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Rock Bass Management and Fishing in Pennsylvania

Prepared by R. Lorantas, D. Kristine and C. Hobbs
PFBC Warmwater Unit

2005


Goal: Maintain or enhance rock bass sport fisheries through harvest management of naturally sustained rock bass populations and through habitat preservation and enhancement. Judiciously stock rock bass into compatible new and reclaimed habitats.


Rock bass occur throughout Pennsylvania and were originally indigenous to the Ohio River and Lake Erie drainages. The Ohio drainage includes the Ohio River, Allegheny River, and Monongahela River drainages. Rock bass occupy reservoir and lake (lentic) habitats as well as river and stream (lotic) habitats within these drainages. Rock bass stocking by the Pennsylvania Fish and Boat Commission into the Delaware, Susquehanna, and Potomac river drainages lead to colonization of waters within these drainages, and rock bass are now self-sustaining throughout Pennsylvania. Most natural warmwater lakes and man-made reservoirs in Pennsylvania contain self–sustaining rock bass populations. In Pennsylvania rock bass generally occur at equal or greater densities in rivers and streams compared to lakes and reservoirs.

Rock bass populations, both indigenous and those that have become naturalized, are managed for sport fishing through harvest management and more recently through stocking. Stocking has occurred in conjunction with establishing self-sustaining rock bass populations in newly reclaimed waters. Abatement of acid mine drainage on the Cassleman River in Somerset County has lead to stocking programs designed to establish this species on a self-sustaining basis. Stocking is typically carried out from one to several years. Rock bass populations in Pennsylvania waterways are not sustained through annual maintenance stocking.

With respect to harvest management, inland regulations accommodate harvest of 50 panfish, combined species, which includes rock bass. No minimum size limit or seasonal restrictions apply. Rock bass are generally considered a prolific species, which has lead to liberal harvest rules. Despite liberal harvest rules the average creel size of an angler completing their fishing trip in Pennsylvania who have kept at least one rock bass is a little over 3 rock bass. Low average harvest reflects an increased practice of catch and release fishing, however in some cases angler may encounter few rock bass of desirable size in the population. Many small rock bass may be a result of slow growth, or may reflect angler removal of desirable size rock bass such that small size specimens remain.

If a biologist is faced with angler harvest reducing density of desirable size rock bass, harvest restrictions may be applied and were applied to the Juniata River and tributaries where the daily creel limit of rock bass was reduced to 20 rock bass per day in 2002. The effectiveness of this size enhancement program in Pennsylvania is under evaluation.

Biologists regularly sample fish populations and measure their density and size structure, fish habitat is also described by measuring water productivity and aquatic vegetation density. Following such evaluations management plans are prescribed to enhance density and size structure of rock bass within resource limits.

In association with these evaluations growth of rock bass is examined by measuring length, weight, and taking a scale sample to determine age. In Pennsylvania, a 7 inch rock bass is approximately 3 years old (Fig. 1) and weighs 0.2 pounds, when rock bass are 9 inches in length they are approximately 6 years old and weigh approximately 0.4 pounds. We have tabulated average ages and weights for a variety of lengths of rock bass in Pennsylvania (Table 1). Anglers find these tables useful in approximating the weight and age of their catch. In standard biological collections, the decrease in relative or absolute number of rock bass at each age, can be used to describe the total annual mortality rate of rock bass. In addition to measuring losses biologists index annual production of young rock bass by measuring catch of juveniles. Growth of rock bass, recruitment of young rock bass to the population and loss of older rock bass are important considerations in developing harvest regulations that produce desirable size rock bass for harvest.

Figure 1. Average length of rock bass and redbreast sunfish collected by Fisheries Biologists in assessment gear in Pennsylvania (July-September).

Figure 1

Inches Pounds Years Inches Pounds Years
4.5 0.1 1.4 11 0.9 > 10.1
5 0.1 1.7 11.5 1.0 > 10.1
5.5 0.1 2.1 12 1.2 > 10.1
6 0.1 2.4 12.5 1.3 > 10.1
6.5 0.1 2.8 13 1.5 > 10.1
7 0.2 3.3 13.5 1.7 > 10.1
7.5 0.2 3.8 14 1.9 > 10.1
8 0.3 4.3 14.5 2.2 > 10.1
8.5 0.4 5.0 15 2.4 > 10.1
9 0.4 5.8 15.5 2.7 > 10.1
9.5 0.5 6.8 16 3.0 > 10.1
10 0.6 8.1 16.5 3.3 > 10.1
10.5 0.8 10.1  

Tabulating catch and harvest by anglers from various waterways is essential in developing harvest regulations. Information derived from creel surveys frequently yields information of interest to anglers since seasonal peaks in catch occur for most species. Rock bass can be caught most any time of year, generally though, highest catch per hour occurs in spring and early summer in large reservoirs and rivers (Fig. 3 and 4). In addition to spring and summer, fall can yield especially high catch rates in medium size reservoirs (Fig. 2). Since rock bass defend nests in late spring in association with spawning and brood guarding, adults can be concentrated and quite vulnerable to anglers. With fishing destinations identified from maps on this site and information describing the best seasons to catch rock bass anglers need only select an effective bait or lure. Most anglers catch rock bass drifting a worm or minnow in rocky near-shore habitat. Small jigs, spinners, spoons and crank baits are effective baits. The abundance of rock bass in many waters across the state, particularly in rivers and streams and in near shore zone of reservoirs makes them an especially popular panfish among youthful anglers. Rock bass are fun to catch by anglers of all ages.

Figure 2. Average catch per angler hour of rock bass from medium size Pennsylvania reservoirs.

Figure 2

Figure 3. Average catch per angler hour of rock bass from large size Pennsylvania reservoirs.

Figure 3

Figure 4. Average catch per angler hour of rock bass from Pennsylvania rivers.

Figure 4

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