Page 36 - wmo-51st-magazine

Trying to capture a blue marlin hunting predatory behavior without sustaining regulate body temperature. By adjusting
and killing its prey remains one of the damage to its sensitive mouth and jaw blood flow to the dorsal fin, blue marlin
hardest events to record in nature. Pho- structures. Sharks, killer whales, and can regulate heat exchange with the sur-
tographers and videographers can fol- even bluefin tuna have been caught/ob- rounding water, enabling it to maintain
low a pack of lions, a tagged great white served with broken bills impaled into optimal body temperature in different
shark, or a school of orcas and eventu- the fish. While the tuna are likely hunt- thermal environments.
ally they’ll capture the circle of life to ing defense wounds, those in sharks and
share and for scientific documentation. orcas are likely defense wounds from As fishermen know, the dorsal fin of the
But tracking, following, and documenting blue marlin. There is evidence that mar- blue marlin serves as a communication
a blue marlin is almost impossi- tool, signaling the marlin’s
ble. But, if you’re one of the lucky Sharks, orcas, and bluefin tuna presence and status to oth-
few who have witnessed a blue er individuals in its species.
marlin busting into a school of have been caught / observed with During courtship displays
mahi or tuna, you’ve gotten to or aggressive interactions,
experience a marvel of evolution broken bills logged in them. the dorsal fin may be raised
from one of the most formidable or lowered to convey dom-
predators in the ocean. lin bills do grow back once broken, but inance, submission, or reproductive
the evidence supports that it only grows readiness.
Its sheer size, capable of exceeding back in younger fish.
1,000 pounds, combined with remark- The shape and positioning of the pecto-
able speed and agility, positions it at the The bill is also believed to play a big role ral fins enable blue marlins to generate
top of the marine food chain. When it in the reduction of hydrodynamic drag, hydrodynamic lift as they move through
strikes, the blue marlin is employing which greatly benefits the speed of the the water. This lift helps to counteract
a blend of brute force and precision blue marlin. By disrupting the flow of the force of gravity and provides ad-
strikes with speed and agility. Under- water around the bill, the dermal denti- ditional propulsion, allowing them to
standing the mechanics of the blue mar- cles contribute to smoother movement swim more efficiently and conserve en-
lin not only highlights the intricacies of and increased efficiency during hunting ergy during long-distance migrations or
its biology but also underscores the im- pursuits. It’s the same reason a golf ball high-speed pursuits. By manipulating the
portance of conserving this icon species. is textured versus being smooth. movement of their pectoral fins, they
can quickly change direction, adjust their
It’s believed that the blue marlin bill The legendary sharp dorsal fin also speed, and evade obstacles or threats in
serves multiple purposes related to serves a vital role in their hydrodynamic their environment.
hunting and feeding. The sandpaper-like efficiently. The dorsal provides stability
texture to a bill is lined with small, back- and aids in maneuverability, particular- Beyond their physical adaptations, blue
ward-facing transverse ridges call marlins possess a highly effi-
Dermal Denticles, or “bill rack- A blue marlin bill serves multiple cient cardiovascular system.

ers” by fishermen. These special- Their hearts are relatively
ized structures help the marlin purposes related to hunting, large and capable of pumping
capture and secure its prey more feeding and defending. oxygen-rich blood through-
effectively. When striking its prey, out their bodies. This efficien-
the rough texture of the bill cy is critical for maintaining
helps to prevent the prey from slipping ly during high-speed pursuits and rapid high levels of activity over extended pe-
away, allowing the marlin to maintain a changes in direction. The pointed shape riods. This capability to maintain a body
firm grip. helps to minimize turbulence and resis- temperature higher than the surround-
tance, allowing the marlin to maintain ing water enables blue marlins to func-
When it comes to defending itself from balance and control while navigating. It tion effectively in a variety of thermal
Photograph by: Harry R. Hindmarsh that enables the marlin to engage in its known as the rete mirabile, which helps they encounter during deep dives.
predators, the bill acts as a durable tool also contains a network of blood vessels conditions, including the cooler waters

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