Gar are unique freshwater fish native to North American waters for millions of years. Despite their long history and ecological significance, these ancient fish are often misunderstood and mistakenly labeled as invasive. This article clarifies what defines an invasive species, where gar naturally reside, their ecological contributions, and why they are misperceived.
Defining an Invasive Species
An invasive species is an organism non-native to an ecosystem that causes, or is likely to cause, harm to the environment, economy, or human health. These species are introduced outside their historical distribution, often by human activities, either intentionally or unintentionally. A key characteristic of an invasive species is its ability to establish and spread rapidly, outcompeting native organisms for resources or preying upon them. Examples include the zebra mussel or Asian carp, which have drastically altered ecosystems they have invaded.
The impact of invasive species can be severe, reducing biodiversity and altering habitats. They often thrive in new environments due to a lack of natural predators or diseases. This unchecked growth allows them to dominate ecosystems and disrupt natural balances.
Where Gar Naturally Live
Gar species are native to a wide geographic range across North and Central America, and Cuba. Their presence in these waters dates back millions of years, with ancestors found in fossil records from the Permian period. This long history firmly establishes them as indigenous inhabitants.
Five of the seven recognized gar species are native to the United States: the alligator, longnose, shortnose, spotted, and Florida gars. These species are found from the Great Lakes basin, south through the Mississippi River drainage, and into Texas, Florida, and Mexico. The Cuban gar is native to Cuba, while the tropical gar inhabits southern Mexico and Central and South America.
Gar’s Role in Ecosystems
Gar play an important role as apex predators within their native freshwater and sometimes brackish ecosystems. They help maintain the balance of fish populations by preying on abundant species like buffalo, carp, and shad. This predation helps prevent overpopulation of certain fish, which in turn promotes biodiversity and contributes to a healthier aquatic environment.
Beyond population control, gar contribute to the genetic health of prey populations by selectively consuming weaker, slower, or diseased individuals. This natural selection process ensures that the remaining fish are more resilient. Gar also utilize periodically connected floodplains for spawning and as nursery and feeding grounds, highlighting their integration into the natural cycles of their habitats.
Why Gar Are Often Misunderstood
Gar are frequently misunderstood due to their appearance, predatory nature, and historical misinformation. Their ancient, “prehistoric” look, characterized by long, cylindrical bodies, armored scales, and sharp teeth, can be off-putting to some. This unique appearance sometimes leads to them being unfairly labeled as undesirable or even threatening.
For decades, gar were regarded as “trash fish” or nuisance species by many anglers and resource managers. This perception stemmed from the mistaken belief that gar consumed sport fish, thereby harming recreational fisheries. Research shows that gar primarily consume more abundant, slower-moving fish, and their presence is beneficial for ecosystem balance. Their resilience and ability to survive in low-oxygen waters, due to their unique swim bladder, have also been misinterpreted as an invasive trait, rather than an evolutionary adaptation allowing them to thrive in their native habitats.