Aggregative Response of Common Mergansers (Mergus merganser): Predicting Flock Size and Abundance on Vancouver Island Salmon Streams

1985 ◽  
Vol 42 (7) ◽  
pp. 1259-1271 ◽  
Author(s):  
C. C. Wood
Keyword(s):  
Social Interactions ◽  
East Coast ◽  
Vancouver Island ◽  
Flock Size ◽  
Size Distributions ◽  
Similar Model ◽  
Aggregation Model ◽  
Parsimonious Explanation ◽  
Mergus Merganser ◽  
Aggregative Response

The abundance of common mergansers (Mergus merganser) was monitored on four salmon-producing streams on the east coast of Vancouver Island, B.C., during the spring and summer of 1980–83. Overall, merganser abundance declined steadily from March through June but increased following recruitment of juvenile birds. Mergansers congregated on streams where juvenile salmonid migrations were enhanced by hatcheries or spawning channels. Movement between streams was evident from inverse trends in abundance on three adjacent streams differing in juvenile salmonid production. At least 8 of 12 mergansers resighted after being marked and released on the Big Qualicum River visited other nearby streams. Flock-size distributions predicted by an equilibrium arrival–departure model were consistent with those observed during May–mid-june, but not those during late June. Social interactions and reduced flight activity appeared to influence dispersion to a greater extent during late June to August so that assumptions of the model were violated. A similar model was used to predict aggregation patterns on hatchery streams from observed relationships between fish availability and frequencies of arrival and departure. The aggregation model provides a parsimonious explanation of merganser aggregation patterns during March–June and is a potentially useful tool for designing fish release schedules to minimize predation by mergansers.

Observations on social behaviour of Atlantic walruses (Odobenus rosmarus (L.)) during terrestrial haul-out

1980 ◽  
Vol 58 (3) ◽  
pp. 461-463 ◽  
Author(s):  
R. E. Salter
Keyword(s):  
Social Interactions ◽  
Social Behaviour ◽  
East Coast ◽  
Adult Males ◽  
Agonistic Interactions ◽  
Age Composition ◽  
Body Contact ◽  
Adult Females ◽  
Odobenus Rosmarus

Social interactions in walrus herds of mixed sex and age composition were recorded at a haul-out site on the east coast of Bathurst Island, N.W.T., during July–August 1977. Most walruses maintained body contact with at least one other walrus while hauled out on land; herds were usually circular in shape. Adult males, adult females, and immatures all displaced other walruses, and thus entered herds, by jabbing with the tusks. Dominance during agonistic interactions was related to relative tusk length and sex and age of interactants. Behaviour of walruses on land suggested an energetic advantage in mutual body contact, which would be maximized by occupation of interior positions within herds.

Discovery of Brachiella lageniformis (Copepoda: Lernaeopodidae) in the Canadian Pacific and its Significance to Zoogeography of the Genus Merluccius (Pisces: Teleostei)

1970 ◽  
Vol 27 (12) ◽  
pp. 2159-2165 ◽  
Author(s):  
Z. Kabata
Keyword(s):  
East Coast ◽  
Atlantic Coast ◽  
Vancouver Island ◽  
Male And Female ◽  
Merluccius Productus

Brachiella lageniformis, hitherto known only from the Atlantic coast of Argentina, was found off the east coast of Vancouver Island, on the gills of Merluccius productus. Both male and female are described and illustrated in detail. The significance of this find for Szidat's views on the origin of the genus Merluccius is discussed. A proposal is made to suppress the genus Parabrachiella and to place all its five species (P. rostrata, P. insidiosa, P. australis, P. spinicephala, and P. incurva) in the genus Brachiella.

Notes on Polychaeta from the East Coast of Vancouver Island and from Adjacent Waters, with a Description of a New Species of Aricidea

1956 ◽  
Vol 13 (4) ◽  
pp. 541-546 ◽  
Author(s):  
E. Berkeley ◽  
C. Berkeley
Keyword(s):  
New Species ◽  
North America ◽  
East Coast ◽  
Vancouver Island ◽  
Western Canada ◽  
Western North America ◽  
A New Species

Records are given of two species and a variety new to western Canada and notes on three other species already known from the region. A new species, Aricidea lopezi, and four species new to western North America, are described from the neighbourhood of Friday Harbour, Washington.

The Nutritive Value of Marine Products: X. Proximate Analysis of Ling Cod

1936 ◽  
Vol 2 (5) ◽  
pp. 461-462
Author(s):  
F. D. White
Keyword(s):  
Nutritive Value ◽  
East Coast ◽  
Vancouver Island ◽  
Proximate Analysis ◽  
Ophiodon Elongatus ◽  
Marine Products ◽  
Ling Cod ◽  
Proximate Analyses

Separate proximate analyses of the flesh and skin of three freshly-caught ling cod (Ophiodon elongatus) from the east coast of Vancouver island are reported. Average percentages of protein in the flesh and skin were 18.1 and 26.9 (moist) or 87.0 and 88.5 (dry); ash, 1.2 and 2.5 (moist); fat, negligible; Calories per 100 g. (moist), 81 and 117.

HEIGHT GROWTH LOSSES DUE TO ANIMAL FEEDING IN DOUGLAS FIR PLANTATIONS, VANCOUVER ISLAND, B.C.

1964 ◽  
Vol 40 (3) ◽  
pp. 298-307 ◽  
Author(s):  
K. J. Mitchell
Keyword(s):  
Pseudotsuga Menziesii ◽  
East Coast ◽  
Growth Curves ◽  
Tree Height ◽  
Vancouver Island ◽  
Height Growth ◽  
Douglas Fir ◽  
Average Height ◽  
Animal Feeding ◽  
Rotation Age

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantations on the east coast of Vancouver Island, British Columbia, were examined to determine the effect of animal feeding upon height growth.Length of internodes and evidence of past leader damage were recorded and cumulative average height-age growth curves compared for undamaged trees and for trees suffering various intensities of damage.The average reduction in tree height attributable to animal feeding in heavily browsed plantations varied from one-half to two feet over a period of 8 to 10 years. It is unlikely that either tree volume or quality at rotation age would be seriously affected.Exposed trees were browsed more heavily than those protected by vegetation or logging slash.

Predation of Juvenile Pacific Salmon by the Common Merganser (Mergus merganser) on Eastern Vancouver Island. II: Predation of Stream-Resident Juvenile Salmon by Merganser Broods

1987 ◽  
Vol 44 (5) ◽  
pp. 950-959 ◽  
Author(s):  
C. C. Wood
Keyword(s):  
Body Weight ◽  
Census Data ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Vancouver Island ◽  
Juvenile Salmonids ◽  
Mergus Merganser ◽  
The Common ◽  
Tidal Waters ◽  
Common Merganser

Predation of stream-resident juvenile salmonids by broods of the common merganser (Mergus merganser) was investigated in three streams on eastern Vancouver Island from 1980 to 1982. Daily fish consumption by merganser ducklings was estimated to range from 80% of body weight for ducklings at 10 d of age to 40% of body weight for those at 40 d of age. Merganser ducklings were never observed to eat juvenile salmonids on tidal waters, but did eat them on the freshwater reaches of streams studied. Typically, broods inhabited only the freshwater reaches of their natal stream while young, but spent progressively more time foraging on tidal waters as they grew older. The biomass of broods (and hence potential consumption) on fresh water was estimated by reconstructing the history of individual broods from census data. These results suggest that merganser broods consumed on the order of 82 000–131 000 coho salmon (Oncorhynchus kisutch) fry in the Big Qualicum River between June 10 and August 25. This is equivalent to 24–65% of the observed wild smolt production from this system, assuming that these fry would otherwise have survived as well as uneaten fry.

Phenotypic and genotypic spacing within an aggregation of the anemone, Actinia equina

1983 ◽  
Vol 63 (3) ◽  
pp. 493-515 ◽  
Author(s):  
D. L. J. Quicke ◽  
R. C. Brace
Keyword(s):  
East Coast ◽  
Allelic Variation ◽  
Size Distributions ◽  
Nearest Neighbour ◽  
Founder Effects ◽  
Genetic Composition ◽  
Colonization History ◽  
Hardy Weinberg Equilibrium ◽  
High Level ◽  
Over Time

Enzyme and colour phenotypes were determined within a single mid-shore aggregation (n = 106) of the anemone, Actinia equina L. on the east coast of Britain. On the basis of allelic variation at four enzyme loci, a large number (n ≃ 30) of genotypes were distinguished of which only three consisted often or more anemones. Little evidence was found of obvious genotypic clustering, a result which was unexpected since this species broods young which are genetically identical with their parents, and which are potentially available for local (within site) colonization. We propose that the unexpectedly high level of genetic variability encountered at this site, can be explained by the following factors: (1) site and anemone longevities are probably measurable in tens of years, (2) distances travelled by anemones during their lifetime may be considerable, thus resulting in extensive inter-digitation of clones over time, and (3) the reproductive strategy of A. equina incorporates sexual reproduction with a planktonic dispersal phase.Nearest-neighbour analyses applied to the distribution of phenotypes within this aggregation revealed several examples of auto-phenotypic under-dispersion. These results, together with (1) departure from Hardy–Weinberg equilibrium at a hexokinase locus, (2) evidence of linkage disequilibrium between hexokinase and malate dehydrogenase alleles, and (3) linkage between alleles at both these loci with a colour phenotype (grey pedal disc), all indicate that the genetic composition of this group of anemones had been strongly influenced by founder effects followed by clonal reproduction.A comparative analysis of the size distributions of the various phenotypes and genotypes yielded few conclusions relating either to colonization history or to differential selection; reasons are given to account for this failure.

A new species of Leuckartiara (Pandeidae, Hydrozoa) from the east coast of Vancouver Island

1980 ◽  
Vol 58 (8) ◽  
pp. 1491-1493
Author(s):  
Mary Needler Arai ◽  
Anita Brinckmann-Voss
Keyword(s):  
New Species ◽  
East Coast ◽  
Vancouver Island ◽  
A New Species

A new species of Leuckartiara, Leuckartiara foersteri n.sp., is described and illustrated. It is differentiated from all other species of the genus by marginal tentacles without abaxial spurs, and gonads with parallel folds, situated on adradial sides of cross-shaped manubrium with no distinct interradial connection.

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