In the Russian Far East, the first attempts at tagging newborn Steller sea lion pups to study their winter migrations occurred during the mid-1960s. However, the sample sizes were small (45 pups), and the work did not provide any useable results. Ultimately, several more attempts were made to tag pups with metal and plastic tags, and the results of this work provided the first data on migrations of young Steller sea lions between rookeries and haulouts. However, these tags were only retained for 3-4 years.
The first mass branding of pups in Russia was performed during the joint research cruise of TINRO and NMML scientists in summer 1989, and branding has been carried out regularly since 1996 (Table 2). In total, 8,486 Steller sea lions have been marked on 9 of the 10 major Steller sea lion rookeries in Russian waters, including 1,524 sea lions that were tagged with front flipper tags and 6,962 that were branded (Fig. 1, Table 2).
In parallel with pup branding, morphometric data (body length, axillary girth, and weight) were regularly collected and, beginning in 2002, a small tissue sample was taken from each branded pup for genetic research. In addition, blood samples were collected from 10-30 animals at each site to monitor health conditions and for archival purposes.
Table 2. Summary of Steller
sea lion branding and tagging in Russia, 1985-2008.
YEAR
R O O K E R Y
TOTAL
Grand Total
Manati
Medney
Zozlov
Zheleznaya
Antsiferov
Raykoke
Lovushki
Srednego
Brat Chirpoev
Iony
Matykil'
MPT*
Brand
1985
2
2
2
1987
20
20
20
1988
8
8
8
1989
3
139
200
200
200
3
739
742
1991
50
100
200
100
450
450
1992
100
82
12
194
194
1993
100
74
174
174
1994
100
47
147
147
1995
100
50
101
100
100
451
451
1996
100
50
100
100
100
100
550
550
1997
25
50
100
100
100
100
100
25
550
575
1998
87
50
100
100
100
100
150
687
687
1999
100
50
50
100
100
80
100
580
580
2000
50
90
50
90
140
2001
95
100
100
100
100
76
143
81
795
795
2002
85
50
100
150
385
385
2003
54
100
100
77
100
100
531
531
2004
100
50
150
150
450
450
2005
100
100
105
100
100
505
505
2006
100
50
150
150
450
450
2007
100
100
100
100
100
500
500
2008
100
50
150
150
Total MPT
33
475
303
12
201
300
100
100
1,524
Total brand
821
400
750
939
882
780
976
793
621
6,962
Grand Total
33
1,296
703
12
750
1,140
1,182
880
1,076
793
621
1,524
6,962
8,486
*MPT
= metal or plastic tags.
Numbers in regular font are metal or plastic tags.
Numbers in bold font are brands.
- Observations of Branded Sea Lions:
In Russia, observations of branded Steller sea lions are carried out mainly on the breeding rookeries (Table 3). Two or three observers spend up to 3 months camped near 8 of the 10 primary rookeries to collect daily resights of branded sea lions. As with similar work in Alaska, digital photos are collected for verification of the encounter and for positive identification of individual animals (photos of brands are compared with the brand resight database).
For juvenile animals (ages 1-3), all observations note the presence or absence of a tending adult female, and for mature females the presence of an older dependent or a newborn pup is also noted. All observations also note whether the adult female is nursing and if any copulations are observed. Data are entered into a database daily.
Table 3. Steller sea lion brand resight effort (days) on Russian rookeries
during the breeding season, 2002-08.
Rookery
2002
2003
2004
2005
2006
2007
2008
Total
Medny/Yugo-Vostochny
78
83
73
86
80
87
71
558
Kozlov Cape
52
47
43
64
81
60
3
350
Antsiferov/rookery
33
53
57
49
60
47
45
344
Lovushki/Dolgaya
35
51
55
54
59
51
38
343
Raykoke
39
52
54
54
56
44
24
323
Brat Chirpoev/rookery
37
50
51
54
55
43
290
Sakhalin/Tuleny
59
43
40
28
30
33
233
Yamsky Islands
34
38
43
115
Total
333
379
373
423
459
408
181
2,556
In addition to the ground-based observations on the rookeries, vessel surveys over large areas are conducted to record and photograph branded sea lions seen on haulouts, and similar data are collected on reproductive status. Ultimately, all of this information is collated at the completion of the field season and combined into a single Steller sea lion brand resight database.
All the data received from occasional respondents—fishermen, hunters, local residents, etc.—are also entered in this database. Data on the branded sea lion encounters along the coast of Hokkaido (Japan) are regularly provided by students of Hokkaido University and biologists from the Hokkaido National Fisheries Research Institute. There are currently more than 100,000 records about encounters of 2,648 branded Steller sea lions in the database. (continued)