The Atlantic salmon, 'the leaper', has been called the king of fish, due primarily to their spectacular ability to clear seemingly insurmountable obstacles. Their large body is long and hydrodynamic and can measure up to 150 cm in length and weigh up to 39 kg. Adults are usually a silvery grey colour with some black spots but become more reddish with purple spots in the breeding season, and males develop a hooked lower jaw for fighting.