Samples historically collected and analysed by the Continuous Plankton Recorder survey were used to examine long-term (1958 to 1994) patterns in the normal diel vertical migrat~on (NDVM) behaviour of 7 copepod taxa in the North Sea: Calanus finmarchicus C5-C6; Calanus spp. Cl-C4; Cenlropages typicus; Centropages hamatus; Temora longicornis; Acartia clausii and Para-Pseudocalanus (this last group included all Paracalanus and Pseudocalanus species). The ratio of night:day abundance near the surface was used as a measure of the extent of NDVM. For all 7 taxa, the extent of NDVM between 1958 and 1994 CO-varied wlth the abundance of herring Clupea harengusin the North Sea. Fisheries data show that during this period the herring stock was a good indicator of the overall abundance of planktivorous fish in the North Sea. These results suggest that changes in the abundance of planktivorous fish in the North Sea over recent decades have resulted in modifications in the NDVM behaviour of many zooplankton taxa.
ABSTRACT. Samples historically collected and analysed by the Continuous Plankton Recorder survey in the North Atlantic and adjacent seas were used to examine temporal patterns in the near-surface abundance of copepodite stages V and V1 Calanus hyperboreus (n = a total of 32836 samples; mean latitude of samples = 54" N. SD = 6.7'). The occurrence of CV and V1 C. hyperboreus was largely restricted to samples collected in April, May and June. During t h~s period there was a diel cycle in near-surface abundance which was consistent with a normal pattern of diel vertical migration. For example, CV-V1 C. hyperboreus were 1.9 times more abundant at night than during the day, a difference which was highly significant (t-test, t,,,;, -3.9. p c 0.001). The ratio of n1ght:day abundance was similar In CV-V1 C finmarchicus (night:day abundance = 1.4), but markedly higher in CV-V1 Metridia lucens (n1ght:day abundance = 12.3) and CV-V1 M. longa (night:day abundance = 15.0).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.