Schooling of the vertically migrating mesopelagic fish Maurolicus muelleri in light summer nights

Abstract

Vertically migrating Maurolicus mueUerj arrested periods at subsurface depths (Giske et al. 1990, Giske their nocturnal ascent below the peak zooplankton concen~k~~~~ 1992, ~ ~ l i f i ~ & ~k~ ~~ 1993, ~~~d~~~ et trations during light summer nights at 62N. At 6g0N, the behavior was further modified, with M. muelleri forming 1995, Torgersen et al. 1997). schools in the upper layer at night. We suggest that M. As nights become less dark, the optimal vertical dismuellen used schooling as a n anbpredator strategy due to the tribution for simultaneously catching food and avoidabsence of dark periods. ing predators is altered. We studied the DVM behavior