Retrospective Analysis
Existing data sets need re-examination, and data sets that are
particularly useful for examining past ocean conditions in relation to
climate change, for example, paleoceanographic records, need to be
developed. Data from fisheries have been collected for centuries, large
hydrographic archives exist, and extensive specimen collections and data
from environmental monitoring surveys are also available and need to be
explored in an interdisciplinary climate context. Moreover,
paleoecological data exists which extends fisheries, ecosystem and
hydrographic data back in time beyond the limits of historical
observation. Such data provide a window to the long time scale
processes that characterize climate variability. A special property of
the long historical records of fish, mammals and birds, is that they
provide not only a history of the variation in population size, but also
provide estimates of the life table variables (growth, mortality,
maturity, and reproduction) that regulate population growth. It is
these variables that respond directly to changing environmental
conditions and must be linked to physical forcing which will enable
forecasting of the effect of climate change on marine animal
populations. The need for retrospective work is obvious when one
considers that the five year duration of U.S. GLOBEC field programs
corresponds to only 2-3 generations of most living marine resources
(fish, benthic invertebrates) and perhaps 5-10 generations of most
macrozooplankton, while climate change effects will be mediated over
many generations. The U.S. GLOBEC program recognizes that retrospective
data are indispensable for expanding the results of site-specific
process studies to the larger scales that characterize the biogeographic
distribution of populations and climate. Consequently, the
identification, assembly and analysis of relevant existing data sets is
important to achieving U.S. GLOBEC's goal of understanding the
interrelationships of animal populations to ocean physics, climatic
variability and long-term change.