Abundance of pelagic fish during the 19th and 20th centuries as recorded in anaerobic sediment off the Californias

Anaerobic sediment preserves a chronographic record of the bioclimatological conditions in coastal seas. Of the myriad elements within this record, the accumulation ofpelagic.fish debris is ofparticular interest. The deposition of scales of the Pacific sardine, the northern anchovy, the Pacific hake, the Pacific saury, and the Pacific mackerel in the sediment of the Santa Barbara Basin, Alta California, and the Soledad Basin, Baja California, is generally in accord with available population estimates. The relation between scale deposition and population, when applied to the sedimentary record over the past 150 yr, suggests that major pelagic.fish productivity between 1925 and 1970 was substantially below pre-1925 levels. Man in his search for an environmental perspec-tive has unearthed a number of natural chrono-graphic records. These include the well-known growth rings oftrees (Fritts, 1972), the deposition of annual strata in the snowfields of Greenland and Antarctica (Murozumi et aI., 1969), the in-