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Washing Procedures for Oiled Sea Otters

Sea otters have the densest fur of any mammal and, unlike most other marine mammals, replace their fur throughout the year instead of undergoing a seasonal molt (Tarasoff 1974; Williams and Allen et al., 1995). Sea otters have guard hairs and many fine under-hairs that are microscopically interlocked in order to trap air and thus provide waterproofing, thermal insulation, and buoyancy.

Oil contamination causes fur clumping which leads to a loss of insulation and predisposes sea otters to hypothermia from the cold ocean water. (Protocols for the care of oil-affected marine mammals, 2004)

Current Recommendations

An updated protocol for the care of oil-affected sea otters is currently in development. In the meantime, the current recommendations for washing oil-affected sea otters are as follows:

  • Wash sea otters that have significant oiling (detectable by smell or test kit) and/or that show loss of waterproofing in any area larger than a lemon. Sea otters should be medically stable and at an initial core body temperature of at least 99 F (a higher temperature is better).
  • Induction with 0.22 mg/kg fentanyl and 0.07 mg/kg midazolam, maintenance on 1% isoflourane. Reverse in about 2 hours with 0.66 mg/kg naltrexone. Room temp 60–70 F. Warm IV fluids may help during recovery.
  • The choice of soap and method of working it in will depend on the type and character of the oil, location of oiling, and other variables, but for general purposes 2–3 liters of 4% Dawn in 85 F water works well.
  • If it is tar or very thick oil on the sea otter, a cup of olive or canola oil should be massaged into the affected fur for 10–15 minutes to soften it.
  • Plan on spending 1 ½ to 2 hours on the washing procedure. Core body temperature can be allowed to drop to the low end of normal range, about 95 F, but you must be prepared to warm them up by increasing rinse temperature to 95 F. It appears that rinsing temps may be raised to 100 F if necessary.
  • In general, rinse time should be about double wash time and be very complete (40–60 minutes).
  • Wash and rinse sea otter with soft water (4 grains of hardness) at 90–95 F, and release into soft water for 24–48 hours. This makes a HUGE difference and may even allow for a reduced rinsing time.
  • Air dry sea otter with warm (not hot) high volume blow dryers for 5–8 minutes after toweling.
  • Reverse and recover sea otter indoors under observation for at least an hour.
  • Track core temperature before, during, and after washing. Watch out for initial hyperthermia, then serious hypothermia. The core temperature should recover to near normal within a few hours after washing. If it drops precipitously during the next 24 hours, you are in trouble. During the days after washing, core temperature may “overshoot” due to increased metabolic rate. SQ temperature (via PIT tags) more accurately reflects when coat recovery has occurred.
  • IR thermography, SQ temperature, and observation of behaviors are all useful, but the former two are less time consuming and perhaps more precise. The sum of the three criteria defines recovery.
  • Provide the sea otter with a relatively warm haul out area if at all possible.
  • Optimize conditions that encourage grooming behavior that allows hair shafts to interlock and form plates that hold air. Natural oils may be much less important than previously thought.
  • Swimming in softened fresh water for 24–48 hours makes sea otters more comfortable. Warmer water may help with sea otters that are more compromised and promote swimming, grooming, eating, and less frantic behaviors, as well as reduce the time until coat recovery and temperature stability by about 50% (maybe more) and head off medical problems.
  • Temporary mild corneal opacity may occur in sea otters with physical or chemical damage to cornea
  • Get them to eat. Feed small calorie-dense meals frequently. Watch for melena as gastric ulceration common.