Scientists engaged in a 20-year study of Antarctic fur seal pups have found that the increased monthly average sea surface temperature, which they link to climate change, can explain the recent reductions in pup production.

• Forcada, Jaume et al. "The Effects of Global Climate Variability in Pup Production of Antarctic Fur Seals." Ecology 86(9): 2408–2417. 25 January 2005 at www.esajournals.org/esaonline/?request=search-simple

The authors argue that anomalies in the sea surface temperature likely caused a reduction in available prey populations of krill (the base of the seal food chain). Resulting undernourishment has in turn significantly reduced the breeding potential of Antarctic fur seal females. Thus, a 20-year trend of increased monthly average sea surface temperature, driven by climate change, can explain the recent reductions in seal pup production.

Implications: This study demonstrates the potential for climate change to severely impact marine ecosystems throughout the entire food chain. While no specific studies have yet been undertaken, it may be anticipated that, by extension, reductions in fur seal populations will in turn negatively impact their own predators, including leopard seals and killer whales. Furthermore, it demonstrates that indirect effects quite far down the animal food chain can have devastating effects at the top of the food chain and in large and often already threatened megafauna.