Zooplankton variability on the Faroe Shelf and in the surrounding oceanic area in relation to phytoplankton and physical conditions E. Gaard, H. Debes, B. Hansen, H. Hátún, K. M. H. Larsen Faroe Marine Research Institute ICES/NAFO Symposium on the Variability of the North Atlantic and its Marine Ecosystems during Santander, Spain, May 2011

Nordic Seas

Content Variability: – North of the Faroes Warm Atlantic Cold East Icelandic current water – Outside the shelf front – On the Faroe shelf

North of the Faroes

Copepod life cycle

Calanus life cycle

Calanus finmarchicus May

Chlorophyll a May

Temperature Annual mean

The Faroe Shelf Ecosystem Separate water mass Distinct ecosystem Largely neritic zooplankton. Mixed with variable abundances of oceanic zooplankton

Copepods on and around the Faroe shelf June 2009 Copepods Calanus finmarchicus

Zooplankton monitoring Late June

Zooplankton dry weight (g/m 2 ) Outside the shelf, late June

Outside the shelf front, late June Zooplankton biomass Calanus finmarchicus Stage composition Calanus finmarchicus Relative stage composition

Faroe Self copepods Seasonal development, 2004

Faroe Self Calanus finmarchicus Seasonal development, 2004

Zooplankton dry weight (g/m 2 ) Shelf and Outside the shelf, late June

Faroe shelf Late June, CopepodsCalanus finmarchicus Temora: 10 X increase

Shelf temperature and chl. a Chl. a: 15 April - 30 June Temperature Mean, 15 April – 30 June

Calanus finmarchicus Stage duration 5°C 8°C 7°C

Summary Atlantic and shelf water: – 10x increase in Temora (shelf), – Zooplankton biomass increase (C. finmarchicus) during the 2000s – Phenology changes. – No relationship with chlorophyll a. – Shorter stage duration induced by higher temperature (~1°C) only shortherns the generation time ~1 weak. East-Icelandic current water: – Large phenology shift in Earlier reproduction. – No relationship with chlorophyll a – Most like caused by temperature increase and/or changes in currents