Recent studies have suggested a link between mass stranding of beaked whales and the use of naval mid-frequency sonar. The whales experienced symptoms that were similar to those caused by gas bubbles in human divers. These reports have increased the concern that anthropogenic sound, such as that created by military sonar or during seismic exploration, may harm marine animals. It has been suggested that alteration in physiology or diving behavior may increase the risk of decompression sickness (DCS). A diagnostic tool for DCS in dolphins is very desirable.
Bubble formation is believed to be the crucial event in the etiology of DCS, but the role bubbles play in the disease process remains unclear. Recent studies have shown that Microparticles (MPs) correlate with the level of decompression stress in both the mouse and human. MPs are particles between 0.3 to 3 µm in size that are shed from various cells. MPs are present in stranded dolphins and they can be detected by standard assays. Thus, MPs may be suitable biomarkers to assess decompression stress. The study is aimed at verifying a relationship between decompression stress and MPs in sea lions and then transferring this knowledge to assess decompression stress of cetaceans in the field. We collaborated with the Chicago Zoological Society health assessments in Sarasota to sample dolphins when they are first restrained, during examination on deck, and back in the water, to get baseline data for shallow-swimming and out-of-the-water dolphins.
In total, 123 blood samples from 58 wild-caught-and-released dolphins in Sarasota Bay, Florida, were analyzed for MPs over the 2012 to 2014 period. The samples were obtained Pre-, Mid-, and Post-procedure. Preliminary analyses of data from the first 2 years of this study found an apparent increase in MP count with removal of the animal from the water, but subsequent analysis of all MP counts now available for this study showed no significant impact of removal from, or return to the water. This work is supported by the Office of Naval Research.
This article was published on page 11 in the November 2014 issue of Nicks n Notches