For Immediate Release, March 19, 2007
GALVESTON, Texas -- Since the end of February, about 60 dead bottlenose dolphins, including a number of neonates with umbilical cords still attached, have washed ashore on Texas beaches from Galveston to Sabine Pass about 120 miles to the northeast. This tally represents more than three times number of such occurrences in a similar period in previous years and is a cause for concern, according to Dr. Daniel F. Cowan, professor of pathology at the University of Texas Medical Branch at Galveston (UTMB) and director of the Texas Marine Mammal Stranding Network (TMMSN).
"As animals at the top of the food chain, marine mammals such as dolphins are like canaries in the coal mines reflecting the health of the oceans," Cowan noted. Like other top ocean predators, dolphins bio-accumulate substances such as heavy metals and pesticides and thus serve as key indicators of the health of the Gulf of Mexico and Galveston Bay ecosystems, he explained. Suspected causes of this spike in dolphin deaths range from biotoxins such as red tide (an algal bloom prompted by fertilizers or other excess nutrients), infectious diseases such as morbillivirus (a dolphin infection similar to distemper in dogs), and parasites to industrial toxins (like mercury and other heavy metals), Cowan said - although no industrial spills are known to have occurred.
Most of the carcasses found so far have been in such advanced stages of decomposition that TMMSN volunteers buried them on the beaches. However, one freshly deceased dolphin washed up last week and Cowan performed a necropsy - the animal version of an autopsy - on it. "That animal had a belly full of blood, probably from a ruptured blood vessel; it was more like those we usually see and probably was not related to this increase in deaths," he said. The cause of that animal's illness likely was parasites, although that remains to be confirmed, he added. "We still don't know what's killing the rest."
Heidi Watts, state coordinator of the TMMSN, boarded a helicopter this morning to join Coast Guard personnel scouring beaches for additional evidence of dead or stranded dolphins. They sighted nine additional dolphin carcasses, in addition to four discovered last weekend. The total as of last Friday had been 47.
Cowan is available at (409) 772-7220 or through UTMB Public Affairs. Ms. Watts is available via cell phone at (832) 385-7811.