Model
Digital Document
Description
Background: Free-ranging common bottlenose dolphins (Tursiops truncatus) can become entangled in fishing line
and other marine debris. Infrequently, dolphins can be successfully disentangled, released back into the wild, and
later examined postmortem to better understand the pathology and long-term effects of these entanglements.
Case presentation: An entangled common bottlenose dolphin (Tursiops truncatus) calf was observed in the Indian
River Lagoon, Florida, USA, with monofilament fishing line wrapped tightly around its maxilla. A multi-agency team
successfully disentangled the dolphin for immediate release back into its natural habitat. A year after
disentanglement, photos and observations indicated that the now independent calf showed a decline in body
condition, characterized by grossly visible ribs and a prominent post-nuchal depression. More than 2 years postdisentanglement,
the freshly dead carcass of this juvenile dolphin was recovered with extensive predation wounds.
Despite the forestomach being ~ 50% full of ingesta (fish), the dolphin was emaciated. During postmortem
examination, we collected and evaluated photographs and measurements of the maxillary damage resulting from
the entanglement.
Conclusion: The monofilament entanglement caused permanent, bilateral deformation of the maxillary dental
arcade, including a 4.0–4.2 cm long, 0.5 cm deep linear groove where the entanglement eroded the lateral edges of
the maxilla. There was no evidence of maxillary fracture and the dolphin survived for more than 2 years after
disentanglement. External evidence of propeller scars and a fishing hook discovered embedded in the laryngeal
mucosa at necropsy indicated repeated human interactions.
Keywords: Odontocete, Maxilla, Monofilament, Fisheries interaction
and other marine debris. Infrequently, dolphins can be successfully disentangled, released back into the wild, and
later examined postmortem to better understand the pathology and long-term effects of these entanglements.
Case presentation: An entangled common bottlenose dolphin (Tursiops truncatus) calf was observed in the Indian
River Lagoon, Florida, USA, with monofilament fishing line wrapped tightly around its maxilla. A multi-agency team
successfully disentangled the dolphin for immediate release back into its natural habitat. A year after
disentanglement, photos and observations indicated that the now independent calf showed a decline in body
condition, characterized by grossly visible ribs and a prominent post-nuchal depression. More than 2 years postdisentanglement,
the freshly dead carcass of this juvenile dolphin was recovered with extensive predation wounds.
Despite the forestomach being ~ 50% full of ingesta (fish), the dolphin was emaciated. During postmortem
examination, we collected and evaluated photographs and measurements of the maxillary damage resulting from
the entanglement.
Conclusion: The monofilament entanglement caused permanent, bilateral deformation of the maxillary dental
arcade, including a 4.0–4.2 cm long, 0.5 cm deep linear groove where the entanglement eroded the lateral edges of
the maxilla. There was no evidence of maxillary fracture and the dolphin survived for more than 2 years after
disentanglement. External evidence of propeller scars and a fishing hook discovered embedded in the laryngeal
mucosa at necropsy indicated repeated human interactions.
Keywords: Odontocete, Maxilla, Monofilament, Fisheries interaction
Member of