Trauma and injuries related to fishing nets in sea lions
Sea lions live near the coast and often come across fishing nets, ropes or abandoned marine debris. These objects can wrap around the animal's neck, fins or body. Over time, the material tightens the skin and then deeper tissues, causing wo...
What is it?
Sea lions live near the coast and often come across fishing nets, ropes or abandoned marine debris.
These objects can wrap around the animal's neck, fins or body.
Over time, the material tightens the skin and then deeper tissues, causing wounds that are sometimes very serious.
Key point
This is a potentially fatal emergency for the animal; any sightings must be reported immediately to a marine wildlife rescue center or to the competent authorities, without attempting to handle the sea lion yourself.
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:
A deep circular mark is often seen around the neck, a fin or the base of the tail, where the net or rope tightens the skin.
The affected area may be swollen, red, oozing, or infected.
Over time, the bond can carve a deep furrow into the flesh, sometimes to the bone.
The animal may appear emaciated, listless, and have difficulty swimming or moving on the beach.
A wound that does not heal, despite the animal's attempts to scratch or rub, is a characteristic sign.
In advanced cases, generalized infection or difficulty breathing may occur if the mesh compresses the neck or thorax.
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 cause is purely accidental: the sea lion swims through or near a fishing net, line, rope or plastic debris and becomes entangled.
Curious young animals are particularly exposed, as are sea lions that follow fishing boats to feed on catches or discards.
The material stays in place, sometimes for months, tightening as the animal grows or the tissue around it becomes inflamed.
Intensive fishing areas or significant presence of abandoned nets (ghost nets).
Young sea lions, more curious and less experienced in facing obstacles.
Presence of plastic waste or fishing equipment lost at sea.
Frequency of coastal areas heavily frequented by human activity and navigation.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian or marine rescue team first examines the animal from a distance to assess the severity of the entanglement without further stressing it.
A capture is then arranged, often with sedation, to safely remove the net or rope.
The wound is cleaned, evaluated in depth, sometimes x-rayed to check for bone or joint damage.
Follow-up may require several wound treatments, treatment of the infection and a period of observation in a marine wildlife care center before possible release.
Treatment
Treatment is based on manual or surgical removal of the net or rope, under sedation or anesthesia depending on the severity.
Cleaning and debridement of the wound is carried out to remove damaged tissue.
Antibiotics are used in cases of infection, combined with painkillers to manage pain.
In very serious cases with deep tissue or bone damage, further surgical treatment may be necessary.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
The best prevention is collective: reduce nets and ropes lost or abandoned at sea, educate fishermen to recover their equipment, and clean coastal areas of fishing debris.
Sea lion colony monitoring programs can quickly identify entangled animals before the injury worsens.
There is no individual prevention possible for the animal itself, action must come from humans.
Possible complications
Deep infection that can reach the bone or joints.
Partial amputation of a fin in very advanced cases.
Sepsis if the infection becomes widespread.
Difficulty eating or swimming normally, leading to severe weight loss.
Death if the animal is not rescued in time, in particular by strangulation, drowning or generalized infection.
When to see a veterinarian
Observation of a net, rope or debris wrapped around a sea lion's neck, body or fin
Presence of a deep, oozing or non-healing wound
Animal that is emaciated, listless or has difficulty moving
Sea lion isolated on a beach, not fleeing from human approach
Any signs of respiratory distress or significant swelling around the neck
Prognosis
The prognosis strongly depends on the precocity of treatment.
If the mesh is removed early, before the wound is too deep or infected, healing is often complete.
On the other hand, an old entanglement with bone involvement or generalized infection clearly darkens the prognosis.
Without human intervention, many animals do not survive this type of trauma.
Frequently asked questions
Can you remove a net wrapped around a sea lion yourself?
No, you should never approach a wild sea lion alone. It is a powerful animal that can bite and further injure itself by panicking. A specialist marine rescue team or the relevant authorities should be contacted.
How to recognize an entanglement in a sea lion?
There is often a deep furrow or circular mark around the neck, fin or body, sometimes accompanied by a visible sore, redness or swelling.
Is this problem common in Tunisia or the Mediterranean?
Fishing net-related injuries affect pinnipeds in many coastal areas, including the Mediterranean, where fishing activity is high or nets are lost at sea.
Can a tangled animal heal on its own without intervention?
It's rare and risky. The mesh usually continues to tighten and dig into the wound over time. Human intervention is almost always required to remove the material and treat the injury.
References
WOAH — Organisation mondiale de la santé animale (ex-OIE)
Content reviewed by the TunisieVet editorial team · Updated 18 August 2026
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