Seasonal ecology and life-history strategy of the high-latitude predatory zooplankter Parasagitta elegans

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 499:77-88 (2014) - DOI: https://doi.org/10.3354/meps10676 Seasonal ecology and life-history strategy of the high-latitude predatory zooplankter Parasagitta elegans Jordan J. Grigor1,2,*, Janne E. Søreide1, Øystein Varpe1,3 1The University Centre in Svalbard, 9171 Longyearbyen, Norway 2Takuvik Joint International Laboratory, Université Laval (Canada)—CNRS (France), Département de biologie and Québec-Océan, Université Laval, Québec, Québec G1V 0A6, Canada 3Akvaplan-niva, Fram Centre, 9296 Tromsø, Norway *Corresponding author: jordangrigor@gmail.com ABSTRACT: Organisms residing in seasonal environments schedule their activities to annual cycles in prey availability and predation risk. These cycles may be particularly pronounced in pelagic ecosystems of the high-Arctic, where the seasonality in irradiance, and thus primary production, is strong. Here we report on the seasonal ecology and life strategy of a predatory planktivore in a high-Arctic fjord (Billefjorden, Svalbard ~78°N). We studied the chaetognath Parasagitta elegans (var. arctica), an abundant zooplankter of high-latitude seas, focusing on its age structure, seasonal vertical distribution, growth and timing of reproduction. The body-length data (range: 2 to 44 mm) revealed the presence of 3 size cohorts (Cohorts 0, 1 and 2), suggesting a 3 yr life span. Spring and early summer (May/June) was the main spawning season, as revealed by inspection of gonads and the presence of well-developed seminal receptacles prior to high numbers of newborns. Both Cohorts 1 and 2 reproduced, with male gonads maturing first in this hermaphrodite. Growth rates for all cohorts were highest in spring and early summer, and at this time of the year, the youngest year class (Cohort 0) was distributed near the surface where their feeding opportunities may peak. In winter, however, all cohorts were in deeper waters, suggesting seasonal migrations, possibly to follow the distributions of overwintering copepods. Scheduling of growth, maturation and reproduction in Arctic zooplankton populations is important baseline information for predictions of zooplankton responses to environmental change, particularly those associated with timing and phenology, pinpointing the need for more high-resolution studies on zooplankton annual routines. KEY WORDS: Annual routines · Arctic · Arrow worms · Seasonal environments · Zooplankton Full text in pdf format Supplementary material PreviousNextCite this article as: Grigor JJ, Søreide JE, Varpe Ø (2014) Seasonal ecology and life-history strategy of the high-latitude predatory zooplankter Parasagitta elegans. Mar Ecol Prog Ser 499:77-88. https://doi.org/10.3354/meps10676 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 499. Online publication date: March 03, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.