David B. Field
Tim R. Baumgartner
Publisher: Cambridge University Press
Print Publication Year: 2009
Online Publication Date:January 2010
Chapter DOI: http://dx.doi.org/10.1017/CBO9780511596681.006
Records of variability in populations of small pelagic fishes exist from a variety of historical sources that precede industrial fishing catch records. We review the historical records of artisanal fisheries, archeological remains, and fish remains from marine sediments. Fish scale deposition rates from ocean sediments offer the most quantitative records with little bias from anthropogenic factors. As quantitative estimates from fish scale deposition rates and their comparison with other records depend on chronostratigraphies, we discuss chronological development in detail, as well as the preservation and significance of fish scale flux. The different historical records indicate considerable variability in small pelagics prior to industrial fishing. However, the historical records provide little support for paradigms of ecosystem variability based on industrial catch records, such as synchronous worldwide fluctuations in abundance of small pelagic from different boundary currents or alternations of sardines and anchovies within a given boundary current. Rather, a variety of different modes of variability in small pelagics is consistent with paleoceanographic evidence for many different climate states and modes of variability.
Some of the best evidence of long-term variability in marine populations comes from different records of pelagic fishes. There is evidence from industrial catch records of many decades in length, artisanal catch records, historical observations, archeological remains, and fossil remains in marine sediments. Small pelagics reflect many aspects of climate change effects on fisheries, since their recruitment and population size are sensitive to environment conditions. However, understanding variability in population size of small pelagics is intertwined with understanding their migrations (presumably in search of ideal environmental conditions).