photo courtesy of Wikipedia

photo courtesy of Wikipedia

Dolphins Dying on the East Coast

written by: Brian Kokonya

 

Over the past few months, carcasses of dolphins of the bottlenose species have been discovered on the shores of the ocean across the United States from Virginia to New York raising concerns over the environmental health of the oceans and the future of aquatic life in general. Several scientists have expressed concerns over the rising number of deaths and are working to find a quick and lasting solution.

Many Dead Dolphins, No Answers

Several remains of dozens of dolphins have been washed up on the shores of the east coast prompting scientists to start looking for answers. This year, 164 of the dead dolphins have been identified in Virginia alone and almost half of those have already reached the shore. According to the federal authorities, 228 deaths have been already recorded this year from Virginia to New York. In 2012, they recorded a total of 111 deaths. The rising numbers of these deaths have caused the authorities to invest a lot of resources to try and establish the root cause of the deaths to avert further deaths of the Bottlenose dolphins.

In response to these deaths, the National Oceanic and Atmospheric Administration (NOAA) has already declared an Unusual Mortality Event (UME). This declaration brings a concentrated attention to this kind of deaths as a result of wanting oceanic health which may have larger environmental implications to humans. Since its inception in 1991 under the Marine Mammal Protection act, this current declaration is among the 60 UMEs the NOAA has had to declare. In about 29 of those cases, the major causes of deaths includes but is not limited to malnutrition, human intervention, biotoxins and infections. Though not known, the latest cause of deaths are speculated to be as a result of an infection but all possible causes are to be evaluated to establish the actual cause.

Virus to Blame For Dolphin Deaths?

The research coordinator for Virginia Science centre, Susan Barco, said that preliminary tests indicate traces of lesions in the lungs of the dead dolphins which points to a respiratory infection. The active lymph nodes is an indication that the dolphins are actively fighting a severe infection. Barco further added that the scientists are taking a closer look at the morbillivirus which was considered to be behind the 1987 deaths of 740 dolphins on the east coast. The virus has already been identified in some of the dolphins that have been under the microscope this year. Speaking to NPR, Charlie potter of National Museums of History said Morbilli is a family of viruses and may include things like measles and the big question right now is whether the infection has always been there and may just be circumstantial or if it is the actual cause, to what extent has the infection gone. He added that the infection of the lung is one of the characteristics of morbilli but there are also other causes of lung infections so they can not entirely base their arguments on this one particular symptom. There could be other causes too. Also, there are problems in many of the dolphins’ other organs further complicating the diagnosis on whether they are just sick.

 

The daily feeding of bottlenose Dolphins.

(Photo credit: Wikipedia)

According to Potter, the virus could be compounded by other factors in the dolphins’ habitual environment including pollution or even hydrocarbons. The high number of calves and the male species of the dead dolphins surfaces these speculations. This is because the males usually do not have a way of shedding of extra contaminants unlike the female dolphins. With the claves, the high level of contaminants is a result of the female shedding of theirs through lactation resulting in high quantities of contaminants in calves.

 

According to Susan, the bottlenose dolphins’ deaths are a clear warning to the human population. Being higher order predators, healthy bottlenose dolphins would well mean that the ecosystem is fairly healthy. However, if this particular type of dolphins are dying, it is a clear indication that the ecosystem’s health is under threat. She further said that as the dolphins move, they could be spreading the infection and this will result in the expansion of the affected areas, going as far as Florida.

 

The state of Florida has had its own UME this year. The deaths of Manatee happened and up until now, according to NOAA, no cause has been established. During the interview with NPR, Potter, who has worked with the response teams for the stranded dolphins in Virginia, said the deaths of these dolphins sometimes has a personal effect on his person. He is of the opinion that if you critically think about it, the deaths stick with you. Considering the fact that a number of the dolphins are infants, it is difficult to absorb their deaths.

 

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