Late Holocene paleofish populations in Effingham Inlet, British Columbia, Canada

摘要

Paleontological studies of fish remains in laminated sediments provide a proxy relationship between fish populations and ocean climate. This study examines climate variability from approximately 500 y B.P. to 4000 y B.P. as recorded in fish remain abundances (primarily scales) collected from laminated sediments within Effingham Inlet on the west coast of Vancouver Island, British Columbia. The study also discusses technical issues involving fish remains from laminated sediments, including sampling resolution, sediment volume, identification of remains and appropriate abundance considerations.The dominant species in the assemblage include Northem anchovy and Pacific herring, with lesser percentage-abundances from rockfish, hake, elasmobranches and surfperch. The data indicate that Northem anchovy experienced a shift in scale deposition abundance at approximately 2800 y B.P. with not only a greater total abundance but also a greater consistency of deposition with time. Pacific herring underwent cyclical deposition that changed little through time. Statistical analysis reveals that none of these species is directly responding to climatic signals as indicated in the lithological and palynological record, but that this could have been partially due to the sampling resolution of the piston core. Analysis indicates a lack of correlation between the two dominant species, as might be expected on the basis of their opposing lifestyle strategies with respect to sea surface temperatures.With appropriate sampling strategies, palcohistorical fish remains from laminated sediments reflect changes in population structure and behaviour for some species, illustrate basic secondary trophic information, and provide potential clues to basin-scale oceanographic/climatological variability. (c) 2005 Elsevier B.V. All rights reserved.