DR. L. G. HALSEY
Current Research
Interests:
While highly desirable, the regular monitoring of the fish stocks
of
the
Southern Ocean is difficult to conduct because of the high cost
of at-sea surveys. It has been proposed that seabirds could be useful
bio-indicators of any changes in these fish stocks. However, to use
seabirds successfully for these means, we need to quantifiably
understand their energy requirements through each stage of their yearly
cycles, as well as the correlations between their energetic costs of
foraging and the levels of available fish resources.
The king
penguin (Aptenodytes patagonicus), as a top predator, is a very
useful species with which to investigate changes in fish stocks and is
the study species of my present post-doc research. The main aims of the
project are to answer questions regarding:
-
The energy expenditure of breeding king penguins on
Possession Island, Crozet Archipelago
-
The effects of their unusual breeding cycle and seasonal
changes on energy costs of foraging
-
The effectiveness of this species as a bio-indicator of
pelagic fish stocks
-
The extent of regional hypothermia and buoyancy changes
employed by this species to save energy during periods of foraging
(diving)
To
achieve these aims, implantable data loggers are deployed on
free-ranging penguins for complete breeding cycles at Possession Island,
situated in the sub Antarctic region of the Southern Indian Ocean. Heart
rate is used as a proxy for metabolic rate and therefore energy
expenditure. Various body temperatures and pressure (indicating dive
depth) are also recorded by these loggers. Further, behavioural loggers
are employed to ascertain the exact position of the bird at any
particular time, providing detailed information on the movements of
these animals and their foraging behaviour. The project is ongoing until
summer 2006.
