Otolith chemistry to describe movements and life-history parameters of fishes: Hypotheses, assumptions, limitations and inferences

In ever-increasing numbers, researchers wish to extract information based on cher cal analyses from otoliths to determine movements and life-history patterns of fish. Such analy: make assumptions about chemical incorporation and interpretation that are beyond those that important for stock discrimination studies, another common application. The authors aim to clar the methods of determining fish movement based on natural and artificial otolith chemical tags review current trends in determining movement using otolith chemistry, otolith sampling meth and what influences otolith chemistry. Both spatial and temporal variability in water and OL chemistries, which underpin the assumptions of several methods, are discussed. Five method determining movement and migration of fish are outlined: (1) estimates of movement and life-hf traits of a single fish group, (2) assessing connectivity among groups using natural chemical t otoliths, (3) transgenerational marks to determine parentage and natal origins, (4) profile an to define life-history variation within a population and (5) profile analysis to describe move through different environments. Within each of these methods, background information, hypotheses being tested and assumptions and limitations of each technique are provided. research directions required to fill current knowledge gaps and enhance the usefulness of otolith chemistry to determine fish movement are identified.