Trauma linked to fishing nets and accidental capture of sailboats
The sailfish (Istiophorus platypterus) is a large pelagic fish prized for its speed and its sword-shaped rostrum. It is regularly caught accidentally in nets intended for other species, or injured by lines, hooks and fishing gear. These inc...
What is it?
The sailfish (Istiophorus platypterus) is a large pelagic fish prized for its speed and its sword-shaped rostrum.
It is regularly caught accidentally in nets intended for other species, or injured by lines, hooks and fishing gear.
These incidents cause varied physical trauma, ranging from simple lacerations to serious internal injuries.
Key point
Prolonged incidental captures can result in the death of the animal even after an apparently successful release, due to cumulative exhaustion and physiological stress.
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:
The signs depend on the severity and type of trauma.
Open sores or lacerations are often seen on the body, fins or around the mouth, caused by net mesh or hooks.
The rostrum (long pointed beak characteristic of the sailfish) can be broken, twisted or nicked when entangled in the nets.
Abnormal or disorganized swimming may appear, reflecting extreme fatigue or muscular or skeletal damage.
Breathing difficulties are common: the animal having fought against the net may show exhaustion of the gill apparatus, with accelerated or irregular breathing.
Pallor of the mucous membranes or gills may signal significant blood loss or lack of oxygenation.
Subcutaneous swellings or hematomas are sometimes visible around the stricture areas (where the mesh has compressed the body).
In the most severe cases, the animal may find itself in shock, floating on the surface or unable to swim normally, which constitutes a life-threatening emergency.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
Trauma occurs when the sailfish finds itself trapped in a fishing net (gillnet, seine, trawl) or hooked to a line intended for other species such as tuna or swordfish.
The animal's struggle to free itself causes friction, lacerations and sometimes fractures.
The very sensitive rostrum gets stuck easily in the mesh and can break under tension.
Prolonged capture time aggravates injuries and exhausts the animal, reducing its chances of survival even after release.
Areas of high commercial fishing activity, particularly sailfish migration areas in the Mediterranean and the Atlantic, increase the risk of accidental capture.
The use of drifting gillnets or non-selective longlines encourages bycatch.
Young individuals and weakened animals (after breeding or a long swimming effort) are more vulnerable to serious injury during an entanglement.
The proximity of intensive fishing areas to natural sailfish migration corridors constitutes a major risk factor.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
A professional (marine biologist or veterinarian specializing in aquatic fauna) evaluates the animal by external visual examination: looking for wounds, hematomas, deformations of the rostrum or fins.
Observation of swimming behavior and respiratory rate (opercular movement) provides information on the general condition.
In a rescue context, a rapid assessment of vitality (reactivity, coloring of the gills) makes it possible to decide on immediate return to the water or more in-depth treatment if the animal is kept in a pool.
Treatment
The treatment aims above all to limit stress and facilitate recovery.
It may include local wound care (cleaning, disinfection) if the animal can be handled without additional danger to it.
Respiratory support by water oxygenation can be offered in a specialized structure.
In cases of rostrum fractures or deep lesions, only a structure with suitable marine veterinary resources can consider more in-depth care; Most of the time, a quick return to the water remains the best option to limit additional stress.
No specific standardized drug treatment exists for this wild species in the natural environment.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Prevention is mainly based on fisheries management measures: use of selective gear limiting accidental catches, exclusion devices, and respect for fishing restriction zones and periods during migrations.
Raising fishermen's awareness of techniques for quickly and carefully releasing animals caught alive reduces post-capture mortality.
Monitoring and marking programs help to better understand risk areas and adapt fishing practices.
Possible complications
Secondary wound infection can occur in the marine environment.
Prolonged exhaustion can lead to severe muscle acidosis, sometimes fatal even after release (delayed capture-mortality syndrome).
Damage to the rostrum or fins can permanently compromise the animal's swimming and hunting ability, reducing its chances of long-term survival.
Hemorrhagic shock is possible in the event of a deep injury affecting important vessels.
When to see a veterinarian
A sailboat found entangled in a net or line, while still alive, must be reported quickly to a marine rescue structure or to a competent biologist.
Presence of deep wounds or significant bleeding.
Very abnormal swimming, disoriented or inability to maintain a normal position in the water.
Very slowed, irregular breathing or absence of opercular movement.
Animal floating passively on the surface without reaction after accidental capture.
Prognosis
The prognosis depends heavily on the severity of the injuries and the time spent trapped in the fishing gear.
A quick return to the water after a brief capture, with superficial injuries, offers a good chance of survival.
On the other hand, prolonged entanglement, deep lesions or marked exhaustion clearly darken the prognosis, with a risk of delayed mortality even after apparent release.
Frequently asked questions
Can an accidentally captured sailboat survive if released quickly?
Yes, if the capture was brief and the injuries superficial, the chances of survival after a quick and careful return to the water are good. The longer the entanglement time, the greater the risk of delayed mortality.
What should I do if I find a sailboat caught in a net?
You must quickly contact a marine rescue structure or a competent fishing authority. Handling the animal yourself without experience can aggravate its injuries, particularly to the very sensitive rostrum.
Does the broken rostrum grow back?
No, unlike other tissues, the sailfish's rostrum does not completely regenerate after a serious fracture, which can permanently affect its hunting ability.
Are these traumas common on sailboats?
Yes, the sailfish is one of the species regularly caught accidentally in fisheries targeting tuna or swordfish, particularly with gillnets or non-selective longlines.
References
FAO — Organisation des Nations unies pour l'alimentation et l'agriculture
WOAH — Organisation mondiale de la santé animale (ex-OIE)
Content reviewed by the TunisieVet editorial team · Updated 18 August 2026
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