Length Limits Fail to Restructure a Largemouth Bass Population: A 28‐Year Case History

Abstract

Length limits have been implemented by fisheries management agencies to achieve population density, size structure, and angler satisfaction objectives. By redirecting harvest towards or away from particular length‐ or age‐groups, length limits rely on harvest by anglers to maintain a population at or near a desired state. The fish population changes that follow the implementation of harvest regulations may take several years to manifest, so long‐term monitoring may be needed to adequately evaluate length limits. We used an innovative application of cluster analysis to facilitate evaluation of the effects of three consecutive length limits on a population of Largemouth Bass Micropterus salmoides over a 28‐year period in Ross Barnett Reservoir, Mississippi. A 13–16‐in protected slot length limit (10 years), followed by a 15‐in minimum length limit (MLL; 11 years), followed by a 12‐in MLL (7 years) failed to restructure the Largemouth Bass population due to what we suggest was the expansion of a voluntary catch‐and‐release attitude that started in the first decade of the study period. Various population metrics shifted towards values expected in an unharvested population, and the observed shifts can be attributed to a harvest deficit created by the prevailing catch‐and‐release attitude. Largemouth Bass harvest regulations may no longer be relevant in many waters. The utility of regulations for restructuring Largemouth Bass populations is largely dependent on harvesting attitudes that vary geographically, depending on cultural characteristics and demographics. Received September 15, 2016; accepted March 15, 2017 Published online May 4, 2017

The Effect of Water Temperature, Angling Time, and Dissolved Oxygen on the Survival of Largemouth Bass Subjected to Simulated Angling and Tournament Handling Procedures

“…; Miranda et al. ), catch‐and‐release angling has contributed to contemporary high‐quality Largemouth Bass fisheries and has become the accepted practice among black bass anglers (Quinn ; Siepker et al. ; Myers et al.…”

Weak Effects of Density on Mean Length at Age and Condition of Largemouth Bass at Large Alabama Reservoirs

“…In a single, large (~13,000 ha) reservoir in Mississippi, Miranda et al. () also found that Largemouth Bass condition indices were unchanged during a 28‐year period in which angler harvest rates dramatically declined and catch rates (in both assessment and angler creel surveys) of recruited size‐classes increased. Beyond this work, we know of no studies that have evaluated the density‐dependent growth of recruited age‐classes of Largemouth Bass across multiple large reservoirs (>4,000 ha) and a nearly 20‐year time frame, as our study has done.…”

“…Instead, population metrics in this reservoir shifted toward values expected in an unharvested population over this time, likely due to increased adoption of catch‐and‐release practices (Miranda et al. ). Therefore, while the negative consequences of stockpiling may be avoided in larger reservoir systems, the ability of minimum length limits to meet management objectives may ultimately depend on anglers’ willingness to harvest larger fish above the minimum length limit (Quinn ; Allen et al.…”

“…Despite this, the ultimate effectiveness of minimum length limits may depend on angler attitudes regarding harvest. For example, in Ross Barnett Reservoir, Mississippi, a series of length-based regulations over the past 28 years failed to restructure the Largemouth Bass population in line with management objectives (Miranda et al 2017). Instead, population metrics in this reservoir shifted toward values expected in an unharvested population over this time, likely due to increased adoption of catch-and-release practices (Miranda et al 2017).…”

“…Size-based limits, however, may have the unintended consequence of reducing growth through density-dependent effects if the abundance of younger, smaller fish increases, as has been observed in some systems (Johnson and Anderson 1974;Wilde 1997). Furthermore, the utility of minimum length limits may be further reduced if overall exploitation declines over time Miranda et al 2017).…”