There are about 370 species of sharks, from the 9 inch midwater shark to the 45+ foot whale shark.  They live everywhere but are most common in warm waters.  Most sharks give live birth after a long gestation period, & the pups are born fully equipped to fend for themselves. 

Sharks have evolved over millions of years and are superbly equipped to compete.  They can hear low frequency sounds like the thrashing of an injured fish from two miles.  They can smell as little as 1 part per million of blood from a mile away, and sense the electrical field of another animal within several yards.  They see colors and can see in the dark like a cat, so they can feed 24 hours a day.

The skeleton of a shark is not bone, but cartilage.  Its body shape allows it to swim with minimum energy and many compensate for their lack of a buoyant air sac with an enlarged liver full of light oil, or by “gulping” air from the surface.  In this way they can “hang” suspended with minimum energy.  Shark’s fins are rigid so their maneuverability and stopping ability is limited, giving rise to their famous “circling” behavior in the face of prey.

Most sharks have 5 rows of teeth, as many as 3000 at a time, but the front row does most of the work.  They are replaced rapidly, sometimes a row per week.  Most sharks are not fussy about what they eat although certain of them “specialize” in certain prey.  They grow slowly and do not eat voraciously, only consuming from 1-10% of their body weight per week.  (Of course, some of them are pretty large!)

Sharks enjoy a bad, and probably undeserved reputation. Worldwide, only 70-100 shark attacks on humans are reported each year, although the real number is probably higher.  The vast majority are “hit and run” attacks in water 4-6 feet deep, usually with minor injuries.  These may be cases of “mistaken identity” or accidental brushes.  The more dangerous “bump and bite” or “sneak” attacks occur in deeper water, usually to swimmers or divers.  Here, repeated attacks are more common and the mortality rate is higher.

 Only a few dozen sharks have the physique to threaten humans and only 3 types are known to make unprovoked attacks:  the great white, the tiger and the bull shark.  They alone are responsible for 55% of all recorded attacks with only 8 species responsible for 75% of them.  All of these species are large and normally consume large prey.  None are common in Acapulco.

From the above, you can conclude that the risk of a shark attack on your fishing trip is low.  Nevertheless, we cannot allow swimming off the boat in the open sea.  Especially if you are bleeding, eating something bloody, or if you thrash around a lot when you swim, we would suggest you hold off on your swim until we return to Roqueta Island, Acapulco Bay, or Puerto Marques!


The Pacific Sharpnose is the most common shark in Acapulco waters. It is a member of the Requiem shark family, which includes the blue, reef and sand sharks.  It grows to 5-6 feet, reaching maturity at 3 feet.

The Pacific Sharpnose, is dark gray above and white below, with razor-sharp, triangular serrated teeth.  Although it may be the most abundant shark from California to Peru, relatively little is known about it.

Sharpnose pups frequent coastal waters, then move offshore as adults so sport fishermen usually catch adults.  Their diet includes small fish and squid but, like most sharks, they are not fussy.  Although they are here year-round, the easiest time to catch them is during the rainy season from July through October.  Then, they are attracted to the baitfish found around weeds, logs and debris washed offshore.

Sharks will sometimes hit moving trolling baits or baits dead in the water while landing other species.  It is also possible to stop and chum for hours to attract them.  This either results in a very interesting day or, without success, one of the most boring imaginable.

We catch most sharks after a visual sighting, usually near something floating.   Then we drift fish or cast to them using live bait or chunks of barrilete attached to strong hooks and wire leaders.  Catching 15-25 in this way is not unusual.  Even the small ones can be dangerous (especially to the bare-footed crew) so they go immediately into a fish box.  No attempt is made to remove the hooks until we return to port.

Sharpnose sharks are fished commercially by long line and other gear.  Their flesh is excellent, known locally as cazon, and is available fresh or frozen in most of the local markets and supermarkets in Acapulco.


The hammerhead shark is perhaps the most recognizable of all sharks.  Its unusual head, with eyes and nostrils on the lateral ends, provides it with unusual maneuverability and ability to track prey.

The scalloped hammerhead, with its serrated head, is the most abundant hammerhead and the one most often found near Acapulco.  It seldom grows to more than 10 feet and 350 pounds and frequents tropical and warm temperate waters worldwide.  Hammerheads are usually loners but for unexplained reasons, small ones sometimes form large schools during the day.  The hammerhead is not particularly swift, and often basks near the surface on open waters.  At these times they can be caught by presenting live bait, or large pieces of bonito.

Hammerheads are fish eaters with a special liking for sting rays.  They have a relatively small mouth, limiting their ability to take very large prey.  Their reputation for aggressiveness may be due more to their frightening appearance than their actions.  They have been linked to some attacks on humans, but very few.

The scalloped hammerhead gives live birth to 15-30 pups, about 2 feet long, in shallow coastal waters.  As they grow, they move toward the open sea, where they prefer to remain as adults.

During the days of heavy commercial shark fishing hammerheads were in demand for use in fish meal, liver oil and leather production.


The thresher shark is distinctive for its very long tail.  It can reach up to 20 feet and 1000 pounds, but seldom exceeds 500 pounds on the Pacific coast.  The thresher is native to warm seas worldwide and is usually found in the upper layer of deep water along continental shelves. 
During the spring and summer smaller threshers may be seen leaping completely out of the water near the shore.

The thresher gets its name from the way it hunts its prey.  It is a very quick shark that pounces on schools of fish and flails at them repeatedly with its tail to stun them in the same way as a billfish uses its bill.  Small fish and squid are its main diet.  It is sought after as a fine big game species and, unusually for a shark, often puts on an aerial display when hooked.

The thresher matures in 6 -7 years at about 10 feet, and normally bears 4 live young per year.  The largest embryos consume their smaller siblings during the gestation period until only 2-4 are left.  One 18 foot female contained four young  4 to 4.5 feet long and weighing 14 pounds each.

Threshers can be seen on the surface in much the same way as hammerheads.  In these instances, live bait on a large hook attached to a heavy wire leader is the most effective means of catching them. 

Threshers are considered harmless to humans, although several attacks have been recorded on boats.

Although uncommon in North American fish markets, threshers are consumed in many other parts of the world.

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