270
MAICOTO OMORI
oriviroiiniorititl kmptwiturcn (20--iiO m depth) excced 18°C (Omori,
Miito i ~ i i d Kw4,src, unpuhlished). Tht! spawning season of Acetea
japorbicu,u; in the Ariiiki! Sea (33"N) bvgins at about the end of May and
Lists until early October (Ikematwu, 1953), but' it occurs from late
July to August in the Yellow %a off west Korea (38"-37"N) (Yoshida,
1949).
In thc tropical region off Houtlzcrn India (1 2"-8"N) Acetes erythmeus iiritl A . serru1otu.s johrbi possass mature ovaries from January
to April (Naturaj, 1!)47), aid the plankton collections from October to
MLwuh Itre rich in the larval forms (Menon, 1933). Le Reste (1970)
reports thiLt the spawning of A . erythrneus in Ambaro Ray, Madagascar
( 13"s) is htwviest in Novembor-March. Spawning of Acetes australis
Colsfax (possibly u synonyin of A. eihogae Hansen) is supposed to be
heaviest. (litring mid- m d later summer (December to February) in
the l'uggeruh Lake (33OS), Australia (Morris, 1948). Apparently the
spawning of shallow-living penueids and sergestids in the temperate
region is related to temperature. Whereas, in the tropical region the
spawning almost certctinly occurs throughout the whole twelve months
of tnhe year, but the occurelwe of rich larvae along the coast is probably
related to precipitation and wind direction of the monsoons.
As described later, there are two types of generations in Acetea
japonir*us, namely, the winter or long-term generation and the
Ruiniiier or short-term generation, and the durations of the two
spawning~ overlup (Ikematsu, 1953; Yasuda et al., 1953). Females of
Bergin lucens produce eggs during one spawning season only. However,
no proof has so fur hecn obtained to deny that IS. lucens produces
scverul broods in one npuwning season. This species often retainR
coiisidcrltble number8 of imrnature ova in the ovary after spawning,
as observed in various penseids. Although it is not confirmed yet, the
possibility liits been pointod out that in the penaeids these small ova
develop later and produce a second spawning (King, 1948; Ikematsu,
1955). Newly hatched larvae of S'ergia 1ucen.s oceur in the plankton
of Suruga Ray from June to November but the abundance is not the
mme t'hrorighout the whole period. There is some tentative evidence
to suggest that occasionally two spspctwnings per female occur in a
year. The first clutch is produced in July and the second clutch in
October, when large quantities of food were available and moderate
environmental t,emperatures prevailed.
Presumably, the carids produce a sequence of broods, A female of
h@$M%" sivado spawns twice u year, in early summer and early
wint
MAICOTO OMORI
oriviroiiniorititl kmptwiturcn (20--iiO m depth) excced 18°C (Omori,
Miito i ~ i i d Kw4,src, unpuhlished). Tht! spawning season of Acetea
japorbicu,u; in the Ariiiki! Sea (33"N) bvgins at about the end of May and
Lists until early October (Ikematwu, 1953), but' it occurs from late
July to August in the Yellow %a off west Korea (38"-37"N) (Yoshida,
1949).
In thc tropical region off Houtlzcrn India (1 2"-8"N) Acetes erythmeus iiritl A . serru1otu.s johrbi possass mature ovaries from January
to April (Naturaj, 1!)47), aid the plankton collections from October to
MLwuh Itre rich in the larval forms (Menon, 1933). Le Reste (1970)
reports thiLt the spawning of A . erythrneus in Ambaro Ray, Madagascar
( 13"s) is htwviest in Novembor-March. Spawning of Acetes australis
Colsfax (possibly u synonyin of A. eihogae Hansen) is supposed to be
heaviest. (litring mid- m d later summer (December to February) in
the l'uggeruh Lake (33OS), Australia (Morris, 1948). Apparently the
spawning of shallow-living penueids and sergestids in the temperate
region is related to temperature. Whereas, in the tropical region the
spawning almost certctinly occurs throughout the whole twelve months
of tnhe year, but the occurelwe of rich larvae along the coast is probably
related to precipitation and wind direction of the monsoons.
As described later, there are two types of generations in Acetea
japonir*us, namely, the winter or long-term generation and the
Ruiniiier or short-term generation, and the durations of the two
spawning~ overlup (Ikematsu, 1953; Yasuda et al., 1953). Females of
Bergin lucens produce eggs during one spawning season only. However,
no proof has so fur hecn obtained to deny that IS. lucens produces
scverul broods in one npuwning season. This species often retainR
coiisidcrltble number8 of imrnature ova in the ovary after spawning,
as observed in various penseids. Although it is not confirmed yet, the
possibility liits been pointod out that in the penaeids these small ova
develop later and produce a second spawning (King, 1948; Ikematsu,
1955). Newly hatched larvae of S'ergia 1ucen.s oceur in the plankton
of Suruga Ray from June to November but the abundance is not the
mme t'hrorighout the whole period. There is some tentative evidence
to suggest that occasionally two spspctwnings per female occur in a
year. The first clutch is produced in July and the second clutch in
October, when large quantities of food were available and moderate
environmental t,emperatures prevailed.
Presumably, the carids produce a sequence of broods, A female of
h@$M%" sivado spawns twice u year, in early summer and early
wint