Development, Dispersal and Recruitment:
A Paradox for Survival Among Antarctic Fish
Martin G. White
British Antarctic Survey, NERC, High Cross, Madingley Road, Cambridge CB3
OET, UK
Introduction
At first sight, the life-history strategies adopted by Antarctic fish appear to
be a paradox. The majority of fish species are demersal and inhabit the
peri-Antarctic islands that are isolated, separated by deep ocean, and
subject to the influence of strong currents of the West Wind Drift. In
common with Antarctic benthic invertebrates, nearly all of the Antarctic
fish have protracted early development but by contrast most Antarctic fish
have retained a pelagic larval phase that extends over several months.
The presence of a protracted pelagic phase vulnerable to losses by
advection from favourable habitats seems inconsistent with a successful
survival strategy.
Antarctic Fish Fauna Composition and Life-History
The Antarctic fish fauna is unusual because it exhibits low species
diversity but has high levels of endemism. There are some 274 recognized
species of fish that inhabit the Southern Ocean and more are being
described, as the less well researched taxa are re-examined. The majority
(>71 %) are bottom dwelling and this demersal group is dominated in
terms of numbers and biomass by the sub-order Notothenioidei [1]. Many
notothenioids are endemic and confined to specific island groups or show
circum-continental distribution patterns [2].
Notothenioids lack swim bladders, most are demersal and are dependent
upon shelf habitats as adults. Only a few species have become adapted to
the pelagic system.
The life-history is fully known only for a small number of species but it
is generally accepted that most Antarctic notothenioids are characterized
by delayed maturation, have low relative fecundity, and produce large
yolky eggs [3,4]. The majority of species spawn demersally. The eggs may
remain benthic and the adults of some species are known to protect the egg
mass while other species have pelagic eggs [5].
G. di Prisco, E. Pisano, A. Clarke (Eds)
Fishes of Antarctica. A biological overview
© Springer-Verlag Italia 1998
A Paradox for Survival Among Antarctic Fish
Martin G. White
British Antarctic Survey, NERC, High Cross, Madingley Road, Cambridge CB3
OET, UK
Introduction
At first sight, the life-history strategies adopted by Antarctic fish appear to
be a paradox. The majority of fish species are demersal and inhabit the
peri-Antarctic islands that are isolated, separated by deep ocean, and
subject to the influence of strong currents of the West Wind Drift. In
common with Antarctic benthic invertebrates, nearly all of the Antarctic
fish have protracted early development but by contrast most Antarctic fish
have retained a pelagic larval phase that extends over several months.
The presence of a protracted pelagic phase vulnerable to losses by
advection from favourable habitats seems inconsistent with a successful
survival strategy.
Antarctic Fish Fauna Composition and Life-History
The Antarctic fish fauna is unusual because it exhibits low species
diversity but has high levels of endemism. There are some 274 recognized
species of fish that inhabit the Southern Ocean and more are being
described, as the less well researched taxa are re-examined. The majority
(>71 %) are bottom dwelling and this demersal group is dominated in
terms of numbers and biomass by the sub-order Notothenioidei [1]. Many
notothenioids are endemic and confined to specific island groups or show
circum-continental distribution patterns [2].
Notothenioids lack swim bladders, most are demersal and are dependent
upon shelf habitats as adults. Only a few species have become adapted to
the pelagic system.
The life-history is fully known only for a small number of species but it
is generally accepted that most Antarctic notothenioids are characterized
by delayed maturation, have low relative fecundity, and produce large
yolky eggs [3,4]. The majority of species spawn demersally. The eggs may
remain benthic and the adults of some species are known to protect the egg
mass while other species have pelagic eggs [5].
G. di Prisco, E. Pisano, A. Clarke (Eds)
Fishes of Antarctica. A biological overview
© Springer-Verlag Italia 1998