The Canadian Field-Naturalist (E-Journal)
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Diet of cisco (Coregonus spp.) in Algonquin Park region lakes: variation among forms
Full text linkEfforts 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
First records of the ant genus Dolichoderus (Hymenoptera: Formicidae) from Saskatchewan, Canada
Full text linkWe report the first provincial records of the genus Dolichoderus in Saskatchewan, represented by two species: Taschenberg’s Long-necked Ant (Dolichoderus taschenbergi) and Mary’s Long-necked Ant (Dolichoderus mariae). These species are previously known from eastern Canada and the eastern United States. The new discoveries fill in the range for D. taschenbergi, which has previously been found in Alberta and Manitoba, but has not been reported from Saskatchewan, and they represent a significant westerly range expansion of D. mariae, which has previously been reported in southeastern Manitoba and Ontario.
A review of beaked whale (Ziphiidae) stranding incidents from the inshore waters of eastern Canada
Full text linkCetaceans of the family Ziphiidae (beaked whales) include some of the least known whale species. We review 78 ziphiid stranding incidents from the inshore waters of eastern Canada (defined as the Atlantic provinces north to central Labrador, including the Gulf coast of Quebec, from ~latitude 43.5°N to 55.0°W), with outcomes that involve 84 individual whales. This includes all eastern Canadian ziphiid stranding incidents known to us from the first report of 24 February 1934 to 31 December 2021 for the five species documented from eastern Canada: Northern Bottlenose Whale (Hyperoodon ampullatus), Sowerby’s Beaked Whale (Mesoplodon bidens), Blainville’s Beaked Whale (Mesoplodon densirostris), True’s Beaked Whale (Mesoplodon mirus), and Cuvier’s Beaked Whale (Ziphius cavirostris). Northern Bottlenose Whale (41.0% of incidents, 40.4% of individuals) and Sowerby’s Beaked Whale (46.1% of incidents, 46.4% of individuals) have stranded most frequently, with the remaining three species stranding very rarely in the region. An average of 0.55 individual ziphiids/year were reported stranded from 1934 to 1999 in eastern Canada, but since 2000 this has increased to an average of 2.2 stranded individuals/year. Much of this increase is undoubtedly due to improved reporting, but other factors may also be involved. We emphasize the importance of the ongoing documentation of cetacean stranding incidents, but especially the need to better understand causes of ziphiid mortality, particularly for those species that reach the edge of their range in the western North Atlantic or are of conservation concern
"Sex in City Plants, Animals, Fungi, and More: a Guide to Reproductive Diversity" by Kenneth D. Frank, foreword by Jonathan Silvertown, 2022 [book review]
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"Turtles of North America: an Illustrated Field Guide to the Turtles of the Continental United States and Canada" by Kyle Horner, 2024 [book review]
No full textDeclining population of Harlequin Duck (Histrionicus histrionicus) on the Bow River, Alberta, Canada: 25 years of monitoring: 25 years of monitoring
No full textHarlequin Duck (Histrionicus histrionicus) is a small sea duck that winters in coastal waters and breeds on fast-movingmountain streams in western North America. Because of its dependency on streams and coastal near-shore habitat with healthy macroinvertebrate populations, population trends of this species can be used as an indication of healthy freshwater and marine ecosystems. From 1995 to 2020 we conducted roadside surveys for Harlequin Ducks on the Bow River in Banff National Park, Alberta. We calculated the population’s trend by modelling maximum annual count, which showed a population decline over the 25 years of 3.3% per year. The trajectory varied over time: a relatively stable population from 1995 to 2005, a steep decline until 2011, then stabilising at a much lower level with a slight rebound in recent years. The predicted number of ducks from our state-space model closely tracked the maximum number of ducks observed in annual counts. During stable or slightly increasing population estimates the male:female (M:F) ratio fluctuated considerably but stayed high (1.4:1 and 1.3:1, respectively), and during the period of steep population decline the M:F ratio was at its lowest (1.1:1). This declining population trend is concerning because it is occurring in a protected area, but it is similar to data from other studies in the Rocky Mountains and at the coastal wintering area, suggesting that causes may not be solely due to issues on the breeding streams