The fisherman, waded into the North Fork of the Shenandoah River somewhere near the remains of the old wing dam just above the confluence with Pugh’s Run. He cast a black and gold tube jig toward the river bank and let it drift and tumble on the bottom toward the sharply undercut stream bank under the root ball of the old sycamore that had fallen there. He felt the tap he had been anticipating, and after two or three patient seconds, gave the rod he was holding a quick meaningful jerk. Suddenly, it seemed that a miniature bomb had exploded in mid-stream as the smallmouth bass exhibited the aerial leaps and savage rushes characteristic of the gamest of all game fishes in North America. Soon, the 15-inch fish came to the net held by the happy outdoorsman, to be released to grow, propagate, and perhaps reward another fishermen on another day.
Indeed, because of these characteristics, the smallmouth bass is the most sought after game fish in the Shenandoah River watershed, and it is of critical importance to the economy of the Shenandoah Valley. An economic study by Dr. Maria Papadakis of James Madison University calculated the annual economic cost to the valley due to the recent troubling kills of smallmouth in the Shenandoah River system at nearly $700,000. Therefore, a brief discussion of the life history of smallmouth bass may help people understand the importance of maintaining the river’s quality and quantity at levels that maintain a healthy population of this fabulous game species.
Is the smallmouth native to the Valley?
No. Until the mid-1800’s, the smallmouth bass was native to and found only in the Great Lakes and Ohio River watersheds. When the railroads spread throughout the country in the second half of the 19th century, so did the smallmouth. The historical record indicates that the species was first introduced by rail into a Virginia drainage system – the Potomac – in 1854 and the fish commissions of both Maryland and Pennsylvania actively stocked tributaries in their states throughout the 1860’s and 70’s. While descendents of these fish undoubtedly moved upstream into Virginia waters, the state began its own stocking program in 1871. These transfers have been highly successful, and the species is now distributed in freshwaters throughout the state.
QUESTION: What is the preferred habitat of smallmouth bass?
Smallmouth bass inhabit cool and warm (not hot) large creeks, streams, and rivers with gravelly and rocky substrates and a frequent succession of riffles, runs, and pools. They often become a dominant species in reservoirs that impound streams that had these attributes. They typically occupy the pools and runs waiting for insects and smaller fish on which they feed to wash down from the riffle areas. In the heat of summer, they seek out shade below overhanging banks or the cover of large rocks or downed trees. In the winter, they seek cover in the deeper larger pools. Because they feed by sight, smallmouth bass do not tolerate prolonged periods of heavy siltation after storms well. This, and prolonged summer water temperatures at the high end of their tolerance level (80 degrees), make the Shenandoah River rather marginal habitat at best.
What is their basic biology?
Smallmouth spawn in the spring, when water temperatures approach 60 to 65 degrees. The males build nests, typically by clearing a depression in the gravel a few inches deep and 18 to 30 inches across with their tails. Bass in the North Fork have adapted to building nests in the cracks and hollows of the limestone ledges that characteristically cut across the river. Males work to attract the females to the nest where more than one will spawn on the same nest, laying 2,000 to 4,000 eggs per pound of body weight. Because the females spawn at different times, the eggs do not hatch at the same time. Depending on water temperature, eggs hatch in 2 to 7 days, and the young fish leave the nest in about a week after hatching. In rivers, ultimate spawning success depends on the absence of severe spring storms resulting in high stream flows that cause loss of nests and fry and rapidly rising water temperature that allows the young fish to grow quickly and more easily defy predators.
Young smallmouths eat tiny plankton in the water, but graduate to insect larvae, crayfish, and minnows or smaller fish. They can grow to up to 4 inches the first year, and attain lengths of 14 inches or greater in 5 to 6 years. They reach sexual maturity at 3 to 4 years of age. A few North Fork fish have been recorded over 20 inches and 5 pounds.
Has the smallmouth bass population in the Shenandoah River watershed recovered from the fish kills of 2004 to 2007? Has the cause of these kills been deterimined?
Various theories concerning the cause of the fish kills have been extensively studied by scientists at state and federal agencies and universities. None of the studies has provided a smoking gun. We do know that there was a near absence of kills in 2008 in the Shenandoah and Potomac systems, and the problem shifted farther south into the Rappahanock and James systems. Hopefully, such kills will prove a transient phenomenon and will not be a future problem. Rivers are open systems, and when habitat comes open, as it did with the fish kills, other individuals can move in quickly and take advantage of the open space and abundant food. This seems to have happened in the North Fork. Smallmouth populations seemed to have rebounded almost completely this year. Also, the species is prolific enough, that given good spring spawning conditions, reproduction can quickly aid recovery. Still, as pointed out earlier, the Shenandoah River provides marginal habitat, especially in mid-summer, and any degradation in water quality will only be detrimental. We must all be diligent in conserving the habitat for this exceptional sport fish.