3GG
THE BIOLOGY O F lN7PIIAUSIIDS
(Cuv. & Val.), eats Euphausia similis, Thysanopoda distinguenda (?),
and Nyctiphanes capensis to a large extent except in the case of the
largest fish. The euphausiids, Euphausia similis and Nyctiphanes
capensis, constituted about 14% of the diet of the sandcord, Helicolenus
maculatus (Cuv. & Val.), but were not important, although present, in
the diet of the smooth rat tail, Lionurus nigromaculatus (McCulloch).
Maasbankers, Trachurus trachurus (L.)) fed on euphausiids and Nepgen
(1957) found them to constitute as much as 64% of the stomach contents
of fish caught in deep water.
I n Australian waters, according to Sheard (1953)) aggregations of
adult and larval Nyctiphanes australis are eaten by the southern bluefin
tuna, Thunnus maccoyii, the striped tuna, Katsuwonis pelamis (L.), the
barracouta, Thysites atun Euphras., the Australian pilchard, Sardinops
neopilchardus, and the tiger flathead, Neoplatycephalus macrodon.
Blackburn (1957) made a special study of the feeding of the Australian
barracouta which occurs in large numbers off the southeastern coasts.
Its staple food is Nyctiphanes australis but occasional specimens of
Thysanoessa gregaria, Nematoscelis megalops, and Euphausia recurva
were recorded in the stomachs of fish from the coasts of eastern Victoria
and New South Wales. Barracouta can apparently work together in a
group to herd these sinall euphausiids into a packed mass so that they
can feed easily on them. Barracouta off New Zealand include Nyctiphanes australis and off South Africa N . capensis in their diets.
Very little is known about the feeding habits of Antarctic fish.
Marr (1962) has reviewed the subject and concludes that the
following species are predators of Euphausia superba: Electrona
antarctica (Gunther), Lampanyctus braueri (Lonnberg), Notothenia
rossii Richardson, Notolepis coatsi Dollo, Dissostichus mawsoni Norman,
Neopagetopsis ionah (Nybelin), Trematomus lonnbergi Regan, Prionodraco sp., P. evansii Regan, Champsocephalus gunnari Lonnberg,
Pseudochaenichthys georgianus Norman, and Parachaenichthys georgianus
(Fischer). The first five species of fish mentioned are probably the most
predatory on euphausiids but Champsocephalus gunnari may also
be one of this group ; in fact Marr considers that the most numerous
species is Notothenia rossii and that Champsocephalus gunnari may be
the second most important predator of euphausiids. It is difficult to
estimate how great the predation of euphausiids is by the Antarctic
fish populations because no valid estimations of these fish populations
exist. More efficient methods of pelagic trawling may show that the
fish are extremely important predators, an idea advanced by Marr and
contrary to that of Walford (1958) who does not consider fish to be
important in these regions.
THE BIOLOGY O F lN7PIIAUSIIDS
(Cuv. & Val.), eats Euphausia similis, Thysanopoda distinguenda (?),
and Nyctiphanes capensis to a large extent except in the case of the
largest fish. The euphausiids, Euphausia similis and Nyctiphanes
capensis, constituted about 14% of the diet of the sandcord, Helicolenus
maculatus (Cuv. & Val.), but were not important, although present, in
the diet of the smooth rat tail, Lionurus nigromaculatus (McCulloch).
Maasbankers, Trachurus trachurus (L.)) fed on euphausiids and Nepgen
(1957) found them to constitute as much as 64% of the stomach contents
of fish caught in deep water.
I n Australian waters, according to Sheard (1953)) aggregations of
adult and larval Nyctiphanes australis are eaten by the southern bluefin
tuna, Thunnus maccoyii, the striped tuna, Katsuwonis pelamis (L.), the
barracouta, Thysites atun Euphras., the Australian pilchard, Sardinops
neopilchardus, and the tiger flathead, Neoplatycephalus macrodon.
Blackburn (1957) made a special study of the feeding of the Australian
barracouta which occurs in large numbers off the southeastern coasts.
Its staple food is Nyctiphanes australis but occasional specimens of
Thysanoessa gregaria, Nematoscelis megalops, and Euphausia recurva
were recorded in the stomachs of fish from the coasts of eastern Victoria
and New South Wales. Barracouta can apparently work together in a
group to herd these sinall euphausiids into a packed mass so that they
can feed easily on them. Barracouta off New Zealand include Nyctiphanes australis and off South Africa N . capensis in their diets.
Very little is known about the feeding habits of Antarctic fish.
Marr (1962) has reviewed the subject and concludes that the
following species are predators of Euphausia superba: Electrona
antarctica (Gunther), Lampanyctus braueri (Lonnberg), Notothenia
rossii Richardson, Notolepis coatsi Dollo, Dissostichus mawsoni Norman,
Neopagetopsis ionah (Nybelin), Trematomus lonnbergi Regan, Prionodraco sp., P. evansii Regan, Champsocephalus gunnari Lonnberg,
Pseudochaenichthys georgianus Norman, and Parachaenichthys georgianus
(Fischer). The first five species of fish mentioned are probably the most
predatory on euphausiids but Champsocephalus gunnari may also
be one of this group ; in fact Marr considers that the most numerous
species is Notothenia rossii and that Champsocephalus gunnari may be
the second most important predator of euphausiids. It is difficult to
estimate how great the predation of euphausiids is by the Antarctic
fish populations because no valid estimations of these fish populations
exist. More efficient methods of pelagic trawling may show that the
fish are extremely important predators, an idea advanced by Marr and
contrary to that of Walford (1958) who does not consider fish to be
important in these regions.