Not Being Eaten I: Diel Vertical Migration
Abstract Early near-surface zooplankton sampling revealed more of many species being caught at night than in daylight. Hypotheses abounded, several still current. For many species the answer is daily (“diel”) vertical migration (DVM): down to darker waters during daylight, up to better feeding at ni...
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| Format: | Book Part |
| Language: | English |
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Oxford University PressNew York
2023
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| Online Access: | http://dx.doi.org/10.1093/oso/9780197637326.003.0008 https://academic.oup.com/book/chapter-pdf/58024354/oso-9780197637326-chapter-8.pdf |
| Summary: | Abstract Early near-surface zooplankton sampling revealed more of many species being caught at night than in daylight. Hypotheses abounded, several still current. For many species the answer is daily (“diel”) vertical migration (DVM): down to darker waters during daylight, up to better feeding at night. Daytime abundance increases in deeper, darker strata. A 1930s study by the late G. L. Clarke demonstrated DVM by Calanus finmarchicus. Algae and animals eating algae (protozoa to copepods) are more abundant in the surface; migrators must go there to feed. However, visual predators (e.g., fish) are more dangerous there in daytime. Avoiding visual predators is obviously advantageous, but selection of DVM for that advantage is difficult to prove. Chapter 8 details five studies demonstrating that predation-avoidance is usually the main gain. Bios cover the careers of Steven Bollens and Mark Ohman. |
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