356 K. K. C. NAIR et al.: Distribution and Abundance of Planktonic Amphipods in the Indian Ocean
1969). The greater abundance of amphipods in night hauls in the upper 200 m layer may
well be due to diurnal vertical migration.
Formation of swarms is also noted among pelagic amphipods. During an oceanographic cruise of "Blue Fin" (April, 1970) a swarm of hyperiid amphipods mostly constituted by a single genus, Hyperia (family Hyperiidae) was observed extending for more
than 20 miles along the coast of Kerala; flying fishes in large numbers were seen feeding
on them.
1969). The greater abundance of amphipods in night hauls in the upper 200 m layer may
well be due to diurnal vertical migration.
Formation of swarms is also noted among pelagic amphipods. During an oceanographic cruise of "Blue Fin" (April, 1970) a swarm of hyperiid amphipods mostly constituted by a single genus, Hyperia (family Hyperiidae) was observed extending for more
than 20 miles along the coast of Kerala; flying fishes in large numbers were seen feeding
on them.