open access

https://hdl.handle.net/2115/45763

Diel vertical migration, population structure and life cycle of the copepod Scolecithricella minor (Calanoida: Scolecitrichidae) in Toyama Bay, southern Japan Sea

英語

Japan Sea

1999-02

The Plankton Society of Japan

Plankton biology and ecology

46(1)

54-61

The seasonal population structure (copepodite-2 stage through adults) and diel vertical migration pattern of Scolecithricella minor in Toyama Bay, southern Japan Sea, were investigated. Eggs and nauplii were reared in the laboratory at three different temperatures (0.5, 5 and 10°C) as a basis to estimate generation length. Most copepodite stages occurred throughout the year; young copepodites (C2 to C5) were most abundant in May-October, while adults were most abundant in March-August. Reproduction continued throughout the year, with a peak in April-August. All copepodite stages were consistently distributed at 100-400 m depth. Limited nocturnal ascent was seen in adults, but not always for younger copepodites. Based on habitat temperature, development times of eggs and nauplii expressed as a function of temperature, and assumed proportion of these developmental times in one life cycle of calanoid copepods, the generation length of S. minor was estimated to be 44-76d. Using this estimated generation length range as a guide, the sequential development of five cohorts was identified. An additional two extra cohorts, which were not clearly traceable, are considered to have occurred for a total of 7 cohorts per year for S. minor in Toyama Bay. The present data on the vertical distribution of S. minor are compared with those reported from other regions for the same species. Since S. minor is considered to be a typical detritus feeder, trophic-type-related sequences in major reproduction seasons are discussed by comparing the data of other calanoid copepods reported from Toyama Bay.

学術雑誌論文

Version of Record

© 1999 The Plankton Society of Japan

1343-0874