Asian Diver – March 2018

Atlantic Ocean Pacific Ocean

BULL SHARK

DANGER TO HUMANS

Because of its large size, abundant

distribution, and preference for shallow

water near populated areas, bull sharks

pose more of a threat to humans than any

other shark. Most incidents occur in low

visibility, close to the coastline, and it is

likely that many recorded attacks by

unidentified sharks can be attributed to

this species

GEOGRAPHICAL DISTRIBUTION

Bull sharks are common along the

continental coasts of all tropical and

subtropical seas worldwide, as well

as numerous river systems and some

freshwater lakes

Western Atlantic: Massachusetts, USA to

Argentina

Eastern Atlantic: Morocco, Senegal to

Angola

Indo-Pacific: Kenya and South Africa

to India, Vietnam to Australia; southern

Baja California, Mexico to Ecuador and

possibly occurring in Peru

Maximum Size

Average size

Maximum Weight

4 metres

2.6 metres

316.5 kilograms

SCIENTIFIC CLASSIFICATION

Kingdom : Animalia

Phylum : Chordata

Class : Chondrichthyes

Subclass : Elasmobranchii

Superorder : Selachimorpha

Order : Carcharhiniformes

Family : Carcharhinidae

Genus : Carcharhinus

Species : C. leucas

CONSERVATION STATUS

Extinct Threatened Near Threatened

EXEWCRENVUNTLC

Area of distribution

FRESHWATER TOLERANCE

Bull sharks are one of the few cartilaginous fish able to swim between salt and fresh

water with ease. They possess several organs with which to maintain the appropriate

salt and water balance in their body. Unlike other sharks, the gills, kidneys, rectal gland

and liver are all able to adapt to changes in water salinity and work to excrete excess

urea and water while conserving sodium and chloride

Rectal Gland

Rectal Gland

Excretion of salt from rectal gland and

small amounts of water from kidneys

Decreased salt excretion from rectal gland and

excretion of large amounts of water in dilute

urine from kidneys

Kidneys

Kidneys

Intestine

Intestine

Ingested salts

from food and

seawater

Influx of

water

Slight influx

of water

Fresh Water

Salt Water

HABITAT

Usually found close to shore in shallow

water less than 30 metres deep around

river mouths, bays, lagoons and estuaries.

It is the only wide-ranging shark that

is able to survive for extended periods

in both saltwater and freshwater

environments. Normally found cruising

the bottom and rarely seen at the surface

unless attracted by food

TOURISM

Due to its widespread distribution and

preference for shallow coastal areas,

encounters with bull sharks are fairly

common, and there are a number of

tour operators around the world who

specialise in diving with these impressive

animals. Some places to reliably encounter

the species include Fiji, Playa Del Carmen

in Mexico, the Bahamas, Costa Rica

and Florida