Taylor and Francis Group, Marine Biology Research, 7(8), p. 605-614, 2012
DOI: 10.1080/17451000.2011.653370
Full text: Download
Abstract A diel vertical migration (DVM) pattern of Norwegian spring spawning herring (Clupea harengus) larvae was investigated during 19 and 20 April 2009. Factors influencing DVM included physical and biological properties of the water column. Data on larvae, prey and predators were collected with a depth-stratified multisampling device, inshore of Sklinna bank, close to the Norwegian coast, while light conditions were calculated using a Matlab? algorithm. A type I DVM pattern (i.e. deep during daytime, shallow at night) was observed for herring larvae, mainly occurring above the thermocline. No size-dependent differences were observed for larval vertical positioning. The highest overlap in depth distribution with their main prey was observed during daytime, when larvae were distributed deeper in the water column. From acoustics and macroplankton trawl data, a type I DVM was also observed for krill, although their concentrations were relatively low in the area. Cumulative predator?prey overlap plots