Gentoo Chick Mortality
(A detailed report can be downloaded as a pdf HERE.
Visitors to South Georgia this season have reported that many of the Gentoo Penguin colonies are showing signs of high chick mortality. In some cases there are no chicks at all in colonies.
The Government of South Georgia has tasked scientists to collect samples of dead chicks. Diet sampling of adults is also taking place as part of longer-term monitoring which was already underway at two locations on the island.
Preliminary investigations suggest that the mortality is caused by lack of food. Gentoo penguins feed on krill which moves around in the current of the southern ocean after spawning under Antarctic ice. There have been other indications that there is a scarcity of krill around South Georgia this season, although other species which feed on krill do not appear to be affected to the same extent.
Krill is only fished in South Georgia outside the breeding season in winter months (May – August) and the swarms which are targeted will already have moved away from the Island in the currents. Krill abundance tends to be cyclical. The present lack of krill is most likely to be caused by a poor spawning season further south. The last three recorded instances of such high chick mortality were in 1991, 1994 and 1998.
As a precaution, all visitors have been asked to remain up to 200m away from gentoo colonies. This will ensure surviving birds do not suffer any undue stress from external pressures. If further research reveals a disease is identified this will also help to minimise the risk of spreading pathogens.
Excerpts from the South Georgia Society's Newsletter of December 2008 @
http://www.sgisland.gs/index.php/(h)South_Georgia_Newsletter%2C_December_2008?useskin=
Another hearty thanks goes to Paul,from NZ, for the heads-up! :)
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