Mechanisms for emergence from diapause of Calanoides carinatus in the Somali current

Abstract

We studied mechanisms that might control the emergence of the last juvenile stage of Calanoides carinatus from diapause in the Arabian Sea. Diapaused copepods are modeled as Lagrangian particles that include a simplified means for lipid catabolism during diapause. The advective field for the particles, which are released at intermediate and deep layers off the Somali shelf, is determined by a regional version of the Miami isopycnic coordinate model (MICOM). Dormant copepods emerge from diapause in response to either onshore advection (physical upwelling) or depletion of lipid reserves to an assumed critical level (internal biological clock). The majority of the diapaused copepods that successfully complete their life cycle are those retained within the coastal upwelling zone and emerge as a consequence of depletion of the lipid reserves.