The Vertical Distribution of Marine Macroplankton. XII. Some Observations on the Vertical Distribution of Calanus finmarchicus in Relation to Light Intensity.

• Published in: Journal of the Marine Biological Association of the United Kingdom
• Main Author: Russell, F. S.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1934
• Subjects: Aquatic Science; Calanus finmarchicus
• Online Access: http://dx.doi.org/10.1017/s0025315400046646; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0025315400046646

1. Observations are given on the vertical distribution of adult Calanus finmarchicus in the daytime off Plymouth in July and August, 1931, as a result of collections made simultaneously with the photo-electric measurement of submarine illumination. 2. A series of nets, usually six, was towed simultaneously in such a manner that the depth of each net was known approximately. 3. The female Calanus in July preferred higher intensities of light than did the females in August; this change was coincident with a change in the Calanus population as shown by size measurements. A similar change in distribution and in population was shown by the males. 4. The females in July were living in intensities of 20,000 m.c. and more; but those in August were avoiding such high intensities. The males in July avoided intensities of 40,000 m.c. and over, while in August their upper limit was about 10,000 m.c.