IUCN Red List Assessment
Red List Category
Red List Criteria
IUCN Evaluation of the Southern Elephant Sea, Mirounga leonina
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.
Generation time is approximately 9-10 years. Some populations decreased markedly in the last 50 years to levels that meet the CR criterion locally. But, in the last 30 years (assuming a generation time of 10 years), some stopped declining while others are increasing but have not as yet recovered to baseline numbers.
The most recent information available for the largest population (South Georgia) is that it is stable. One of the five most important populations (PenÃnsula ValdÃ©s) has been growing and it is now apparently stable. Based on best available information, the combined size of the declining colonies do not in combination bring the global status into a vulnerable condition according to IUCN criteria.
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.
Local population reductions have been observed in the past 30 years for not well-understood reasons.
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.
Predicted reduction in sea ice habitats due to continued climate warming will impact the distribution of food and breeding habitat for the species. Predictions are not clear yet regarding how these effects will impact the size of the populations.
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.
A global population reduction for the species has not occurred in the past 30 years.
B. Geographic range in the form of either B1 (extent of occurrence) AND/OR B2 (area of occupancy)
B1. Extent of occurrence (EOO): CR < 100 kmÂ²; EN < 5,000 kmÂ²; VU < 20,000 kmÂ²
Elephant Seals reproduce in colonies where harems are dispersed over a few km of coastline. Colonies may be thousands of km away from each other. Distribution at sea is over millions of square km.
B2. Area of occupancy (AOO): CR < 10 kmÂ²; EN < 500 kmÂ²; VU < 2,000 kmÂ²
See above for B1. The AOO on land is relatively small for each stock but significantly larger than the above numbers during the pelagic phases (when animals are apparently solitary and disperse widely away from breeding sites).
AND at least 2 of the following:
(a) Severely fragmented, OR number of locations: CR = 1; EN < 5; VU < 10
(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.
Besides a few colonies in the Antarctic and the temperate SW Atlantic, subpopulations are distributed among sub-Antarctic islands around the Antarctic continent, but this is the normal pattern, not the result of induced fragmentation of the population(s).
C. Small population size and decline
Number of mature individuals: CR < 250; EN < 2,500; VU < 10,000
The current abundance is > 10,000.
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 < 50; EN < 250; VU < 1,000
(a ii) % individuals in one subpopulation: CR = 90â100%; EN = 95â100%; VU = 100%
(b) Extreme fluctuations in the number of mature individuals.
D. Very small or restricted population
Number of mature individuals: CR < 50; EN < 250; VU < 1,000 AND/OR restricted area of occupancy typically: AOO < 20 kmÂ² or number of locations < 5
E. Quantitative analysis
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. It is unlikely that the species will meet any of the above criteria, although the effects of global warming are unknown.
Listing recommendation â The Southern Elephant Sea should be classified as Least Concern. No serious threats have been affecting the land breeding colonies of the species in the last 30 years. The foraging areas may be affected by the impact on the distribution of prey by climate change effects, although it is unknown how this may actually influence the species distribution and numbers. Some local declines are a cause for concern and should be assessed at the level of populations by the IUCN SSC Pinniped Specialist Group