Composite image: Diversity in the upper Amazon Basin of Knifefishes

From the mouth of the Amazon River to some of the springs that feed the mighty system in the Andes Mountains, there exists a distance of roughly 6,518 km (~4,075 miles). Two of the longer tributary rivers to the Amazon are the Juruá and Madeira Rivers, both of which are in excess of 3,300 km (2,060+ miles) long. There are over 1000 tributaries to the Amazon; many are expansive. The drainage systems traverse dozens of habitat types including montane forests in the headwaters region, seasonally flooding as well as terra firme forests, palm and liana forests, swamps, and many more diverse habitat types. The waters flow through different terrain and form murky waterways and well as blackwater and clear systems. Swamps, oxbow lakes, floodplain systems, slow and fast water drainages – a huge diversity of aquatic systems exist in the mix with all of these characters – physical and biological. These tributary systems, as well as the Amazon itself, provide a lot of habitat for aquatic wildlife, including the knifefishes. Knifefishes are amazing animals for a variety of reasons – not the least of which is the fact that they can generate and detect weak electrical fields around their bodies. I say “weak” but there are exceptions – electric eels belong to this order (Gymnotiformes) and they use their strong electrical discharges for stunning prey and in defense. Most commonly, the electrical fields in knifefishes are used to navigate their surroundings, find food, communicate between individuals, and even identify specific individuals (same species). There are over 200 described knifefishes and undoubtedly more awaiting discovery. Fish are a huge part of the biodiversity of these rainforests and are an integral component to healthy forests - including just a few of the many species of knifefishes, which are depicted here. Now consider these things the next time you read about an oil spill on one of these rivers or a new gold mining project or a palm oil plantation going in. These human activities have real consequences for this biodiversity - all negative. If you don't stand up for the environment, who will? Time to get involved. Support any conservation agency with which you connect but do your homework...there are bad apples in the cart but they can be easily ferreted out if you do just a few minutes of background checking online before donating. Please, support the environment in a time where it desperately needs it.