Update on Bottlenose Dolphin Strandings
This summer’s unusual mortality event (UME) involving bottlenose dolphins continues into the fall. In the Mid-Atlantic region, the current strandings are still over nine times the historical average. The strandings range from a few live animals to mostly dead animals, with some dolphins presenting with lesions on their skin, mouth, joints, or lungs.
Early indications point to the cetacean morbillivirus as the cause of the UME, based upon preliminary diagnostic testing and discussion with marine mammal disease experts. The table below lists the total number of morbillivirus cases identified so far, based on data collected from the National Marine Fisheries Service:
State |
Suspected |
Confirmed |
Total |
Delaware |
1 |
1 |
2 |
Maryland |
3 |
0 |
3 |
New Jersey |
14 |
6 |
20 |
New York |
3 |
0 |
3 |
North Carolina |
4 |
4 |
8 |
Virginia |
19 |
3 |
22 |
Total |
44 |
14 |
58 |
The UME investigation is still in progress, and investigators are looking at other factors such as pathogens, biotoxins, and range expansion. The investigation is expected to continue over the next several months as new animals are found or new evidence alters the path of the investigation. There are simultaneous studies, collaboration with several NOAA laboratories and science centers, which are researching the characteristics of morbillivirus and the potential impacts of this virus on dolphin stocks.
Anyone who sees a stranded dolphin should alert the Town to contact the local stranding network authority; this provides an opportunity for stranding network responders to get to the site and collect fresh data. Quality data collection increases the chances of identifying the underlying cause of the stranding.
Efforts by the National Marine Fisheries Service, as well as State services, to examine carcasses of live and stranded animals have been critical in increasing understanding of mortality rates and causes. The goal is to achieve a better understanding about the kinds of stressors and threats that put marine populations at risk. Tangentially, the investigation of marine mammal UMEs can also serve as an indication of ocean health, providing data as it relates to broader environmental issues, which may also have implications for human health and welfare.
Current Standings as of Sept 9th:
Week of: |
NY |
NJ |
DE |
MD |
VA |
NC |
Weekly Totals |
July 1 |
3 |
0 |
0 |
0 |
3 |
3 |
9 |
July 8 |
3 |
2 |
1 |
2 |
5 |
0 |
13 |
July 15 |
1 |
5 |
0 |
2 |
7 |
4 |
19 |
July 22 |
4 |
8 |
0 |
3 |
17 |
2 |
34 |
July 29 |
6 |
11 |
1 |
0 |
29 |
2 |
49 |
Aug 5 |
6 |
10 |
0 |
1 |
23 |
3 |
43 |
Aug 12 |
1 |
22 |
2 |
4 |
46 |
10 |
85 |
Aug 19 |
1 |
13 |
7 |
4 |
49 |
20 |
94 |
Aug 26 |
5 |
4 |
8 |
9 |
43 |
6 |
75 |
Sept 2 |
1 |
8 |
3 |
8 |
20 |
6 |
46 |
Sept 9 |
0 |
0 |
0 |
7 |
2 |
0 |
9 |
Total |
31 |
83 |
22 |
40 |
244 |
56 |
476 |
The local stranding network is the Virginia Aquarium & Marine Science Center, 757-385-7576.
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