Iodine is an essential
micronutrient for elasmobranchs in order to prevent
goiter. Preventing
goiter requires bioavailable
iodide: either oral
iodide or maintaining adequate aquarium water
iodide concentrations. The objective of this study was to determine how oral and water supplementation affected
iodine (I2) and
iodide (I-) concentrations in artificial seawater aquaria housing captive white-spotted bamboo sharks ( Chiloscyllium plagiosum). Daily water samples were collected and free
iodine (I2) was determined using ultraviolet-absorbance spectrophotometry (a relatively simple in-house assay) and total
iodide (I-) via liquid chromatography (a more time- and expertise-intense quantification method) to learn the effects of supplementation. One water system received
iodine and
iodide supplementation in the form of 5%
Lugol's iodine solution added directly to the water, while a second water system received no supplementation. In addition, one tank of sharks in each water system received oral
iodide supplementation. Results indicated that oral supplementation provides greater increases in water concentrations of bioavailable
iodide (I-) than direct water supplementation. In addition, the chromatographic results suggested that
iodide is present in higher concentrations in the systems not receiving water supplementation. Increased
iodide concentrations were detected in water samples after water changes and after oral
iodide supplementation was administered, but total
iodine (I2) concentration changes were not detectable within the same time frame.