Habitat selection by common eiders in winter and its interaction with flock size

1993 ◽  
Vol 71 (6) ◽  
pp. 1259-1266 ◽  
Author(s):  
Magella Guillemette ◽  
John H. Himmelman ◽  
Cyrille Barette ◽  
Austin Reed
Keyword(s):  
Habitat Selection ◽  
Shallow Water ◽  
Prey Density ◽  
Sea Urchins ◽  
Day Length ◽  
Antipredator Behaviour ◽  
Somateria Mollissima ◽  
Flock Size ◽  
Eastern Canada ◽  
Diving Depth

We studied habitat selection in relation to prey density and water depth in the common eider, Somateria mollissima L., wintering in the Gulf of St. Lawrence, eastern Canada. In this region, eiders are confronted with low temperatures, ice cover, and reduced day length. We predicted that they should select feeding habitats characterized by high prey density and shallow water to minimize the time and energy spent while diving. About 1000 flocks were localized by triangulation on our study site (20.5 km2). We inferred the diving depth and the habitat being used from the position of eiders on bathymetric and community maps. The highest density of prey occurred in shallow water reefs where there were patches of blue mussels, Mytilus edulis L., and green sea urchins, Strongylocentrotus droebachienensis (Müller). Despite the fact that eiders can dive to depths as great as 42 m to feed, they strongly aggregate in shallow water, and their distribution closely coincides with the highest density of prey. The degree of selection for the reef habitat varies with seasonal variations in the size of flocks and in the total number of eiders present. Although flocking as an antipredator behaviour cannot be rejected, we interpret the high degree of flocking by eiders in our study area as a strategy to facilitate feeding in winter.

Availability and consumption of food by common eiders wintering in the Gulf of St. Lawrence: evidence of prey depletion

1996 ◽  
Vol 74 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Magella Gulllemette ◽  
John H. Himmelman ◽  
Austin Reed
Keyword(s):  
Prey Availability ◽  
Prey Selection ◽  
Sea Urchins ◽  
Stomach Contents ◽  
Somateria Mollissima ◽  
Eastern Canada ◽  
Common Eiders ◽  
Large Populations ◽  
Average Size ◽  
Density And Biomass

To quantify the influence of common eiders (Somateria mollissima) on their food supply in the Gulf of St. Lawrence, eastern Canada, we measured prey availability and patch utilization during two consecutive winters. In this region, eiders fed predominantly near submerged reefs where large populations of blue mussels (Mytilus edulis) and green sea urchins (Strongylocentrotus droebachienensis) were present. Density and biomass of mussels and urchins were estimated for two reefs at the beginning of the winter of 1985 – 1986 using SCUBA and quadrat sampling. Prey selection was assessed by comparing the size of prey from stomach contents of shot eiders with that of prey found in the habitat. Patch use was quantified from elevated blinds by regularly counting eiders from December to April. Mussels in the habitat were small (mean length 6.5 mm) and formed dense beds (mean density 25 398 individuals/m2), whereas urchins were large (mean diameter 35 mm) and occurred at lower densities (114 individuals/m2). However, the average biomass for these two prey species was similar, 2.8 and 3.1 kg wet mass/m2 for mussels and urchins, respectively. The mussels eaten by common eiders tended to be larger than the average size of those available. In contrast, urchins eaten were smaller than the average size present in the habitat. Depending on the reef, consumption of food by eiders ranged from 48 to 69% of the biomass for eiders feeding on mussels and from 3 to 6% of the biomass for urchins. We compared these estimates with those from similar studies and concluded that eiders substantially deplete mussel beds in winter, which in turn seems to affect their distribution.

Adaptive radiation of the comatulid crinoids

Paleobiology ◽  
1977 ◽  
Vol 3 (1) ◽  
pp. 74-82 ◽  
Author(s):  
David L. Meyer ◽  
Donald B. Macurda
Keyword(s):  
Habitat Selection ◽  
Shallow Water ◽  
Adaptive Radiation ◽  
Late Mesozoic ◽  
Behavioral Adaptations ◽  
Bony Fishes ◽  
Survival Capacity ◽  
Stalked Crinoids ◽  
Permanent Fixation

Modern crinoids are dominated by the comatulids (unstalked forms) which range from the intertidal to abyssal depths. Modern stalked crinoids are restricted to depths greater than about 100 m. In the geologic past some stalked crinoids lived at depths of a few tens of meters or less in reef and bank environments. The primary vehicles postulated for the post-Triassic radiation of comatulids are lack of permanent fixation to the substratum and the capacity for mobility. Development of complex muscular articulations has enabled crawling or swimming which serve in habitat selection and avoidance of stress and predators. These and other adaptations may have bestowed on comatulids a higher survival capacity in shallow-water environments compared to stalked crinoids. Modern stalked crinoids lack mobility and complex behavioral adaptations seen in comatulids. Possibly, stalked crinoids in shallow water were unable to cope with the radiation of abundant, predaceous bony fishes in the late Mesozoic and became restricted to greater depths while the more adaptable comatulids gained ascendancy in shallow water.

The Effect of Water Depth on the Predatory Behavior of the Water Stick Insect, Ranatra-Dispar (Heteroptera, Nepidae)

1987 ◽  
Vol 35 (5) ◽  
pp. 443 ◽  
Author(s):  
PCE Bailey
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Prey Density ◽  
Vertical Component ◽  
Stick Insect ◽  
Predatory Behavior ◽  
Sensory Organs ◽  
Capture Success ◽  
Effect Of Water

The effect of water depth and prey density on the capture success (as measured by the number of prey eaten) of the aquatic, sit-and-wait predator, Ranatra dispar, was examined in the laboratory. When water depth was held constant at 5, 10, 20 or 30 cm, prey densities of 10, 15, 30 or 40 prey per container had no effect at the two shallowest depths, where very few prey were caught or eaten at any density. At 20 and 30 cm, density had a significant effect with progressively more prey being consumed as density increased. When prey density was held constant at 1, 2, 4 or 8 prey per litre, water depth significantly affected the proportion of prey eaten. At each density, predators held in 5 cm of water and, to some extent, those in 10 cm consumed significantly fewer prey than those in 20 or 30 cm. It is suggested that fewer prey are caught in shallow water because: (1) the predator cannot put itself in the position which most favours an efficient strike; (2) the absence of a significant 'vertical' component in the environment reduces the effectiveness of the sensory organs in locating prey. The lower capture success in shallow water may cause adult R. dispar to avoid shallow water, thus providing a partial refuge in which small R. dispar can avoid competing with adults for prey of similar sizes.

Destructive Grazing of Kelp by Sea Urchins in Eastern Canada

1976 ◽  
Vol 33 (6) ◽  
pp. 1278-1283 ◽  
Author(s):  
P. A. Breen ◽  
K. H. Mann
Keyword(s):  
Nova Scotia ◽  
Sea Urchin ◽  
Sea Urchins ◽  
Large Contribution ◽  
Eastern Canada ◽  
Kelp Beds ◽  
Urchin Grazing

Destruction of kelp beds by sea urchins has been documented in St. Margaret’s Bay, Nova Scotia, and also appears to be taking place in other parts of eastern Canada. Continued sea urchin settlement onto grazed areas prevents the return of kelp and other algae for long periods. Because of the large contribution of kelp beds to coastal productivity, the disappearance of kelp from large areas is alarming. Dynamics of sea urchin grazing are discussed.

Age- and Density-Dependent Bathymetric Pattern of Atlantic Cod (Gadus morhua) in the Southern Gulf of St. Lawrence

1993 ◽  
Vol 50 (6) ◽  
pp. 1255-1264 ◽  
Author(s):  
Douglas P. Swain
Keyword(s):  
Habitat Selection ◽  
Density Dependence ◽  
Shallow Water ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Age Groups ◽  
Low Density ◽  
Positive Correlation ◽  
Using Data ◽  
Trawl Surveys

I examined the bathymetric pattern of Alantic cod (Gadus morhua) in September in the southern Gulf of St. Lawrence for age groups 3–8+ over the period 1971–91 using data from annual bottom trawl surveys. Mean age of cod tended to increase with depth in all years. The age-specific bathymetric patterns underlying this relationship differed markedly between periods of low and high abundance. When abundance was high, cod densities tended to be highest at intermediate depths, and the positive correlation between age and depth reflected a tendency for density to be highest in progressively deeper water for older fish. When abundance was low, density was either unrelated to depth or highest in shallow water, and the positive correlation between age and depth reflected a tendency for older cod to be more widely distributed than younger cod (i.e., density decreased less sharply with depth for older cod). I suggest explanations for this density dependence of cod bathymetric pattern and discuss these results in relation to the factors underlying habitat selection and bathymetric segregation by age in this population.

A large arthropod trackway from the Gaspé Sandstone Group (Middle Devonian) of eastern Canada

1998 ◽  
Vol 35 (10) ◽  
pp. 1116-1122 ◽  
Author(s):  
Simon J Braddy ◽  
Andrew RC Milner
Keyword(s):  
Shallow Water ◽  
Middle Devonian ◽  
Eastern Canada

A large arthropod trackway from the Cap-aux-Os Member of the Battery Point Formation (Gaspé Sandstone Group, Middle Devonian), from the Baie de Gaspé, eastern Canada, is described and assigned to the ichnotaxon Palmichnium (= Paleohelcura) antarcticum (Gevers et al., 1971). A large stylonurid eurypterid or scorpion is considered the most likely producer. A shallow-water marginal fluvial environment is inferred as the setting, the animal making a transition from walking to swimming along the course of the trackway.

Hierarchical habitat selection by North American porcupines in southern boreal forest

2005 ◽  
Vol 83 (10) ◽  
pp. 1333-1342 ◽  
Author(s):  
Patrick Morin ◽  
Dominique Berteaux ◽  
Ilya Klvana
Keyword(s):  
Habitat Selection ◽  
Home Range ◽  
Populus Tremuloides ◽  
North American ◽  
Deciduous Trees ◽  
Home Ranges ◽  
Trembling Aspen ◽  
Eastern Canada ◽  
Erethizon Dorsatum ◽  
Multi Scale

In habitat-selection studies, a multi-scale approach is considered necessary to ensure that all elements of selection are depicted and that management decisions accurately reflect the needs of the species under study. We examined hierarchy in summer habitat selection in North American porcupines (Erethizon dorsatum (L., 1758)) in Eastern Canada at the scales of landscape, home range, and single tree. We used radiotelemetry to locate and observe animals visually to record their behaviour and exact location in the habitat. Den use in summer was unexpectedly high for some of our animals, which forced us to use a restricted number of locations per individual for comparison among scales. Although porcupines are generalists at the landscape level, selection patterns appear at the home-range and tree levels. Human-used land and conifer forests were least selected features of home ranges, while deciduous forests dominated by trembling aspen (Populus tremuloides Michx.) and mixed forests were most selected. At the tree scale, trembling aspen was found to be selected over other deciduous trees. However, fruit-producing trees were even more selected. This study shows the importance of a multi-scale approach that includes fine-scale selection.

Suspension freezing of bottom sediment and biota in the Northwest Passage and implications for Arctic Ocean sedimentation

1992 ◽  
Vol 29 (4) ◽  
pp. 693-703 ◽  
Author(s):  
Erk Reimnitz ◽  
Louie Marincovich Jr. ◽  
Michael McCormick ◽  
W. M. Briggs
Keyword(s):  
Arctic Ocean ◽  
Shallow Water ◽  
Sea Urchins ◽  
The Arctic ◽  
River Flooding ◽  
Northwest Passage ◽  
Beaufort Gyre ◽  
Transpolar Drift ◽  
Living Organisms ◽  
Northern Alaska

Ice observations and sediment collected in a summer transit through the Northwest Passage provide insights on suspension freezing, the most important sediment entrainment mechanism for the Arctic Ocean. No evidence was seen for entrainment by bottom adfreezing, bluff slumping, river flooding, dragging ice keels, or significant eolian transport from land to sea. Lack of eolian sediment loading in the Northwest Passage, together with that already reported for northern Alaska, eliminates wind as an important source for fine sediment in the pack of the Beaufort Gyre and related parts of the Transpolar Drift. Muddy sediment with pebbles and cobbles, algae with holdfasts, ostracodes with appendages, and well-preserved mollusks and sea urchins were collected from two sites in a 50 km long stretch of turbid ice. These materials indicate that suspension freezing reaching to a water depth of 25–30 m during the previous fall was responsible for entrainment. This mechanism requires rapid ice formation in open, shallow water during a freezing storm, when the ocean becomes supercooled, and frazil and anchor ice attach to and ultimately lift sediment and living organisms to the sea surface. The mechanism, already known to be important in the Beaufort Sea, probably also affects wide, shallow Siberian shelves and leads to cross-shelf transport of shallow-water organisms and dropstones with "glacial striations" toward deep basins. This makes distinguishing glacial–interglacial cycles more difficult.

scholarly journals Size, growth, and density data for shallow-water sea urchins from Mexico to the Aleutian Islands, Alaska, 1956-2016

Ecology ◽  
2018 ◽  
Vol 99 (3) ◽  
pp. 761-761 ◽  
Author(s):  
Thomas A. Ebert ◽  
Louis M. Barr ◽  
James L. Bodkin ◽  
Dirk Burcham ◽  
Dominique Bureau ◽  
...  
Keyword(s):  
Shallow Water ◽  
Sea Urchins ◽  
Aleutian Islands ◽  
Density Data ◽  
Size Growth

scholarly journals It is time to move: linking flight and foraging behaviour in a diving bird

2007 ◽  
Vol 3 (4) ◽  
pp. 357-359 ◽  
Author(s):  
David Pelletier ◽  
Magella Guillemette ◽  
Jean-Marc Grandbois ◽  
Patrick J Butler
Keyword(s):  
Permutation Test ◽  
Dynamic Environment ◽  
The Body ◽  
Somateria Mollissima ◽  
Data Logger ◽  
Body Angle ◽  
Diving Depth ◽  
Adaptive Value ◽  
Duck Species ◽  
Diving Bird

Although the adaptive value of flight may seem obvious, it is the most difficult behaviour of birds to monitor. Here, we describe a technique to quantify the frequency and the duration of flights over several months by implanting a data logger that records heart rate ( f H ), hydrostatic pressure (diving depth) and the body angle of a large sea duck species, the common eider ( Somateria mollissima ). According to the mean f H recorded during flight and the parameters recorded to identify the f H flight signature, we were able to identify all flights performed by 13 individuals during eight months. We cumulated local flight time (outside migrations) and found that activity occurs primarily during dawn and morning and that flying activities are strongly related to diving activities (Pearson's r =0.88, permutation test p <0.001). This relationship was interpreted as a consequence of living in a dynamic environment where sea currents move the ducks away from the food patches. We believe that the technique described here will open new avenues of investigation in the adaptive value of flight.

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