Haul-out behaviour of two Ross seals off eastern Antarctica

[摘要] Accurate assessment of the abundance of pinnipeds fromvisual surveys requires estimation of both the available(hauled-out) and unavailable (in-water) components of thepopulation (Eberhardt et al. 1979). Continental estimates ofthe abundance of the four Antarctic seals are based onlimited information on haul-out behaviour. In developingcontinental estimates, Erickson & Hanson (1990) correctedvisual surveys of the hauled-out component of the species'populations using data from observational studies of hauloutbehaviour by Erickson et al. (1989). Erickson & Hanson (1990) point out that, because the observational studies didnot account for an unknown fraction of seals that remainedin the water during the peak haul-out period, theirabundance estimates are minimum values. Further,Erickson & Hanson (1990) corrected the visual surveys forall four species using haul-out data for the crabeater sealonly, as observational data for the other species were notavailable. This assumes that haul-out patterns are constantacross species, which is largely untested. Consequently,there is potential for bias, in both a relative and absolutesense, in the estimated abundance of Antarctic seals.

[学科分类] 自然科学（综合）