Donald J. Orth

The New River, Virginia, supports a trotline fishery for catfish (Ictaluridae) that coexists with popular recreational fisheries for smallmouth bass (Micropterus dolomieu), muskellunge (Esox masquinongy), and walleye (Sander vitreus), yet no studies have examined trotline catches or bycatch of these game fish. Trotline effort was estimated by conducting off-site interviews of trotline fishers and field counts of active trotlines. Catch of catfish and bycatch were estimated with experimental trotline sets that used circle or J hooks and two bait types (i.e., live or cut bait). Catch...

In the 1970s and 1980s, blue catfish (Ictalurus furcatus) were introduced to the tidal rivers of Virginia. Current abundances and uncertainty about population characteristics of blue catfish generated concern for other economically important and imperiled species. We estimated natural mortality and size structure of blue catfish for four tidal river systems (i.e., James, Mattaponi, Pamunkey and Rappahannock). Using common empirical estimators with pooled data from the period 2002-2016, we calculated five estimates of natural mortality. Proportional size distributions were used to examine...

Smallmouth bass (Micropterus dolomieu) have been the preferred species of New River anglers since the early 1960s. Since the early 1960s, shifts in New River smallmouth bass population conditions have occurred. Some of these shifts are due to changed size limits which altered angler behavior. However, a number of unexplained changes prevent definitive analysis of causative factors. The New River smallmouth bass fishery of 1982 and 1983 was characterized by high numbers of sublegal fish (< 305 mm), slow growth, poor survival, and low relative weights. These characteristics shifted to...

Food habits of redbreast sunfish (Lepomis auritus), smallmouth bass (Micropterus dolomieu), and white sucker (Catostomus commersoni) populations in the Shenandoah River Basin, Virginia, were assessed during 2002 to identify dietary pathways and patterns potentially affecting mercury uptake. Aquatic insects (71% to 83%) were the principal food item of redbreast sunfish, while smallmouth bass mainly consumed aquatic insects (32% to 48%), crayfish (19% to 31%), and fish (22% to 29%). Principal food items of white sucker included aquatic insects (20% to 26%) and detritus (66% to 70%)....

A 1-year creel survey of New River, Virginia and West Virginia, was conducted to assess the effects of a 305-mm minimum length limit on the angler harvest of smallmouth bass (Micropterus dolomieui) and associated fishes from the Virginia portion of the New River. Anglers in Virginia harvested 0.06 smallmouth bass per hour averaging 322 mm total length (TL) and released 1.27 smallmouth bass per hour. West Virginia anglers harvested 0.40 smallmouth bass per hour averaging 242 mm TL and released 0.65 smallmouth bass per hour. Total catches per hour (1.33 in Virginia and 1.05 in West Virginia...