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Factors Affecting Haul-Out Behavior of Harbor Seals (Phoca vitulina) in Tidewater Glacier Inlets in Alaska: Can Tourism Vessels and Seals Coexist?

Blundell GM, Pendleton GW - PLoS ONE (2015)

Bottom Line: Cruise ships had the strongest negative effect; however, most vessel types negatively affected haul-out probability.End of haulouts was associated with increasing cloud cover, low ice availability, and vessel presence; large-sized tourism vessels or all-vessel-types combined were significant predictors of ending a haul-out bout.Potential disturbances of harbor seals could be reduced, enabling longer resting times for seals and fewer interruptions for nursing pups, if vessels focused the majority of visits to glacial habitat to before or after the hours of 08:00-17:00 or, less optimally, 09:00-16:00.

View Article: PubMed Central - PubMed

Affiliation: Alaska Department of Fish and Game, Division of Wildlife Conservation, Juneau, Alaska, United States of America.

ABSTRACT
Large numbers of harbor seals (Phoca vitulina) use habitat in tidewater glaciers in Alaska for pupping, breeding, and molting. Glacial fjords are also popular tourist destinations; however, visitation by numerous vessels can result in disturbance of seals during critical life-history phases. We explored factors affecting haul-out behavior of harbor seals at a glacial site frequented by tourism vessels. In 2008-10, we deployed VHF transmitters on 107 seals in Endicott Arm, Alaska. We remotely monitored presence and haul-out behavior of tagged seals and documented vessel presence with time-lapse cameras. We evaluated the influence of environmental and physical factors on the probability of being hauled out, duration of haul-out bouts, and as factors associated with the start and end of a haulout. Location, season, hour, and interactions of location by year, season, hour, and sex significantly influenced haul-out probability, as did ice, weather, and vessels. Seals were more likely to be hauled out with greater ice availability during the middle of the day, and less likely to be hauled out if vessels were present. Cruise ships had the strongest negative effect; however, most vessel types negatively affected haul-out probability. Haul-out duration was longest in association with starting on incoming tides, clear skies, no precipitation, occurring in the middle of the day, and ending in the late afternoon or evening. End of haulouts was associated with increasing cloud cover, low ice availability, and vessel presence; large-sized tourism vessels or all-vessel-types combined were significant predictors of ending a haul-out bout. Probability of being hauled out was highest in June, during pupping season. Potential disturbances of harbor seals could be reduced, enabling longer resting times for seals and fewer interruptions for nursing pups, if vessels focused the majority of visits to glacial habitat to before or after the hours of 08:00-17:00 or, less optimally, 09:00-16:00.

No MeSH data available.


Haul-out duration for radio-tagged harbor seals by season and inlet.Geometric mean duration (in hours) of haulouts for seals in Endicott and Tracy Arms during each ~2 week season.
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pone.0125486.g010: Haul-out duration for radio-tagged harbor seals by season and inlet.Geometric mean duration (in hours) of haulouts for seals in Endicott and Tracy Arms during each ~2 week season.

Mentions: Geometric mean haul-out durations, similar to haul-out probabilities, were low for outer Endicott, high for inner Endicott, and intermediate for Tracy; mean durations in Tracy showed the most variation across seasons (Table 5; Fig 10). Mean haul-out durations were generally highest for bouts that started during the middle of the day and ended in the afternoon or evening (Fig 11). The daily pattern varied strongly among locations, with little hourly variation at outer Endicott, strong variation at inner Endicott, and Tracy had intermediate variation (Fig 11).


Factors Affecting Haul-Out Behavior of Harbor Seals (Phoca vitulina) in Tidewater Glacier Inlets in Alaska: Can Tourism Vessels and Seals Coexist?

Blundell GM, Pendleton GW - PLoS ONE (2015)

Haul-out duration for radio-tagged harbor seals by season and inlet.Geometric mean duration (in hours) of haulouts for seals in Endicott and Tracy Arms during each ~2 week season.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4446219&req=5

pone.0125486.g010: Haul-out duration for radio-tagged harbor seals by season and inlet.Geometric mean duration (in hours) of haulouts for seals in Endicott and Tracy Arms during each ~2 week season.
Mentions: Geometric mean haul-out durations, similar to haul-out probabilities, were low for outer Endicott, high for inner Endicott, and intermediate for Tracy; mean durations in Tracy showed the most variation across seasons (Table 5; Fig 10). Mean haul-out durations were generally highest for bouts that started during the middle of the day and ended in the afternoon or evening (Fig 11). The daily pattern varied strongly among locations, with little hourly variation at outer Endicott, strong variation at inner Endicott, and Tracy had intermediate variation (Fig 11).

Bottom Line: Cruise ships had the strongest negative effect; however, most vessel types negatively affected haul-out probability.End of haulouts was associated with increasing cloud cover, low ice availability, and vessel presence; large-sized tourism vessels or all-vessel-types combined were significant predictors of ending a haul-out bout.Potential disturbances of harbor seals could be reduced, enabling longer resting times for seals and fewer interruptions for nursing pups, if vessels focused the majority of visits to glacial habitat to before or after the hours of 08:00-17:00 or, less optimally, 09:00-16:00.

View Article: PubMed Central - PubMed

Affiliation: Alaska Department of Fish and Game, Division of Wildlife Conservation, Juneau, Alaska, United States of America.

ABSTRACT
Large numbers of harbor seals (Phoca vitulina) use habitat in tidewater glaciers in Alaska for pupping, breeding, and molting. Glacial fjords are also popular tourist destinations; however, visitation by numerous vessels can result in disturbance of seals during critical life-history phases. We explored factors affecting haul-out behavior of harbor seals at a glacial site frequented by tourism vessels. In 2008-10, we deployed VHF transmitters on 107 seals in Endicott Arm, Alaska. We remotely monitored presence and haul-out behavior of tagged seals and documented vessel presence with time-lapse cameras. We evaluated the influence of environmental and physical factors on the probability of being hauled out, duration of haul-out bouts, and as factors associated with the start and end of a haulout. Location, season, hour, and interactions of location by year, season, hour, and sex significantly influenced haul-out probability, as did ice, weather, and vessels. Seals were more likely to be hauled out with greater ice availability during the middle of the day, and less likely to be hauled out if vessels were present. Cruise ships had the strongest negative effect; however, most vessel types negatively affected haul-out probability. Haul-out duration was longest in association with starting on incoming tides, clear skies, no precipitation, occurring in the middle of the day, and ending in the late afternoon or evening. End of haulouts was associated with increasing cloud cover, low ice availability, and vessel presence; large-sized tourism vessels or all-vessel-types combined were significant predictors of ending a haul-out bout. Probability of being hauled out was highest in June, during pupping season. Potential disturbances of harbor seals could be reduced, enabling longer resting times for seals and fewer interruptions for nursing pups, if vessels focused the majority of visits to glacial habitat to before or after the hours of 08:00-17:00 or, less optimally, 09:00-16:00.

No MeSH data available.