George D. Scholten

Population Characteristics and Assessment of Overfishing for an Exploited Paddlefish Population in the Lower Tennessee River

Abstract Paddlefish Polyodon spathula (n = 576) were collected from Kentucky Lake, Kentucky–Tennessee, with experimental gill nets in 2003–2004 to assess population characteristics and the potential for commercial overfishing. Additional data were collected from 1,039 paddlefish caught by commercial gillnetters in this impoundment. Since the most recent study in 1991, size and age structure have been reduced and annual mortality has tripled. In the 1991 study, 37% of the fish collected were older than the maximum age we observed (age 11), and in 2003 annual mortality for paddlefish age 7 and older was high (A = 68%). Natural mortality is presumably low (<10%) for paddlefish; therefore, exploitation in recent years is high. Estimates of total annual mortality were negatively related to river discharge in the years preceding each estimate. The number of paddlefish harvested since 1999 was also negatively related to river discharge because gill nets cannot be easily deployed when discharge exceeds approximat...

Protecting Paddlefish from Overfishing: A Case History of the Research and Regulatory Process

Abstract A commercial fishery for paddlefish ( Polyodon spathula ) in the Tennessee River was largely unregulated through the 1990s. Beginning in 2002, attention devoted to the plight of caviar-yielding species around the world resulted in much more scrutiny of the Tennessee paddlefish industry. This article describes the stock assessment of a paddlefish stock and the approach taken to present research findings to state and federal regulators and a skeptical fishing community. The end result for the fishery, and lessons learned from a series of public, facilitated, and state commission meetings are discussed. The need to compromise with the fishing industry meant that not all of the measures proposed to protect the fishery from overfishing were enacted; however, the fishery entered the 2006–2007 season with more regulations in place than ever before and with a promise by the regulatory commission that more restrictive regulations will be imposed in the future if warranted.

Anchoring Submersible Ultrasonic Receivers in River Channels with Stable Substrate

Abstract We developed an anchoring system for submersible ultrasonic receivers (SURs) that we placed on the bottom of the riverine reaches of three main-stem reservoirs in the upper Tennessee River. Each anchor consisted of a steel tube (8.9 × 35.6 cm) welded vertically to a round plate of steel (5.1 × 40.6 cm). All seven SURs and their 57-kg anchors were successfully deployed and retrieved three times over 547 d by a dive team employing surface air-breathing equipment and a davit-equipped boat. All of the anchors and their SURs remained stationary over two consecutive winters on the hard-bottom, thalweg sites where they were deployed. The SUR and its anchor at the most downriver site experienced flows that exceeded 2,100 m3/s and mean water column velocities of about 0.9 m/s.