Sea Turtle Strandings in the Gulf of Mexico
 Kemp's Ridley Turtle (Lepidochelys kempii) Photo: NOAA » Sea turtle photos |
Increase in Sea Turtle Strandings
The Sea Turtle Stranding and Salvage Network (STSSN) has documented large numbers of stranded sea turtles in the north-central Gulf of Mexico in 2010-2012. The majority of these turtles have been endangered Kemp's ridleys, loggerhead, and green turtles. The STSSN is monitoring and investigating this increase. Please refer to our FAQs for more information.
Data
Data are compiled through the efforts of network participants who document sea turtle strandings in their respective areas and contribute those data to the centralized STSSN database.
2012 Sea Turtle Strandings Documented in AL, LA, MS, and TX (upper TX coast: zone 18)
314 total strandings in 2012, through May 20, 2012
| Alabama Strandings |
2012 Total |
Jan 2012 |
Feb 2012 |
Mar 2012 |
Apr 2012 |
May 2012 |
June 2012 |
July 2012 |
Aug 2012 |
Sep 2012 |
Oct 2012 |
Nov 2012 |
Dec 2012 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Loggerhead | 2 | 0 | 0 | 2 | 0 | 0 | |||||||
| Green | 0 | 0 | 0 | 0 | 0 | 0 | |||||||
| Kemp's ridley | 29 | 0 | 0 | 6 | 19 | 4 | |||||||
| Unidentified | 2 | 0 | 0 | 0 | 2 | 0 | |||||||
| Total | 33 | 0 | 0 | 8 | 21 | 4 | - | - | - | - | - | - | - |
| Louisiana Strandings |
2012 Total |
Jan 2012 |
Feb 2012 |
Mar 2012 |
Apr 2012 |
May 2012 |
June 2012 |
July 2012 |
Aug 2012 |
Sep 2012 |
Oct 2012 |
Nov 2012 |
Dec 2012 |
| Loggerhead | 2 | 0 | 0 | 2 | 0 | 0 | |||||||
| Green | 3 | 1 | 1 | 1 | 0 | 0 | |||||||
| Kemp's ridley | 76 | 3 | 4 | 37 | 18 | 14 | |||||||
| Unidentified | 8 | 1 | 0 | 1 | 5 | 1 | |||||||
| Total | 89 | 5 | 5 | 41 | 23 | 15 | - | - | - | - | - | - | - |
| Mississippi Strandings |
2012 Total |
Jan 2012 |
Feb 2012 |
Mar 2012 |
Apr 2012 |
May 2012 |
June 2012 |
July 2012 |
Aug 2012 |
Sep 2012 |
Oct 2012 |
Nov 2012 |
Dec 2012 |
| Loggerhead | 2 | 1 | 0 | 1 | 0 | 0 | |||||||
| Green | 1 | 1 | 0 | 0 | 0 | 0 | |||||||
| Kemp's ridley | 122 | 2 | 0 | 56 | 46 | 18 | |||||||
| Unidentified | 3 | 0 | 0 | 1 | 2 | 0 | |||||||
| Total | 128 | 4 | 0 | 58 | 48 | 18 | - | - | - | - | - | - | - |
| Texas Strandings (for the Upper Coast: Zone 18) |
2012 Total |
Jan 2012 |
Feb 2012 |
Mar 2012 |
Apr 2012 |
May 2012 |
June 2012 |
July 2012 |
Aug 2012 |
Sep 2012 |
Oct 2012 |
Nov 2012 |
Dec 2012 |
| Loggerhead | 9 | 0 | 1 | 1 | 6 | 1 | |||||||
| Green | 13 | 1 | 0 | 0 | 7 | 5 | |||||||
| Leatherback | 2 | 0 | 0 | 0 | 1 | 1 | |||||||
| Hawksbill | 1 | 0 | 0 | 0 | 0 | 1 | |||||||
| Kemp's ridley | 39 | 1 | 2 | 18 | 13 | 5 | |||||||
| Unidentified | 0 | 0 | 0 | 0 | 0 | 0 | |||||||
| Total | 64 | 2 | 3 | 19 | 27 | 13 | - | - | - | - | - | - | - |
2012 Map of Sea Turtle Strandings in the Gulf of Mexico
This map represents the sea turtle strandings documented from January 1, 2012-May 20, 2012 for which location information has been received. Each species is shown in a different shape.
2011 Sea Turtle Strandings Documented in AL, LA, and MS
525 total strandings in 2011, through December 31, 2011
*2011 data are pending validation
| Alabama Strandings |
2011 Total |
Jan 2011 |
Feb 2011 |
Mar 2011 |
Apr 2011 |
May 2011 |
June 2011 |
July 2011 |
Aug 2011 |
Sep 2011 |
Oct 2011 |
Nov 2011 |
Dec 2011 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Loggerhead | 10 | 0 | 1 | 1 | 1 | 0 | 4 | 1 | 0 | 0 | 1 | 1 | 0 |
| Green | 4 | 2 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| Kemp's ridley | 66 | 0 | 0 | 6 | 21 | 11 | 11 | 8 | 7 | 1 | 2 | 0 | 0 |
| Unidentified | 14 | 0 | 0 | 1 | 5 | 5 | 1 | 1 | 0 | 0 | 0 | 0 | 0 |
| Total | 94 | 2 | 1 | 9 | 27 | 16 | 16 | 10 | 7 | 1 | 3 | 1 | 1 |
| Louisiana Strandings |
2011 Total |
Jan 2011 |
Feb 2011 |
Mar 2011 |
Apr 2011 |
May 2011 |
June 2011 |
July 2011 |
Aug 2011 |
Sep 2011 |
Oct 2011 |
Nov 2011 |
Dec 2011 |
| Loggerhead | 19 | 1 | 0 | 4 | 1 | 5 | 3 | 0 | 0 | 0 | 0 | 5 | 0 |
| Green | 6 | 0 | 2 | 0 | 3 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Kemp's ridley | 104 | 0 | 2 | 15 | 24 | 13 | 21 | 10 | 0 | 3 | 5 | 7 | 4 |
| Unidentified | 19 | 1 | 0 | 3 | 1 | 1 | 7 | 0 | 0 | 3 | 1 | 0 | 2 |
| Total | 148 | 2 | 4 | 22 | 29 | 19 | 32 | 10 | 0 | 6 | 6 | 12 | 6 |
| Mississippi Strandings |
2011 Total |
Jan 2011 |
Feb 2011 |
Mar 2011 |
Apr 2011 |
May 2011 |
June 2011 |
July 2011 |
Aug 2011 |
Sep 2011 |
Oct 2011 |
Nov 2011 |
Dec 2011 |
| Loggerhead | 4 | 0 | 0 | 0 | 1 | 2 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Green | 7 | 1 | 0 | 1 | 2 | 0 | 1 | 0 | 0 | 1 | 0 | 1 | 0 |
| Kemp's ridley | 265 | 2 | 1 | 47 | 128 | 31 | 31 | 14 | 3 | 4 | 2 | 2 | 1 |
| Unidentified | 7 | 0 | 0 | 0 | 3 | 0 | 0 | 3 | 0 | 0 | 0 | 0 | 0 |
| Total | 283 | 3 | 1 | 48 | 134 | 33 | 33 | 17 | 3 | 5 | 2 | 3 | 1 |
2011 Map of Sea Turtle Strandings in the Gulf of Mexico
This map represents the sea turtle strandings documented from January 1, 2011-December 31, 2011 for which location information has been received. Each species is shown in a different shape.
*2011 data are pending validation
What is the STSSN?
The Sea Turtle Stranding and Salvage Network (STSSN) was formally established in 1980 to collect information on and document strandings of marine turtles along the U.S. Gulf of Mexico and Atlantic coasts. The network encompasses the coastal areas of the 18 states from Maine through Texas, and includes portions of the U.S. Caribbean.
What is a "stranding"?
Strandings are defined as turtles that wash ashore, dead or alive, or are found floating dead or alive (generally in a weakened condition).
What is causing the increase in strandings?
There are many possible reasons for the increase in strandings in the Northern Gulf of Mexico, both natural and human caused. We are working with the STSSN and the states to investigate potential causes, including:
- fishing activities that may result in turtle bycatch and mortality
- biotoxins, such as harmful algal blooms, which can occur in the Gulf of Mexico
- possible impacts from the Deepwater Horizon Oil Spill
Efforts are underway to collect sea turtle carcasses for examination to try to determine the cause of death. A cause of death in sea turtles is often difficult to pinpoint, especially in carcasses that are not fresh. Most sea turtle carcasses wash ashore moderately or severely decomposed and some are too decomposed to provide meaningful information.
What has NMFS learned so far from the ongoing investigations?
As indicated in the tables above, over 450 sea turtles have stranded along the coasts of LA, MS, and AL since the beginning of 2011. Most of these strandings occurred during March and April and many dead turtles were too decomposed to provide meaningful information.
We have been able to perform necropsies on 78 turtles (47 from Mississippi, 27 from Louisiana, and 4 from Alabama) that were stranded between March and June 2011. Most of these carcasses were moderately or severely decomposed, indicating that they had likely died within one week of discovery. Limited examinations of some additional extremely decomposed turtles also have been conducted.
One sea turtle had a small amount of tar from the BP Deepwater Horizon oil spill on its shell. No visible external or internal oil was observed in any other animals.
Of the 78 necropsied sea turtles:
- 14 had major traumatic injuries (10 consistent with watercraft strikes, 3 with known or suspected internal hooking injuries and 1 entanglement)
- 6 turtles had shark bite wounds, the nature of which suggests the sharks scavenged on turtles that were already dead
- 3 turtles had signs of weight loss and infections, indicating the animals were not healthy
- 55 sea turtles had no external traumatic injuries, were in fair to good nutritional condition and did not have evidence of any significant disease process. This group is of special concern because these 55 animals represent the large majority of examined dead sea turtles, and thus reflect a significant factor in the large number of strandings.
Most of the 55 sea turtles in the group of special concern had been feeding on fish. Sea turtles typically do not prey on live fish, but will scavenge dead fish, most often available as discarded dead bycatch or as a result of fish kills. There were 14 turtles with food (mostly fish) still in the esophagus, suggesting a sudden death. Also, most turtles had food (primarily fish) in their stomachs.
Evidence of drowning (including aspiration of sediment-rich water) was observed in many animals.
Based on these findings, the two primary considerations for the cause of death in these cases are
- forced submergence or
- acute toxicosis, such as a harmful algal bloom (HAB)
The only known plausible cause of forced submergence that could explain this event is incidental capture in fishing gear. We are assembling information regarding fisheries operating in the area during and just prior to these strandings.
We have been working closely with scientists in partner state agencies and universities to look at environmental data to see if HABs may be the cause of the mortality. After analyzing turtle samples for toxins associated with harmful algae, we have not found any evidence that a HAB is the cause of mortality. Additional testing for contaminants related to the recent oil spill is in process.
What sea turtle species can be found in the area?
There are 5 species of sea turtles known to inhabit the waters of the Gulf of Mexico and U.S. Atlantic, and all are protected under the Endangered Species Act:
- loggerhead turtle (Caretta caretta)
- green turtle (Chelonia mydas)
- Kemp's ridley turtle (Lepidochelys kempi)
- hawksbill turtle (Eretmochelys imbricata)
- leatherback turtle (Dermochelys coriacea)
More Information
To learn more about sea turtles and how NOAA was involved in their rescue during the Deepwater Horizon BP oil spill, please visit our websites.
Updated: May 22, 2012
