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The family Cryptacanthodidae comprises 4 species: 3 in the North Pacific Ocean and 1 in the western North Atlantic Ocean. Two species in particular, Cryptacanthodes aleutensis and C. giganteus, occur sympatrically in the eastern North Pacific from the Bering Sea to off the coast of northern California. Both species have neustonic larvae with elongate bodies and heavy pigmentation. Descriptions and illustrations of larvae for both species are provided. Meristic and pigmentation characters can be used to distinguish between the species, with C. giganteus having higher total vertebral and dorsal-fin spine counts and less overall pigmentation than C. aleutensis. Comparisons are also provided to distinguish both species from other elongate, heavily pigmented neustonic larvae that co-occur in the eastern North Pacific Ocean. In general, cryptacanthodids can be distinguished from other neustonic larvae because they have a higher total vertebral count, a long dorsal fin composed solely of spines, and an absence of pelvic fins.
Predator avoidance strategies are often viewed in the context of innate or learned, yet a true test of this hypothesis requires animals that are completely naïve to potential predators. We examined the predator avoidance behavior of juvenile Rough-skinned Newts (Taricha granulosa) that had been reared in captivity since being deposited as eggs and had never been exposed to predators or predator stimuli. In contrast to a previous study on adult newts, juveniles avoided a broader range of chemical stimuli from potential predators, including alarm cues from damaged conspecifics and stimuli from 2 Common Gartersnakes (Thamnophis sirtalis) that had recently consumed newts. These results suggest that predator avoidance in Taricha granulosa is innate. Unlike adult newts, the avoidance of a wider range of stimuli by juvenile newts is likely an effective strategy at reducing predation risk given their small size and lower tetrodotoxin concentrations (compared to adults), both of which render them vulnerable to predation by gartersnakes.
The Northern Idaho Ground Squirrel (NIDGS, Urocitellus brunneus brunneus) is threatened by habitat loss due to fire exclusion in west-central Idaho. Increases in Ponderosa Pine (Pinus ponderosa) density and extent have closed historically open meadows. Management practices for NIDGS recovery include thinning and burning to reduce tree encroachment. Baseline habitat data help create restoration goals and refine present management plans, but no pristine reference sites exist for the NIDGS, due to 100 y of land use and a lack of historical records. Therefore, we provided the first quantitative habitat descriptions of NIDGS habitat at 7 currently occupied sites that may be useful as an ecosystem of reference. We chose habitat attributes that are likely important to NIDGS, as well as attributes that are potentially altered by restoration treatments, which included overstory canopy cover, tree density, ground cover, litter depth, and soil texture. Habitat attributes were described with Bayesian 95% credibility intervals. Sites occupied by NIDGS had tree canopy cover of 10 to 15%, tree densities of 64 to 118 trees/ha, and understory height was 20 to 25 cm. Understory vegetation of occupied habitat consisted of 20 to 30 species, while across-site richness was 153 species. We also identified 15 understory species with the highest constancy and cover across the 7 sites. Litter depth was 0.7 to 0.9 cm, and the soil texture was clay loam. Our study provides valuable baseline information about NIDGS habitat. Managers may use our results to develop appropriate restoration targets when implementing habitat restoration. Information on occupied habitat may increase the efficacy of currently implemented restoration techniques and provide knowledge to be used in an adaptive management framework.
Growth, reproduction, and diet of the Yellow Irish Lord (Hemilepidotus jordani) were examined and compared between 2 adjacent geographical regions of Alaska, the eastern Bering Sea and Aleutian Islands, where its biology is not well understood. The Yellow Irish Lord is the most common member of the genus Hemilepidotus encountered during Alaska Fisheries Science Center bottom-trawl surveys of these regions. Based on our data, there was no significant difference in sizes of Yellow Irish Lords caught between regions. The von Bertalanffy growth models fitted to length-at-age data, however, indicate that male and female Yellow Irish Lords in the Aleutian Islands grew more slowly than those in the eastern Bering Sea. Histological assessment of ovary condition indicated that Yellow Irish Lords from both regions appear to spawn once annually during the summer. Relationships between size (length and weight) and fecundity between the 2 regions were significantly different, with Yellow Irish Lords from the Aleutian Islands being more fecund. Diet analysis showed that the Yellow Irish Lord is a benthic predator and their summer diets in both regions consist of a wide variety of prey, but appear to favor benthic crustaceans, particularly abundant crab species. However, the largest individuals appear to have more opportunities for piscivory in the Aleutian Islands. It appears that at least some variation in the life-history aspects of this species exists between these regions. This information may provide a scientific basis for developing management strategies of the Yellow Irish Lord in Alaskan waters.
Deer-vehicle collisions are on the rise in North America, requiring a better understanding of road use patterns by deer. We examined summer use of roadside areas by White-tailed Deer (Odocoileus virginianus) and Mule Deer (Odocoileus hemionus) in the central Rocky Mountains, Alberta. Deer surveys were conducted along the main highway at dawn and dusk for 6 summers. We observed more White-tailed Deer than Mule Deer along the highway during the study. White-tailed Deer were also involved in collisions with vehicles more often than Mule Deer, and may pose a higher risk for collisions because they tend to flee when approached. Time of day did not affect Mule Deer sightings during the study period, but White-tailed Deer were observed more frequently in the morning than evening. Both species were observed more frequently in May than other months. While little association was observed between deer species, large-scale spatial segregation along the highway did not occur. Our data suggest that drivers were likely to encounter deer in single-species pairs, and based on deer roadside use, we suggest that the potential for deer-vehicle collisions was highest in May, close to dawn, and along the northern sections of the highway. Deer-vehicle collision data indicated that the predominant locations of collisions reflected the spatial patterns of roadside usage by deer, but temporal patterns of collisions are also affected by visibility and traffic patterns. Collision-mitigation strategies incorporating deer behavior and driver-education are discussed.
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