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Cetacean Unusual Mortality Event in Northern Gulf of Mexico (2010-2014): CLOSED

Results and Publications

Here are the latest findings in the investigation of the ongoing Cetacean Unusual Mortality Event in the northern Gulf of Mexico.  Results and publications will be updated as they become available.

Summary

Under the Marine Mammal Protection Act of 1972 (as amended), an Unusual Mortality Event (UME) has been declared for dolphins and whales (cetaceans) in the northern Gulf of Mexico (Texas/Louisiana border through Franklin County, FL) from February 2010 through the present. Based upon analysis of stranding data, and recommendations from the UME investigative team and the Working Group on Marine Mammal Unusual Mortality Events (an advisory group of marine mammal health and biology experts), NOAA has declared the northern Gulf of Mexico cetacean UME closed. The temporal and spatial boundaries have been redefined to include the following: 

The UME investigation and the Deepwater Horizon Natural Damage Resource Assessment have determined that the Deepwater Horizon oil spill resulted in the death of marine mammals and is the most likely explanation of the persistent, elevated stranding numbers in the northern Gulf of Mexico after the spill.  The evidence to date supports that exposure to Deepwater Horizon petroleum products was the most likely explanation of the adrenal and lung disease in dolphins, which has contributed to increased deaths of dolphins living within the oil spill footprint and increased fetal loss. While the number of dolphin mortalities in the area decreased after the peak from March 2010 – July 2014, it does not indicate that the effects of the oil spill on these populations have ended. Researchers still saw evidence of chronic lung disease and adrenal impairment even 4 years after spill (in July 2014) and saw evidence of failed pregnancies in 2015. Research into the long-term health effects of the spill on marine mammal populations is ongoing.  For more information on proposed restoration and monitoring activities please see the (PDARP).  Additionally, more details are available in the following publications.

These numbers are preliminary and may be subject to change. The UME involves 1,141 Cetacean "strandings" in the Northern Gulf of Mexico (5% stranded alive and 95% stranded dead). Of these:

Cetaceans Stranded Phase of Oil Spill Response Dates
89 cetaceans stranded prior to the response phase for the oil spill March 1, 2010- April 29, 2010
119 cetaceans stranded or were reported dead offshore during the initial response phase to the oil spill April 30, 2010- November 2, 2010
933 cetaceans stranded* after the initial response phase ended November 3, 2010 - July 31, 2014**

*This number includes 13 dolphins that were killed incidental to fish related scientific data collection and 1 dolphin killed incidental to trawl relocation for a dredging project.

**The initial response phase ended for all four states on November 2, 2010. Response re-opened for eastern and central Louisiana on December 3, 2010 and closed again on May 25, 2011.


Brucella fact sheet
[pdf]

Brucella bacteria

In addition to investigating all other potential causes, scientists are investigating what role Brucella may have in the Unusual Mortality Event.

Since our finding of Brucella in 5 stranded dolphins from Louisiana in 2011, scientists have been concentrating testing on cases that show pathological changes consistent with the fetal pneumonia or adult meningitis identified in the first 5 cases. Here are our results showing the total number of Brucella cases identified.  Additional information about Brucella in stranded dolphins can be found in Colegrove et al. 2016.

FAQs

FAQs on the investigations of the ongoing dolphin die-off and the potential impacts of the Deepwater Horizon BP oil spill on marine mammals are available.

Data

By month/year: All stranded cetaceans (dolphins and whales) from Franklin County, FL to Louisiana and bottlenose dolphins from Louisiana to Alabama.
NOTES:. Historical data from 2008 through present are unvalidated and numbers may be subject to change as more information becomes available. Current UME Data are considered preliminary and may be subject to change as more information becomes available. They include any strandings that occurred on or before July 31, 2014 as well as 13 cases that were incidental scientific data collection takes and 1 take incidental to trawl relocation for a dredging project. Raw historical data are also available for download.

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average (2002-2009) 5.5 3.6 16.3 11.1 4.8 3 3.9 3.3 4.1 3.3 2.4 2
2010 Total     53 36 39 30 11 18 15 6 11 12
2011 Total 20 62 64 35 20 22 16 30 15 26 17 15
2012 Total 21 21 43 17 11 6 7 5 10 13 16 13
2013 Total 22 24 45 65 29 12 3 7 4 8 4 9
2014 Total(Jan-Jul) 14 28 30 34 24 15 8          

By state All stranded cetaceans (dolphins and whales) from Franklin County, FL to Louisiana and bottlenose dolphins from Louisiana to Alabama

NOTES: Historical data from 2008 through present are unvalidated and numbers may be subject to change as more information becomes available. Current UME Data are considered preliminary and may be subject to change as more information becomes available. They include any strandings that occurred on or before July 31, 2014 as well as 13 cases that were incidental scientific data collection takes and 1 take incidental to trawl relocation for a dredging project. Raw historical data are also available for download.

 

FL
Panhandle

AL

MS

LA

Average (2002-2009)

8

14

20

21

2010 (Mar-Dec)

12

21

63

135

2011 Total

8

59

111

164

2012 Total

9

30

50

94

2013 Total

7

27

51

147

2014 (Jan-Jul)

4

32

43

74

 

Number of strandings by month per state/region (change graphs to reflect only through July 2014)

 

 

Number of strandings per state or region from March 2010 through July 2014.
The red line represents the number of cetacean strandings in each region over time. The green line represents the reported number of stillborn, premature, or neonate stranded bottlenose dolphins (actual or estimated whole carcass lengths less than 115 cm) in each region over time (Feb. 2010-Jul. 2014). The blue line represents the historical average per month calculated from 2002-2009 stranding data.
NOTES: Historical data from 2008 through present are unvalidated and numbers may be subject to change as more information becomes available. Current UME Data are considered preliminary and may be subject to change as more information becomes available. They include any strandings that occured on or before July 31, 2014 as well as 13 cases that were incidental scientific data collection takes and 1 take incidental to trawl relocation for a dredging project. Raw historical data for 2002-2009 are also available for download.

 

All stranded bottlenose dolphins from Alabama through Louisiana by month.
NOTES: Historical data from 2008 through present are unvalidated and numbers may be subject to change as more information becomes available. Current UME Data are considered preliminary and may be subject to change as more information becomes available. They include any strandings that occured on or before July 31, 2014 as well as 13 cases that were incidental scientific data collection takes and 1 take incidental to trawl relocation for a dredging project. Raw historical data are also available.

 

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Average (2002-2009)

4.3

3.4

14.5

9.6

4.3

2.5

3

2.5

2.0

2.9

1.5

1

2010 Total (Mar-Dec)

 

 

46

34

37

22

9

18

11

6

7

11

2011 Total

19

58

60

31

18

21

16

25

10

24

16

12

2012 Total

17

17

36

15

9

3

5

3

7

9

13

12

2013 Total

20

21

41

48

25

9

3

4

 3

 6

1

 9

2014 (Jan-Jul)

10

24

28

28

22

12

2

 

 

 

 

 


 

Stranded bottlenose dolphins from Alabama throughLouisiana with reported actual or estimated whole carcass lengths less than 115 cm (partial carcasses excluded). Bottlenose dolphins <115 cm in total length are either premature, stillborn, or neonatal.
NOTES: Historical data from 2008 through present are unvalidated and numbers may be subject to change as more information becomes available. UME Data are considered preliminary and may be subject to change as more information becomes available. They include any strandings that occured on or before July 31, 2014 as well as 13 cases that were incidental scientific data collection takes and 1 take incidental to trawl relocation for a dredging project. Raw historical data are also available.

 

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Average (2002-2009)

0.9

0.8

5.8

2.1

0.9

0.3

0

0

0.1

0

0.1

0.1

2010 Total (Mar-Dec)

 

 

11

8

4

0

0

1

0

0

0

2

2011 Total

4

35

24

9

2

2

0

0

0

0

0

1

2012 Total

6

5

9

2

0

0

0

1

0

0

0

1

2013 Total

9

10

10

9

2

1

0

0

 0

 1

0

1

2014 Total (Jan-Jul)

5

11

10

14

1

0

0

 

 

 

 

 



Map

The following map displays stranding locations from the 2010-2014 Cetacean Unusual Mortality Event in the Northern Gulf of Mexico. Bottlenose dolphin stranding locations are represented by circle symbols, while stranding locations for all other cetacean species are represented by square symbols. Symbols containing a black dot indicate that the reported actual/estimated length of the stranded cetacean was less than 115 cm. Symbols that are colored pink, represent the most recently reported data. Dropdown boxes located above the map allow filtering of the mapped locations and clicking on a mapped location will open an information window containing data associated with the selected stranding.

Filter Stranding Locations:
Year
Month
Species Class

More Information

 

Updated: May 26, 2016