FISHERIES SCIENCE 2000; 66: 180–181
Short Paper
Satellite tracking of young Steller sea lion off the coast of
northern Hokkaido
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Norihisa BABA, * Hiroshi NITTO AND Akira NITTA
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National Research Institute of Far Seas Fisheries, Shimizu, Shizuoka 424-8633, Otaru Aquarium, Shukutu,
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Otaru 047-0047 and Nihon NUS Co. Ltd, Kaigan, Minato, Tokyo 108-0022, Japan
KEY WORDS: migration, satellite tracking, Steller sea lion.
Steller sea lions Eumetopias jubatus occur in the coastal
waters of Hokkaido, Japan in the western North Pacific
Ocean during the winter and along the coast of the Kam-
chatka peninsula and Kuril Islands in the western North
Pacific and the islands off Sakhalin in the Sea of Okhotsk
Platform Transmitter Terminal 5167 was attached to
the pelage on the top of the head and PTT 17974 was
attached on the back of the Steller sea lion with epoxy
resin (Quick 5; Conishi Co. Ltd, Osaka, Japan) at the
Otaru Aquarium on November 24, 1993. The attach-
ment process was completed in 27 min and the air tem-
perature was -6°C. The Steller sea lion was transported
by rail for 10 h to Hama-Onisibetu where it was released
at 11:55 am on November 25, 1993.
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during the summer. It has been assumed that Steller sea
lions occurring off the coast of Hokkaido are from the
Kuril Islands, and that those seen in the Sea of Japan are
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from Sakhalin. However, Steller sea lion that was tagged
on Kuril Islands was caught near Shakotan in the Sea of
Japan off the coast of Hokkaido. These reports demon-
strate the need for additional information on the distri-
bution and migration of Steller sea lions.
Location information from the PTT was obtained
through CLS (Ramonville cedex, France) and location
errors were estimated at 150 m, 350 m, and 1 km for class
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3, 2, and 1 locations, respectively. Prior to development,
To collect many location data and assess movement
patterns of Steller sea lions in the southeastern portion
of their range, two Platform Transmitter Terminals
it was determined that the maximum error of a Class 0
location was 19 km (n = 4, mean = 7 km, SD = 8.2). All
data from class 0–3 were used to determine locations, dis-
tance traveled and estimated speed according to local
time.
(
PTTs), 5167 and 17974 were deployed on the same
Steller sea lion. Platform Transmitter Terminal 5167
model T-2050; Toyocom Co. Ltd) had a transmission
(
Radio signals from PTT 5167 were not received, but
signals from PTT 17974 were received for 52 days from
November 25, 1993 to January 16, 1994. A total of 41
transmissions were recorded and 18 provided location
information (12 = class 0, 6 = class 1, Table 1). After
deployment, the Steller sea lion landed near the Cape
Kuznetsova (46∞03¢N, 141∞55¢E) south of Sakhalin on
December 2, 6 and 10. On December 18, the Steller sea
lion moved to a northwestern location approximately 32
km from Rebun Island; then the animal moved to a
southern location 6 km from Skala Kamen rocks on
December 30; and it subsequently returned to the vicin-
ity of Cape Kuznetsova on December 31. On January 3,
the Steller sea lion moved through the Sea of Okhotsk
to the coastal waters near Cape Soya, Hokkaido (about
6 km east from Cape Soya) and then into the Sea of
Japan on January 11 (20 km south of the Cape Nosappu;
Fig. 1). Total migration distance was approximately
power of 0.125 W and was approximately 8 cm in diam-
eter, 3 cm in height, 140 g in weight, and had a battery
life of 120 days with continuous transmission (no duty
cycle). Platform Transmitter Terminal 17974 (model T-
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038; Toyocom Co. Ltd, Kanagawa, Japan) had a trans-
mission power of 0.5 W and was approximately 7 cm in
diameter, 19 cm in length, 500 g in weight, and had a
battery life of about 1 year with a duty cycle of 24 h on
and 72 h off.
The Steller sea lion involved in this study was cap-
tured in a set net off the coast of Hama-Onisibetu, Saru-
futu in northern Hokkaido on June 14, 1993 and to
recover from the capture damage was kept in captivity
for 5 months at the Otaru Aquarium prior to instru-
mentation and release. The Steller sea lion was 93 kg in
weight, approximately 150 cm in length and was esti-
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mated to be 1 year of age.
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40.4 km, and maximum migration speed was estimated
at 7.1 km/h (mean = 0.4 km/h).
Three Argos locations were received on three differ-
ent days near Cape Kuznetsova. The number of trans-
*Corresponding author: Tel: 0543 366038. Fax: 0543 359642.
Received 31 May 1999.