temperatures.

One


method


uses

waste

heat


from

factories


and

power


stations.


China

is


the


largest


Tilapia
producer

in


the


world,


seconded


by

Egypt.
Commercially
grown


Tilapia


are


almost


exclusively


male.


Cultivators


use

hormones


such

as

testosterone


to
reverse

the


sex

of


newly

spawned


females.


Because


tilapia

are


prolific


breeders,


the


presence

of


female
tilapia
results


in


rapidly


increasing

populations

of


small


fish,


rather

than


a

stable

population

of


harvest

-

size
animals.
Whole

tilapia

fish

can

be

processed

into

skinless,


boneless


(PBO)


fillets:

the


yield

is


from

30

percent


to


37
percent,

depending

on

fillet


size


and

final


trim.


The


use

of


tilapia

in


the


commercial


food


industry


has

led


to


the
virtual

extinction


of


genetically


pure


bloodlines.


Most


wild


tilapia

today


are


hybrids


of


several


species.
Nutrition
Tilapia

have

very


low


levels

of


mercury

as

they


are


fast

-

growing


and

short

-

lived

with


a

primarily


herbivorous
diet,

and

thus


do

not


accumulate

mercury

found


in


prey.


Tilapia


is


a

low


saturated

fat,


low


calorie,


low
carbohydrate

and

low


sodium

protein

source.


It

is


a

source


of


phosphorus,


niacin,


selenium,


vitamin

B12


and
potassium.
However,

aquaculture


raised


tilapia

(the


least


expensive


and

most


popular)


has

a

high


fat


content


(though


low
in

saturated

fats).


According


to


research


published


in


July


2008,


farm

raised


tilapia

may


be

worse

for


the


heart
than

eating


bacon


or


a

hamburger.


The


research


suggests


the


nutritional


value


of


farm

raised


tilapia

may


be
compromised

by

the


amount


of


corn


included


in


the


feed.


The


corn


contains


short


chain


omega-

6s

that
contribute

to


the


buildup


of


these


materials

in


the


fish.


"Ratios


of


long

-

chain


omega-

6

to


long

-

chain


omega-

3,
AA

to


EPA


respectively,

in


tilapia

averaged

about


11:1,


compared


to


much


less


than


1:1


(indicating

more


EPA
than

AA)


in


both


salmon


and

trout."


Wide


spread

publicity

encouraging


people


to


eat


more


fish

has

seen
tilapia
being


purchased

by

those


with


lower


incomes


who


are


trying


to


eat


a

well


balanced

diet.


The


lower
amounts

of


omega-

3

and

the


higher


ratios


of


omega-

6

compounds

in


US


farmed

tilapia

raise

questions


of


the
health

benefits


of


consuming


this

fish.
Adequate

diets

for


salmon


and

other


carnivorous

fish

can

alternatively


be

formulated


from

protein

sources
such
as

soy,


although


soy-

based


diets

may


also


change


in


the


balance


between


omega-

6

and

omega-

3

fatty
acids.
Exotic
species
Tilapia

are


unable


to


survive

in


low


temperate


climates

because


they


require

warm


water.


The


pure


strain


of
the

Blue


Tilapia,


Oreochromis


aureus,


has

the


greatest


cold


tolerance

and

dies


at


45

°F


(7


°C)


while


all


other
species

of


tilapia

will


die


at


a

range

of


52

°F


(11


°C)

-

62

°F


(17


°C).


As

a

result,


they


cannot


invade


temperate
habitats

and

disrupt


native

ecologies


in


temperate


zones;


however,

they


have

spread

widely


beyond


their
points
of


introduction

in


many


fresh


and

brackish


tropical


and

subtropical


habitats,


often


disrupting


native
species

significantly.


Because


of


this,


tilapia

are


on

the


IUCN's


100

of


the


World's

Worst


Alien


Invasive
Species
list.

In


the


United


States,


tilapia

can

live


only


in


Florida

south


of


a

line

crossing


the


state

horizontally
about

as

far


north


in


the


state

as

Orlando

and

a

few

other


isolated


areas


such

as

power


plant


discharge
zones.

Many


state

fish

and

wildlife


agencies


in


the


United


States,


Australia,


South

Africa

and

elsewhere
consider

them

an

invasive

species.