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Effects of climate variability on Calanus dormancy patterns and population dynamics in the Northwest Atlantic
J.A. Runge, A. Leising, C. Johnson
• Mechanistic explanation of dormancy in species of Calanus
• Development of Calanus life cycle model
• Evaluate how year-to-year variability in environmental conditions interacts with dormancy-control mechanisms to control Calanus population dynamics.
Lipid accumulation window hypothesis
• Individual Calanus can only enter diapause if their food and temperature history allows them to accumulate sufficient lipid for overwintering and gonad development
• Decision to proceed to dormancy is initiated when lipid stores reach a preset threshold (% by weight in stage CIV)
• Exit from dormancy by endogenous timer or when lipid stores decrease below a preset threshold
Life cycle model with lipid diapause rule:
comparison with observations
Data sources
Data from:
DFO – AZMP: 1999 – 2005 (E.Head, P.Pepin)
DFO – IML:1990 – 1991 (S. Plourde, P. Joly)
US-GLOBEC: 1995 – 1999 (E. Durbin, M. Casas)
PULSE – NEC: 2003 – 2005 (R. Jones)
UNH COOA (Center for Coastal Ocean Observation and Analysis) (triangles) and Northeast Consortium PULSE fixed stations, (red circles: 2003-05 and 2007)
Western Gulf of Maine fixed station sampling: 2003-2007
0 %
2 0 %
4 0 %
6 0 %
8 0 %
1 0 0 %
J F M A M J J A S O N D J F M A M J J A S O N D J F M AM J J A S O N J F M AM J J A S O D
2 0 0 3 2 0 0 4 2 0 0 5 2 0 0 7
Calanus_finm archicus O ithona_sim ilis Pseudocalanus_spp.Centropages_sp T em ora_longicornus O ikopleura_sp.Balanus M eroplankton O ther Copep
Zooplankton Species CompositionJeffreys Ledge
2003 2004 2005 2007
Cfin
J F M A M J J A S O N D
A decline in the abundance of Calanus finmarchicus in 2004-2005
Abundance of Calanus finmarchicus
CV
Total
summer
Adults
May June
Oct-Dec
Spawning
Cod
Herring
Northwest Atlantic Marine Alliance (NAMA)-UNH Western Gulf of Maine Inshore Fisheries
and Ecosystems Project
Cartographer: A. Holt Cline
NH
Cape Ann
28.5
29.0
29.5
30.0
30.5
31.0
31.5
32.0
32.5
33.0
Salinity by 1m depth for New Scantum (2003-2005)
365 730
-50
-40
-30
-20
-10
0
2003 2004 2005
Ma
r
Ma
y
Ju
ly
Se
pt
No
v
Ma
r
Ma
y
Ju
ly
Se
pt
No
v
Ma
r
Ma
y
Ju
ly
Se
pt
No
v
Ja
n
Ja
n
Salinity on Jeffreys Ledge: 2003-2005
2003 20052004M M MM MJ JS SN NS N
Chlorophyll a standing stock“B”
Jeffreys Ledge
2003
2005
Hypothetical metapopulation structure of Atlantic Cod in the GoM/GGB system
Based on Wirgin et al. 2007; A. Kovach, UNH, G. Sherwood and S. Tallack, GMRI