Moisture content in Dalls porpoise (Phocoenoides dalli) tissues: a reference base for conversion factors between dry and wet weight trace element concentrations in cetaceans

Concentration of trace elements measured by dry weight basis has become more commonly used in recent studies on cetaceans than wet weight basis, which was used more in earlier studies. Because few authors present moisture content data in their papers, it is difficult to compare the concentrations of trace elements between various studies. Therefore, we felt that it would be useful if a reference conversion factor (CF) for tissue types could be found to convert between wet weight and dry weight data on trace element concentrations. We determined the moisture contents of 14 tissues of Dallʹs porpoise (Phocoenoides dalli), and then, calculated the CF values for those tissues. Because the moisture content of each tissue differs from other tissues, it is necessary to use a specific CF for each tissue rather than a general CF for several tissues. We have also found that CF values for Dallʹs porpoise tissues are similar to the same tissues in other cetaceans. Therefore CF values from Dallʹs porpoise can be reliably used to convert between wet and dry weight concentrations for other cetacean tissues as reference data.