Geoduck (Panopea abrupta) recruitment in the Pacific Northwest- Long-term changes in relation to climate

J. L. VALERO; C. HAND; J.M. ORENSANZ; A.M. PARMA; D.A. ARMSTRONG; R. HILBORN

CALCOFI Reports

CAlcofi

Año: 2004 p. 80 - 86

Investigation of climatic forcing on recruitment is often complicated by a scarcity of data at relevant spatial and time scales. Skeletal structures of long-lived sedentary animals can yield valuable long-term retrospective information, with fine spatial resolution. Geoducks are in that category: these gigantic and commercially valuable clams can reach an age of 168 years, and they aggregate in dense coastal beds from southeastern Alaska to Washington. Back-calculation of recruitment from age frequency distributions compiled in 1979 83 in British Columbia and Washington shows a decades-long decline in recruitment over a vast geographical realm (British Columbia to Washington) that reached a minimum during the mid-1970s. Analysis of data collected between 1993 and 2002 confirms a large-scale pre-1970s decline and reveals a post-1975 rebound. Recruitment in British Columbia is correlated with coastal environmental indexes, such as river discharges (negatively) and coastal sea-surface temperature (positively).