CRUI: Assessing Environmental Life Histories of Freshwater Fish: Applications of Otolith Microchemistry

Arkansas State University Main Campus, Jonesboro AR

Investigators

Abstract

This interdisciplinary investigation will foster a better understanding of the variations in trace element concentrations in fish ear stones (otoliths) and study the utilization of these variations in reconstucting environmental life histories of freshwater fish. A central goal is to develop this technique for use in freshwater fisheries studies by testing the ability of otolith microchemistry to record small variations in water chemistry within a watershed. This research is made possible by recent developments in analytical chemistry. Specifically, the development of laser ablation-inductively coupled plasma mass spectroscopy (LA-ICP-MS) makes possible an interdisciplinary collaboration that brings together complementary expertise in field ecology, trace element geochemistry and analytical chemistry. The otoliths of fish are key indicators of fish life history as the layers of the otolith record the chemistry of the water in which the fish lived at the time of otolith deposition. With these layers deposited daily we can use the chemical variations in the otoliths to chemically fingerprint the nursery habitats. The distribution of a suite of elements and isotopes in otoliths (including Ba, Sr, Mg, Ca, the rare earths, Pb, d18O, d13C, and 87Sr) will be studied to determine elemental and isotopic variation within a population of brown trout, Salmo trutta, in the Little Red River watershed of central Arkansas. The major thrust of this project is to develop the technique of using otolith microchemistry to reconstruct environmental life histories of fresh water fish. This study will provide a better understanding of otolith microchemistry which could be applied to a wide range of concerns that may be biological, anthropological or environmental in nature. The project will also train students in these various cross-disciplinary studies.