TllN tt10140(lY OF PELA(;HC StfHIMPS IN THE OCEAN
269
number of eggs curried by a female in the latter group is much greater
than that in the former group.
On the whole, the lower mc'so- and bathypelagic species produce
lurpr but fewer egg8 and larvae rclative to the epipelagic species.
This rneans that the large larvae hatched from the large yolk-filled
eggs survive with internal yolk alone during their long journey to the
shallow layers where there is a rich supply of food. After metamorphosis they can utilize a wider range of material aa food.
In any one species a large female spctwns a larger number of eggs
than a small female. Therefore, the nurnbcr of eggs produced by a
decapod crustacean is dependant not only upon the volume of the
eggs bnt also upon the size of the parent. Generally, the number of
eggs per female is a linear function of the size of the female (Jensen,
1958). Measurements and counts of the eggs of twelve common species
of penaeids and carids reported in the literature (Kubo, 1951 ; Jensen,
1958; Ikematsu, 1963; Apollonio, 1969; Omori, 1971b) suggest that
the maximum/minimum ratio of the number of eggs produced by a
female in one breeding season at one locality varies from 2 to 10, with
an average of 4.5. The weight of the ovary in Sergiu lucens is equal to
about 11-14% (average of 26 specimens, 12.5%) of the body weight
of the parent and that of 8. prehensilis is 1613% (average of 21
specimens, 11.4%). In the pelagic carids the proportion of the weight
of the fertilized eggs to the total body weight (weight of the eggs plus
weight of thc: purent) was 10~0-10~50/, in Pa.?ipka sp., 7. 8O%, in
Oplophorus graciliroatris A. Milne Edwards, 7.3%, in 0. spinosua, 9.5%
in Amnthephyru cximia, 11 -8% in Notostomus japonicw Bate, 13.2% in
Iiymenodora froiitnlis, 7.4% in Systellaspi,? braueri (Balss) and 9.7 % in
S. Zanceocnzufuata Hate (Omori, unpublished).
Sergesles siwilis in Monterey Ray spawns in December-January
and in Jiine-July. and two overlapping size-groups undergo the same
developmental history but six months out of phase (Barham, 1967).
According to Permy and Form (1969) the species spawns throughout
most of the yew otf the Oregon coast. However, young shrimps were
not uniformly abundant, suggesting pulses of spawning in spring and
wintcr. Matthews and Pinnoi (1973) state that Seryestea urclicw
breeds in spring in Korsfjorden, Norway.
In the temperate waters around Japan the spawning of shallow
benthic penaeids is usually heaviest during summer. That of the
carids generally takes place in spring and autumn (Yasuda, 1957;
Ikematsu, 1963). Like the penaeids, the spawning of Sergia lucena
in Suruga Bay (35'N) occurs from late May to mid-November, and
it is heitviest in June-August. The spawning starts exactly after
269
number of eggs curried by a female in the latter group is much greater
than that in the former group.
On the whole, the lower mc'so- and bathypelagic species produce
lurpr but fewer egg8 and larvae rclative to the epipelagic species.
This rneans that the large larvae hatched from the large yolk-filled
eggs survive with internal yolk alone during their long journey to the
shallow layers where there is a rich supply of food. After metamorphosis they can utilize a wider range of material aa food.
In any one species a large female spctwns a larger number of eggs
than a small female. Therefore, the nurnbcr of eggs produced by a
decapod crustacean is dependant not only upon the volume of the
eggs bnt also upon the size of the parent. Generally, the number of
eggs per female is a linear function of the size of the female (Jensen,
1958). Measurements and counts of the eggs of twelve common species
of penaeids and carids reported in the literature (Kubo, 1951 ; Jensen,
1958; Ikematsu, 1963; Apollonio, 1969; Omori, 1971b) suggest that
the maximum/minimum ratio of the number of eggs produced by a
female in one breeding season at one locality varies from 2 to 10, with
an average of 4.5. The weight of the ovary in Sergiu lucens is equal to
about 11-14% (average of 26 specimens, 12.5%) of the body weight
of the parent and that of 8. prehensilis is 1613% (average of 21
specimens, 11.4%). In the pelagic carids the proportion of the weight
of the fertilized eggs to the total body weight (weight of the eggs plus
weight of thc: purent) was 10~0-10~50/, in Pa.?ipka sp., 7. 8O%, in
Oplophorus graciliroatris A. Milne Edwards, 7.3%, in 0. spinosua, 9.5%
in Amnthephyru cximia, 11 -8% in Notostomus japonicw Bate, 13.2% in
Iiymenodora froiitnlis, 7.4% in Systellaspi,? braueri (Balss) and 9.7 % in
S. Zanceocnzufuata Hate (Omori, unpublished).
Sergesles siwilis in Monterey Ray spawns in December-January
and in Jiine-July. and two overlapping size-groups undergo the same
developmental history but six months out of phase (Barham, 1967).
According to Permy and Form (1969) the species spawns throughout
most of the yew otf the Oregon coast. However, young shrimps were
not uniformly abundant, suggesting pulses of spawning in spring and
wintcr. Matthews and Pinnoi (1973) state that Seryestea urclicw
breeds in spring in Korsfjorden, Norway.
In the temperate waters around Japan the spawning of shallow
benthic penaeids is usually heaviest during summer. That of the
carids generally takes place in spring and autumn (Yasuda, 1957;
Ikematsu, 1963). Like the penaeids, the spawning of Sergia lucena
in Suruga Bay (35'N) occurs from late May to mid-November, and
it is heitviest in June-August. The spawning starts exactly after