Growth of Euphausia pacifica in the upwelling zone off the Oregon coast

摘要: Abstract Growth rates and intermolt periods for Euphausia pacifica were determined from individual growth rate (IGR) experiments carried out over a 7-year period (2000–2006) on euphausiids collected off the Oregon Coast. Adult averaged 0.020 mm total length (TL) day−1 during summer upwelling season 0.011 mm TL day−1during winter downwelling season. Average (IMP) was 8 d 11 d downwelling. IMPs highly variable, not related to surface chl-a concentration or of euphausiid. Negative occurred at all times year. most likely poor feeding conditions, while negative result investing ingested energy towards reproduction rather than somatic growth. this study using IGR method generally lower E. other studies that used cohort analysis method. Since are difficult capture analysis, we calculated seasonal only positive values our compare with rates. These 0.08 mm TL d−1 (2.4 mm month−1) 0.04 mm TL d−1 (1.2 mm month−1) season, equivalent weight-specific 0.0135 d−1 (upwelling) 0.0089 d−1 (downwelling), comparable obtained in analysis. Highest annual measured 2004 (warm) 2006 (cold), suggesting is less affected by warm cool types zooplankton, such as copepods.