Ž . Parasitology International 50 2001 115119 Element concentration variability in the whaleworm Anisakis simplex s.l. Elvira Abollo, Santiago Pascual  ´ Area de Parasitologıa, Facultad de Ciencias, Uni  ersidad de Vigo, 36200 Vigo, Spain ´ Received 29 January 2001; received in revised form 26 March 2001; accepted 30 March 2001 Abstract Concentrations of the elements C, N, Fe, Na, K, Ca and Mg were analysed by chromatography and atomic absorption spectrometry in the whaleworm Anisakis simplex sensu lato. Nearly all mean inorganic element concentrations measured were higher in adult worms than in larval forms. Similarly, adults contained significantly Ž . higher nitrogen i.e. lower CN ratio values than either eggs or larvae. Evidence for the significance of the parasitic life cycle stage and the systematic position of their hosts on the element concentration variability is discussed.  2001 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Whaleworm; Anisakis simplex s.l.; Element concentration 1. Introduction Organic and trace inorganic elements in the body of helminth parasites play a vital role in physiology, metabolism and immune mechanisms   1,2 . In the recent past several attempts have been made to identify and quantify certain inor-   ganic elements in individual helminths 3  6 or  Corresponding author. Tel.: 34-986-812550; fax: 34- 986-812556. Ž . E-mail address: spascual@correo.uvigo.es S. Pascual . individual elements in different groups of   helminths 7,8 . Furthermore, an attempt by  Chowdhury and Singh 9 was made to analyse certain inorganic elements which later displayed variations among different developmental stages of the endogenous daughter cysts of the cestode Echinococcus granulosus. Notwithstanding the growing number and use of the chemical compo- sition in the understanding of the helminth growth and survival, no study on elemental concentra- tions and potential differential changes in the distribution of any inorganic andor organic ele- ment has been undertaken in anisakid nema- 1383-576901$ - see front matter  2001 Elsevier Science Ireland Ltd. All rights reserved. Ž . PII: S 1 3 8 3 - 5 7 6 9 01 00069-1