8/22/2019 Hawaii's Great Ocean Predators: Sharks

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GRAPHIC BY MARTHA HERNANDEZ, BRYANT FUKUTOMI AND DAVID SWANN / STAR-ADVERTISER

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A8 >> H O N O L U L U S T A R - A D V E R T I S E R >> SUNDAY 8 / 4 / 1 3

HAWAIIS GREAT OCEAN PREDATORS

SHARKS

Human surfer

Sea turtle

Sea lion

SIGNS OF TROUBLEIt has been observed that when a shark feels threatened byother predators or humans who get too close, it exhibits pat-terns of aggression.

ANATOMY OF A SHARKThe tiger shark is most often involved in attacks in Hawaiian waters.

GALAPAGOS SHARK

This potentially aggressive shark does not normally at-tack humans. Performs a seemingly awkward threat dis-play before attacking.SIZE AT BIRTH: 23-25 inchesMAX. LENGTH: 12 feetHABITAT: Just beyondouter reef edgeDIET: Reef fish

GREAT WHITE SHARKThe most feared of sharks, it prefers shallow, cool coastalwaters, but occasionally has been seen in Hawaiian wa-ters. Hunts during the day.

SIZE AT BIRTH: 3-4 feetMAX. LENGTH: 24 feetHABITAT: Open ocean, tropics to cooler coastal watersDIET: Includes other sharks, dolphins, seals, sea lions,seabirds, turtles and invertebrates

TIGER SHARK

One of the few true scavenger sharks, it is known to eatturtles, fish and virtually anything that falls overboard cattle, pigs, sheep, humans. It enters shallow reefs andlagoons at night to feed.Can live for about 12 years.

SIZE AT BIRTH: 20-30 inchesMAX. LENGTH: 24 feetHABITAT: Beyond the reefs edge during the day, inshorealong coral and rocky reefs at nightDIET: Wide-ranging, including seals, birds, carrion,almost anything

WHITETIP REEF SHARK

This sluggish, shallow-water shark is found in caves orunder rocks or coral ledges and is active at night andduring slack tides. Not usually aggressive toward humans.SIZE AT BIRTH: 21-24 inchesMAX. LENGTH: 7 feetHABITAT: Shallow-water reef dwellerin depths to 1,000 feetDIET: Bottom fish, crustaceans and cephalopods

1. The jaw beginsto open as theshark attacks...

2. The snoutlifts as the upperjaw protrudes...

3. The upper jawmoves downwardand, along with thelower jaw, is simul-taneously thrustforward. Themoveable eyelidcalled the nictitat-ing membranemoves upward toprotect the eye asthe shark feeds...

4. Jaw closesagain on theprey.

NostrilsKnown for itsextrordinarysense ofsmell, a sharkcan track ascent manymiles away.

Pectoral fin

Stomach

Pancreas

Heart

Liver

Gallbladder

Kidney

Upperlobe

Lowerlobe

Pelvic fin

Anal fin

Caudal finA sharks main means of propulsion. Although itdiffers greatly among species, the fin is always di-vided into upper and lower lobes. The size of thelobes is key to a sharks pattern of activity. For in-stance, a tiger sharks upper lobe is longer andheavier than the lower. This configuration deliv-ers powerful bursts of speed and quick turns andtwists needed to pursue prey. A great white shark,on the other hand, has nearly symmetrical lobes,which deliver enormous thrust.

First dorsal finPrevents the shark from rollingover. Appears rigid, but is actu-ally pliable. A sharks skeleton ismade of cartilage, not bone.

Second dorsal fin

Snout

Testes

EarsHearing is apparently directional, which may help sharks findstruggling or injured prey. They are sensitive to low-frequencysounds 10 to 800 hertz (cycles per second). The human hear-ing range is much greater at about 25 to 16,000 hertz.

MOST RECENT ATTACKSThere have been five shark attacks in Hawaiian waters this year.

ATTACKS THROUGH THE YEARS

CHOMP!A sharks upper jawtypically detachesfrom its skull during

an attack. This loosesuspension

IN HAWAIIAN WATERSThe most common sharks found in waters aroundthe Hawaiian Islands:

BLACKTIP REEF SHARK

This active, shallow-water shark is found in lagoons andon coral reefs and moves with the tide. Not usuallyaggressive toward humans.SIZE AT BIRTH: 20 inchesMAX. LENGTH: 6 feetHABITAT: Shallow reef flatsto outer reef edgeDIET: Primarily reef fish

CanalSkin

Pore

Lateral tube

Lateral linesA pair of sensorytubes filled witha jelly-likesubstance thatextends from thehead to caudal fin.

CiliaThey are stimulated bymovement and pressure,alerting the sharks brain tonearby predators or prey.

Neuromasts

THE SIXTH SENSEIn addition to the five senses, sharks have a unique sixth sense the ability to detect move-ment and disturbances from prey or predator even in murky water through the lateral linesthat run along the length of its body.

EyesThey are posi-tioned on the sideof the sharks head,creating a widerrange of visionthan many otheranimals. The size

of the eyes also isan indicator of ac-tivity. The sluggishcarpetshark, for in-stance, has smalleyes, suggesting itrelies less on sight.A deep-dwellingshark, such as agreat white, has ex-tremely large eyes.

At 4:30 p.m. on Jan. 16, a man was surfing in 10 feet of water about200 yards off Kiholo Bay, Hawaii island, when a 10-foot-long tigershark attacked him. He suffered lacerations to his right forearm and his lowerright leg.

At about 6 p.m. Feb. 21, Jacob Lansky was surfing about 75 yards offshore of Paia Bay,Maui, when a 6-foot-long reef shark bit the rail of his foam board. Lansky was not injured.

At 8:30 a.m. on April 2, a 58-year-old California man visiting Maui was attacked off Kaanapaliwhile surfing. He suffered two deep lacerations on his right thigh.

At 2 p.m. Monday, a 19-year-old Kaneohe man was attacked by what was believed to be atiger shark at White Plains Beach. Kiowa Gatewood underwent emergency surgery.

Between 8:30 and 8:45 a.m. Wednesday, a woman was attacked about 30 feet off a rockypoint fronting Ulua Beach in Wailea in murky water. The California visitor was taken to MauiMemorial Medical Center and underwent surgery.

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Hunched position:

When approached tooclosely, a shark will arch its

back and push its pectoralfins downward. The snout isalso raised with its jawsslightly open.

Tail cracking:

A shark swims toward athreat, turning suddenlyand flicking its tail toproduce a loud crackingsound.

Side display:

A shark swims in a stifffashion and follows a figure-eight loop when confrontedby another shark or preda-tor. It also stretches to itsfull length to intimidate orestablish dominance. If thisfails, it attacks.

MISTAKEN IDENTITYScientists theorize thatsharks see silhouetteswhen hunting frombelow in deeper water.

OAHU

MAUI

HAWAII

Sources: The Little Guides Sharks, Cape Cod Times; Florida Sun Sentinel; Hawaiisharks.com; State Shark Task Force