Oiled Sea Otter Rehabilitation Course

Water Quality, Cleanliness and Disease Prevention

Water quality is very important for successful rehabilitation. If untreated seawater is used in the facility, it should be obtained from area that are uncontaminated by chemical or biological waste. Recirculating seawater systems should be professionally engineered and have adequate filtration and sterilization (chlorination followed by dechlorization or ozonation) to keep the water clean and bacteria-free. To further guard against disease transmission, the recirculating seawater systems of pens and pools should be completely separate (see Chapter 12). If other species of animals are held in the same facility, those pools also should have separate seawater systems. Water flow to the pens and pools should be sufficient so that the entire volume is replaced every thirty minutes. Coliform bacteria concentrations in every pool should be monitored weekly and should not exceed 1,000 colonies per 100 ml of water (USDA, 1992). If treated fresh water is used in the pens or pools, it must be dechlorinated.


Leftover food, shells, and feces should be removed from pens and cages with small hand-held nets; surfaces should be rinsed with water several times daily. As otters are moved, or at least every three days, enclosures should be drained and washed with detergent, disinfected with dilute chlorine bleach (one part bleach to thirty parts water) to kill bacteria and algae, and then rinsed to remove all residues. Gloves, dip nets, and other equipment should be disinfected by daily soaking in dilute chlorhexidine (NolvasanTm). Food containers and utensils should be washed with detergent, soaked in dilute bleach as above, and then thoroughly rinsed between each feeding. The husbandry staff should wear rubber gloves when handling food, bedding, or waste. This is for their own protection and to prevent contamination.

Rehabilitation facility visitors should be restricted and domestic pets excluded at all times. Footbaths containing dilute bleach or chlorhexidine should be used at the facility entrance to prevent the formite transmission of disease. Coveralls issued within the center should be worn over regular clothing, and street shoes should be exchanged for rubber boots before beginning work. These garments should be cleaned after each shift. Personnel should wash their hands with povidone iodine or chlorhexidine hand soap regularly; this is especially important before and after handling otters or their food, and after cleaning pens. Sinks, showers, and appropriate disinfectants should be provided at strategic locations.

Disease Prevention

Information on the naturally occurring contagious diseases of all marine mammals is minimal and often incomplete. Clinical signs, routes of transmission, incubation periods, and testing procedures have been partially described for a handful of clinical syndromes such as San Miguel sea lion virus, Erysipelas, Vibriosis, and a few pox viruses. Leptospirosis has been implicated as a cause for chronic renal disease in sea lions along the California coast and for a hemorrhagic perinatal syndrome in Northern fur seals (Dunn, 1990). Other species of mustelids are susceptible to domestic animal diseases including canine distemper, feline panleukopenia, leptospirosis, toxoplasmosis, and rabies (Fowler and Theobald, 1978; Wallach and Boever, 1983). None of these diseases has been documented in sea otters, but the possibility of introducing an infection to an immuno-compromised group of sea otters in the rehabilitation center should be considered. Enhanced serum antibody titers to Salmonella, Vibrio, and Pasteurella bacterial pathogens were detected in sea otters during the EVOS (Wilson et al., 1990), possibly as a result of food contamination during captivity. Harris et al. (1990) have reported finding oral ulcers, associated with an apparent herpes virus, at one of the EVOS rehabilitation centers. These oral ulcers were later found to occur naturally in the sea otter population of Prince William Sound.

When sea otters first arrive at the rehabilitation center, they should be held in individual critical care cages and observed for signs of contagious or infectious disease before being moved into pens with other otters. This procedure should reduce the risk of introducing disease, but it can be difficult to accomplish under emergency conditions. Strict disinfection of transport kennels, cages, pools, food- handling utensils, and restraint equipment must be enforced. Animals should be moved as rapidly as possible through the rehabilitation process and constantly monitored for possible signs of contagious disease. Quarantine procedures should be instituted if an infectious or contagious disease is suspected.

Sampling programs such as coliform counts, hematology, serology, bacteriologic, fungal and viral cultures, and the results of necropsy examinations should be utilized to alert staff to potential disease problems. The usefulness of some tests is often quite limited. Specific serologic tests may be inaccurate in species other than those for which the tests were designed. Negative results may create a false sense of security and should not be allowed to justify deviations from disease prevention control protocols and strict quarantine procedures within the rehabilitation facility.