Seeps Impact Marine Wildlife

How Seeps Impact Marine Wildlife

Our coastal waters are home to rich and diverse marine environments. The areas offshore Santa Barbara support a great diversity of marine species, many of which are extremely rare and given special protection under federal and state law. These include over 195 species of birds that use the open water, shore, or island habitats in the area; at least 33 species of cetaceans; 7 species of seals; and the southern sea otter.

Though we more commonly hear of oiled seabirds and marine mammals, invertebrates are not immune to impacts. This photo shows a closeup of a dead Phacellophora camtschatica jellyfish as it floats through the slicks. The bell filled with seep gas as it entered the seep field and the gas floated it to the surface where it expired.


Oil pollution, in general, can have a smothering effect on marine life, fouling feathers and fur. It is a toxic poison that birds and mammals often ingest while trying to clean themselves. Fish absorb it through direct contact and through their gills. Contact with oil and fumes can also cause nausea and health problems for people in affected areas, the extent of which can vary depending on weather, temperature and wind.

Even when the oil does not kill, it can have more subtle and long-lasting negative effects. For example, it can damage fish eggs, larva and young — wiping out generations. It also can bio-accumulate up through the food chain as predators (including humans) eat numbers of fish that have sub-lethal amounts of oil stored in their bodies.

Marine Mammals

The natural oil seeps in Santa Barbara’s Channel produce a persistent oil slick on the ocean’s surface. It is the same oil that is extracted from formations in the area, and can impact marine mammals that reside in or migrate through the Santa Barbara Channel.

The lethargic behavior of oiled seals following the Exxon Valdez oil spill was not attributed to blanketing effects from a catastrophic spill, but rather to brain damage from inhalation of volatile fumes, since they breathe just above the water’s surface. This was suggested as being especially threatening with less weathered oil on the calm waters and on haulouts early in the spill (Parks Canada 1999). The seeps at Coal Oil Point provide a constant supply of fresh oil and associated volatile fumes in an area frequented by harbor seals.

Fur-Bearing Marine Mammals

Fur-bearing marine mammals, such as sea otters and fur seals, are especially vulnerable to the effects of crude oil. Fur seal pups drown if oil sticks to their flippers or to their bodies, and when it sticks to their fur it reduces or destroys the insulation of their wooly fur (called lanugo) and causes hypothermia. Adult fur seals have blubber and would not suffer from hypothermia if oiled. Sea otters are the marine mammals most sensitive to the effects of oil contamination since they do not have a layer of blubber to protect them from cold water. Therefore, they must maintain a layer of warm, dry air in their dense (300,000 hairs per square inch) under-fur to insulate against the cold. Oil compromises this protective coat and even a small oiled area of their fur can cause hypothermia and potentially death of the sea otter.

The treatment program for oiled sea otters, including the type and temperature of the water, has been carefully researched over recent years to improve the animals’ survival rate. Innovative technologies being used in sea otter rehabilitation include infrared imaging and a temperature-sensitive chip (like those used to identify lost pets) under the sea otter’s skin to track its condition at each stage of the recovery process.

An oiled sea otter rescued at Sunset State Beach in Monterey Bay in 2009 was cleaned and rehabilitated at the California Department of Fish and Game’s (CDFG’s) marine mammal care facility in Santa Cruz. The endangered marine mammal had likely come in contact with oil from a natural seep off the Monterey coast. New research and technologies aided in the successful rehabilitation of the ailing sea otter, estimated to be about 1 year old. The young female received care that included being bathed in olive oil and then washed intensively.

sea otter

The sea otter, shown above, is named Olive. Following full rehabilitation, she was fitted with a transmitter and released. Good news is that, even after her encounter with natural pollution, she is doing well, and you can follow her (and her pups!) on her very own Facebook page!


Visit Olive’s Facebook Page >>

Cetaceans (Whales and Dolphins)

Studies have shown that cetacean skin is nearly impenetrable to even the highly volatile components in oil. However, the toxic, volatile fractions in fresh crude oils could irritate and damage cetacean soft tissues, such as the mucous membranes of the eyes and airways and the effects could be as severe as death in extreme cases. Oil could also adhere to the fringed plates that  baleen whales use to filter their food, blocking the flow of water and interfering with feeding. Gray whales are among the most vulnerable of the baleen whales to effects of ingesting oil-contaminated prey or bottom sediments since they are mainly bottom feeders.

Twice each year, from December to May, the population of the gray whale passes through southern California on its migration between breeding and calving lagoons in Mexico and summer feeding grounds off Alaska. During this journey, most gray whales stay close to the coastline and pass through the Santa Barbara Channel and the Santa Maria Basin—areas where most of southern California’s natural oil and natural gas seeps are located.


Oil can be especially harmful to seabirds—particularly diving birds, which must get their nourishment by entering the water. In the case of species such as the common murre and western grebe, oil interferes with a seabird’s ability to maintain its body temperature by reducing or destroying the insulation and waterproofing properties of its feathers, which can result in death from hypothermia. An oiled seabird would also lose body weight as its metabolism tries to combat low body temperature. Oiled birds also become easy prey, as they are unable to fly when their feathers are matted from oil.

Chronic, low-level pollution may have a greater effect on bird populations than episodic spills (Camphuysen 1989; Wiens et al. 1996). Also, oil is particularly threatening at locations where seabirds are attracted, such as continental shelf and upwelling areas and areas of other ocean processes that concentrate fish and plankton feed (Berger 1993 b). Therefore, the chronic nature of the continuing release of oil and Coal Oil Point’s location on the Continental Shelf make it a particularly threatening area for seabirds that frequent the Santa Barbara Channel.When it comes to natural seepage, where crude oil bubbles up from the depths, the most common species to be found oiled and stranded on Malibu beaches is the grebe—Western and Clark’s. One reason is that grebes float together offshore in “rafts,” in the hundreds, even thousands.

The State of California does not fund the of birds that are injured by natural seeps. The Lampert-Keene-Seastrand Oil Spill Prevention and Response Act  has called for better response and protection of wildlife injured by petroleum products, and resulted in the creation of the state Office of Spill Prevention and Response (OSPR). In California, the International Bird Rescue Research Center (IBRRC) bears the expense of cleaning and rehabilitating these injured birds. Each year, 75 to 100 birds oiled by natural seeps survive to be admitted into one of two facilities and it is estimated that each bird, its care and feeding, costs an average of $200 (Malibu Surfside News).

murre coated in oil

A murre coated in oil begins its rehabilitation at International Bird Rescue. (International Bird Rescue photo)

Noozhawk Article –  Oiled Common Murres

As of March 2012, the IBRRC had seen nearly 140 oiled birds come into its facility for rehabilitation after run-ins with natural oil seeps, including those off Santa Barbara County’s Coal Oil Point, since the beginning of that year. A majority of the birds brought in were murres, which float on top of the water and dive for food, but the group also reported that other birds types had been oiled. Common and Pacific loons, Western grebes, an eared grebe, a surf scoter and a rhinocerosauklet were among those brought in for care.