0.69) and slopes approaching 1 for linear regression comparisons (r2 > 0.80). Sequential image analysis revealed no changes in orientation or posture of imaged animals. We also assessed the acoustic properties of the small UAS in relation to low ambient noise conditions using sound equivalent level (Leq) measurements with a calibrated U-MIK 1 and a 1/3 octave band soundscape approach. The results of Leq measurements indicate that small fixed-wing UAS are quiet, with most energy above 160 Hz, and that levels across 1/3 octave bands do not greatly exceed ambient acoustic measurements in a quiet field during operations at standard survey altitudes. As such, this platform is unlikely to acoustically disturb gray seals at breeding colonies during population surveys. The results of the present study indicate that the effects of small fixed-wing UAS on gray seals at breeding colonies are negligible, and that fixed-wing UAS-based approaches should be considered amongst best practices for assessing gray seal colonies.

Nasal heat and water exchange in gray seals

1987 ◽  
Vol 253 (6) ◽  
pp. R883-R889 ◽  
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.

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

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.

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

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

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

1969 ◽  
Vol 47 (2) ◽  
pp. 229-233 ◽  
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.

scholarly journals EPIZOOTIOLOGY OF MORBILLIVIRUS INFECTION IN NORTH AMERICAN HARBOR SEALS (PHOCA VITULINA) AND GRAY SEALS (HALICHOERUS GRYPUS)

1995 ◽  
Vol 31 (4) ◽  
pp. 491-501 ◽  
Author(s):  
Pádraig J. Duignan ◽  
Jeremiah T. Saliki ◽  
David J. St. Aubin ◽  
Greg Early ◽  
Samuel Sadove ◽  
...  
Keyword(s):  
North American ◽  
Phoca Vitulina ◽  
Halichoerus Grypus ◽  
Harbor Seals ◽  
Gray Seals

Selective Blubber Fatty Acid Mobilization in Lactating Gray Seals (Halichoerus grypus)

2013 ◽  
Vol 86 (4) ◽  
pp. 441-450 ◽  
Author(s):  
Aline Arriola ◽  
Martin Biuw ◽  
Mike Walton ◽  
Simon Moss ◽  
Patrick Pomeroy
Keyword(s):  
Fatty Acid ◽  
Halichoerus Grypus ◽  
Fatty Acid Mobilization ◽  
Gray Seals
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