Summary: Diel vertical migration of the deep-water jellyfish Periphylla periphylla simulated as
individual responses to absolute light intensity
Nicolas Dupont,a,* T. A. Klevjer,b S. Kaartvedt,b and D. L. Aksnesa
a Department of Biology, University of Bergen, Bergen, Norway
bDepartment of Biology, University of Oslo, Oslo, Norway
We evaluate the hypothesis that the vertical migration of Periphylla periphylla is governed by its sensitivity to
light intensity. By applying an individual-based model where random walk is combined with assumed individual
responses to light, we compare the predicted vertical distributions with acoustical observations. Important
features of the observed P. periphylla distributions can be explained by a simple proximate light response where
individual P. periphylla avoids light above a certain threshold but also has a preference for very low light
intensities. In addition to accounting for the observed synchronous diel vertical migration phenomenon in P.
periphylla, this simple mechanism also accounts for simultaneous asynchronous vertical migrations observed for
part of the population.
Periphylla periphylla is a mesopelagic coronate scypho-
medusae of the family Periphyllidae and is considered to be
a deep-water species with a global distribution (Fossa°
1992). This species is established in exceptionally high
abundances in at least three Norwegian fjords (Sørnes et al.
2007), but mass occurrences have also been recently