Comparison of Solution and Laser Ablation ICP-MS

Otolith chemistry is a widely used tool for fisheries research.  This is due to the need for accurate information on stock composition.  However, most studies have either sampled only juveniles as a proof of concept, or sampled only adults and subsequently tried to identify differences in nucleus (nursery ground) chemistry.  Relatively few studies have sampled discrete cohorts of fish from multiple nursery grounds and applied the resulting discriminant function to the adult (mixed stock) population.  Moreover, a number of these studies have used solution based analyses to build the discriminant function from the juvenile known origin collections and subsequently used laser based analyses to sample the chemistry of the adult unknown origin samples.  Ludsin et al. (2006) advocates against this approach for a number of reasons.  In short, their findings indicate that the two techniques do not produce comparable estimates of nursery signatures.  I further discuss these approaches and provide additional strategies that result in these two approaches becoming more comparable.