DORSAL SCUTE AND GROWTH DEVELOPMENT IN ACIPENSER FULVESCENS IN DIFFERENT ENVIRONMENTAL CALCIUM CONCENTRATIONS**

Calcium (Ca2+) is an important element in growth and development of vertebrate species. In fish, the relationship between environmental concentration and internal availability are closely linked, and thus environmental conditions are predicted to have substantial effects on early life stages and growth. Environmental Ca2+ limitation could therefore limit healthy growth, and reduce development of predatory defenses. This study examined whether different environmental Ca2+ levels affect the growth and development of the dorsal scutes and body size in the lake sturgeon, Acipenser fulvescens. Predicted effects include: 1) A. fulvescens in water with higher Ca2+ levels will develop scutes before A. fulvescens in water with lower levels of Ca2+, 2) The rate of overall growth will stabilize to body size earlier in water with higher Ca2+ compared to lower Ca2+, and 3) A. fulvescens in higher Ca2+ water will have larger scutes relative to body size than A. fulvescens found in lower levels of Ca2+. We reared sturgeon in two recirculating tank systems containing water from two sources varying in ionic composition: the Warm Springs National Fish Hatchery, and the Coosa River. Each water type maintained stable pH and temperature throughout the experiment, and the environmental concentrations of Ca2+, Na+, Mg2+, and K+ were quantified for collected water samples. These same ions will also be quantified by ICP-OES in the tissue and scutes of A. fulvescens, sampled weekly during the first ten weeks of development post-hatch. Initial results indicate that scutes do contain high levels of Ca2+ and the growth rate is slower in water with lower Ca2+ levels. Understanding environmental impacts on growth rate and development of defensive structures is important to re-establishing a self-recruiting A. fulvescens population in Georgia waterways