recent trends in eastern bering sea zooplankton: data and confessions
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Recent Trends in Eastern Bering Sea Zooplankton: Data and Confessions. J.M. Napp 1 , P.J. Stabeno 2 , D.V. Holliday 3 and G.L. Hunt, Jr. 4. 1 NOAA – Fisheries, Alaska Fisheries Science Center 2 NOAA – Research, Pacific Marine Environmental Laboratory - PowerPoint PPT PresentationTRANSCRIPT
Recent Trends in Eastern Bering Sea Zooplankton:
Data and Confessions
J.M. Napp1, P.J. Stabeno2, D.V. Holliday3 and G.L. Hunt, Jr.4
1NOAA – Fisheries, Alaska Fisheries Science Center2NOAA – Research, Pacific Marine Environmental Laboratory 3University of Massachusetts, Dartmouth, School for Marine Science and Technology, and University of Rhode Island, Graduate School of Oceanography4School of Aquatic and Fishery Sciences, University of Washington
Value of Zooplankton Times Series
• Establishes “baseline” conditions.• Demonstrates lower trophic level
responses to perturbations.• Provides insight and understanding into
natural cycles or stochastic environmental forcing.
• Provides insight and connectivity to fisheries recruitment and the productivity of upper trophic levels.
Time Series of the Northeast Pacific,
Mackas, Batten, and Trudel (2007) Prog. Oceanogr.
Warm / Less Productive
Cool / Most Productive
Napp and Yamaguchi, unpubl.
Eastern Bering Sea, T/S Oshoro maru
AFSC – RACE Groundfish Survey Zooplankton Sampling
2006
, L
eg 2
2007
, L
egs
1 &
2 2008
, L
egs
1, 2
& 3
Recent Trends in C. marshallae
Coyle et al. “Zooplankton species composition on the southeastern Bering Sea shelf during summer…”
1966
1993
1998
Napp et al., (2002) Deep-Sea Res., II
Spatial Variability in T/S Oshoro maru Sampling
Temporal Variability in T/S Oshoro maru Sampling
25th
Temporal Aliasing in Sampling
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1B
iom
ass
(mg
m-3)
Date
Acoustically-Determined Zooplankton Biomass @ M2B
iovo
lum
e (
mm
3 m
-3)
2006 2006
2007 2007
Conclusions
• Total zooplankton biomass appears to be “recovering” from the recent warm period.
• The abundance of Calanus marshallae over the middle shelf is an important contributor to that biomass, and it is also increasing.
• Present time series need to be strengthened, expanded and further tested for potential aliasing.– Retrospective analysis of T/S Oshoro maru species data.– Comparability among shipboard acoustics, moored
acoustics, net samples.
• Eastern Bering Sea zooplankton data are an excellent candidate metric for an aggregate index to explain ecosystem productivity.
BEST-B
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Acknowledgements
• Funding from NPRB (regular and BSIERP) and NOAA’s NPCREP Programs.
• Mooring group at PMEL.
• AFSC RACE Bering Sea Groundfish Assessment Group.
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RP E
cosy
stem
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May and September
Mackas, Batten, and Trudel (2007) Prog. Oceanogr.
Time Series of the Northeast Pacific, II
M. Flint et al., (1994)
33 C. marshallae m-3
51 C. marshallae m-3
134 C. marshallae m-3