Opening Lecture

What controls the population dynamics of a Japanese sardine species?
A case study important to the GLOBEC synthesis effort.

D. Townsend

As we move into the "Final Phase" of Georges Bank Globec, we should pause for a moment to reflect upon a number of issues. For example, our original overarching goal was:

"... as climate changes, so will the physics of the ocean, and by extension, the ocean's animal populations will (somehow) be affected..."

Georges Bank was selected as our region of study, primarily because it is a physically dynamic and biologically productive system. We identified "target species", and off we went.

We should keep in mind a number of general questions as we move ahead, such as: What is the ecological role of each of our target species in the Georges Bank ecosystem? (How does Georges Bank work?) Given our overall goal, are we/have we, been asking the right research questions? Is there anything missing? Have we acquired the right information to meet our goal(s)? How does what we've done fit together? Specific questions to keep in mind might include: With regard to ocean physics, what is most likely to change as our global climate changes? With regard to ocean biology, what processes/patterns might reflect these physical changes?

It is sometimes useful to step back for a moment and look at another part of the world for some inspiration. In particular, we should all make ourselves familiar with the 10-year study of recruitment dynamics of the Japanese sardine, called BIOCOSMOS, which I review in this presentation. Much of what I am presenting in this talk stems from a review paper, in manuscript form, entitled: Japanese Sardine Recruitment Project: Investigation of Population Structure and Recruitment in the Japanese Sardine, by Dr. Yoshioki Oozeki of the National Research Institute of Fisheries Science. In his review we see similarities in overall goals between our Georges Bank study, and the Japanese study of the sardine recruitment and the oceanography of the Kuroshio Current region. Only by extending their vision to include domains once thought to be outside their interest with respect to sardine life history events did these Japanese scientists begin to unravel intricate patterns in sardine recruitment as they related to inter-annual and inter-decadal variability in the Kuroshio Extension.

For our work we too need to extend our vision, not only in space, but in time scales of variability. For example: how connected are the Gulf of Maine, Georges Bank and the Nova Scotia Shelf? Answer: much more so than we initially thought before Georges Bank Globec began. And have we been concerning ourselves with the correct temporal scales? What influence might the North Atlantic Oscillation impart upon the functioning of Georges Bank? What patterns might its dynamics help to explain?

This overview talk was designed to stimulate our imaginations, to consider questions that never even occurred to us 5-8 years ago, and to begin to wrap much of what we have been doing in a framework that relates clearly back to our overall goal: to relate our work to climate change.