The Bering Sea FOCI program was established in 1991 to address the critical
walleye pollock management issues in the region: what causes the observed
large fluctuations in year class size 
and what is the stock structure
of the population? These questions are interrelated and important to management
since we do not currently know the impact of harvesting fish in any part
(eastern or western) of the Bering Sea on the population of the entire region.
An important goal is to reduce uncertainty in resource management decisions
through ecological research. To investigate these issues, FOCI has developed
new research tools and methods to examine walleye pollock recruitment and
populations. Advances toward defining the stock structure of walleye pollock
in the Bering Sea have come by determining basin circulation patterns through
analysis of recent and historical survey data and development of genetic
testing methods. Surveys showing large numbers of spawning adults support
the importance of the southeastern Bering Sea shelf stock. FOCI is investigating
whether there are repeatable, significant differences in genetic structure
between fish from the eastern and western portions of the Bering Sea.
FOCI scientists have made important advances in their knowledge of processes
important to recruitment. In areas where walleye pollock 
spawn,
conditions in basin and slope waters have been contrasted with those of
the shelf, and the results show that the shelf provides a better environment
for survival of larvae. High concentrations of larvae and eddies are often
observed together, 
and
the existence of eddies seems to fluctuate with the strong interannual differences
in transport from the North Pacific Ocean. Bering Sea FOCI scientists deploy
sophisticated biophysical moored 
platforms in the harsh
environment of the wintertime Bering Sea. A biophysical simulation model
tuned to initial conditions present in the Bering Sea produces results consistent
with our observations in the field. The Bering Sea FOCI program's juvenile
studies have attracted researchers investigating other ecological aspects
of the Bering Sea; this has also led to lasting, productive, international
ties with Korean and Japanese scientists.
A cyclonic gyre dominates circulation over the Bering Sea basin with the Kamchatka western boundary current along the Asian side. The gyre is an extension of the Alaskan Stream and most transport enters through the eastern passes and exits via the Kamchatka Current. When instabilities in the Alaskan Stream inhibit flow into the Bering Sea through Near Strait, transport in the Kamchatka Current can be reduced by 50%. Storms dominate the surface stress at periods of less than a month, and they serve principally to mix the upper ocean. At longer periods, wind forcing accounts for half of the transport by the Kamchatka Current. The flux of Alaskan Stream waters through Amchitka and Amukta passes in the eastern Aleutian Islands has a significant influence on regional water properties and circulation. These waters then flow northwestward along the slope carrying a subsurface temperature maximum that can be traced for hundreds of kilometers along the slope. The southeastern basin waters are also rich in eddies, some of which are formed by flow through Amukta Pass. In the eastern Bering Sea, the presence of relatively small eddies has recently been documented. These are formed in regions of high current shear in open waters, or by interaction of inflowing Alaskan Stream water with the topography of passes in the eastern Aleutian chain.