Temperate Basses (Moronidae)

In the freshwaters of North America, Moronidae is represented by one genus and four species. Fishes found within this family include important game and commercial species, such as the white and striped bass. Additionally, some native moronids are considered "anadromous" species, that is, fish that inhabit marine environments but spawn in freshwater systems.

Figure 1

Figure 1. Family level identifiers. Yellow bass (Morone mississippiensis).

Family Level Identifiers (see Fig. 1):

First dorsal with 8-10 spines, second dorsal with 1 spine and 10-13 soft rays.
Anal fin with 3 spines and 9-12 soft rays.
Lateral line complete.
More - tips about genus identification. Also, visit our photo library on temperate basses.

Habitat:

Native moronids are primarily large water body inhabitants, common to lakes, reservoirs, marine and brackish environments. Spawning runs often occur in large rivers where access is not restricted by dams. The striped bass (Morone saxatilis) and white perch (Morone americana) are two species that once migrated freely between marine and freshwater envrionments.

Pollution Tolerance:

In general, native temperate basses are considered "intermediate species" in terms of pollution tolerance. As mentioned previously, spawning obstacles are more likely to impact moronids than slight to moderate water pollution. For example, Boschung and Mayden (2004) noted that "as a result of the impounding of the Alabama River, native striped bass have been virtually extirpated in Alabama since the early 1960s."

Use in IBI:

Moronid presence and diversity is not evaluated under a specific metric. In certain scenarios, temperate basses might be placed into Metric 9: Proportion of Individuals as Top Predators, as adults often feed on shad, silversides, crustaceans and occassionally young sunfish.

Introduction:

The white bass and striped bass have been introduced extensively throughout the United States. In some states, white bass x striped bass hybrids are used due to their tolerance of warmer temperatures.

Table 1. Tolerance designations for selected sculpins.
Species Name	Common Name	Pollution Tolerance	Habitat Disturbance
Morone americana	White Perch	M	NR
Morone chrysops	White Bass	M	MT
Morone mississippiensis	Yellow Bass	M	MT
Morone saxatilis	Striped Bass	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