Harbor Seal Census for the Inland Waters of Washington, 1977-1978

Calambokidis, John; Everitt, Robert D.; Cubbage, James C.; Carter, Susanne D.

doi:10.2307/3534278

Cited by 11 publications

(9 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These include sleep (Schneider et al 1980), predator avoidance (Terhune 1985), mate selection (Renouf and Lawson 1986), and skin cell maintenance (Feltz and Fay 1966). Numerous field studies have reported (mainly negative) correlations between hauling out and various environmental factors, including tide (Calambokidis et al 1979;Krieber and Barrette 1984;Schneider and Payne 1983;Sullivan 1980), air temperature (Krieber and Barrette 1984), high winds (Schneider and Payne 1983), and precipitation (Krieber and Barrette 1984). For the most part, however, such studies simply report the existence of these correlations without much meaningful discussion of any underlying functional relationships.…”

Section: Introductionmentioning

confidence: 93%

Thermal constraints on hauling out by harbour seals (Phoca vitulina)

Watts¹

1992

Can. J. Zool.

View full text Add to dashboard Cite

WATTS, P. 1992. Thermal constraints on hauling out by harbour seals (Phoca vitulina). Can. J. Zool. 70: 553 -560.Measurements of the thermal environment were made in conjunction with regular counts of hauled out harbour seals at three sites in the Pacific Northwest. Solar radiation, wind speed, and air temperature were all significantly correlated with numbers of seals on land. These were incorporated into a thermal index of heat flux (expressed in watts per square metre) between the seal and its environment. Numbers of seals hauled out at midday declined sharply as flux increased above 0 W . m-2 (i.e., when seals theoretically gained net heat from their environment), but remained constant at all measured negative values of flux. This relationship could be described by a nonlinear piecewise regression equation ( t d j = 0.648). No significant differences in hauling activity were detected between sites throughout most of the year. During the summer, however, one site with significantly higher mean flux than the others also exhibited significantly lower hauling activity. These findings are consistent with the hypothesis that under temperate summer conditions, hauling out can result in overheating. This may be an important constraint on hauling behaviour. WATTS, P. 1992. Thermal constraints on hauling out by harbour seals (Phoca vitulina). Can. J. Zool. 70 : 553-560. Des mesures de l'environnement thermique ont CtC prises lors du dknombrement de Phoques communs en repos hors de l'eau B trois sites du Nord-Ouest amkricain. Les variables suivantes, radiation solaire, vitesse du vent et tempkrature de l'air, Ctaient toutes en corrklation significative avec le nombre de phoques hors de l'eau. Ces variables ont CtC incorporkes B un indice thermique du flux de chaleur (exprim6 en watts par mktre carrC) entre le phoque et son environnement. Le nombre de phoques hors de l'eau au milieu de la journCe diminuait brusquement au moment oh l'indice atteignait des valeurs supCrieures B 0 W -m-2 (i.e., lorsque les phoques faisaient thkoriquement des gains nets de chaleur), mais ce nombre Ctait constant B toutes les valeurs nCgatives de flux. La relation pourrait &re dCcrite par une Cquation de rkgression non linCaire segmentCe (rzdj = 0,648

show abstract

Section: Introductionmentioning

confidence: 93%

Thermal constraints on hauling out by harbour seals (Phoca vitulina)

Watts¹

1992

Can. J. Zool.

View full text Add to dashboard Cite

show abstract

“…In contrast, Hayward et al [] showed that on Violet Point, Protection Island, haulout was directly related to tide height if all other variables were held constant. Similarly, Calambokidis et al [] found that maximal haulout in Hood Canal, in the south Salish Sea, Washington, occurred at high tide, although London et al [] hypothesized this was because the haul‐out locations in the tidal sloughs were available only at high tide.…”

Section: Discussionmentioning

confidence: 99%

“…Several important caveats for the aerial survey/telemetry method have been established by a number of studies. First, the method assumes that seals show significant haul‐out site fidelity (Calambokidis et al []). Radio‐tagged seals must return to a haul‐out site within range of the telemetry receiver to be counted as hauled out, and aerial surveys of a regional stock assume that few animals travel outside the region (Boveng []).…”

Section: Introductionmentioning

confidence: 99%

“…Fourth, a correction factor computed from a sample associated with more than one haul‐out site is unlikely to be accurate. Not only do the environmental factors that affect haulout vary between sites, but haul‐out patterns themselves, as functions of environmental factors, vary between sites, necessitating a different correction factor for each site (Calambokidis et al [], Olesiuk et al [], Baird []; Huber et al [], Simpkins et al [], Cunningham et al []).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A METHOD FOR PREDICTING HARBOR SEAL (PHOCA VITULINA) HAULOUT AND MONITORING LONG‐TERM POPULATION TRENDS WITHOUT TELEMETRY

Cowles

Henson²,

Hayward

et al. 2013

Natural Resource Modeling

View full text Add to dashboard Cite

Abstract. Monitoring population trends in harbor seals (Phoca vitulina) generally involves two steps: (i) a census obtained from aerial surveys of haul-out sites, and (ii) an upward correction based on the proportion of seals hauled out as estimated from a sample of telemetry-tagged seals. Here we present a mathematical method for obtaining site-specific correction factors without telemetry. The method also determines site-specific environmental factors associated with haulout and provides algebraic equations that predict diurnal haul-out numbers and correction factors as functions of these variables. We applied the method at a haul-out site on Protection Island, Washington, USA. The haul-out model and correction factor model were functions of tide height, current velocity, and time of day, and the haul-out model explained 46% of the observed variability in diurnal haul-out dynamics. Although the particular models are site-specific, the general model and methods are portable. A suite of such models for haul-out sites of a regional stock would allow managers to monitor long-term population trends without telemetry.

show abstract

“…Johnson and Jeffries 1977, Calambokidis et al 1979, Everitt et al 1980, Brown 1981, Graybill 1981, Brown and Mate 1983, Roffe and Mate 1984. But with the exception of Brown and Mate's 4.5-yr project these studies were brief (i.e.…”

mentioning

confidence: 95%

Six Years of Harbor Seal Censusing at Yaquina Estuary, Oregon

Bayer¹

1985

The Murrelet

View full text Add to dashboard Cite

Harbor Seal Census for the Inland Waters of Washington, 1977-1978

Cited by 11 publications

References 0 publications

Thermal constraints on hauling out by harbour seals (Phoca vitulina)

Thermal constraints on hauling out by harbour seals (Phoca vitulina)

A METHOD FOR PREDICTING HARBOR SEAL (PHOCA VITULINA) HAULOUT AND MONITORING LONG‐TERM POPULATION TRENDS WITHOUT TELEMETRY

Six Years of Harbor Seal Censusing at Yaquina Estuary, Oregon

Contact Info

Product

Resources

About