Supplementary Methods Population data
During aerial surveys, photographs were taken of sea lions on all rookery and haul-out sites in the Gulf of Alaska and Aleutian Islands in approximately two weeks during the breeding season (June/July). At this time, newborns (pups) and reproductive adults are observed on rookeries where adult males...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.183.6436 http://www.fakr.noaa.gov/sustainablefisheries/sslmc/april-06/HolmesSuppInfo.pdf |
| Summary: | During aerial surveys, photographs were taken of sea lions on all rookery and haul-out sites in the Gulf of Alaska and Aleutian Islands in approximately two weeks during the breeding season (June/July). At this time, newborns (pups) and reproductive adults are observed on rookeries where adult males defend territories and mating and birthing occur. Adults that are not breeding that year and pre-reproductive juveniles (age 1 to 3 years old) are observed on haul-out sites where sea lions predictably rest on land but where no or few pups are born. Non-pups include all juveniles and adults but not newborn pups. The National Marine Fisheries Service designates rookeries and haul-outs as trend or non-trend sites (NMFS 1992). Trend sites have been regularly surveyed since 1976, while non-trend sites have not been counted as consistently; animals on trend sites account for 60-70 % of the total count. For this paper, we used the 1976-2004 total nonpup count on trend rookeries and haul-outs in the CGOA during June/July. The raw data with references are given in Supplementary Table 1. Steller sea lion pup censuses |
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