Brown bear (Ursus arctos) foraging in a mosaic of spatially discrete and variable habitats over 25 years of shifting Pacific salmon densities
Canadian Journal of Zoology, Ahead of Print. Many foraging models assume “perfect information” and “free movement” when describing predator foraging behavior, although this is rare in nature. Here, we quantified predation by brown bears (Ursus arctos Linnaeus, 1758) on adult sockeye salmon (Oncorhynchus nerka (Walbaum, 1792)) in a series of spatially proximate po nds that largely satisfied both assumptions. Salmon abundance varied among years, but pond area and depth were fixed, allowing us to examine interactions between prey abundance and habitat features. We applied versions of two models to 25 years of data o...
Source: Canadian Journal of Zoology - November 6, 2023 Category: Zoology Authors: Katherine N. McElroy Ray Hilborn Curry Cunningham Thomas P. Quinn Source Type: research
Combining two user-friendly machine learning tools increases species detection from acoustic recordings
Canadian Journal of Zoology, Ahead of Print. Passive acoustic monitoring usually generates large datasets that require machine learning algorithms to scan sound files, although the complexity of developing machine learning algorithms can be a barrier. We assessed the ability and speed of two user-friendly machine learning tools, Kaleidoscope Pro and BirdNET, for detecting the American toad (Anaxyrus americanus (Holbrook, 1836)) in sound recordings. We developed a two-step approach, combining both tools to maximize species detection while minimizing the time needed for output verification. When considered separately, Kaleid...
Source: Canadian Journal of Zoology - November 6, 2023 Category: Zoology Authors: Cristian P érez-Granados Mariano J. Feldman Marc J. Mazerolle Source Type: research
Size at first maturity on the mussel Mytilus platensis d'Orbigny, 1842 at the Southwest Atlantic
Canadian Journal of Zoology, Ahead of Print. The size at first maturity of the bivalve Mytilus platensis d'Orbigny, 1842 was estimated in the intertidal population of Villa Gesell (37 °15′S; 56°57′W), Buenos Aires, Argentina. We hypothesize a variation in population maturity associated with shell length (SL) and differences between females and males. Individuals were analyzed histologically, sexed (females and males), and classified as mature and immature. We carried out a kernel density estimation to allow us to visualize the distribution of the classifications based on the SL and used a generalized linear model to ...
Source: Canadian Journal of Zoology - November 3, 2023 Category: Zoology Authors: M.C. Yuvero M.E. Torroglosa B.J. Lomovasky J. Gim énez Source Type: research
Population growth rates of pronghorn: influence of temporally and spatially explicit conditions, density dependence, and scale
We examined density-dependent and density-independent factors on growth rates of pronghorn (Antilocapra americana (Ord, 1815)) using a retrospective analysis of population survey data. Across Idaho, we found that as the proportion of the subpopulation harvested the previous year increased, growth rates increased. Similarly, as fawn recruitment increased, growth rates increased. We also found when the growth rate in the previous year increased, the growth rate the subsequent year decreased. When subpopulations were examined independently, we found that in a low-elevation desert subpopulation, growth rates were influenced by...
Source: Canadian Journal of Zoology - November 3, 2023 Category: Zoology Authors: Eric M. Gese Cole A. Bleke Shane B. Roberts Paul Atwood Patricia A. Terletzky Source Type: research
Oocyte development, packing in the ovary, and spawning pattern of squid Lolliguncula panamensis in the Mexican South Pacific
This study examines the mode of oocyte development, packing in the ovary, and spawning pattern of this understudied species. Lolliguncula panamensis presents a synchronous oocyte growth in batches, with multiple spawnings, with the presence of post-ovulatory follicles and atretic follicles, including the constant presence of pre-vitellogenic and vitellogenic oocytes. The size frequencies of oocytes of ripe ovaries exhibit a pronounced morphological and size separation between the late yolk stage and mature oocytes, suggesting that the oocytes pass through this size range very fast. These oocytes adopt a geometrical shape t...
Source: Canadian Journal of Zoology - October 31, 2023 Category: Zoology Authors: Hugo Guzm án Intzin Mar ía del Carmen Alejo Plata Miguel Ángel del Río Portilla Sa úl Serrano Guzmán Pedro Cervantes Hern ández Source Type: research
Overwintering site fidelity and communal hibernation predispose Northern Map Turtles to mass mortality events
We report on a mass mortality event in a population of Northern Map Turtles (Graptemys geographica (LeSueur, 1817)). At a communal overwintering site, 142 carcasses (ca. 10% of population) were recovered, seemingly depredated by river otters (Lontra canadensis (Schreber, 1777)). We compared the size and sex of the carcasses to those of turtles that survived. Smaller turtles and males were more likely to be depredated than larger turtles and females. Using captures made at the same overwintering site between 2003 and 2022, we assessed the vulnerability of this population to mass mortality events during winter. Nearly 60% of...
Source: Canadian Journal of Zoology - October 27, 2023 Category: Zoology Authors: Gr égory Bulté Jessica A. Robichaud Erika J. Shadlock Steven J. Cooke Gabriel Blouin-Demers Source Type: research
Effect of feeding history on metabolic rate of largemouth bass (Micropterus nigricans): implications for bioenergetics models
In this study, we tested the hypothesis that metabolic rate varies with growth history of age-1 largemouth bass Micropterus nigricans Cuvier, 1828. Two groups of fish were fed alternating maintenance or ad libitum rations of fathead minnow Pimephales promelas Rafinesque, 1820, so that over a 9-week period, initial and ending size of fish was similar. After 9 weeks, oxygen consumption was measured using static, closed respirometry. Although final body weight was similar between the two groups (means, 104–108 g), specific oxygen consumption for fish fed maintenance rations (0.094 mg O2 g−2 h−1) was 38% les...
Source: Canadian Journal of Zoology - October 27, 2023 Category: Zoology Authors: Steven H. Ranney Steven R. Chipps David H. Wahl Source Type: research
How do latitude and urban heat islands affect larval melanization in monarch butterflies (Danaus plexippus) ?
Canadian Journal of Zoology, Ahead of Print. As temperatures warm in response to anthropogenic changes (climate change and urbanization), animals must respond adaptively to these changes or be displaced. Here, we use community science data (iNaturalist and BugGuide) to show that melanization in larval monarch butterflies (Danaus plexippus (Linnaeus, 1758), an endangered species in Canada) is correlated with latitude and temperature across a latitudinal gradient, indicating likely use in thermoregulation. We also predicted that melanization would decrease in cities where temperatures are consistently higher than rural areas...
Source: Canadian Journal of Zoology - October 25, 2023 Category: Zoology Authors: Rohab Batool Juriyah Jenan Madeline Schuster Rosalind L. Murray Source Type: research
Density estimates of unmarked mammals: comparing two models and assumptions across multiple species and years
Canadian Journal of Zoology, Ahead of Print. Density estimation is a key goal in ecology, but accurate estimates for unmarked animals remain elusive. Camera trap data can bridge this gap, but accuracy, precision, and concordance varies among estimators. We compared estimates from unmarked spatial capture –recapture (spatial count (SC)) models, and time in front of camera (TIFC) models, for four large mammal species in boreal Canada. Species differed in movement rates, behaviours, and sociality—traits related to model assumptions. TIFC densities typically exceeded SC model estimates for all speci es. Two- to five-fold d...
Source: Canadian Journal of Zoology - October 19, 2023 Category: Zoology Authors: J.T. Fisher M. Dickie J.M. Burgar A.C. Burton R. Serrouya Source Type: research
Moult migrant Tennessee Warblers undergo extensive stopover in peri-urban forests of southern Quebec
This study illustrates the importance of including stopover sites in conservation plans, particularly in cities where quality habitats are scarce. (Source: Canadian Journal of Zoology)
Source: Canadian Journal of Zoology - October 19, 2023 Category: Zoology Authors: Vanessa Poirier Barbara Frei Mathilde Lefvert Ana Morales Kyle H. Elliott Source Type: research
Are juveniles full-scale replicas of adults? Evaluation of anuran special locomotion and digging adaptations during and after metamorphosis
We examined specimens from four different species of Leptodactylidae and six species of Hylidae. For the digging behavior, we evaluated the progress of calcification in the anterior region of the skulls, as well as the development of the snout-ridge. To assess climbing ability, we examined the ossification rate, the variation in the shape of the phalanx, the progress of the offset angle, and the distance between the terminal phalanx and the penultimate phalange of finger IV. The ossification of the skull and phalanges, along with the development of the snout-ridge, progresses and reaches completion during the juvenile phas...
Source: Canadian Journal of Zoology - October 5, 2023 Category: Zoology Authors: Lu ísa de Paula Reis Jessica Fratani Mar ía Laura Ponssa Source Type: research
Distribution and characterization of nematodes in above-ground microhabitats in a natural pristine cedar forest in Yakushima Island, Japan
This study aimed to characterize the community and trophic compositions of nematodes in relation to different microhabitats in old-growth Japanese cedar (Cryptomeria japonica (L. f.) D. Don) forests in Yakushima Island, Japan. To this aim, nematodes retrieved from four different types of microhabitats were morphologically identified at the family/genus level and divided into five trophic groups. A nonmetric multidimensional scaling scatterplot showed that nematode communities clustered significantly in each microhabitat and their community compositions were significantly affected by C/N ratio. With respect to nematode trop...
Source: Canadian Journal of Zoology - October 4, 2023 Category: Zoology Authors: Yudai Kitagami Yosuke Matsuda Source Type: research
Field observations of the movements of locally adapted Atlantic cod (Gadus morhua) living in zero and sub-zero centigrade temperatures for half the year
Canadian Journal of Zoology, Ahead of Print. Atlantic cod (Gadus morhua Linnaeus, 1758) can experience mortality at sub-zero (<0 °C) temperatures in ice-infested waters, and many populations migrate to deeper and warmer areas during winter. An exception is the resident population in Gilbert Bay, Labrador, which annually experiences 6 months of sub-zero temperatures. We used the VEMCO Positioning System to estimate fish loc ations to determine depth utilization and seasonal movements of tagged Gilbert Bay cod ranging in size from 43 to 75 cm. This is the first study to directly monitor the movements of adult Atlantic...
Source: Canadian Journal of Zoology - September 28, 2023 Category: Zoology Authors: John M. Green Dustin Schornagel Khanh Q. Nguyen Curtis Pennell Corey J. Morris Source Type: research
Comparing whole body and red muscle mitochondrial respiration in an active teleost fish, brook trout (Salvelinus fontinalis)
Canadian Journal of Zoology, Ahead of Print. Understanding how metabolic costs change in relation to increasing temperature under future climate changes is important to predict how ectotherms will be affected across the globe. In fish, whole body respiration is traditionally used to estimate aerobic performance via an organism ’s minimum and maximum oxygen consumption rates. However, mitochondria play a crucial role in the aerobic cascade and may be a useful surrogate of aerobic performance. To test whether whole body oxygen consumption and mitochondrial capacity are correlated, we estimated whole body metabolic and mit ...
Source: Canadian Journal of Zoology - September 27, 2023 Category: Zoology Authors: Travis C. Durhack M élanie Aminot Jason R. Treberg Eva C. Enders Source Type: research
Phenotypic plasticity in reproductive and somatic efforts of female Columbian ground squirrels
We examined a 27-year dataset of life-history traits on these long-living (8 –10 years), hibernating, montane-living mammals. Environmental variation was estimated from two important traits of mothers, their relative timing of breeding and spring maternal body mass (initial “capital” for use in subsequent reproduction). Results from 183 known-aged mothers and 508 litte rs revealed considerable variation in the relative timing of breeding, initial maternal mass, and reproductive and somatic efforts, as well as significant variation among ages and years. Results from 125 mothers that reproduced more than once (and 450 ...
Source: Canadian Journal of Zoology - September 27, 2023 Category: Zoology Authors: F. Stephen Dobson Claire Saraux Vincent A. Viblanc Source Type: research
