GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
Document type
Publisher
Years
  • 1
    facet.materialart.
    Unknown
    In:  http://aquaticcommons.org/id/eprint/8984 | 403 | 2012-08-03 19:03:11 | 8984 | United States National Marine Fisheries Service
    Publication Date: 2021-06-30
    Description: Walleye pollock (Theragra chalcogramma) is widely distributed in the North Pacific Ocean and plays an important role in coastal subarctic ecosystems. The Japanese Pacific population of this species is one of the most important demersal fishes for commercial fisheries in northern Japan. The population is distributed along the Pacific coast of Hokkaido and the Tohoku area (Fig. 1), which is the southern limit of distribution of the species in the western North Pacific. In Funka Bay, the main spawning ground for this population, pollock spawn from December to March (Kendall and Nakatani, 1992). Planktonic eggs and larvae are transported into the bay, where juveniles usually remain until late July when they reach 60−85 mm in total length (Hayashi et al., 1968; Nakatani and Maeda, 1987). These juvenile pollock then migrate from Funka Bay eastward to the Doto area off southeastern Hokkaido (Honda et al., 2004). Many studies on eggs, larvae, and juveniles of the species have been conducted in or near Funka Bay, but little information is available on the ecology of the early life stages in the Tohoku area. Hashimoto and Ishito (1991) suggested that eggs are transported from Funka Bay southward to the Tohoku area by the coastal branch of the Oyashio Current, but there has been no study to verify this hypothesis.
    Keywords: Biology ; Ecology ; Fisheries
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 468-475
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    facet.materialart.
    Unknown
    In:  http://aquaticcommons.org/id/eprint/9020 | 403 | 2012-08-03 15:13:20 | 9020 | United States National Marine Fisheries Service
    Publication Date: 2021-06-30
    Description: The annual ovarian cycle, mode of maturation, age at maturity, and potential fecundity of female Rikuzen sole (Dexistes rikuzenius) from the North Pacific Ocean off thecoast of Japan were studied by 1) histological examination of the gonads, 2) measurement and observation of the oocytes, and 3) by otolith aging. The results indicated that ovulation occurs from September to December and peaks between September and October. Vitellogenesis began againsoon after the end of the current season. Maturity was divided into eight phases on the basis of oocytedevelopmental stages. Mature ovaries contained developing oocytes and postovulatory follicles but no recruitingoocytes, indicating that this species has group-synchronous ovaries and is a multiple spawner. Almost all females matured first at an age of 1+ year and spawned every yearuntil at least age 8+ years. Potential fecundity increased exponentially with body length and the most fecund fish had 15 times as many oocytes as the least fecund fish. Potential fecundity and relative fecundity were bothpositively correlated with age from 1 to 6+ years, but were negatively correlated, probably because of senescence, in fish over 7 years. These results emphasize that the total productivity of a D. rikuzenius population depends not only on the biomass of females older than 1+ but also on the agestructure of the population.
    Keywords: Biology ; Ecology ; Fisheries
    Repository Name: AquaDocs
    Type: article , TRUE
    Format: application/pdf
    Format: application/pdf
    Format: 635-647
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1573-5133
    Keywords: Community ; Density ; Species diversity ; Seasonality ; Physiculus maximowiczi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Fish assemblages at an artificial reef site, a natural reef site and a sandy-mud bottom site, on the shelf (depth 130 m) off Iwate Prefecture, northern Japan, were surveyed by using a bottom trammel net from May 1987 to March 1993. A total of 12 173 fishes of 48 species were recorded. Physiculus maximowiczi was dominant and comprised 69% of the total numerical abundance. Total fish number was lowest in March at all the 3 sites when P. maximowiczi migrated to deeper and warmer waters. Assemblage equitability and species diversity also varied seasonally in accordance with the abundance fluctuation of P. maximowiczi. P. maximowiczi, Alcichthys alcicornis and Hexagrammos otakii were more abundant at the artificial reef and natural reef sites, while Dexistes rikuzenius and Hemitripterus villosus were more abundant at the sandy-mud bottom site; total fish abundance was largest at the artificial reef site mainly due to the large number of P. maximowiczi. Species richness was similar among sites, but equitability, and consequently species diversity, was lowest at the artificial reef site. The main effect of the artificial reef seemed the attraction of P. maximowiczi from nearby bottoms, especially from natural rocky reefs; its large abundance determined the structure of the artificial reef fish community.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...