IUCN Red List Assessment
Red List Category
LC
Least Concern
Red List Criteria
Version
3.1
Year Assessed
2008
Assessor/s
Hofmeyr, G. & Kovacs, K. (IUCN SSC Pinniped Specialist Group)
Reviewer/s
Kovacs, K. & Lowry, L. (Pinniped Red List Authority)
Justification
Due to its large and apparently increasing population size, the Subantarctic Fur Seal should remain classified as Least Concern.
IUCN Evaluation of the Subantarctic Fur Seal, Arctocephalus tropicalis
Prepared by the Pinniped Specialist Group
A. Population reduction Declines measured over the longer of 10 years or 3 generations
A1 CR > 90%; EN > 70%; VU > 50%
Al. Population reduction observed, estimated, inferred, or suspected in the past where the causes of the reduction are clearly reversible AND understood AND have ceased, based on and specifying any of the following:
(a) direct observation
(b) an index of abundance appropriate to the taxon
(c) a decline in area of occupancy (AOO), extent of occurrence (EOO) and/or habitat quality
(d) actual or potential levels of exploitation
(e) effects of introduced taxa, hybridization, pathogens, pollutants, competitors or parasites.
All subpopulations of Subantarctic Fur Seals are currently either increasing or stable.
A2, A3 & A4 CR > 80%; EN > 50%; VU > 30%
A2. Population reduction observed, estimated, inferred, or suspected in the past where the causes of reduction may not have ceased OR may not be understood OR may not be reversible, based on (a) to (e) under A1.
All subpopulations of Subantarctic Fur Seals are currently either increasing or stable.
A3. Population reduction projected or suspected to be met in the future (up to a maximum of 100 years) based on (b) to (e) under A1.
A population reduction of Subantarctic Fur Seals is not expected in the future. It is possible, however, that global climate change may alter environmental conditions to the detriment of this species.
A4. An observed, estimated, inferred, projected or suspected population reduction (up to a maximum of 100 years) where the time period must include both the past and the future, and where the causes of reduction may not have ceased OR may not be understood OR may not be reversible, based on (a) to (e) under A1.
All subpopulations of Subantarctic Fur Seals are currently either increasing or stable. While a population reduction is not expected in the future, it is possible that global climate change may alter environmental conditions to the detriment of this species.
B. Geographic range in the form of either B1 (extent of occurrence) AND/OR B2 (area of occupancy)
B1. Extent of occurrence (EOO): CR
The EOO of Subantarctic fur seals is > 20,000 km².
B2. Area of occupancy (AOO): CR
The AOO of Subantarctic fur seals is > 2,000 km².
AND at least 2 of the following:
(a) Severely fragmented, OR number of locations: CR = 1; EN (b) Continuing decline in any of: (i) extent of occurrence; (ii) area of occupancy; (iii) area, extent and/or quality of habitat; (iv) number of locations or subpopulations; (v) number of mature individuals.
(c) Extreme fluctuations in any of: (i) extent of occurrence; (ii) area of occupancy; (iii) number of locations or subpopulations; (iv) number of mature individuals.
Subpopulations are not severely fragmented. Subantarctic Fur Seals are found at numerous breeding rookeries on eight islands or island groups. This species is not experiencing continuing decline or extreme fluctuations in extent of occurrence, area of occupancy, number of subpopulations, number of mature individuals or area, extent or quality of habitat.
C. Small population size and decline
Number of mature individuals: CR AND either C1 or C2:
C1. An estimated continuing decline of at least: CR = 25% in 3 years or 1 generation; EN = 20% in 5 years or 2 generations; VU = 10% in 10 years or 3 generations (up to a max. of 100 years in future)
C2. A continuing decline AND (a) and/or (b):
(a i) Number of mature individuals in each subpopulation: CR or
(a ii) % individuals in one subpopulation: CR = 90–100%; EN = 95–100%; VU = 100%
(b) Extreme fluctuations in the number of mature individuals.
The current abundance of Subantarctic Fur Seals is well in excess of 10,000. The number of mature individuals in 5 of 8 subpopulations is estimated to be over 1000. Approximately 50 % of individuals belong to the Gough Island subpopulation.
D. Very small or restricted population
Number of mature individuals: CR AND/OR restricted area of occupancy typically: AOO
The current abundance of mature Subantarctic Fur Seals is well in excess of 1,000, the AOO is far larger than 20 km² and the number of locations is > 5.
E. Quantitative analysis
Indicating the probability of extinction in the wild to be: Indicating the probability of extinction in the wild to be: CR > 50% in 10 years or 3 generations (100 years max.); EN > 20% in 20 years or 5 generations (100 years max.); VU > 10% in 100 years
There has been no quantitative analysis of the probability of extinction of Subantarctic Fur Seals.
Listing recommendation — Estimates indicate a Subantarctic Fur Seal abundance of several hundred thousand individuals breeding at numerous sites on eight islands or island groups. 95% of Subantarctic Fur Seals breed at just three of these sites: Gough Island, the Prince Edward Islands and Amsterdam Island. Two other subpopulations are estimated to contain of more than a 1,000 adults. All subpopulations are either stable or increasing. No major threats currently affect any subpopulations and it is unlikely that any will do so in the near future. This being said, Subantarctic Fur Seals may be affected by global climate change should it impact upon their abiotic environment or prey species. It should also be noted that Subantarctic Fur Seals experienced a severe population bottleneck during the 19th and 20th Centuries that has reduced their genetic variation and which may render this species vulnerable to disease or climate change. Under present conditions Subantarctic Fur Seals qualify for listing in the category Least Concern.
IUCN Evaluation of the Subantarctic Fur Seal, Arctocephalus tropicalis
Prepared by the Pinniped Specialist Group
A. Population reduction Declines measured over the longer of 10 years or 3 generations
A1 CR > 90%; EN > 70%; VU > 50%
Al. Population reduction observed, estimated, inferred, or suspected in the past where the causes of the reduction are clearly reversible AND understood AND have ceased, based on and specifying any of the following:
(a) direct observation
(b) an index of abundance appropriate to the taxon
(c) a decline in area of occupancy (AOO), extent of occurrence (EOO) and/or habitat quality
(d) actual or potential levels of exploitation
(e) effects of introduced taxa, hybridization, pathogens, pollutants, competitors or parasites.
All subpopulations of Subantarctic Fur Seals are currently either increasing or stable.
A2, A3 & A4 CR > 80%; EN > 50%; VU > 30%
A2. Population reduction observed, estimated, inferred, or suspected in the past where the causes of reduction may not have ceased OR may not be understood OR may not be reversible, based on (a) to (e) under A1.
All subpopulations of Subantarctic Fur Seals are currently either increasing or stable.
A3. Population reduction projected or suspected to be met in the future (up to a maximum of 100 years) based on (b) to (e) under A1.
A population reduction of Subantarctic Fur Seals is not expected in the future. It is possible, however, that global climate change may alter environmental conditions to the detriment of this species.
A4. An observed, estimated, inferred, projected or suspected population reduction (up to a maximum of 100 years) where the time period must include both the past and the future, and where the causes of reduction may not have ceased OR may not be understood OR may not be reversible, based on (a) to (e) under A1.
All subpopulations of Subantarctic Fur Seals are currently either increasing or stable. While a population reduction is not expected in the future, it is possible that global climate change may alter environmental conditions to the detriment of this species.
B. Geographic range in the form of either B1 (extent of occurrence) AND/OR B2 (area of occupancy)
B1. Extent of occurrence (EOO): CR
The EOO of Subantarctic fur seals is > 20,000 km².
B2. Area of occupancy (AOO): CR
The AOO of Subantarctic fur seals is > 2,000 km².
AND at least 2 of the following:
(a) Severely fragmented, OR number of locations: CR = 1; EN (b) Continuing decline in any of: (i) extent of occurrence; (ii) area of occupancy; (iii) area, extent and/or quality of habitat; (iv) number of locations or subpopulations; (v) number of mature individuals.
(c) Extreme fluctuations in any of: (i) extent of occurrence; (ii) area of occupancy; (iii) number of locations or subpopulations; (iv) number of mature individuals.
Subpopulations are not severely fragmented. Subantarctic Fur Seals are found at numerous breeding rookeries on eight islands or island groups. This species is not experiencing continuing decline or extreme fluctuations in extent of occurrence, area of occupancy, number of subpopulations, number of mature individuals or area, extent or quality of habitat.
C. Small population size and decline
Number of mature individuals: CR AND either C1 or C2:
C1. An estimated continuing decline of at least: CR = 25% in 3 years or 1 generation; EN = 20% in 5 years or 2 generations; VU = 10% in 10 years or 3 generations (up to a max. of 100 years in future)
C2. A continuing decline AND (a) and/or (b):
(a i) Number of mature individuals in each subpopulation: CR or
(a ii) % individuals in one subpopulation: CR = 90–100%; EN = 95–100%; VU = 100%
(b) Extreme fluctuations in the number of mature individuals.
The current abundance of Subantarctic Fur Seals is well in excess of 10,000. The number of mature individuals in 5 of 8 subpopulations is estimated to be over 1000. Approximately 50 % of individuals belong to the Gough Island subpopulation.
D. Very small or restricted population
Number of mature individuals: CR AND/OR restricted area of occupancy typically: AOO
The current abundance of mature Subantarctic Fur Seals is well in excess of 1,000, the AOO is far larger than 20 km² and the number of locations is > 5.
E. Quantitative analysis
Indicating the probability of extinction in the wild to be: Indicating the probability of extinction in the wild to be: CR > 50% in 10 years or 3 generations (100 years max.); EN > 20% in 20 years or 5 generations (100 years max.); VU > 10% in 100 years
There has been no quantitative analysis of the probability of extinction of Subantarctic Fur Seals.
Listing recommendation — Estimates indicate a Subantarctic Fur Seal abundance of several hundred thousand individuals breeding at numerous sites on eight islands or island groups. 95% of Subantarctic Fur Seals breed at just three of these sites: Gough Island, the Prince Edward Islands and Amsterdam Island. Two other subpopulations are estimated to contain of more than a 1,000 adults. All subpopulations are either stable or increasing. No major threats currently affect any subpopulations and it is unlikely that any will do so in the near future. This being said, Subantarctic Fur Seals may be affected by global climate change should it impact upon their abiotic environment or prey species. It should also be noted that Subantarctic Fur Seals experienced a severe population bottleneck during the 19th and 20th Centuries that has reduced their genetic variation and which may render this species vulnerable to disease or climate change. Under present conditions Subantarctic Fur Seals qualify for listing in the category Least Concern.
History
- 1996Lower Risk/least concern
