Hooking mortality was determined for 96 lake trout Salvelinus namaycush caught through the ice by jigging and by set‐lining with large dead baits on Gunflint Lake, Cook County, Minnesota, in January 1991. The estimated mortality rate for all released lake trout was 24%; estimated mortality rates for lake trout caught by set‐lining and jigging were 32 and 9%, respectively. Hooking location strongly influenced lake trout mortality. Mortalities of lake trout hooked in the gills or gut, inside the mouth, or in the lip were 36, 29, and 0%, respectively. Seventy percent of the lake trout caught by set‐lining were hooked in the gills or gut, compared with 9% of the lake trout caught by jigging. The lack of mortality for lip‐hooked lake trout suggested that capturing fish from deep water (25–50 ft), handling in cold temperatures (–20 to 20°F), fin‐clipping, and cribbing had little effect on mortality during the study. High hooking mortality rates for lake trout taken by set‐lining suggested that the use of this fishing method should be restricted when management strategies require the release of winter‐caught lake trout.
Tag recoveries of angler-caught smallmouth bass Micropterus dolomieu were monitored in a 1.9-mi special regulation area of the Zumbro River where anglers were required to release fish greater than 9 in and in two areas where mandatory release was not required. For all areas combined, an average of 16% of the fish that were caught at least one time and released were recaught by anglers during the 2 years the fishery was studied. Estimates of numbers of fish recaught were affected by high tag loss (46%) and unknown angler nonresponse rates. Previously released smallmouth bass contributed to angler catch in all areas, including an area downstream of the primary survey site; however, the majority of the fish that were recaught were released by anglers in the special regulation area. Catch rates in the special regulation area averaged 1.1 fish/h and were greater than in standard regulation areas: however, they were influenced by numbers of smallmouth bass and angler skill and effort. Most fish within the 1.9-mi reach were protected from harvest, and 60% of the fish tagged in the special regulation area were caught by anglers in the same area. Stream lengths of less than 2 mi may adequately function as special regulation areas for smallmouth bass where fishing pressure is concentrated during the summer; however, movement of fish into areas with legal harvest may reduce the numbers of fish that are recaught.Length limits are often used to manage fisheries for smallmouth bass Micropterus dolomieu (Jones
Abstract:Leafy spurge (Euphorbia esula L.), a noxious weed infests some of the 1.2 million hectares of Conservation Reserve Program (CRP) land in North Dakota. Once established a leafy spurge monoculture will reduce expected CRP benefits and impact returns to some post-CRP land uses. The study estimated statewide direct economic impacts of about $351,000 on post-CRP land maintained in vegetative cover, $1.118 million on post-CRP grazing land, and negligible (assumed $0) on post-CRP cropland, for a total of $1.469 million. Total annual direct and secondary economic impacts to North Dakota's economy were estimated to be $4.665 million, which would support about 57 jobs.
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