, the reproduction of the blue shark, Prionace glauca, in the southwestern equatorial Atlantic Ocean was studied. During this period, 88 females and 82 males were examined. Females were found in 4 different sexual stages: preovulatory (22), pregnant (47), postovulatory (non-pregnant) (7), and subadult (12). Their fork length ranged from 162 to 225 cm. Half of the females were in early pregnancy. Embryos in completely different stages of development were found in 4 of them. Oviducal glands of 44 females were examined and in 38 spermatozoa were found. These results indicate that ovulation and fertilization took place from December to July.Most of the males were adult and only 14 specimens seemed to be sexually immature. Many adult males were lacking sperm packs and had a very low volume of seminal fluid, suggesting that they were probably sexually resting. Theirfork length ranged from 156 to 228 cm.

No abstract

The influence of water temperatures on prey-predator interaction of walleye pollock was examined in the eastern Bering Sea during summers from 1979 to 1984. Walleye pollock was partitioned into 18 categories by sex and body lengths.The common occurrence of Greenland turbot, arrowtooth flounder, Pacific halibut, flathead sole, large Pacific cod, thorny sculpin, spinyhead sculpin, and pollock (female<56cm) which are major predators of walleye pollock with several size classes of walleye pollock was found to have a significant relationship to bottom water temperature.This study has suggested that bottom water temperature promotes species overlap which accelerates and changes predation and competition between predator and prey populations of walleye pollock.

No abstract

The recurrent groups were analyzed in order to clarify the mean pattern of the benthic species communities in the eastern Bering Sea during the summers from 1966 to 1977 excluding 1972 and to elucidate the variations of these communities during the summers from 1966 to 1971 excluding 1969. The mutual affinities between L. aspera, T. chalcogramma, G. macrocephalus and P. quadri tuberculatus were great and stable through these summers of five years. These species groups were defined as the core species group of the benthic species communities in the , central region of this continental shelf. The structures of these communities are considered to be formed and to change according to the stable and the unstable relations between the species and the core species group.