Displacement of migratory Bull Trout (Salvelinus confluentus) spawning by a newly constructed beaver (Castor canadensis) dam in a west-central Alberta stream

Despite broad overlap of the ranges of Bull Trout (Salvelinus confluentus) and North American Beaver (Castor canadensis),relatively little is published in the peer-reviewed literature on their interaction. Beavers are ecosystem engineers with the potential to transform lotic environments, while Bull Trout are of conservation concern and subject to various protective measures throughout their range. The impact of beaver activity on trout populations is context dependent, and our appreciation of the scope of this impact depends on documentation. We report on the disruption of Bull Trout spawning migration by a newly constructed beaver dam in Fall Creek, a west-central Alberta stream in the North Saskatchewan River drainage system. Large Bull Trout have been documented travelling up to 74 km to spawn in Fall Creek. Since 2007, we have used autumn redd counts to monitor the abundance of spawning Bull Trout in the stream. In 2022, we documented displacement of Bull Trout spawning in Fall Creek by a newly constructed beaver dam. Over 60% of Bull Trout redds were observed in a reach downstream of the dam rarely used by spawning fish. We also observed seven post-spawn Bull Trout, representing over 10% of the spawning run, apparently stranded in a shallow impoundment upstream of the dam. It is unclear whether this displacement will have a long-term impact on the Fall Creek Bull Trout population. However, the seasonal impact on spawning adults is unprecedented in the 15 years we have monitored the population

Video-documentation of American Black Bear (Ursus americanus) foraging on algae in livestock tanks on a conservation property in western Montana, USA: Algae foraging by black bears

Algae is an important food for many wildlife species. For ursids, marine algae is documented in Polar Bear (Ursus maritimus) diets, but freshwater algae has not been reported in American Black Bear (Ursus americanus) diets. We installed remote cameras at livestock tanks, in which freshwater algal blooms grew, to document Black Bear foraging behaviour. We video-documented algae foraging by four unique bears of both sexes and of different age classes. Algae foraging by two cubs and one adult female likely represented exploratory sampling because these three bears minimally foraged and did not subsequently return to the livestock tanks to forage on algae again. One adult male foraged on algae during three separate occasions, indicating his algae foraging was non-exploratory. We discuss possible hypotheses to explain freshwater algae consumption by Black Bear, including nutritional benefit, physiological relief, and parasite expulsion. Our study is the first to report algae foraging by American Black Bear, and our findings suggest that the benefits of Cladophora species for wild animals may be greater than is currently understood

The occurrence of introduced rosy red minnows (Pimephales promelas) in Alberta, Canada

Rosy red minnows are a golden morph of Fathead Minnow (Pimephales promelas) commonly sold in pet shops and used, in some jurisdictions, as baitfish. They have formed several naturalized populations in British Columbia, where they are considered a priority conservation concern. The Government of Alberta had noted two occurrences of rosy red minnows in 2016 and 2017, but their identification could not be independently confirmed without photographic or physical vouchers. Based on our own collections, Royal Alberta Museum specimens, community science initiatives, and enquiries to other field researchers, we report that rosy red minnows have been present in Alberta earlier than previously thought, are likely breeding in Alberta, and have a widespread distribution from Fort McMurray to Lethbridge. Given that Alberta has native populations of wild-type Fathead Minnow, the impacts of rosy red minnows on native populations requires immediate attention

First known observations of migratory Army Cutworm Moth (Euxoa auxiliaris) in the southern Canadian Rocky Mountains

Army Cutworm Moth (Euxoa auxiliaris) migrates long distances to mountain talus slopes where they aggregate in prodigious numbers over summer. Composed of ~70% lipid and ~25% protein at the height of summer, the moths attract Grizzly Bear (Ursus arctos horribilis) to talus slopes in certain mountain ranges in the contiguous United States to forage at aggregations. We present the first known observations of migratory Army Cutworm Moths aggregating on talus slopes in the southern Canadian Rocky Mountains of British Columbia and Alberta. Because this is a potential food resource for the bears, managers may wish to evaluate suitable moth habitat

Diet of cisco (Coregonus spp.) in Algonquin Park region lakes: variation among forms

Efforts to conserve cisco (Coregonus spp.) diversity in Canadian lakes have been impeded by the unresolved taxonomy of North American ciscoes. When a strictly taxonomic-based approach is not possible, conservation units of infraspecific diversity can be identified using biological, morphological, ecological, and genetic evidence. Distinct cisco forms have been reported from deep oligotrophic lakes within boundaries of the historical outflow of glacial Lake Algonquin. In this study, we described the diet of three cisco forms netted from eight lakes located in or adjacent to Algonquin Provincial Park, Ontario. Opossum Shrimp (Mysis diluviana) was the dominant prey of benthic, low gill raker count forms in Trout and White Partridge Lakes, and of a large-bodied, high gill raker count form in Hogan Lake. Zooplankton was the most important prey item of small-bodied, pelagic forms in White Partridge Lake, and Cisco (Coregonus artedi) collected from five other Algonquin Park lakes. The diet of Trout Lake Cisco was a broader mix of prey items, including chironomid pupae, Opossum Shrimp, phantom midges (Chaboridae spp.), and zooplankton. Our study provides strong dietary evidence of the special ecological context occupied by cisco forms in White Partridge Lake, and moderate evidence for Trout Lake. Past reports of Shortjaw Cisco (Coregonus zenithicus) in six of the study lakes were not supported by our sampling, because low gill raker count forms were not captured