Continued Impacts of the Oil Spill on the Gulf's Turtles

Just a brief update on the sea turtles in the Gulf, as we enter the 8th week of spill impact. From NOAA's Office of Response and Restoration, as of June 13th:

• 411
  
• total number of sea turtles verified from April 30 - June 13 within the designated spill area

• 48 or 12%
  
• of the 411; the number of turtles actively rescued on-water
• 3 and 3
• of the 48; the number found dead, and the number that later died
  

• 363 or 88%
  
• of the 411; the number of turtles that have stranded

• 330 or 91%
  
• of the 363; the number of turtles stranded dead

• 33 or 7%
  
• of the 363; the number of turtles stranded alive
  
• 4
  
• of those 33, the number that subsequently died
  

• 57
• total number of captured (42 live, 3 dead, 3 later died) and stranded (5 live, 4 dead) turtles found with visible external oil
  

• 67
• turtles currently in rehabilitation

Dolphins are another marine megafauna affected by the spill and the impact is also being tracked by NOAA's ORR. As of June 13th, a total of 41 dead dolphins have been found. 39 were found dead, one later died at the beach, and the other was euthanized.

Marine turtles and dolphins share similarities which put them at risk for similar impacts concerning this oil spill:

• Use coastal areas and the Gulf to feed
• They will likely ingest oil and associated toxins mixed into the water, as well as tarballs
• According to NOAA's "Oil and Sea Turtles: Biology, Planning and Response"guide, tar balls in the gut may cause blockage leading to starvation, inadequate nutrition absorption, absorbed toxins, intenstinal blockage, trouble utilizing energy (fat) resources, and bouyancy problems caused by internal gas buildup - making feeding and predator/boat avoidance difficult.

• They breath air at the ocean's surface
• This exposes the marine animals to surface oil entering the body, as well as the potential inhalation of the petroleum fumes

• They live in the water all* the time (*the exception of course being nesting females on the beach)
• And unless they can actively avoid the spill-impacted area, they have no choice but to remain in the oil-contaminated water. Continued exposure to the oil and all its associated chemicals and compounds will likely cause physiological and biological impacts (i.e. sloughing of exposed skin, leading to parasite and disease risks; limited food in-take; organ dysfunction; hormone imbalance; abnormal development; changes in blood chemistry; difficulty with salt excretion)

Photo by author: Loggerhead sea turtle (Caretta caretta) in rehabilitation at
Loggerhead Marinelife Center in Juno Beach, Florida (2004).

Other serious impacts to marine turtles are also shared with coastal wildlife rather than dolphins, and affects the breeding, nesting, and hatching turtles. As outlined in Chapter 4 of the same NOAA guide, potential impacts include:

• Interference with breeding behavior and location of breeding/nesting sites
• The oil may affect breeding success and put males as well as females at risk if they aggregate closer to shore than they would otherwise while feeding or migrating
• The oil may disrupt environmental cues that are thought to guide breeding and nesting turtles to the nesting and breeding sites (i.e. masking olfactory cues)

• Reduced food supply
• This includes the kill-off and/or contamination of fish and invertebrates, as well as damaged seagrass beds, and reefs, especially as the oil begins to wash ashore and congeals

• Reduce nesting and hatchling succes
• Nesting females:
  
• Oil and tarballs washed ashore may deter or impede nesting females from successfully nesting
• They may not emerge at all
• They may not be able to dig a body pit/nest cavity
• They will put themselves into direct contact with the oil
• They may become entangled in oil-contaminated debris and beach wrack
• The eggs may be buried with oil-contaminated sand
• All of these impacts threaten the long-term turtle population levels

• Eggs:
• The eggs/hatchlings are at high risk for decreased survival and increased deformities when exposed to "freshly" spilled oil (i.e. the oil spill occurs during nesting season; as opposed to heavily weathered oil)
• Nests could become smothered in oil/tarballs, which would prevent the exchange of air (oxygen and carbon dioxide) as well as inhibiting the proper amount of moisture within the nest
  
• The nest temperature may be increased due to the darker color of the oil-contaminated sand - and because male/female ratio of hatchlings in a nest is determined by nest-temperature; oil on the nest or in the sand would raise the nest temperature, creating more females and fewer males
• All of these impacts threaten the long-term turtle population levels

• Hatchlings:
• Oil on the beach could trap, entangle, contaminate/poision emerging hatchlings
• Once in the water, hatchlings are moved by currents, gathering them with other floating objects - which usually includes seaweed and food - but now also includes oil
• Hatchlings do not dive the way older turtles do, instead they spend much more time at the surface, exposing them to aggregated oil and the fumes
• Hatchlings and juvenile turtles are often thought to be indiscriminate foragers, which means they eat what they find - which now includes oil and tarballs
• All of these impacts threaten the long-term turtle population levels

Sea turtles are long-lived creatures, which have navigated the oceans for hundreds of millions of years. The list of threats sea turtles encounter throughout their lives is long; and this horrible human-error is just one more giant black mark we have made on their (and our!) environment.

Feel sad, yes. Feel mad, yes. Help, yes.
But most of all - look at the way you live your life.

What choices do you make everyday that are related to this human impact?
What could you do differently to make that impact just a little bit smaller?

(Need a few ideas to get started - check out this article from sea turtle researcher, Wallace J. Nichols, written on World Ocean Day and Jacques Cousteau's 100th birthday, "What Would Jacques Do? One Hundred Years of Oil")

Good. Now do it.