Billfishes
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Billfishes
Billfishes are sleek tuna-like fishes with the upper jaw extended into a long, bony spear.
There are six kinds of billfishes found in Guam's waters. The most abundant kind is the Indo-Pacific blue marlin. Sailfish are relatively uncommon and spearfish, black marlin, and striped marlin are rare. The broadbill swordfish also occurs on Guam, but only in the deeper, cooler waters fished by longline. All billfishes are highly migratory, and all but the swordfish are caught by trolling with lures or live bait.
Indo-Pacific Blue Marlin / Båtto
Image from Coral Reefs CD
The Indo-Pacific blue marlin or båtto' as it is called in Chamoru, is the world's largest species of billfish, reaching a fork length of nearly 15 feet (4.6 m) and weight of about 2,500 pounds (1,134 kg; measured from the tip of the lower jaw to the notch in the middle of the tail). The largest ever caught on sport fishing tackle weighed 1,805 pounds (819 kg). For many years the all-tackle world record was held by a 1,153 pound (523 kg) fish caught off Guam.
Båtto' occur in all warm seas with temperatures above 68°F (20°C). They inhabit offshore waters from the surface to depths of over 600 feet (182 m). Båtto' feed primarily on tunas and other pelagic fishes, and to a lesser extent, on post-larval reef fishes and squids. They grow rapidly, reaching a weight of about 100 pounds (45 kg) by the age of four to eight years. Females grow faster and attain a much larger size than do males which only reach a weight of about 300 pounds (136 kg). Females can live for more than 16 years. Båtto' are most abundant near Guam during the summer months. Most of the locally-caught marlin are males weighing between 100 to 200 pounds (45 to 90 kg). Recent annual landings by the local small boat fleet have ranged from 15 to 68 tons (14 to 62 MT).
Båtto' occur in all seas warmer than 72°F (22°C) and seem to be most abundant near land masses, occasionally in waters as shallow as 40 feet (12 m). They feed primarily on pelagic fishes and squids, but occasionally feed on bottomfishes and crustaceans. The sailfish is the fastest fish known, capable of speeds as high as 68 miles per hour (109 km/hr). They are caught throughout the year in Guam's waters, but are never abundant with annual catches by the small boat fleet always below three tons. Sailfish reach a weight of 221 pounds (100 kg).
Indo-Pacific Sailfish / Guihan Låyak
Istiophorus platypterus
Guam Comprehensive Wildlife Conservation Strategy, 9/27/2005
