They commonly reach 3 m (9.8 ft) in length, and the maximum reported is 4.55 m (14.9 ft) in length and 650 kg (1,430 lb) in weight. The International Game Fish Association's all-tackle angling record for a swordfish was a 536 kg (1,182 lb) specimen taken off Chile in 1953. Females are larger than males, and Pacific swordfish reach a greater size than northwest Atlantic and Mediterranean swordfish. They reach maturity at 4–5 years of age and the maximum age is believed to be at least 9 years. The oldest swordfish found in a recent study were a 16-year-old female and 12-year-old male. Swordfish ages are derived, with difficulty, from annual rings on fin rays rather than otoliths, since their otoliths are small in size. Swordfish are ectothermic animals however, along with some species of sharks, they have special organs next to their eyes to heat their eyes and brains. Temperatures of 10 to 15 °C (18 to 27 °F) above the surrounding water temperature have been measured. The heating of the eyes greatly improves their vision, and consequently improves their ability to catch prey. Of the 25 000+ fish species, only 22 are known to have a mechanism to conserve heat. These include the swordfish, marlin, tuna, and some sharks. Learn more about Swordfish