Still another reality for concern here is that pesticide residues expressed on the basis of wet weight fish flesh are known to differ empirically from those expressed on fat basis, even after fat or tissue normalization (see, e.g., Hubert and Ricci, 1981; Borgmann and Whittle, 1991; Hebert and Keenleyside, 1995). One reason for such an empirical difference is that the procedures for residue levels measured on fat basis require lipid extraction from meat samples, for which the various analytical techniques available are far from perfect (see, e.g., Randall et al., 1998). Among other things, all lipids are vulnerable to chemical degradation through oxidation by oxygen, enzymes, and solvent, especially in the presence of untoward temperature, pH, or light.