354
THE BIOLOGY OF EUPHAUSIIDS
The baleen whales can only feed efficiently on organisms that form
swarms. The species of copepods, other crustaceans, squids and fish
that are most commonly found in the stomachs of the baleen whales
are shown in Table XXXVIII. These include fish like the herring which
form shoals in the surface layers and so are easily collected by the
whales. In some instances, the fish eaten are those which are preying
on shoals of copepods or euphausiids and are consumed with the copepods or euphausiids. The species of euphausiids fed on by whales are
TABLE XXXVIII. FOOD OF BALEEN WHALES, EXCLUDINQ EUPHAUSIIDS
Calanus finmarchicus
C. helgolandicus
C. plumchrus (tonsus)
Munida gregaria
Pleuroncodes planipes
Copepods
C. cristatus
Metridia lucens
Temora longicornis
Other Crustacea
Parathemisto gaudichaudi
Squids
Ommaatrephes sloani pacificus
Loligo opalescens
Wataaenia scintillans
Fish
Anchovy (Engraulis spp.)
Horse mackerel (Trachurus spp.)
Herring (Clupea harengus, C. pallaaii) Atka mackerel (Pleurogrammus
Sand lance (Ammodytes personatus)
Blind eel (Eptatritus burgeri)
Sardines (Sardinops melanosticta)
Saury (Colorabis saira)
Alaska pollack (Theragra
Myctophid fish
monopterygius)
Mackerel (Scomber japonicua)
Capelin (Mallotus catervarius)
Cod (Gadus macrocephalus)
chaleogramma)
Gonostomid fish
listed in Table XXXIX. Only some twenty species have been recorded
in whale stomachs and some of these have only been found occasionally.
Species such as Nyctiphanes capensis, Pseudeuphausia latifrons,
Euphausia diomedeae, E. recurva, E. lucens, E. hemigibba, E. spinqera,
Thysanoessa gregaria, and Nematoscelis spp. probably do not contribute
much towards the nutrition of whales except when the whales migrate
to subequatorial regions during the polar winters. Present evidence,
however, suggests that they do not feed to any great extent during their
stay in these warmer waters (Mackintosh, 1965 ; Bannister and Baker,
1967). Further species, Euphausia vallentini, E. sirnilis, and Thysanoessa spinifera are important in restricted areas and at certain times.
THE BIOLOGY OF EUPHAUSIIDS
The baleen whales can only feed efficiently on organisms that form
swarms. The species of copepods, other crustaceans, squids and fish
that are most commonly found in the stomachs of the baleen whales
are shown in Table XXXVIII. These include fish like the herring which
form shoals in the surface layers and so are easily collected by the
whales. In some instances, the fish eaten are those which are preying
on shoals of copepods or euphausiids and are consumed with the copepods or euphausiids. The species of euphausiids fed on by whales are
TABLE XXXVIII. FOOD OF BALEEN WHALES, EXCLUDINQ EUPHAUSIIDS
Calanus finmarchicus
C. helgolandicus
C. plumchrus (tonsus)
Munida gregaria
Pleuroncodes planipes
Copepods
C. cristatus
Metridia lucens
Temora longicornis
Other Crustacea
Parathemisto gaudichaudi
Squids
Ommaatrephes sloani pacificus
Loligo opalescens
Wataaenia scintillans
Fish
Anchovy (Engraulis spp.)
Horse mackerel (Trachurus spp.)
Herring (Clupea harengus, C. pallaaii) Atka mackerel (Pleurogrammus
Sand lance (Ammodytes personatus)
Blind eel (Eptatritus burgeri)
Sardines (Sardinops melanosticta)
Saury (Colorabis saira)
Alaska pollack (Theragra
Myctophid fish
monopterygius)
Mackerel (Scomber japonicua)
Capelin (Mallotus catervarius)
Cod (Gadus macrocephalus)
chaleogramma)
Gonostomid fish
listed in Table XXXIX. Only some twenty species have been recorded
in whale stomachs and some of these have only been found occasionally.
Species such as Nyctiphanes capensis, Pseudeuphausia latifrons,
Euphausia diomedeae, E. recurva, E. lucens, E. hemigibba, E. spinqera,
Thysanoessa gregaria, and Nematoscelis spp. probably do not contribute
much towards the nutrition of whales except when the whales migrate
to subequatorial regions during the polar winters. Present evidence,
however, suggests that they do not feed to any great extent during their
stay in these warmer waters (Mackintosh, 1965 ; Bannister and Baker,
1967). Further species, Euphausia vallentini, E. sirnilis, and Thysanoessa spinifera are important in restricted areas and at certain times.