The nighttime distribution of vertically migrating mesopelagic fish in relation to
nocturnal light was studied during a circumglobal survey, in the Red Sea, and in a fjord at
high latitude. The study was based on data derived from ship borne echo sounders
(circumglobal and the Red Sea) as well as using upward looking echo sounders mounted
on the bottom (Masfjorden, Norway). We also applied a numerical model for analyzing
diel vertical migration patterns. The effect of the lunar cycle was the focus in studies at
low latitudes, while seasonal changes in nocturnal light climate was in focus at high
latitude. Lunar phase significantly affected the distribution of mesopelagic fish at the
global scale and in the Red Sea. During nights near full moon, scattering layers of
mesopelagic fish distributed deeper than during darker phases of the moon. At high
latitude, mesopelagic fish switched its behavior along with seasonal changes in nocturnal
lights. In autumn, the population of the studied fish (Maurolicus mueleri) formed
separated layers. Juveniles performed normal diel vertical migration followed by
midnight sinking, with midnight sinking mainly related to temperature minima and also
for avoiding predators. Meanwhile the adults did not migrate vertically, reducing
foraging but increasing the adult survival. From late winter to mid-Spring, interrupted
ascents behavior was noted in the afternoon. Predator avoidance, satiation, and finding
temperature optimum might be the reason behind interrupted ascents. At lighter nights in
mid-summer, M. muelleri took on schooling behavior, likely as an anti-predator behavior
permitting access to the upper waters in the absence of darkness.
| Identifer | oai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/334480 |
| Date | 12 1900 |
| Creators | Prihartato, Perdana |
| Contributors | Kaartvedt, Stein, Biological and Environmental Sciences and Engineering (BESE) Division, Hoteit, Ibrahim, Irigoien, Xabier, Giske, Jarl |
| Source Sets | King Abdullah University of Science and Technology |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
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