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Last updated on April 20, 2014 at 19:30 EDT

Unprecedented Dolphin Die Off Witnessed Along Eastern US Coast

November 10, 2013
Image Credit: Thinkstock.com

Alan McStravick for redOrbit.com – Your Universe Online

The National Oceanic and Atmospheric Administration (NOAA) announced unsettling and unfortunate news this week centered on the bottlenose dolphin and Cetacean populations on the east coast of the United States. We are witnessing the most unprecedented stranding and die-off of these creatures in our recorded history.

The last major incidence of stranding and die-off of these populations occurred in 1987-88 and was responsible for an estimated 30 percent decimation of the coastal population. This current scourge, with data collected between July of this year and November 3, has exceeded the total of the previous epidemic.

According to Teri Rowles, coordinator of the federal fisheries and marine mammal health and stranding response team, “We’re less than halfway through that [1987-88] time frame and we have surpassed the number of Cetaceans in that die-off.”

The east coast, from New York to Florida, has, since July, seen a total of 753 bottlenose dolphins stranded. In a typical year authorities claim the average strand rate rests at 74 dolphins. Of this record number of strandings, a full 95 percent that have washed ashore are dead. Those still alive typically die a short time later.

Worst of all, while experts have identified the cause, there is nothing they can do to abate the tragic consequences. And the strandings and deaths are only expected to continue to rise as the coastal population continues its southward migration into warmer coastal waters.

“There is no vaccine that can be deployed for a large bottlenose dolphin population or any cetacean species,” Rowles said. “Currently there is nothing that can be done to prevent the infection spreading, or prevent animals that get infected from having severe clinical disease.”

This most recent mass die-off has been better monitored than the die-off that occurred in the late 80s thanks in great part to a broad marine mammal stranding, rescue and monitoring network created as a result of the earlier event.

The cause of the current die-off has been attributed to an infection — known as dolphin morbillivirus — that works to suppress the dolphin’s immune systems, leaving the creatures vulnerable to both bacterial and fungal infections. Dolphin morbillivirus is believed to have been the same cause responsible for the die-off 26 years ago.

The source of the virus is, as yet, unknown. Federal officials and local stranding networks believe it has originated in large whale populations where it is eventually passed on to the bottlenose dolphins. However, this is still an untested theory as officials claim there is still uncertainty regarding where the virus originated and how it came to infect the dolphin population.

“There are still a lot of unanswered questions,” Rowles said. “We wish we knew why outbreaks occur.”

To date, a total of 5 types of morbillivirus have been identified among marine mammal populations. While there is no proven link to human infection from the dying and dead dolphins, human-specific forms of morbillivirus have been shown to be a cause for measles in humans.

Officials stated they have identified morbillivirus in a few stranded humpback and pigmy sperm whales as well. What is unclear, according to Rowles, is whether that strain is the same strain found to be responsible for the massive die-off of bottlenose dolphins. As of now, they cannot say, with certainty, whether or not they are identical or if there is a separate outbreak affecting the two whale species as well.

The current population of coastal mammals has, in recent years, been shown to be exhibiting a significant decrease in immunity to the illness responsible for the late 80s outbreak. This has been especially true among the population of younger dolphins.

As the team notes, however, suppressed immunity alone is not enough to trigger a significant mortality event.

NOAA and the stranding network are seeking the assistance and cooperation of citizens residing and vacationing on the east coast. As these animals wash ashore, many are already dead. Those still alive will be in severe distress and will require immediate medical attention. “What we’re trying to prevent people from doing is push them back out,” Rowles concluded.

Citizens who come across a stranded whale or dolphin are urged to contact the local stranding coordinator or call the NOAA hotline at 877-WhaleHelp. Additionally, the federal administration has developed a downloadable app entitled ‘Dolphin & Whale 9-1-1′, which is currently available for Android and iOS6 devices.

Perhaps most important for citizens to know is that NOAA requests and suggests the following when coming into near contact with one of these stranded animals: do not touch the dolphin; don’t allow your pets to approach the animal; and maintain a safe distance of at least 100 yards from which you can observe the beached creature.

Rowles vaguely and ominously concluded her statement saying, “We don’t yet know how this is going to play out.”


Source: Alan McStravick for redOrbit.com - Your Universe Online