The Pelagic Fish Community of the Polar Frontal Zone
off the Kerguelen Islands
Guy Duhamel
Museum National d'Histoire Naturelle, Laboratoire d'Ichtyologie generale et
appliquee, 43 rue Cuvier, 75231 Paris Cedex OS, France
Introduction
Because of the clearly observed increase of the majority of fur seal and
penguin populations in the Southern Ocean new developments in marine
studies are attempting to quantify the impact of predators on marine
resources. The predation in the subAntarctic zone of this ocean is directed
mainly to the mesopelagic fish as noted from studies at the breeding sites
of predators. Guinet et al. [1], studying the Indian sector of the Southern
Ocean, have estimated that the annual consumption of marine seabirds and
fur seals off the Kerguelen Islands was about 1.8xl0 6 tonnes during 1985,
including 26% (0.46x10 6 tonnes) of Myctophidae. At that time they
considered that the king penguin (Aptenodyptes patagonicus) population
(173 000 pairs) takes about 146236 tonnes of Myctophidae annually. The
nearby Crozet Islands, sheltering 1 771 000 king penguins, consume about
744 700 tonnes of myctophids [I]! The potential impact of these top
predators on the marine resources can be estimated when the world
population size is considered. These birds are recognized to be the most
specialized in the predation of mesopelagic fish, specially the Myctophidae
[2-5]. However no real-time study of the pelagic fish community present in
the foraging range of a top predator has ever been published. A joint
ornitho-ichthyological study in summer, in the offshore Polar Frontal Zone
near the eastern coast of the Kerguelen Islands (distance: 20 - 110 miles;
bottom depth: 450 - 2300 m), was the first to investigate the pelagic fish
community of the upper water column. The aims were to study the
distribution and abundance of the prey and to test whether predators could
be used as bioindicators of the marine resources.
Only the fish results were presented subsequently.
Material and Methods
The fish sampling strategy was directly dependent on knowledge of the
geographic position and foraging range of a satellite tracked predator (king
penguin, A. patagonicus), breeding on the eastern coast of the Kerguelen
G. di Prisco, E. Pisano, A. Clarke (Eds)
Fishes of Antarctica. A biological overview
© Springer-Verlag Italia 1998
off the Kerguelen Islands
Guy Duhamel
Museum National d'Histoire Naturelle, Laboratoire d'Ichtyologie generale et
appliquee, 43 rue Cuvier, 75231 Paris Cedex OS, France
Introduction
Because of the clearly observed increase of the majority of fur seal and
penguin populations in the Southern Ocean new developments in marine
studies are attempting to quantify the impact of predators on marine
resources. The predation in the subAntarctic zone of this ocean is directed
mainly to the mesopelagic fish as noted from studies at the breeding sites
of predators. Guinet et al. [1], studying the Indian sector of the Southern
Ocean, have estimated that the annual consumption of marine seabirds and
fur seals off the Kerguelen Islands was about 1.8xl0 6 tonnes during 1985,
including 26% (0.46x10 6 tonnes) of Myctophidae. At that time they
considered that the king penguin (Aptenodyptes patagonicus) population
(173 000 pairs) takes about 146236 tonnes of Myctophidae annually. The
nearby Crozet Islands, sheltering 1 771 000 king penguins, consume about
744 700 tonnes of myctophids [I]! The potential impact of these top
predators on the marine resources can be estimated when the world
population size is considered. These birds are recognized to be the most
specialized in the predation of mesopelagic fish, specially the Myctophidae
[2-5]. However no real-time study of the pelagic fish community present in
the foraging range of a top predator has ever been published. A joint
ornitho-ichthyological study in summer, in the offshore Polar Frontal Zone
near the eastern coast of the Kerguelen Islands (distance: 20 - 110 miles;
bottom depth: 450 - 2300 m), was the first to investigate the pelagic fish
community of the upper water column. The aims were to study the
distribution and abundance of the prey and to test whether predators could
be used as bioindicators of the marine resources.
Only the fish results were presented subsequently.
Material and Methods
The fish sampling strategy was directly dependent on knowledge of the
geographic position and foraging range of a satellite tracked predator (king
penguin, A. patagonicus), breeding on the eastern coast of the Kerguelen
G. di Prisco, E. Pisano, A. Clarke (Eds)
Fishes of Antarctica. A biological overview
© Springer-Verlag Italia 1998