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“When a bill breaks off a marlin, the data suggests that younger fish

are able to slighly regrow some of the bill back, but not entirely.”

- Dr. Kelsey James | MARINE BIOLOGIST, NOAA

remarkable that species can survive being impaled with a broken
bill, it’s even more remarkable that marlin can survive without the
tool that helps them hunt the most.

Some marlin are found with partially broken bills; others are miss-
ing the bill entirely. While the assumption has been that these fish
suffer a reduced chance of survival, anecdotal and observational
data suggest otherwise. We now know that marlin that lose their
bills shift their hunting techniques out of necessity. Without a bill
to stun prey, broken-bill marlin adopt a strategy more akin to tuna
or dolphins—chasing individual fish or stragglers from bait balls
and engulfing them with sudden bursts of speed. While less effi-
cient than slashing through a group, this tactic still allows marlin
to feed adequately.

Another adaption observed is seeking out injured or isolated fish,
scavenging more than they normally would. They’re opportunists,
adapting to take advantage of whatever the ocean offers—even
slower species like squid that have been found in the stomachs of
dead, broken-bill marlins.

Some broken-bill marlin may feed more often or during different
times of day to compensate for reduced catch efficiency. They
may also avoid high-competition scenarios, where their lack of a
bill puts them at a disadvantage.

One of the more interesting observations is “cooperative feeding”.
Marlin often hunt in groups or alongside other species like tuna
or sailfish. A marlin with a broken bill might not be the one slash-
ing through the bait ball but can still benefit from the disorienta-
tion created by others, picking off stunned prey during the frenzy.
They’ve been witnessed following behind other marlin, picking off
the bait that the leading marlin stuns. Are they working together?
Nobody knows for sure.

Observations suggest broken-bill marlin become more conser-
vative in their energy usage. They may strike less frequently or
engage in shorter chases to conserve strength. This efficiency-ori-

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