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Life-history variation among four lake trout Salvelinus namaycush morphs was quantified at six geographically distant locations in Lake Superior (∼30 to 250 km apart), one of the largest freshwater lakes in the world (82,100 km2). Lake trout were sampled using standardized multi-mesh gillnets in three depth strata at six locations in Lake Superior that were known or thought to have multiple morphs. Life-history traits were estimated using length-age analysis of back-calculated growth from sagittal otolith increments. Morphs, assigned using statistical and visual assignment rules, included 122 humpers, 646 leans, 86 redfins, and 1154 siscowets. Density (CPUE) varied 11-fold among morphs, 7-fold among locations, and 3-fold among depths. Morphs seemed to fill the same ecological niche at all locations, because life-history traits related to weight (body condition, buoyancy, mean weight), age, and growth rate varied more among morphs than locations. However, abiotic and biotic variation among locations also seemed to exert control over life-history variation, because life-history traits related to length, maturity, and early life history varied more among locations than morphs. We conclude that lake trout morphs appeared to have a genetic component to their life history that was differentially expressed along environmental gradients. [ABSTRACT FROM AUTHOR]

The North American Great Lakes have been experiencing dramatic change during the past half-century, highlighting the need for holistic, ecosystem-based approaches to management. To assess interest in ecosystem-based management (EBM), including the value of a comprehensive public database that could serve as a repository for the numerous physical, chemical, and biological monitoring Great Lakes datasets that exist, a two-day workshop was organized, which was attended by 40+ Great Lakes researchers, managers, and stakeholders. While we learned during the workshop that EBM is not an explicit mission of many of the participating research, monitoring, and management agencies, most have been conducting research or monitoring activities that can support EBM. These contributions have ranged from single-resource (-sector) management to considering the ecosystem holistically in a decision-making framework. Workshop participants also identified impediments to implementing EBM, including: 1) high anticipated costs; 2) a lack of EBM success stories to garner agency buy-in; and 3) difficulty in establishing common objectives among groups with different mandates (e.g., water quality vs. fisheries production). We discussed as a group solutions to overcome these impediments, including construction of a comprehensive, research-ready database, a prototype of which was presented at the workshop. We collectively felt that such a database would offer a cost-effective means to support EBM approaches by facilitating research that could help identify useful ecosystem indicators and management targets and allow for management strategy evaluations that account for risk and uncertainty when contemplating future decision-making. [ABSTRACT FROM AUTHOR]