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Oil Spill Assessment for Marine Mammals
NOAA Publishes New Guidelines Assessing Exposure and Impacts of Oil Spills on Marine Mammals
Map Below: Current oil spill case locations from NOAA's Damage Assessment Remediation and Restoration Program (NOAA).
Map Above: Current oil spill case locations from NOAA's Damage Assessment Remediation and Restoration Program (NOAA).
Since thousands of oil spills of varying sizes occur in U.S. waters each year, oil spill scientists must be prepared to respond to and assess the impacts of oil on marine mammals.
To do this, the National Oceanic and Atmospheric Administration (NOAA) has published:
"Guidelines for Assessing Exposure and Impacts of Oil Spills on Marine Mammals"
These guidelines provide a review of considerations for marine mammals under NOAA's jurisdiction, incorporating knowledge gained from previous oil spills, especially the 2010 Deepwater Horizon spill.
This story map is an overview of some of the information, tools, and figures found in the report.
Marine Mammal Biology
Marine mammals occupy most offshore and coastal American waters.
Some species occupy nearshore waters, others include mid or deep water as part of their range, while others spend part of their time resting on land or ice.
Killer whale stalks a seal on ice float (NOAA).
All marine mammals occupy the surface waters of oceans, as they breathe air at the surface. This puts them at risk of surfacing in or near floating oil slicks.
Several different species of marine mammals may occupy the same area, so oil spills can impact multiple species of marine mammals.
Marine Mammal Diet
With the exception of manatees, most marine mammals are predatory, feeding on plankton, fish, shellfish, small invertebrates and even other marine mammals.
Consuming oiled prey is one way marine mammals can be exposed to oil during a spill. Contaminated prey can also be a long-term danger of oil spills as contaminants move through the ecosystem.
Baleen whale surfaces while feeding (NOAA).
Marine Mammal Lifecycles
All marine mammals give birth to live young one at a time, produce milk, and nurse their young. Seals and sea lions reach sexual maturity around 4-5 years of age, but it can take whales between 5-14 years before they become sexually mature.
This means that marine mammal populations are vulnerable to traumatic events. It can take populations a very long time to recover after a devastating event like an oil spill.
Mother sea lion and her pup (NOAA).
Marine Mammal Vulnerability to Oil
Petroleum products are complex and contain many compounds that can harm marine mammals and can cause death, cancers, and organ damage. Some oil compounds can linger in the water for a long time and accumulate in the bodies of living things.
Dolphins swimming through oiled water during the Deepwater Horizon oil spill (NOAA).
Marine Mammals Can Be Exposed to Oil In Several Ways
Dolphin with oiled skin during the Deepwater Horizon oil spill (NOAA).
Their bodies can be oiled by swimming through oiled water.
Oil can be inhaled and aspirated as they breathe at the surface.
Oil can be ingested by preening fur seals as they clean themselves.
Oil can be ingested by consuming oiled water or prey.
Mammals break down oil in their bodies quickly, so it can be difficult to determine oil exposure through chemical analysis if much time has passed.
Oil Spill Emergency Response
When spills occur, NOAA provides scientific information to the Unified Command, which coordinates Incident Commanders from all organizations involved in oil sill response.
NOAA may conduct shoreline assessments, aerial overflights and trajectory modeling to identify resources at risk. These activities are critical to guiding decision making by the Unified Command.
Surveying the shore during Deepwater Horizon (NOAA).
Stranding Networks
During an oil spill where marine mammals may be affected, NOAA and stranding networks will participate in the the response to rescue and rehabilitate live animals and study dead animals in the spill area.
There are currently 32 facilities that can rehabilitate stranded marine mammals under NOAA's jurisdiction. In total, there are over 120 organizations or stranding network participants who are authorized to respond to marine mammal strandings.
Dead dolphin washed ashore in Barataria Bay after Deepwater Horizon (NOAA).
Map to Right: Oil footprint of Deepwater Horizon on 5/1/2010 and trajectory estimate of beached oil.
Understanding where oil is, where it is going, and what resources it might impact, is critical to mobilizing stranding networks.
How Stranding Networks Work
Oil spills are not the only reason a marine mammal may become stranded. Other possible causes include disease, parasites, harmful algal blooms, ship strikes, entanglement and weather events.
Some stranding network participants only respond to marine mammals on the beach, lacking facilities for rehabilitation. Other participants do engage in rescue and rehabilitation.
These participants may include Federal, state, and local government entities, non-governmental organizations, academic institutions, museums, and scientists among others.
Seal pup recovered after Exxon Valdez (Alaska Public Archives).
Methods for Assessing Injury to Marine Mammals from Oil Spills
No two oil spills are the same, so it is important for oil spill responders and marine mammal experts to be familiar with methods for assessing injury to marine mammals before disaster strikes.
The methods described in the Slideshow below represent the best starting points when planning a marine mammal oil spill assessment, although there may be other approaches appropriate for specific regions, species, and scenarios.
All field methods that involve approaching, handling, or sampling marine mammals (live or dead) require permits under the Marine Mammal Protection Act and Endangered Species Act.
Gray seal tagging for a research project in Massachusetts (NOAA).
Using Sound Science to Hold Polluters Accountable
America's marine resources are public resources, they belong to us all.
The assessment methods outlined above are best practices to collect quality data after oil spills, hazardous waste spills and ship groundings, allowing NOAA and our partners to hold responsible parties accountable for injuries to marine mammals and fund restoration on behalf of all Americans.
NOAA Damage Assessment Remediation and Restoration Program oil spill, hazardous waste, and ship grounding site locations (NOAA).
Guidelines for Assessing Exposure and Impacts of Oil Spills on Marine Mammals
- Included in this publication are tools and information about marine mammals to help prepare for future disasters. Although the needs of each oil spill are unique, these guidelines serve as a planning tool to use sound science to prepare for future spills.
Experts at NOAA continue to work diligently with our partners, so when oil spill disasters strike we will be even better prepared to respond on behalf of marine mammals.
Mother sea lion and pup (NOAA).
For More Information Please Visit:
Or Contact
- Laurie Sullivan: laurie.sullivan@noaa.gov
- Tom Brosnan: tom.brosnan@noaa.gov
- Megan Ewald: megan.ewald@noaa.gov
All Images Are Credited to NOAA and Are in the Public Domain