168
B. STONEHOUSE
(c) Fish
Dense shoals of Engraulis anchoita and Sardinops sagax are found in
the Peruvian current, where they attract several species of seabirds
including Peruvian and Magellanic penguins. Closely related fish form
huge shoals off southern Chile and Patagonia, and are seasonally abundant at the Falkland Islands. In the Benguela current Sardinops ocellata
and Engraulis japonicus together provide over 50% of the food of
Blackfooted penguins. Off southern and western Australia many small
shoaling fish (e.g. Sardinops neopilchurdus, Clupea bassensis, Engraulis
australis) are available as food throughout the year (Roughley, 1951,
pp. 3-11); while the Northern Blue penguin is reported to feed largely
on fish I can find no record of species actually taken. In Antarctic waters
pelagic and shallow-water demersal fish, notably of the family Notothenidae, are taken by King, Emperor, Addie, Gentoo and other species.
Notothenia rossi were identified from remains on the floor of a King
penguin colony on South Georgia (Stonehouse, 1960, p.54). This fish
feeds on plankton by day in a belt from 15 to 30 miles off the northeastern side of the island (Olsen, 1954, p. 7). Small fish of the family
Scopelidae are taken by Gentoos at South Georgia (Murphy, 1936,
p. 378).
Evidence of competition between closely related penguin species is
confusing. On the Antarctic Peninsula and neighbouring islands Bagshawe (1922, p. 274) reported that Gentoo and Chinstrap penguins were
taking the same food - “the Euphausiae”. Gain (1914) reported Gentoos
and Addlies feeding on euphausids, decapod crustaceans and (especially
in spring and summer) small fish; Chinstraps in the same area took
euphausids only (pp. 60, 61). On the South Orkneys, Ardley (1936,
p. 354) noted that Chinstrap and Adklie colonies respectively had yellow
and reddish faecal deposits, suggesting dietary differences. On South
Georgia, Gentoo and Macaroni penguins take euphausids and mysids but
Kings feed almost exclusively on squid and fish (Stonehouse, in press).
Seasonal availability of food may be a t least as important as changes
in water temperature in determining the winter ranges of some penguin
species. Addies moving northward from their breeding grounds in
autumn escape to places where sea ice, though present as pack, is sufficiently broken to permit feeding. Male Emperors incubating close to the
Antarctic continent in winter remain without food for three to four
months; their females move to open water after laying, and probably
feed, although surface waters are impoverished between May and October.
King penguins feeding their chicks throughout winter on cold temperate
and sub-Antarctic islands show evidence of poor food supply, with a
sudden increase in September and October coinciding with the return of
plankton to surface waters (Foxton, 1956, p. 210; Stonehouse, 1960, p. 54).
B. STONEHOUSE
(c) Fish
Dense shoals of Engraulis anchoita and Sardinops sagax are found in
the Peruvian current, where they attract several species of seabirds
including Peruvian and Magellanic penguins. Closely related fish form
huge shoals off southern Chile and Patagonia, and are seasonally abundant at the Falkland Islands. In the Benguela current Sardinops ocellata
and Engraulis japonicus together provide over 50% of the food of
Blackfooted penguins. Off southern and western Australia many small
shoaling fish (e.g. Sardinops neopilchurdus, Clupea bassensis, Engraulis
australis) are available as food throughout the year (Roughley, 1951,
pp. 3-11); while the Northern Blue penguin is reported to feed largely
on fish I can find no record of species actually taken. In Antarctic waters
pelagic and shallow-water demersal fish, notably of the family Notothenidae, are taken by King, Emperor, Addie, Gentoo and other species.
Notothenia rossi were identified from remains on the floor of a King
penguin colony on South Georgia (Stonehouse, 1960, p.54). This fish
feeds on plankton by day in a belt from 15 to 30 miles off the northeastern side of the island (Olsen, 1954, p. 7). Small fish of the family
Scopelidae are taken by Gentoos at South Georgia (Murphy, 1936,
p. 378).
Evidence of competition between closely related penguin species is
confusing. On the Antarctic Peninsula and neighbouring islands Bagshawe (1922, p. 274) reported that Gentoo and Chinstrap penguins were
taking the same food - “the Euphausiae”. Gain (1914) reported Gentoos
and Addlies feeding on euphausids, decapod crustaceans and (especially
in spring and summer) small fish; Chinstraps in the same area took
euphausids only (pp. 60, 61). On the South Orkneys, Ardley (1936,
p. 354) noted that Chinstrap and Adklie colonies respectively had yellow
and reddish faecal deposits, suggesting dietary differences. On South
Georgia, Gentoo and Macaroni penguins take euphausids and mysids but
Kings feed almost exclusively on squid and fish (Stonehouse, in press).
Seasonal availability of food may be a t least as important as changes
in water temperature in determining the winter ranges of some penguin
species. Addies moving northward from their breeding grounds in
autumn escape to places where sea ice, though present as pack, is sufficiently broken to permit feeding. Male Emperors incubating close to the
Antarctic continent in winter remain without food for three to four
months; their females move to open water after laying, and probably
feed, although surface waters are impoverished between May and October.
King penguins feeding their chicks throughout winter on cold temperate
and sub-Antarctic islands show evidence of poor food supply, with a
sudden increase in September and October coinciding with the return of
plankton to surface waters (Foxton, 1956, p. 210; Stonehouse, 1960, p. 54).