HR: 0800h
AN: PP51D-0628    [Abstracts]
TI: Decadal- to Centennial-Scale Variations in Anchovy Biomass in the Last 250 Years Inferred From Scales Preserved in Laminated Sediments off the Coast of Pisco, Peru
AU: * Salvatteci, R
EM: rsalvatteci@imarpe.gob.pe
AF: Direccion de Investigaciones Oceanograficas, Instituto del Mar del Peru, P.O. Box 22, Callao, 1 Peru
AU: Field, D
EM: David.Field@noaa.gov
AF: Fisheries Resources Division, Southwest Fisheries Science Center, 8604 La Jolla Shores Drive La Jolla, California, 92037-1508 United States
AU: Gutierrez, D
EM: dgutierrez@imarpe.gob.pe
AF: Direccion de Investigaciones Oceanograficas, Instituto del Mar del Peru, P.O. Box 22, Callao, 1 Peru
AU: Baumgartner, T
EM: tbaumgar@cicese.mx
AF: Centro de Investigacion Cientifica y de Educacion Superior de Ensenada CICESE, Km. 107 Carretera Tijuana - Ensenada, Ensenada, 22860 Mexico
AU: Ferreira, V
EM: paleoc@cicese.mx
AF: Centro de Investigacion Cientifica y de Educacion Superior de Ensenada CICESE, Km. 107 Carretera Tijuana - Ensenada, Ensenada, 22860 Mexico
AU: Velazco, F
EM: fvelazco@imarpe.gob.pe
AF: Direccion de Investigaciones Oceanograficas, Instituto del Mar del Peru, P.O. Box 22, Callao, 1 Peru
AU: Niquen, M
EM: mniquen@imarpe.gob.pe
AF: Direccion de Investigaciones Oceanograficas, Instituto del Mar del Peru, P.O. Box 22, Callao, 1 Peru
AU: Guevara, R
EM: rguevara@imarpe.gob.pe
AF: Direccion de Investigaciones Oceanograficas, Instituto del Mar del Peru, P.O. Box 22, Callao, 1 Peru
AU: Sifeddine, A
EM: Abdel.Sifeddine@bondy.ird.fr
AF: UR Paleotropique, Institut de Recherche pour le Developpement, IRD, 32 Henri Varagnat, Bondy, Paris, 93143 France
AU: Ortlieb, L
EM: Luc.Ortlieb@bondy.ird.fr
AF: UR Paleotropique, Institut de Recherche pour le Developpement, IRD, 32 Henri Varagnat, Bondy, Paris, 93143 France
AB: The highly productive upwelling environment off the coast of Peru sustains one of the world's largest fisheries, the Peruvian anchoveta ( Engraulis ringens), but variability on interannual to decadal timescales results in dramatic variations in catch. We quantified variations in anchovy scale abundance preserved in laminated sediments collected at 300 m depth of the Peruvian margin (near Pisco, central Peru) to infer decadal- to centennial-scale population variability prior to the development of the fishery. High-resolution subsampling of 2.5 - 8.2 mm was done following the laminated structure of the core. A chronology based on downcore excess ²¹⁰Pb activities and 14C-AMS ages indicate that samples represent an estimated 1-7 years in time. Anchovy scale deposition is correlated with anchovy landings at Pisco, indicating that scale deposition can be used as a proxy of (at least) local biomass. A small, but significant, reduction in anchovy scale width (0.2 mm) after the development of the fishery suggests a small effect of the fishery on anchovy size distributions. While decadal-scale variability in anchovy scale deposition is persistent throughout the record, a dramatic increase in scale flux occurred around 1860 A.D. and persists for approximately a century. Our results indicate that centennial-scale variability composes a large portion of the variability. However, decadal-scale variability associated with the Pacific Decadal Oscillation is not correlated with the inferred biomass variability prior to the development of the fishery. Shifts in the distribution of the population may account for an additional component of the variability in scale deposition.
DE: 4950 Paleoecology
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005