Elemental signatures have been used as a tool to track individual organisms to their natal site in an attempt to understand stock structure and larval dispersal. However, factors that affect elemental signatures are not well understood. We conducted a factorial experiment using whelk Kelletia kelletii larvae from Salta Verde Point on Catalina Island, Los Angeles Harbor, and White Point, Palos Verdes peninsula, California, USA, to test the effects of egg source, temperature (10, 14 and 18°C) and culture seawater on the elemental composition of larval statoliths. Intra-capsular contents of newly laid capsules were also analyzed to explore whether maternal contributions might affect larval statolith chemistry. Using inductively coupled plasma mass spectrometry we quantified ratios of 7 elements to calcium in both intra-capsular contents and cultured statoliths and provided the first evidence of significant egg-source effects, independent of subsequently experienced environmental conditions, on statolith elemental signatures for Mg:Ca, Ba:Ca and Pb:Ca. Intra-capsular and statolith element ratios showed no clear relationship that might have indicated possible maternal transfer of elements to larvae. Culture seawater elemental concentration was positively related to statolith Ba:Ca and Pb:Ca, and temperature was negatively related to statolith Sr:Ca, Ba:Ca and Pb:Ca, while no significant effects were found for Mn:Ca or Zn:Ca. Effect-size estimates show that elements responded differently to factors within the variation measured in this study; the major effects for Ba and Pb were temperature and egg source, respectively. The significant effect of egg source on elemental signatures has potentially important implications for tracking free-spawned larvae. KEY WORDS: Statolith · LA ICP-MS · Dispersal · Egg source · Relative effects · Elemental signature · Kelletia kelletiiResale or republication not permitted without written consent of the publisher Mar Ecol Prog Ser 353: 115-130, 2008 natural signatures of stock structure (e.g. , as records of dispersal and migration pathways (e.g. Ikeda et al. 2003) and for identifying spawning and nursery grounds (e.g. Gillanders & Kingsford 2003).In particular, the elemental composition of the larval calcified structures of fish (Swearer et al. 1999), crabs (DiBacco & Levin 2000), bivalves (Becker et al. 2007) and gastropods (Zacherl 2005) has potential to elucidate much useful information about larval origin and dispersal trajectories. Many larvae begin forming their calcified structures at or near the site of production and, thus, potentially carry a permanent elemental signature of the site of origin. When larvae enter the water column and move through ocean masses with variable physical and chemical characteristics, these changes can be recorded in the elemental composition of calcified structures. In principle, not only can the site of origin be identified, but subsequent larval movement also can be tracked using statolith elemental signatures.To identify any particul...