Long-Term Assessment of Habitat and Trout Population Responses to Habitat Improvement in a Small, Southwest Michigan Stream

摘要

Stream habitat improvement is a common technique used by fisheries managers desiring to increase production and angler catch rates of important sport fishes. However, high costs of assessment combined with a lack of rigorous scientific evaluation (e.g., long-term data, pre-treatment information, and control sites) and thorough statistical analyses have led to much criticism of this practice in recent years. To address this issue, we measured the physical habitat and trout population in Silver Creek, Michigan before and after the addition of instream structure and control of bank erosion. Channel width decreased in the treated zone and additional coarse substrate was exposed after habitat improvement. These beneficial changes to channel morphology have persisted for more than a decade after project completion and did not cause adverse changes such as increased bank erosion in untreated portions of the stream. Total brown trout Salmo trutta biomass in a treatment zone (TZ) where instream structures were added significantly increased over time in comparison to a reference zone (RZ) without habitat improvement. Increases were driven by an increase in the number of fish in the 812 in size group.