Evaluation of reproductive costs for Weddell seals in Erebus Bay, Antarctica
Article first published online: 16 MAR 2007
Journal of Animal Ecology
Volume 76, Issue 3, pages 448–458, May 2007
How to Cite
HADLEY, G. L., ROTELLA, J. J. and GARROTT, R. A. (2007), Evaluation of reproductive costs for Weddell seals in Erebus Bay, Antarctica. Journal of Animal Ecology, 76: 448–458. doi: 10.1111/j.1365-2656.2007.01219.x
- Issue published online: 16 MAR 2007
- Article first published online: 16 MAR 2007
- Received 8 December 2006; accepted 25 January 2007
- breeding costs;
- breeding state;
- environmental variation;
- Leptonychotes weddellii;
- 1Organisms balance current reproduction against future survival and reproduction, which results in life-history trade-offs. These trade-offs are also known as reproductive costs and may represent significant factors shaping life-history strategy for many species.
- 2Using multistate mark–resight models and 26 years of mark–resight data (1979–2004), we estimated the costs of reproduction to survival and reproductive probabilities for Weddell seals in Erebus Bay, Antarctica and evaluated whether this species either conformed to the ‘prudent parent’ reproductive strategy predicted by life-history theory for long-lived mammals or alternatively, incurred costs to survival in order to reproduce in a variable environment (flexible-strategy hypothesis).
- 3Results strongly supported the presence of reproductive costs to survival (mean annual survival probability was 0·91 for breeders vs. 0·94 for nonbreeders), a notable difference for a long-lived mammal, demonstrating that investment in reproduction does result in a cost to survival for Weddell seals, contrary to the prudent parent hypothesis.
- 4Reproductive costs to subsequent reproductive probabilities were also present for first-time breeders (mean probability of breeding the next year was 31·3% lower for first-time breeders than for experienced breeders), thus supporting our prediction of the influence of breeding experience.
- 5We detected substantial annual variation in survival and breeding probabilities. Breeding probabilities were negatively influenced by summer sea-ice extent, whereas weak evidence suggested that survival probabilities were affected more by winter sea-ice extent, and the direction of this effect was negative. However, a model with annual variation unrelated to any of our climate or sea-ice covariates performed best, indicating that further study will be needed to determine the appropriate mechanism or combination of mechanisms underlying this annual variation.