Cutaneous parasitism by copepods and gills in elephant seals
Cutaneous parasitism by copepods and gills is damage to the skin of elephant seals caused by small parasitic crustaceans that live attached to the surface of the animal's body. These parasites are mainly known in fish, but certain species c...
What is it?
Cutaneous parasitism by copepods and gills is damage to the skin of elephant seals caused by small parasitic crustaceans that live attached to the surface of the animal's body. These parasites are mainly known in fish, but certain species can occasionally colonize the skin of marine mammals, including elephant seals, particularly when the animal spends a lot of time submerged or frequents areas where these crustaceans are abundant. The damage most often remains superficial and localized, but it can weaken the skin and promote other skin problems.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
We observe small irritations or redness on the skin, sometimes tiny crustaceans visible to the naked eye clinging to the coat or bare skin. The animal may rub or scratch itself against the ground, rocks or other animals. Scabs, areas without hair or superficial wounds may appear over time, especially if the animal is injured while scratching. In the majority of cases, the attack remains discreet and does not cause general signs such as fever or loss of appetite.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
The disease is due to the attachment of copepods (small threadlike crustaceans) or gills (flat crustaceans with suction cups) to the skin of the elephant seal. These parasites feed on mucus, skin debris or blood on the surface. They generally benefit from close contact with seawater and associated fauna, particularly during long periods spent in aquatic environments for hunting.
Young animals, weakened individuals or those with pre-existing wounds, and those living in waters rich in small crustaceans are more exposed. A high density of animals on the same beach or the same moulting site can also encourage transmission from one animal to another.
Transmission
Direct contact with infested seawater or with other carrier animals promotes the attachment of parasites to the skin.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian performs a careful visual examination of the skin and coat, looking for visible parasites or lesions. A skin swab or scraping may be done to identify the type of parasite under a microscope. The examination also makes it possible to rule out other causes of skin lesions such as fungi, bacteria or traumatic injuries.
Treatment
Treatment is based, if necessary, on external antiparasitics suitable for marine mammals, applied only under veterinary supervision. Gentle cleaning of lesions and local skin care can be combined. In wild animals, intervention is generally limited to cases where the infestation is significant or complicates the healing of a wound.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
There are no specific prevention measures applicable to wild animals. Maintaining good general health and the absence of skin wounds limits the risk of significant infestation. In captivity or in a care center, good water quality and regular monitoring of the skin make it possible to identify any abnormalities early.
Possible complications
A large or neglected infestation can lead to extensive skin lesions, bacterial superinfection of scratching wounds, or general weakening of the skin exposed to salt and sun.
When to see a veterinarian
Presence of extensive or worsening skin lesions
Intense and repeated scratching or rubbing
Wounds that do not heal or ooze
Visible presence of numerous parasites on the skin
Prognosis
The prognosis is generally good when the damage remains superficial and limited. It becomes more reserved in the event of superinfection or extensive lesions, particularly in an already weakened animal.
Frequently asked questions
Can an elephant seal get sea lice?
Yes, certain parasitic crustaceans normally associated with fish, such as gillfish, can occasionally attach themselves to the skin of marine mammals, including elephant seals.
Is this parasitosis dangerous for elephant seals?
In most cases, it remains superficial and not serious. The main risk is secondary infection if the animal is injured while scratching.
Can a wild elephant seal be treated for these parasites?
In practice, the intervention is rare and reserved for animals cared for in a care center, under veterinary supervision, in the event of significant damage.
Can these parasites be transmitted to humans?
No, the copepods and gills concerned are specific to aquatic fauna and do not pose a known risk to humans.
References
WOAH — Organisation mondiale de la santé animale (ex-OIE)
Content reviewed by the TunisieVet editorial team · Updated 24 September 2026
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