Development of a Riverine Index Netting Protocol: Comparisons of Net Orientation, Height, Panel Order, and Line Diameter

Abstract

We developed a gillnetting protocol by sampling 17 nonwadeable rivers across northern Ontario over the course of four summers from 2005 to 2008. The rivers represented a range of habitats; however, all had a coolwater to warmwater fish community characterized by walleyes Sander vitreus, northern pike Esox lucius, white suckers Catostomus commersonii, yellow perch Perca flavescens, and smallmouth bass Micropterus dolomieu. During the study, three net designs were used. Each net had one to four configurations that varied in height, length, monofilament diameter, and sequence of the mesh sizes. We found that most fish (87%) were captured in the lower half of 1.8‐m‐high gill nets and that there was no difference in catch between gill nets with serial panels (i.e., sequentially increasing mesh sizes) and those with randomly organized panels. Net that were set perpendicular to shore or angled to shore caught approximately twice as many fish as nets that were set parallel to shore. Contrary to expectations, there were no differences in net durability and catch between thick‐ and thin‐diameter monofilament nets. Based on the results of these experiments, we propose an improved net design that we call the large‐mesh riverine index net for use in rivers; it is more versatile, reduces net drag, and fishes more effectively than the traditional gill nets that are used in lakes. The large‐mesh riverine index net has eight panels (3.1 m long × 0.9 m high) and totals 24.8 m in length. Panel stretch measures (and the random order used) for this design are 127, 76, 178, 25, 102, 203, 51, and 152 mm. The nets are set perpendicular to shore in rivers from July 1 to October 1 and should be fished in areas where water velocity is less than 0.1 m/s. Received January 12, 2010; accepted November 2, 2010

Variation in lake sturgeon (Acipenser fulvescens Rafinesque, 1817) abundance in rivers across Ontario, Canada

“…Using a standardized approach enabled the comparisons among different rivers to help ascertain factors affecting Lake Sturgeon abundance. The protocol used a modification from Jones and Yunker (), using 1.8 m high large mesh nets in contrast to the 0.9 m high large mesh nets. Calibration of this gear is still required to ensure that netting results are representative of the population.…”

“…In this study, we take a landscape approach and assess Lake Sturgeon among Ontario rivers using a modification of a standardized protocol (Jones and Yunker, ) to enable comparisons among sites. Our objectives were to (i) assess the variation in relative abundance of Lake Sturgeon subjected to various man‐induced stresses and physical characteristics at a landscape scale across Ontario, and; (ii) ascertain the factors that explain the variability observed among rivers using a multivariate approach.…”

Large‐bodied fish assemblage characteristics in large rivers across Ontario

“…Smaller wadeable rivers have been assessed using electrofishing techniques, especially along Great Lakes tributaries (Reid, Jones, & Yunker, ; Stanfield, Lester, & Petreman, ). Non‐wadeable or medium to large size rivers have been largely neglected given habitat and flow heterogeneity within and among rivers (Casselman et al, ; Cooke et al, ; Jones & Yunker, ). A standardized River Index Netting protocol was developed for non‐wadeable rivers in Ontario using gillnets (Jones & Yunker, ).…”

“…Non‐wadeable or medium to large size rivers have been largely neglected given habitat and flow heterogeneity within and among rivers (Casselman et al, ; Cooke et al, ; Jones & Yunker, ). A standardized River Index Netting protocol was developed for non‐wadeable rivers in Ontario using gillnets (Jones & Yunker, ). This technique proved effective for Walleye ( Sander vitreus ) , Northern Pike ( Esox lucius ) , White Sucker ( Catostomus commersonii ) , Yellow Perch ( Perca flavescens ) and Smallmouth Bass ( Micropterus dolomieu ) .…”

Interaction of sauger Sander canadensis and walleye Sander vitreus in a large, shallow northern river

“…River discharge was the only variable that explained the variation in S. canadensis and S. vitreus abundance. River discharge would affect the efficacy of the gear based on orientation of the fish or bending of the nets due to drag (Jones & Yunker, ).…”