Figure 1. A branded Steller sea lion observed on a resight survey. Photo by Lowell Fritz.
In order to estimate movement patterns, survival, and other vital rates of Steller sea lions, staff of the Alaska Ecosystems Program and the ADF&G have been marking pups with brands or flipper tags at rookeries in the eastern Aleutian Islands; the western, central, and eastern Gulf of Alaska; and in Southeast Alaska.
Between July and August 2007, ship-based surveys were conducted on the chartered research vessels Norseman and Norseman II from the eastern Aleutians through Prince William Sound to resight branded and tagged Steller sea lions (Fig. 1).
Fifty-four sea lion haul-out and rookery sites were visited in the eastern and central Gulf of Alaska in June and July, and 90 branded sea lions were positively identified at 22 sites. Observed animals were born at four different western stock rookeries (Marmot, Sugarloaf, Wooded, Seal Rocks) and three eastern stock rookeries (Hazy, White Sisters, Forrester). In addition, 15 sea lions captured as juveniles by dive or land techniques were identified.
Thirty-seven sea lion haul-out and rookery sites were visited in the eastern Aleutian Islands in August, and 67 branded sea lions were positively identified at 10 sites. Most of the animals resighted in the eastern Aleutians were branded as pups on western stock rookeries. However, four of the sea lions were branded at eastern stock rookeries, and one was branded by Russian colleagues on Medney Island in 2006. Four sea lions captured as juveniles by dive or land techniques were also identified.
By Tonya Zeppelin
