Length Limits: When and Why

February 13, 2023
Industry News Archive

Length limits are a popular tool biologists use for regulating harvest for various reasons, such as preventing over harvest, improving population abundance, and increasing angler catch rates and the size of fish caught. There is no statewide length-based restriction for black bass in Arkansas. That said, AGFC biologists utilize a variety of length limits for black bass in reservoirs depending on management objectives and angler desires. However, when anglers are practicing a high rate of catch-and-release, length limits become irrelevant and do not restructure the fish population. Some black bass harvest is helpful for improving black bass populations.

Most commonly, AGFC biologists use minimum length limits. Minimum length limits allow for the harvest of individuals once they have attained or exceeded a specified length. Minimum length limits are practical when a number of factors are occurring.

·      Anglers are keeping a significant number of fish from the waterbody (high exploitation).

·      Recruitment is low or inconsistent.

·      Growth rates of bass are moderate or fast.

·      The number of bass dying due to predation and disease (natural mortality) is low.

A good example where this regulation works well is on the Arkansas River, where the minimum length limit is 14 inches. Recruitment is inconsistent on the river due to spring floods and degrading backwater habitat, so a minimum length limit allows adult bass to spawn before they have a chance to be harvested. See the Arkansas Fishing Guidebook to find out which other waterbodies throughout the state have minimum length limits. 

Biologists also use slot limits to protect a specific size range of fish. For example, a protected slot limit of 13 to 16 inches allows only fish less than 13 and greater than 16 inches to be harvested while protecting fish between 13 and 16 inches. Slot limits are practical when a few things occur.

·      Anglers are keeping a significant number of fish from the waterbody.

·      Recruitment is high.

·      Growth rates of bass are slow or moderate.

For example, a biologist may use a slot limit to protect bass from 16 to 21 inches, which are desirable to anglers while allowing for harvest of the abundant smaller fish below 16 inches. It is very important that anglers harvest sufficient numbers of fish below the slot limit for a slot limit to be beneficial. Otherwise, stunted populations of small bass can occur (see picture). Slot limits are sometimes used for trophy bass management. Lake Atkins utilizes a 16 to 21 inch slot limit. Slot limits have limited effectiveness when anglers are practicing a high rate of catch-and-release of fish below the slot size. Harvest of small black bass, especially those less than 14 inches, is important for improving black bass populations.