Recent Trends in Eastern Bering Sea Zooplankton: Data and Confessions

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

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eg 2

2007

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2 2008

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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

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Date

Acoustically-Determined Zooplankton Biomass @ M2B

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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.

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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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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