Describing prehistoric human subsistence strategies and mobility patterns using archaeofaunal assemblages requires archaeologists to differentiate the effects of human behavior from natural taphonomic processes. Previous studies demonstrate that differences in bone density both within and between taxa contribute to variation in element representation in archaeofaunal assemblages. Measurements of contemporary Pacific Cod (Gadus macrocephalus) and Pacific Halibut (Hippoglossus stenolepis) skeletal elements using Dual Energy Absorptiometry (DEXA) and hydrostatic weighing revealed differences in bone volume density between elements and taxa. Density values were highest in Pacific cod and halibut jaw elements; the lowest bone volume densities were measured in Pacific cod and halibut basipterygia. While halibut and salmon often exhibited similar bone density values, the densities of Pacific cod elements were consistently higher than those from either salmon or halibut. These density data indicate that the remains of Pacific cod are more likely to persist in archaeological deposits. When combined with existing salmon bone density measurements, these data allow for the identification of density-mediated destruction in fish faunal assemblages from along the North Pacific rim. Analysis of cod, halibut and salmon faunal assemblages from the North Point, Cape Addington Rockshelter, Rice Ridge, Uyak and Amaknak Bridge sites revealed that density-mediated element attrition has not consistently affected cod, halibut and salmon element representation in these sites. Significant correlations identified in aggregate site assemblages were not present at finer scales of analysis; the effects of density-mediated element attrition varied between depositional contexts. This research demonstrates that bone density data can be used to differentiate the effects of density-mediated element attrition from the results of human decision-making. Once density-mediated element attrition is ruled out, archaeologists can examine the effects of human processing, transportation, preparation and disposal activities on the distribution of Pacific cod and halibut skeletal elements both within and between archaeological contexts.