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Historically, less than 2% of steelheadOncorhynchus mykissstocked in river mouths on Minnesota tributaries to Lake Superior returned as adults. To investigate the influence of stocking location on adult return rates, similar proportions of age-1 steelhead were stocked in the mouth and throughout upstream reaches of the Knife River. A subset of steelhead stocked upstream were implanted with coded wire tags (CWT), which resulted in 18% of all fish stocked, regardless of location, possessing a CWT. A fish trap near the mouth of the river was used to sample emigrating age-0 through age-3 juveniles and returning adults. Of the steelhead stocked upstream 45% survived to emigrate. Electrofishing surveys and trap results indicated no steelhead remained in the river past age 2. No evidence was found that larger age-1 stocked steelhead displaced smaller age-1 wild steelhead. Only 12% of returning adults possessed CWTs, 6% less than the percentage stocked with CWTs (18%). Adult return rates for those stocked in the river mouth were 1.0% compared with 0.5% for those stocked upstream. Overall, stocking in the river mouth contributed 69% of the returning adults. Given these results, Minnesota fishery managers should continue to look for alternate ways to increase steelhead return rates if greater adult numbers are desired. Received February 12, 2013; accepted July 3, 2013 [ABSTRACT FROM PUBLISHER]

Populations of cisco Coregonus artedi in the Laurentian Great Lakes supported large-scale commercial fisheries and were the primary forage of piscivores during the first half of the 20th century. However, by 1970 populations had collapsed in all of the lakes. Since then, ciscoes have staged a recovery in Lake Superior. In this synthesis, we describe the status of ciscoes in Lake Superior during 1970-2006 and provide a comprehensive review of their ecology. Better understanding of age estimation techniques, application of hydroacoustic and midwater trawl sampling, and compilation of long-term data sets have advanced our understanding of the species. Management agencies contemplating rehabilitation of cisco populations should recognize that (1) knowledge of cisco ecology and population dynamics is increasing; (2) ciscoes are long-lived; (3) Great Lakes populations are probably composed of both shallow-water and deepwater spawning forms; (4) large year-classes can be produced from small adult stocks; (5) large variation in year-class strength is probably intrinsic to Great Lakes populations; (6) despite the longevity and early maturity of ciscoes, stocks can be overfished because large year-classes are produced infrequently; (7) regional environmental factors appear to play a large role in reproductive success; and (8) rainbow smelt Osmerus mordax are likely to have a negative effect on cisco recruitment under certain conditions. A top-down approach for rehabilitating lake trout Salvelinus namaycush in Lake Superior probably benefited cisco recovery through lake trout predation on invasive rainbow smelt populations. We argue that managing for populations of exotic alewives Alosa pseudoharengus to support popular recreational fisheries of exotic Pacific salmonids in the other Great Lakes conflicts with stocking efforts to rehabilitate native lake trout in those lakes. If native fish rehabilitation is a serious and primary goal for management agencies in the Great Lakes basin, we propose that an ecosystem-based approach to modifying the environment for the benefit of native fish species (i.e., decimation or eradication of invasive species) is required. [ABSTRACT FROM AUTHOR]

Lake Superior's fish community continues to change as a result of the recovery of populations of lake trout Salvelinus namaycush, the naturalization of introduced salmonids Oncorhynchus spp. and Salmo spp., declines in the populations of rainbow smelt Osmerus mordax, and the fluctuating recruitment of cisco Coregonus artedi. This study used bioenergetics modeling of the dominant predator fish in the western arm of Lake Superior in 2004 to provide a comprehensive picture of the relationship between predator demand and prey fish availability. The results, presented for nearshore and offshore areas and three geographically distinct ecoregions, indicate that the western arm is at or near its carrying capacity for predators. Estimated predator demand was about one-half the annual biomass plus production of coregonines but exceeded the biomass plus production of rainbow smelt, possibly because of underestimates of this species in shallow areas and recent shifts in predator diets. Lean lake trout were responsible for most Of the consumption of these prey fish, while the deepwater siscowet form ranked second. The commercial harvest of prey fish biomass was trivial compared with the consumption by predator fish. Chinook salmon Oncorhynchus tshawytscha, along with other nearshore potamodromous species, played minor roles in total consumption. Chinook salmon are an indicator of forage status, as they have responded to declines in the rainbow smelt biomass with a dramatic diet shift to ciscoes and a decline in weight at age since the early 1990s. Slightly reduced lean lake trout growth and density-dependent survival in some areas also indicate that competition for prey is intense. Because most of the predators in the western arm are wild fish, stocked predators no longer have a great impact on prey populations. Bioenergetics modeling of predator demand combined with hydroacoustic estimates of prey supply can be valuable for managing the fisheries of large lakes, allocating resources to various interest groups, and increasing basic understanding of lake production and community dynamics. [ABSTRACT FROM AUTHOR]

Rehabilitation of Lake Superior's coaster brook trout Salvelinus fontinalis hinges not only on resolving critical ecological challenges but also on addressing key human dimensions challenges. This article addresses the key issues of values, agency coordination, stakeholder engagement, and public awareness and outreach and makes relevant recommendations. First, agencies should continue to improve coordination by expanding the scope and membership of the Lake Superior Brook Trout Committee and other forums. The size of the basin and the large number of partners involved requires consistent communication and transparent coordination mechanisms. Second, the range of values currently associated with brook trout and their rehabilitation must be expanded beyond the current focus on fishery interests by incorporating a more diverse array of groups and interests. Third, the number of groups engaged in native brook trout restoration efforts should be enlarged by reaching out to new groups, particularly watershed organizations, local governments, and environmental groups, as the comprehensive nature of the restoration efforts will require the cooperation and support of a broader array of groups. Finally, the level of general public awareness and support for the activities necessary to rehabilitate coasters needs to be increased. An outreach program should engage all stakeholders early in the planning process and provide science-based information to establish reasonable expectations. Fishery managers and their partners should look for opportunities to bring positive attention to ongoing rehabilitation and habitat management activities. [ABSTRACT FROM AUTHOR]

Coaster brook trout are a migratory form of brook trout Salvelinus fontinalis that spend part of their lives in the Great Lakes. Over the last century the abundance of coaster brook trout in Lake Superior has declined dramatically, and only remnant stocks remain. Recently, the rehabilitation of coaster brook trout in Lake Superior has become a goal of fish management agencies. The specific goal agreed upon by all of the agencies involved is to maintain widely distributed, self-sustaining populations in as many of the historical habitats as practical. We discuss realistic expectations for rehabilitation and emphasize the need for management agencies, academia, and angling organizations to work cooperatively. We first present a brief history of coaster brook trout in Lake Superior, then discuss habitat requirements and protection, the regulations required for rehabilitation, stocking, species interactions, and the role that human dimensions play in rehabilitation. The management issues that must be addressed are implementation of a basinwide survey to identify remnant stocks and critical habitat, restrictive harvest regulations, watershed rehabilitation, critical biological review, and the formulation of expectations before experimental stocking programs are initiated, along with coordinated, basinwide information sharing and cooperative management among agencies similar to that undertaken during the rehabilitation of lake trout Salvelinus namaycush in Lake Superior. Future research needs include basic coaster biology and life history, habitat use in streams and the lake, interaction with other species in the Lake Superior fish community, and interaction between stream-resident and coaster brook trout. Successful rehabilitation will require a shift from a harvest fishery to one with minimal or no harvest of coaster brook trout in the Lake Superior basin. Coaster brook trout rehabilitation will take time and will proceed at different rates at different locations, depending on the presence of remnant stocks, quality of habitat, angling pressure, and political will. [ABSTRACT FROM AUTHOR]

Stocks of lake trout Salvelinus namaycush in Lake Superior are recovering from historical collapse. Stocking, control of sea lampreys Petromyzon marinus, and harvest restrictions have aided lake trout recovery, but the contribution of stocked lake trout to contemporary recruitment has not been quantified in western Lake Superior. Using variants of the Ricker stock-recruit model, we evaluated the production of age-7 lake trout (recruits) by examining age-8 and older wild and stocked parental lake trout (spawners). We found that density of wild lake trout spawners and recruits increased during 1980-2003, whereas the density of stocked spawners decreased in all management areas. Two competing models best described recruit density of the 1988-2003 year-classes: (1) wild and stocked parents each contributed to recruitment but stocked parents contributed negatively and (2) only wild parents contributed to recruitment. Recruitment rates declined significantly with increasing spawner density in four of five management areas, which suggests that recruitment is density dependent in much of western Lake Superior. We conclude that stocked lake trout did not contribute significantly to lake trout rehabilitation in western Lake Superior during 1980-1995. [ABSTRACT FROM AUTHOR]

Survival of the 1963-1982 year-classes of stocked yearling lake trout Salvelinus namaycush declined significantly over time in Lake Superior. To investigate possible causes of this decline, a Ricker model of stock-recruitment was used to describe the catch per effort (CPE) of age-7 stocked lake trout in the Michigan, Minnesota, and Wisconsin waters of Lake Superior as functions of the numbers of yearlings stocked 6 years earlier (an index of density dependence), the density (CPE) of wild adult lake trout (an index of predation), and large-mesh (≥114-mm stretch-measure) gill-net fishing effort (an index of fishing mortality). Declining CPE of stocked lake trout in Michigan and Wisconsin was significantly associated with increasing large-mesh gill-net fishing effort. Declining CPE of stocked lake trout in Minnesota was significantly associated with increasing density of wild lake trout. Declining survival of stocked lake trout may therefore have been caused by increased mortality in large-mesh gill-net fisheries in Michigan and Wisconsin, and by predation by wild lake trout that recently recolonized the Minnesota area. We recommend that experimental management be pursued to determine the relative importance of large-mesh gill-net fishing effort and of predation by wild lake trout on the survival of stocked lake trout in U.S. waters of Lake Superior. [ABSTRACT FROM AUTHOR]

An introduction to papers published within the issue is presented, including the genetic issues relates to coaster brook trout rehabilitation and another on the combination of techniques used to document important aspects of coaster brook trout behavior.