Our ocean hosts countless battles between apex predators, often unseen by human eyes. Among these contenders? On one side of the ring, the blue shark (Prionace glauca). On the other, the swordfish (Xiphias gladius). Both are known for their overlapping habitats and diets, leading to inevitable clashes. While such interactions occasionally result in injuries, most documented cases involving impalements end fatally. However, a groundbreaking report has documented the first verified case of a blue shark surviving a (quite severe) head impalement by a swordfish.
On February 17, 2023, fishers off Grama Bay in Albania captured a blue shark measuring about nine feet (275 meters) in total length and weighing just shy of 100 lbs (44 kg). Remarkably, the shark was alive, showing no signs of fresh puncture wounds and even had bait fish in its stomach, indicating recent feeding. But closer examination revealed a fragment of a swordfish bill embedded in the shark’s skull! The bill fragment measured 7.3 inches (18.6 cm) in length and had pierced deeply into the shark’s head, yet it miraculously avoided vital structures. This allowed the shark to not only survive but continue to exhibit feeding behaviors, at least until its capture.
Swordfish are renowned for their speed and aggression, wielding their elongated bills as versatile tools and sometimes weapons. These rostra are used to slash through schools of fish, defend against predators, and, occasionally, strike at competitors or threats. The bills are strong but not invulnerable; fractures often occur during these interactions, leaving pieces lodged in unfortunate victims. While such injuries can be lethal for the struck animal, swordfish themselves are known to adapt remarkably well to rostrum loss, often surviving without their defining weapon.
To date, only eight incidents of blue sharks impaled by swordfish have been documented, all fatal until now. The injuries typically target the head, suggesting they may be possibly aiming to incapacitate rivals or attackers quickly. This case, however, stands apart. The swordfish likely struck the shark from the front at a sharp angle, the bill fragment embedding deeply before snapping. The exact sequence of events remains speculative, but the positioning of the injury indicates a calculated defensive or offensive move.
The predator-prey relationship between blue sharks and swordfish is a complex one. While blue sharks are known to prey on swordfish in some regions, the reverse interaction is less understood. In this case, the swordfish was estimated to be a juvenile, measuring between 3.3-3.8 ft (1-1.15 m). It’s possible that the shark had been pursuing the swordfish as prey when the smaller animal launched a desperate counterattack. Alternatively, the interaction could have stemmed from territorial disputes or competition over shared food resources like squid and schooling fish.
Whatever the reason, this sort of duel isn’t exclusive to just swordfish and blue sharks. Other species, such as the bigeye thresher and shortfin mako, have also been documented with injuries inflicted by billfish. Yet all of these battles raise a slew of questions about the long-term effects of such injuries. Although the shark was alive at the time of capture, it is unclear how the embedded fragment may have affected its behavior or health over time. Past cases have shown that injuries inflicted by swordfish bills often lead to infections or other complications, even if vital organs are spared. In this instance, the absence of encapsulation or severe tissue damage around the bill fragment suggests a degree of resilience, but the full impact on the shark’s life remains unknown.
Like the rest of the ocean, the Adriatic Sea is a theater of both cooperation and conflict among its inhabitants. Understanding these interactions is crucial, as it paints a fuller picture of life beneath the waves and informs strategies to protect different icons. This remarkable event serves as not only an important anecdote in scientific literacy, but a testament to nature’s capacity for life to endure — even with a sword to the head.
