Food habits of the river otter Lutra canadensis in the marine environment of British Columbia

Food habits of river otters (Lutra canadensis) inhabiting coastal British Columbia were studied by examining scat and stomach samples. Fish remains occurred in 99.4% of the scats while crustacean and bird remains were encountered in 7.2 and 4.2%, respectively. The majority of fish identified belong to six groups: Embiotocidae (occurring in 42.2% of the scats), Cottidae (40.5%), Pleuronectiformes (40.0%), Blennioidea (33.3%), Scorpaenidae (30.1%), and Hexagrammidae (13.1%). Of 69 stomachs collected by trappers, 86.9% contained remains of fish and 13% contained bird remains. Only two samples (2.9%) contained crustacean remains. Similar families of fish were found in both scat and stomach samples. Scat samples, collected on 10 consecutive visits to 55 sites from May 1977 through February 1978, indicated that, with the possible exception of bird remains, food types do not appear to vary seasonally. Otters in the marine environment utilize their habitat in the same manner that freshwater otters do; they are opportunistic feeders and rely primarily on midsize, slower moving fish that occur in the intertidal and subtidal regions close to shore.

Download Full-text

River otter hair structure facilitates interlocking to impede penetration of water and allow trapping of air

Canadian Journal of Zoology ◽

10.1139/z05-047 ◽

2005 ◽

Vol 83 (5) ◽

pp. 649-655 ◽

Cited By ~ 14

Author(s):

John W Weisel ◽

Chandrasekaran Nagaswami ◽

Rolf O Peterson

Keyword(s):

Light Microscopy ◽

Thick Layer ◽

Air Bubbles ◽

River Otter ◽

Adjacent Level ◽

River Otters ◽

Lutra Canadensis ◽

Microscopy Images ◽

Scanning Electron ◽

Size And Structure

Unlike many other mammals spending a considerable amount of time in water, river otters (Lutra canadensis (Schreber, 1777)) do not have a thick layer of body fat. Instead, they have a very densely packed layer of thin underhairs. The structure of river otter hair was examined by scanning electron microscopy and polarizing light microscopy. Guard hairs were hollow and became thicker distally and then tapered to a point and had different cuticle scales in proximal and distal regions. The cuticle of the thin underhairs had a striking pattern of sharply sculpted fins with deep grooves between them; usually there were four fins at each level, rotated 45° with respect to those at an adjacent level. Underhairs varied in diameter and the scales were sometimes petal-shaped. Polarizing light microscopy images showed interlocking arrangements of the underhairs that help to impede the penetration of water. Also, these images showed that the grooves between fins or petals of underhairs entrap air bubbles. The structure of the hairs allows them to interact loosely with each other, despite variations in size and structure. Furthermore, the nature of the interactions between the fins and depressions allows space between the hairs that can trap air bubbles to increase the thermal insulation of the otter's coat.

Download Full-text

Intraocular muscles of the Canadian river otter and Canadian beaver and their optical function

Canadian Journal of Zoology ◽

10.1139/z89-068 ◽

1989 ◽

Vol 67 (2) ◽

pp. 469-474 ◽

Cited By ~ 6

Author(s):

K. A. Ballard ◽

J. G. Sivak ◽

H. C. Howland

Keyword(s):

Ciliary Body ◽

Castor Canadensis ◽

Optical Function ◽

River Otter ◽

Microscopic Anatomy ◽

River Otters ◽

Refractive Power ◽

Lutra Canadensis ◽

Corneal Refractive Power

The gross morphology and microscopic anatomy of the ciliary and iris musculature of the Canadian river otter (Lutra canadensis) and Canadian beaver (Castor canadensis) were studied to help evaluate whether either species has an exaggerated accommodative mechanism for use underwater. The intraocular muscles of the otter are of a size and organization indicative of an extreme lens-deforming accommodative ability involving both the ciliary body and iris. By contrast, the intraocular muscles of the beaver eye indicate that accommodation is not significant in this animal. Thus, the intraocular musculature of the class Mammalia is not homogeneous, even within the amphibious mammals. Refractive and corneal measurements on two living river otters confirm that this animal is capable of an accommodative range that can neutralize the loss of corneal refractive power when the eye is in water.

Download Full-text

Influence of the time and rate of liquid-manure application on yield and nitrogen utilization of silage corn in south coastal British Columbia

Canadian Journal of Soil Science ◽

10.4141/cjss96-022 ◽

1996 ◽

Vol 76 (2) ◽

pp. 153-164 ◽

Cited By ~ 48

Author(s):

B. J. Zebarth ◽

J. W. Paul ◽

O. Schmidt ◽

R. McDougall

Keyword(s):

British Columbia ◽

Dairy Manure ◽

Inorganic Fertilizer ◽

N Recovery ◽

Corn Yield ◽

Residual Soil ◽

Soil Nitrate ◽

Liquid Manure ◽

Manure Application ◽

Coastal British Columbia

Manure-N availability must be known in order to design application practices that maximize the nutrient value of the manure while minimizing adverse environmental impacts. This study determined the effect of time and rate of liquid manure application on silage corn yield and N utilization, and residual soil nitrate at harvest, in south coastal British Columbia. Liquid dairy or liquid hog manure was applied at target rates of 0, 175, 350 or 525 kg N ha−1, with or without addition of 100 kg N ha−1 as inorganic fertilizer, at two sites in each of 2 yr. Time of liquid-dairy-manure application was also tested at two sites in each of 2 yr with N-application treatments of: 600 kg N ha−1 as manure applied in spring; 600 kg N ha−1 as manure applied in fall; 300 kg N ha−1 as manure applied in each of spring and fall; 200 kg N ha−1 applied as inorganic fertilizer in spring; 300 kg N ha−1 as manure plus 100 kg N ha−1 as inorganic fertilizer applied in spring; and a control that received no applied N. Fall-applied manure did not increase corn yield or N uptake in the following growing season. At all sites, maximum yield was attained using manure only. Selection of proper spring application rates for manure and inorganic fertilizer were found to be equally important in minimizing residual soil nitrate at harvest. Apparent recovery of applied N in the crop ranged from 0 to 33% for manure and from 18 to 93% for inorganic fertilizer. Key words: N recovery, manure management

Download Full-text

STRUCTURE, STRATIGRAPHY, AND PALEONTOLOGY OF AN UPPER TRIASSIC SECTION ON THE WEST COAST OF BRITISH COLUMBIA

Canadian Journal of Earth Sciences ◽

10.1139/e65-038 ◽

1965 ◽

Vol 2 (5) ◽

pp. 442-484 ◽

Cited By ~ 2

Author(s):

Donald Carlisle ◽

Takeo Susuki

Keyword(s):

British Columbia ◽

Structural Information ◽

Pillow Lava ◽

Middle Part ◽

Upper Triassic ◽

Coast Range ◽

Thermal Alteration ◽

The West ◽

Coastal British Columbia ◽

Sedimentary Unit

The highly deformed section at Open Bay is one of the few good exposures of a thick sedimentary unit within the prebatholithic rocks along coastal British Columbia. It provides new structural information relating to emplacement of a part of the Coast Range batholith and it contains an important Upper Triassic fauna unusually well represented. Structural and paleontological analyses are mutually supporting and are purposely combined in one paper.Thirteen ammonite genera from 14 localities clearly substantiate McLearn's tentative assignment to the Tropites subbullatus zone (Upper Karnian) and suggest a restriction to the T. dilleri subzone as defined in northern California.Contrary to an earlier view, the beds are lithologically similar across the whole bay except for variations in the intensity of deformation and thermal alteration. Their contact with slightly older relatively undeformed flows is apparently a zone of dislocation. Stratigraphic thicknesses cannot be measured with confidence, and subdivision into "Marble Bay Formation" and "Open Bay Group" cannot be accepted. Open Bay Formation is redefined to include all the folded marble and interbedded pillow lava at Open Bay. Lithologic and biostratigraphic correlation is suggested with the lower middle part of the Quatsino Formation on Iron River, 24 miles to the southwest. Basalt flows and pillowed volcanics west of Open Bay are correlated with the Texada Formation within the Karmutsen Group.The predominant folding is shown to precede, accompany, and follow intrusion of numerous andesitic pods and to precede emplacement of quartz diorite of the batholith. Structural asymmetry is shown to have originated through gentle cross-folding and emplacement of minor intrusives during deformation.

Download Full-text

The effects of soil mixing on soil nutrient status, recovery of competing vegetation and conifer growth on cedar-hemlock cutovers in coastal British Columbia

New Forests ◽

10.1007/bf00035485 ◽

1995 ◽

Vol 9 (3) ◽

pp. 163-179 ◽

Cited By ~ 8

Author(s):

Christian Messier ◽

Rodney Keenan ◽

James P. (Hamish) Kimmins

Keyword(s):

British Columbia ◽

Soil Nutrient ◽

Nutrient Status ◽

Soil Nutrient Status ◽

Competing Vegetation ◽

Soil Mixing ◽

Coastal British Columbia

Download Full-text

Paleoclimate and precipitation seasonality of the Early Eocene McAbee megaflora, Kamloops Group, British Columbia

Canadian Journal of Earth Sciences ◽

10.1139/cjes-2015-0160 ◽

2016 ◽

Vol 53 (6) ◽

pp. 591-604 ◽

Cited By ~ 8

Author(s):

Cale A.C. Gushulak ◽

Christopher K. West ◽

David R. Greenwood

Keyword(s):

British Columbia ◽

North American ◽

Leaf Size ◽

Early Eocene ◽

Precipitation Seasonality ◽

Two Samples ◽

Fossil Site ◽

Fossil Floras ◽

Climate Analysis ◽

Early Cenozoic

Early Eocene fossil floras from British Columbia are a rich resource for reconstructing western North American early Cenozoic climate. The best known of these floras reflect cooler (MAT ≤ 15 °C) upland forest communities in contrast to coeval (MAT ≥ 18 °C) forests in lowland western North American sites. Of particular interest is whether Early Eocene climates were monsoonal (highly seasonal precipitation). The McAbee site is a 52.9 ± 0.83 Ma 0.5 km outcrop of bedded lacustrine shale interbedded with volcanic ash. In this report two historical megaflora collections that were collected independently from different stratigraphic levels and (or) laterally separated by ∼100–200 m in the 1980s (University of Saskatchewan) and 2000s (Brandon University) are investigated to (i) assess whether they represent the same leaf population, (ii) assess whether a combined collection yields more precise climate estimates, and (iii) reconstruct paleoclimate to assess the character of regional Early Eocene precipitation seasonality. Combined, the two samples yielded 43 dicot leaf morphotypes. Analysis of leaf size distribution using ANOVA showed no difference between the two samples, and thus they were combined for climate analysis. Climate analysis using leaf physiognomy agrees with previous estimates for McAbee and other regional megafloras, indicating a warm (MAT ∼8–13 °C), mild (CMMT ∼5 °C), moist (MAP > 100 cm/year) ever-wet, non-monsoonal climate. Additionally, we recommend that climate analyses derived from leaf fossils should be based on samples collected within a stratigraphically constrained quarry area to capture a snapshot of climate in time rather than time-averaged estimates derived from multiple quarry sites representing different stratigraphic levels within a fossil site.

Download Full-text

A River Otter's, Lontra canadensis, Capture of a Double-crested Cormorant, Phalacrocorax auritus, in British Columbia's Gulf Island Waters

The Canadian Field-Naturalist ◽

10.22621/cfn.v121i3.483 ◽

2007 ◽

Vol 121 (3) ◽

pp. 325

Author(s):

Michael H. H. Price ◽

Clare E. Aries

Keyword(s):

Lontra Canadensis ◽

Phalacrocorax Auritus ◽

River Otter ◽

Freshwater Lakes ◽

Marine Bird ◽

River Otters

Direct and apparent predation events by River Otters (Lontra canadensis) on birds have been recorded on marine islands and freshwater lakes. We add to this the first known observation of a River Otter capturing a marine bird on the ocean.

Download Full-text

Status of Marine Turtles in British Columbia Waters: A Reassessment

The Canadian Field-Naturalist ◽

10.22621/cfn.v118i1.885 ◽

2004 ◽

Vol 118 (1) ◽

pp. 72 ◽

Cited By ~ 3

Author(s):

Donald F. McAlpine ◽

Stan A. Orchard ◽

Kelly A. Sendall ◽

Rod Palm

Keyword(s):

British Columbia ◽

Marine Environment ◽

Chelonia Mydas ◽

Marine Turtle ◽

Dermochelys Coriacea ◽

Concerted Effort ◽

Leatherback Turtles ◽

Marine Turtles ◽

Green Turtles

Marine turtles in British Columbia have previously been considered off course stragglers. Here we document 20 new reports for Green Turtles, Chelonia mydas, and Leatherback Turtles, Dermochelys coriacea, for the province. Until recently there had been no concerted effort to acquire data on marine turtle abundance or frequency off British Columbia. Observations presented here allow a reassessment of marine turtle status in British Columbia waters. We suggest Green Turtles and Leatherbacks should be considered rare vagrants and uncommon seasonal residents, respectively, off British Columbia and that they are a natural part of the British Columbia marine environment.

Download Full-text

“Boil them Hearts”

Studies in Religion/Sciences Religieuses ◽

10.1177/0008429816660883 ◽

2016 ◽

Vol 46 (1) ◽

pp. 50-74

Author(s):

Jason Redden

Keyword(s):

Nineteenth Century ◽

British Columbia ◽

Indigenous Peoples ◽

Scholarly Literature ◽

Material Resources ◽

Theoretical Inquiry ◽

Critical Exploration ◽

Coastal British Columbia ◽

Academic Study

This paper addresses the academic conversation on Protestant missions to the Indigenous peoples of coastal British Columbia during the second half of the nineteenth century through a consideration of the role of revivalist piety in the conversion of some of the better known Indigenous Methodist evangelists identified in the scholarly literature. The paper introduces the work of existing scholars critically illuminating the reasons (religious convergence and/or the want of symbolic and material resources) typically given for Indigenous, namely, Ts’msyen, conversion. It also introduces Methodist revivalist piety and its instantiation in British Columbia. And, finally, it offers a critical exploration of revivalist piety and its role in conversion as set within a broader theoretical inquiry into the academic study of ritual and religion.

Download Full-text