Individual-based modeling explains the contrasted seasonality in size, growth, and reproduction of the sympatric Arctic (Thysanoessa raschii) and Nordic krill (Meganyctiphanes norvegica) in the St. Lawrence Estuary, eastern Canada

Authored by D Benkort, S Plourde, G Winkler, J Cabrol, A Ollier, L-E Cope, F Maps

Date Published: 2019

DOI: 10.1002/lno.11032

Sponsors: National Science and Engineering Research Council of Canada (NSERC)

Platforms: No platforms listed

Model Documentation: Other Narrative Flow charts Mathematical description

Model Code URLs: Model code not found

Abstract

The Nordic krill Meganyctiphanes norvegica and Arctic krill Thysanoessa raschii both dominate the krill community within the Estuary and Gulf of St. Lawrence system where they are central forage species for its pelagic ecosystem. We developed a species-specific physiological individual based model that implements the critical physiological processes of growth, molting, and reproduction of female adults as responses to environmental forcing. Key innovations of our approach were the decoupling between the molting schedule and growth, as well as considering two distinct sources of prey (phytoplankton and mesozooplankton). Our simulation results revealed that the details of the feeding process were critical for an accurate representation of the production dynamics of adult individuals from both species. Their specific feeding preferences on phytoplankton and mesozooplankton resulted in distinct species-specific phenological patterns that reproduced observations. The present study highlights the importance of detailed knowledge of diet and feeding behavior of krill species to improve our understanding of population responses in a rapidly changing environment.

Tags

Temperature Respiration Diel vertical migration Antarctic krill Euphausia-superba Calanus-finmarchicus Gulf Molt cycle Northern krill M-sars