Ontogenetic diel vertical migration behaviors of the marine planktonic copepods Calanus pacificus and Metridia lucens

Abstract

Daytime and nighttime vertically stratified zooplankton samples spanning the entire water column were obtained from Dabob Bay. Washington. USA, during several years. Vertical distributions of all the copepodid stages of Calanus pacificus and Metndia lucens were analyzed from 8 cruises representing the range of seasons, as well as several dates when inferred invertebrate or vertebrate predation pressures on zooplankton were strong or weak. Migration behaviors of similar-sized stages of C. pacificus and M. lucens differed. C. pacificus was closely associated with the surface waters; a large percentage of every stage was always in the surface 50 m at night except when the C5s were in diapause. During the day the different stages of C. pacificus showed varying degrees of avoidance of the surface layers, with the older, larger stages generally being deeper. The C4 and younger stages were particularly tied to the surface waters, with the majority of the population usually in the top 25 m during the day and night. M. lucens was less strongly associated with the surface layers. While the adult females, and usually the CSs, underwent a normal diel vetical migration (DVM), entering the surface 50 m at night, the vast majority of the adult males always stayed below 75 m. The C4 and younger stages showed more varied behavior. On some dates they underwent a reverse DVM, avoiding the surface 25 m at night, at other times they avoided the surface 10 m particularly during the day, while on still other dates the C3 and younger stages avoided the surface 25 m day and night. On most dates there were significant portions of all the stages in the deepest layers sampled. Differences in the 2 species' migration behavior may be due to differences in their susceptibility to predation, or some additional aspect of their biologies.

Vertical and horizontal larval distribution of an offshore brachyuran crab, <em>Monodaeus couchii</em>, off the south coast of Portugal

“…Even intraspecifically, DVM behaviour might vary with time, location (e.g. distance from coast) or environmental conditions such as fluctuations in predator or prey abundances or vertical stratification (Irigoien et al 2004, Osgood andFrost 2004). In the present study, Monodaeus couchii was most abundant during the day in the top hundred metres of the water column, while at night abundance increased with depth.…”

“…As observed in various copepod species, when predators exhibit nocturnal DVM, their prey may undergo reverse DVM (Irigoien et al 2004, Osgood andFrost 2004). This behaviour has been associated with areas where the predators rely more on tactile stimuli than sight to capture prey, as is the case for many invertebrate predators (e.g.…”

Flexible diel vertical migration behaviour of zooplankton in the Irish Sea

“…Ontogenic differences in DVM have been previously reported for C. pacificus in mesocosm experiments (Huntley & Brooks 1982) and in the field (Osgood & Frost 1994), C. finmarchicus in Scottish lochs and the Norwegian Sea (Nicholls 1933, Marshall & Orr 1955, Dale & Kaartvedt 2000, Metridia lucens in different areas (Osgood & Frost 1994, Hays et al 1995, Falkenhaugh et al 1997, Timonen 1997, and for Neocalanus gracilis, Pleuromamma abdominalis and Euchaeta acuta in the Mediterranean (Andersen et al 2001).…”

Ontogenetic change of foraging behaviour during copepodite development of Acartia clausi

“…, Osgood & Frost 1994, Kiørboe et al 1996, Tiselius et al 1997, Titelman & Fiksen 2004. Much attention has recently been paid to the behaviour of nauplii and their importance as prey organisms (e.g.…”