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Abstract
1) Better information on historical and current population dynamics is central to understanding patterns of growth and decline in the California sea otter population. We developed a maximum likelihood-based analytical method to estimate historical age/sex specific vital rates as well as spatial and temporal variation in vital rates from longitudinal databases on population census numbers and the age-structure of salvaged carcasses.
2) We estimated current demographic parameters by conducting a mark-recapture study, measuring survival and reproduction of 115 radio-tagged individuals between 2001 and 2004. These current estimates were compared to estimates from a similar study of radiotagged otters conducted in the mid-eighties.
3) Together, these two approaches indicated that survival has decreased substantially between the early 1990s and the present and is lowest in the north-central portion of the population's range.
4) The greatest decrease in survival was for adult females (≥ 4 years of age). Variation in the survival of this age/sex class is primarily responsible for regulating population growth and driving population trends.
| Publication type | Book chapter |
|---|---|
| Publication Subtype | Book Chapter |
| Title | Spatial and temporal variation in sea otter demography |
| Chapter | 2 |
| Year Published | 2006 |
| Language | English |
| Publisher | U.S. Department of the Interior: Minerals Management Service, Pacific OCS Region |
| Contributing office(s) | Alaska Science Center |
| Description | 31 p. |
| Larger Work Type | Report |
| Larger Work Subtype | Federal Government Series |
| Larger Work Title | Population dynamics and biology of the California sea otter (Enhydra lutris nereis) at the southern end of its range |
| First page | 12 |
| Last page | 42 |