24 October 2008

Piraiba - The Largest Amazon Catfish

In the Amazon River, there are legends of goliath catfish that grow to over 10 feet long and reach nearly 600 pounds. These giants are the catfish that belong to the Brachyplatystoma genus. This genus has 7 of the largest fish in the world, including B. filamentosum. This fish is so large that locals call the juvenile fish (those weighing under 200 pounds) filhote. Once they reach 200 pounds, locals call them Piraiba. The Piraiba is the largest catfish in this genus, and is notorious for its voracious eating and solitary lifestyle habits.

When they’re juveniles, Piraiba are light to dark grey with small spots on their dorsal and lateral sides. As they get older, Piraiba turn dark grey on the top and light grey on the bottom. This coloration aids in camouflaging their massive bodies as they hunt for food 100-130 feet below the surface of the Amazon River.

Piraiba have an appetite to match their massive bodies. Fishermen who’ve caught these massive giants have found small monkeys, birds, cats and even other catfish in the stomachs of these giants. While they don’t hunt for monkeys or birds, Piraibas have no problem scavenging on already deceased animals that have fallen into the Amazon. Some legends even claim that humans have been found in the stomachs of these enormous fish.

Piraibas not only play an important role as scavenger in the Amazon. They also play an important role as food for locals. Fishermen and anglers who hunt these large fish will drop many lines into the Amazon, weighted down by 2-5 pound bait and rocks. Once the line begins to move, experienced fishermen draw the fish into shallow water. At that point, the fishermen have no option but to jump into the water and literally wrestle the Piraibas to ground. For

 inexperienced fishermen this can be a very dangerous sport to learn—the Piraibas are so powerful that they can drown and even drag the wrestling fishermen to the bottom of the Amazon. A successful catch is well worth it though, as a single Piraiba can contain hundreds of pounds of food for locals and export.

Like other catfish, the Piraiba are active at night between midnight and around 6 a.m. Piraiba catfish look for food as deep as 130 feet under the surface of the Amazon River. They will scavenge and also hunt for smaller fish such as Peacock Bass and Piranha. Piraiba don’t worry about the slicing teeth of the Piranha, even though they inhabit the same waters where hundreds of Piranha school. These giants have extremely thick tough leathery skin that resists such attacks. By the time they are 4-5 feet in length, Piraibas can move freely in the deepest Amazon waters without fear of predators.

Piraibas remain solitary until they are ready to mate somewhere between 2-3 years old. When a male is ready to mate, he will find another female Piraiba and swim alongside her until she releases eggs. The male will inseminate hundreds of eggs, and then chase the female from the

 eggs. The male aerates the eggs and keeps the female away, while the female chases predators away from a distance. Within a week, the fry hatch and are fed by the male stirring up detritus on the Amazon floor. The female remains a guardian during this period.

The fry remain at the nest for up to several weeks, adventuring to find small invertebrates and ghost shrimp to eat. They grow fairly quickly, and by 6-8 months they begin to take on sexual distinction and become solitary. This is the most vulnerable period for the young Piraiba—they are mature enough to hunt on their own, but their size makes them very vulnerable to larger fish, giant otters and predatory birds. The Piraiba’s body does offer some protection against such predators that would eat them whole—a characteristic sharp collection of spines on their dorsal that deters predation.

With such a large potential size and healthy appetite, Piraibas are definitely not suitable for most aquarium owners. The best spot to keep a Piraiba is a large local aquarium that can support at least a 2000 gallon tank. These fish can get up to 400 pounds, and with this much body weight, this fish is one of the most expensive to feed and maintain.

Piraiba are one of the most impressive catfish in the world. They dominate the Amazon with their sheer size, and offer fishermen an exciting, challenging catch. They also play a crucial role in scavenging the bottom of the Amazon as the “clean-up crew” of the largest river system on Earth.

Photos copyright: http://www.catfishheaven.net/flavio.html and Wikipedia.org


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