scholarly journals Percussive underwater signaling in wild gray seals

2020 ◽  
Vol 36 (2) ◽  
pp. 728-732 ◽  
Author(s):  
David P. Hocking ◽  
Ben Burville ◽  
William M. G. Parker ◽  
Alistair R. Evans ◽  
Travis Park ◽  
...  
Keyword(s):  
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.

Chemical Immobilization of Gray Seals

1981 ◽  
Vol 45 (4) ◽  
pp. 986 ◽  
Author(s):  
Katharine Parry ◽  
Sheila S. Anderson ◽  
Michael A. Fedak
Keyword(s):  
Chemical Immobilization ◽  
Gray Seals

Repeatability in lactation performance and the consequences for maternal reproductive success in gray seals

Ecology ◽  
2009 ◽  
Vol 90 (9) ◽  
pp. 2513-2523 ◽  
Author(s):  
S. L. C. Lang ◽  
S. J. Iverson ◽  
W. D. Bowen
Keyword(s):  
Reproductive Success ◽  
Lactation Performance ◽  
Gray Seals

scholarly journals Formant Modification through Vocal Production Learning in Gray Seals

2019 ◽  
Vol 29 (13) ◽  
pp. 2244-2249.e4 ◽  
Author(s):  
Amanda L. Stansbury ◽  
Vincent M. Janik
Keyword(s):  
Vocal Production ◽  
Gray Seals

Genetic evidence for seasonal consumption of monkfish ( Lophius spp.) and salmonids ( Salmo spp.) by gray seals

2020 ◽  
Author(s):  
Mette K. Schiønning ◽  
Martha Gosch ◽  
Eileen Dillane ◽  
Michelle Cronin ◽  
Mark J. Jessopp
Keyword(s):  
Genetic Evidence ◽  
Gray Seals

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.

Study of the relation between the incidence of uterine leiomyomas and the concentrations of PCB and DDT in Baltic gray seals

2008 ◽  
Vol 25 (2) ◽  
pp. 247-255 ◽  
Author(s):  
Carolina Bredhult ◽  
Britt-Marie Bäcklin ◽  
Anders Bignert ◽  
Matts Olovsson
Keyword(s):  
Uterine Leiomyomas ◽  
Gray Seals

scholarly journals BEHAVIORAL EVIDENCE OF THERMAL STRESS FROM OVERHEATING IN UK BREEDING GRAY SEALS

2002 ◽  
Vol 18 (2) ◽  
pp. 455-468 ◽  
Author(s):  
S. D. Twiss ◽  
N. C. Wright ◽  
N. Dunstone ◽  
P. Redman ◽  
S. Moss ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Behavioral Evidence ◽  
Gray Seals

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.

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