iiciinI)(w i n ordiiiury plaiil
The recent
inil)roveriimts in s i ~ ~ ~ i p l i i ~ g
g ~ a r
ittit1 technique, as seen in the Tucker
~tc-t, ('~ii(!Iwr, 1 !)51 ; Ihvies i m t l IJarhkun, 1969), Isaacs-Kidd midwater
trawl ( I Khl'l') ( Lsmcs ;~nd Kidci, I953 ; Aron, 1 sag), OM-net (Omori.
tg(ifi). Bongo-net (Mdhwitn and Brown, 1966) and RMT8 (Clarke,
196$)), hiivc thditatetl t h o study of pelagic shrimps. However such
large iicts imd trawls are mostly towed in depths shallower thap
t (100 i n , ib1id qiiantitat,ivr collection is difficult because shrimps are
goii~ritll.y pitchily ciistxibutetl both vertically and horizontally. The
ttvidablo data enablo us to describe only characteristir features of the
species oompositkm and vertical distributioii in the 0-1 000 m water
roliirnri and the life liist>ory of predominant species.
Siiice 1!)63 thc staff of the plankton laboratory of the Ocean
Itesearc*h I nstitute has conducted an extensive plankton survey
ilsing the 0141-net and ZKMT. The survey covers a wide area in the
north-western Pacific Ocean in depths ranging from the surface to
about 1 500 in. During the course of this investigation, attention has
been paid to the analysis of the life of pelagic shrimps as well as other
midwater animals, and we have obtained much information on their
biology although somc results have not been published as yet.
Such circunistmces prompttad me to summarize our present knowlectgc of thcb biology i m l c~cology of pelagic shrimps, and review all
nvidable previoiis litcwrturc with o u r data. [ hope this study will be
1rsefi11 in fiiturcl invrstigatiotis 01' the shrimps in the ocean.
'rlicy ( v ~ n he c~iy)tru*rtl with lwge nets or t'rawk.
11. (:ENERAL F K A T U ~ ~ I G S
o w YEI,A(XIC SHRIMPS
Tlic iiuiiibcv- of spwics of tlwapo(l crnstiwwxi which pans their
permtuiwt life iii thc prlagicb phiis(. is rrhtivctly small cornpard with
the richiiesx o f the bcnthic. fbrms. Systomatically, a11 reprt*sentative
genera belong to the NiLt,ant i i i hlacriira. The number of pelagic species
is less than 210 out of 21 total of about 1 940 species in this supttrscction,
and most of these are inclrided in the subfamilies Aristeinae and
Sergestinao of the section Penaeidea or the families Pasiphaeidae,
Oplophoridae tuid Pandalidae of the section Caridea. Table I show8
major genera and representative species of pelagic shrimps. For some
species, such as Sympasiphaea imperialis Terao and Eupasiphae gibsi
Wood-Mason, which are rarely found in deep water, i t is uncertain
whether thcy have a true pelagic mode of life. Several benthic shrimps
arv known t,o be distributed in midwater at night, although they live
on or in tht. bottom sediments by day. It, is probable that the species
in such geiiera iis Ariatapus, Aristeomorpha and Benthcscymus of the
The recent
inil)roveriimts in s i ~ ~ ~ i p l i i ~ g
g ~ a r
ittit1 technique, as seen in the Tucker
~tc-t, ('~ii(!Iwr, 1 !)51 ; Ihvies i m t l IJarhkun, 1969), Isaacs-Kidd midwater
trawl ( I Khl'l') ( Lsmcs ;~nd Kidci, I953 ; Aron, 1 sag), OM-net (Omori.
tg(ifi). Bongo-net (Mdhwitn and Brown, 1966) and RMT8 (Clarke,
196$)), hiivc thditatetl t h o study of pelagic shrimps. However such
large iicts imd trawls are mostly towed in depths shallower thap
t (100 i n , ib1id qiiantitat,ivr collection is difficult because shrimps are
goii~ritll.y pitchily ciistxibutetl both vertically and horizontally. The
ttvidablo data enablo us to describe only characteristir features of the
species oompositkm and vertical distributioii in the 0-1 000 m water
roliirnri and the life liist>ory of predominant species.
Siiice 1!)63 thc staff of the plankton laboratory of the Ocean
Itesearc*h I nstitute has conducted an extensive plankton survey
ilsing the 0141-net and ZKMT. The survey covers a wide area in the
north-western Pacific Ocean in depths ranging from the surface to
about 1 500 in. During the course of this investigation, attention has
been paid to the analysis of the life of pelagic shrimps as well as other
midwater animals, and we have obtained much information on their
biology although somc results have not been published as yet.
Such circunistmces prompttad me to summarize our present knowlectgc of thcb biology i m l c~cology of pelagic shrimps, and review all
nvidable previoiis litcwrturc with o u r data. [ hope this study will be
1rsefi11 in fiiturcl invrstigatiotis 01' the shrimps in the ocean.
'rlicy ( v ~ n he c~iy)tru*rtl with lwge nets or t'rawk.
11. (:ENERAL F K A T U ~ ~ I G S
o w YEI,A(XIC SHRIMPS
Tlic iiuiiibcv- of spwics of tlwapo(l crnstiwwxi which pans their
permtuiwt life iii thc prlagicb phiis(. is rrhtivctly small cornpard with
the richiiesx o f the bcnthic. fbrms. Systomatically, a11 reprt*sentative
genera belong to the NiLt,ant i i i hlacriira. The number of pelagic species
is less than 210 out of 21 total of about 1 940 species in this supttrscction,
and most of these are inclrided in the subfamilies Aristeinae and
Sergestinao of the section Penaeidea or the families Pasiphaeidae,
Oplophoridae tuid Pandalidae of the section Caridea. Table I show8
major genera and representative species of pelagic shrimps. For some
species, such as Sympasiphaea imperialis Terao and Eupasiphae gibsi
Wood-Mason, which are rarely found in deep water, i t is uncertain
whether thcy have a true pelagic mode of life. Several benthic shrimps
arv known t,o be distributed in midwater at night, although they live
on or in tht. bottom sediments by day. It, is probable that the species
in such geiiera iis Ariatapus, Aristeomorpha and Benthcscymus of the