Differences in population metrics between bluegill and redear sunfish: Implications for the effectiveness of harvest restrictions

Bluegills Lepomis macrochirus and redear sunfish L. microlophus were collected and aged from three reservoirs in Georgia and Alabama in 2003-2004 to describe population metrics and investigate the potential of harvest restrictions to maintain or improve the size structure of these populations. Redear sunfish grew faster and lived longer than bluegills in all three reservoirs, and estimated natural mortality was greater for bluegills than for redear sunfish; however, total annual mortality was similar between the species in two of the three reservoirs. Population dynamics models did not predict any significant benefits to bluegill size structure and yield from minimum length or bag restrictions. In contrast, redear sunfish populations in each study reservoir showed significant increases to size structure and minimal decline in yield from various harvest restriction scenarios. Because of higher mortality and slower growth in bluegills, harvest restrictions probably will not positively affect their size structure without an unacceptable decline in yield. However, our results indicated that harvest restrictions may have greater potential in managing redear sunfish populations. For redear sunfish, yield was not drastically affected by minimum length limits, but after implementation of harvest restrictions the number of larger, preferred-length (>= 230-mm) fish could increase by over an order of magnitude in moderately to highly exploitative fisheries. Finally, results of this study have demonstrated that the common practice of managing sunfish as a homogenous group may not be appropriate, particularly if the fishery is composed of a diverse array of sunfish species that are targeted by anglers.