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Gars (Lepisosteidae)

With a toothy maw and slender body, gars communicate "predator". This family is represented by just two genera and five species in the United States, including one of America's largest fishes, the fearsome alligator gar, which can reach up to nine feet in length and weigh nearly 300 pounds! This gigantic predator is known to feed on fish, crabs, turtles, ducks and even small mammals.

Family level identifiers. Longnose gar

Figure 1. Family level identifiers. Longnose gar (Lepisosteus osseus).

Family Level Identifiers (see Fig. 1):

Habitat:

Gars prefer sluggish or still waters with good clarity and submersed vegetation. They are perhaps most common in large rivers (sluggish reaches), wetlands, oxbow lakes and coastal marshes.

Pollution Tolerance:

Generally, gars are tolerant of pollution and somewhat tolerant of habitat disturbance. With a unique swim bladder that is described as "lunglike" (Potter, 1927), gars are able to survive in areas of low dissolved oxygen.

Use in IBI:

Lepisosteidae does not have a specific IBI metric. Their presence and diversity would be accounted for in metrics that evaluate the community as a whole, such as Metric 1: Total Number of Fish Species.

Table 1. Tolerance designations for selected gar species.
Species Name Common Name Pollution Tolerance Habitat Disturbance
Lepisosteus oculatus Spotted Gar M MT
Lepisosteus osseus Longnose Gar M T
Lepisosteus platostomus Shortnose Gar M MT
Lepisosteus platyrhincus Florida Gar M NR
Lepisosteus spatula Alligator Gar M MT
Key
Pollution Tolerance Habitat Disturbance
T = Tolerant T = Tolerant
M = Intermediate MT = Moderately Tolerant
I = Intolerant MI = Moderately Intolerant
NR = No ranking I = Intolerant
  NR = No ranking

Biological Indicators | Aquatic Biodiversity | Statistical Primer

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