EMA staff inoculating phytoplankton samples

The Ecosystem Monitoring and Assessment Program’s overall goal is to improve and reduce uncertainty in stock assessment models of commercially important fish species through the collection of observations of fish and oceanography. Observations for fish include abundance, size, distribution, diet and energetic status. Oceanographic observations include conductivity-temperature at depth, nutrient levels, and estimates of the composition and biomass of phytoplankton and zooplankton (includes jellyfish) species. These fish and oceanographic observations are used to connect climate change and variability in large marine ecosystems to early marine survival of commercially important fish species in the Gulf of Alaska, Bering Sea, and Arctic.

The oceanographic component of EMA investigates various physical and biological parameters in the eastern Bering Sea. Spatial and temporal patterns illustrated by these data provide critical insight into how the ecosystem functions. Oceanographic data is analyzed alone and in conjunction with fisheries data for comparisons of water mass characteristics. Water samples collected above and below the pycnocline are analyzed for chlorophyll a concentration to explore productivity and are used in primary production experiments to explore growth rates. Phytoplankton form the base of the food web and perform a critical role in the Bering Sea ecosystem.

Zooplankton and jellyfish are collected for species ID, biomass, and abundance. Zooplankton are an important prey item of numerous Bering Sea fishes including forage fishes and the juvenile stages of many commercially important species. Understanding the links among phytoplankton, zooplankton, and fishes will further our understanding changes in populations of fisheries stocks and the influence of climate change in this region.

Oceanographic Bongo Nets

Oceanographic CTD retrieval

Oceanographic collections in the Bering Sea include:

Physical and Chemical Data collected via CTD and TSG

• Temperature

• Conductivity

• Salinity

• Density

• Light Transmission

• Photosynthetically available radiation (PAR)

• Oxygen

• Chlorophyll a

Jellyfish from biological sample

Biological Data

• Phytoplankton (for discrete analysis of chlorophyll a and primary production experiments using stable isotopes of carbon and nitrogen)

• Zooplankton

• Jellyfish

Collaborating partners include University of Alaska, Fisheries Oceanography Coordinated Investigations (FOCI), Pacific Marine Environmental Laboratory (PMEL), North Pacific Research Board (NPRB), and University of Washington (UW).

Contact:
Lisa Eisner
Auke Bay Laboratories
Alaska Fisheries Science Center, NOAA Fisheries

Ted Stevens Marine Research Institute
17109 Pt Lena Loop Rd
Juneau AK 99801
(907) 789-6602 Lisa.Eisner@noaa.gov