Distribution of two species of Kudoa (Myxozoa: Multivalvulida) in the offshore population of the Pacific hake, Merluccius productus (Ayres, 1855)

1986 ◽  
Vol 64 (10) ◽  
pp. 2103-2110 ◽  
Author(s):  
Z. Kabata ◽  
D. J. Whitaker
Keyword(s):  
Vancouver Island ◽  
Distribution Range ◽  
Intensity Of Infection ◽  
Merluccius Productus ◽  
Parasite Distribution ◽  
The Pacific ◽  
Northerly Direction

Samples of pacific hake (Merluccius productus), a total of 581 fish, were collected along its distribution range from California to Vancouver Island. The fish were examined for prevalence and intensity of infection with Kudoa thyrsitis and K. paniformis (Myxozoa). Fish age 4+ (and older) were more heavily infected than those age 3+, the most heavily infected part of the fish being the dorsal musculature directly behind the head. Although the prevalence of infection with K. thyrsitis increased in a northerly direction, its intensity was markedly lower than the intensity of infection with K. paniformis. Fish of comparable age and size were twice as heavily infected with K. paniformis off California as those taken off Vancouver Island. Fish infected with K. thyrsitis appeared to show a much stronger reaction to the presence of the parasite by producing relatively more black pseudocysts than those infected with K. paniformis. Reasons for this fact and for the observed pattern of parasite distribution are discussed.

The effect of Kudoa paniformis infection on the reproductive effort of female Pacific hake

1998 ◽  
Vol 76 (12) ◽  
pp. 2285-2289 ◽  
Author(s):  
S A Adlerstein ◽  
M W Dorn
Keyword(s):  
Reproductive Effort ◽  
Detrimental Effect ◽  
Parasite Prevalence ◽  
Analysis Of Covariance ◽  
Fish Length ◽  
Intensity Of Infection ◽  
Oregon Coast ◽  
Merluccius Productus ◽  
The Pacific ◽  
Common Parasite

The effect of the myxosporidean Kudoa paniformis on the annual reproductive effort of the coastal stock of Pacific hake (Merluccius productus), on which it is a common parasite, is investigated. Female Pacific hake collected off the central Oregon coast in December 1988 were analyzed for prevalence and intensity of parasites. Reproductive effort was estimated by the number of yolked oocytes present in the ovaries immediately prior to spawning (potential annual fecundity), using the volumetric method. The effect of the parasite was evaluated through an analysis of covariance where fecundity was modeled as a function of fish length and parasite prevalence. An additional analysis of covariance evaluated the effect of the intensity of parasite infection on fecundity. Results show that the fecundity of Pacific hake is significantly reduced in the presence of K. paniformis infections and that the detrimental effect escalates with the intensity of infection. The potential effects on the population dynamics of the Pacific hake coastal stock are discussed.

Relationships between temperature and Pacific hake distribution vary across latitude and life-history stage

2020 ◽  
Vol 639 ◽  
pp. 185-197 ◽  
Author(s):  
MJ Malick ◽  
ME Hunsicker ◽  
MA Haltuch ◽  
SL Parker-Stetter ◽  
AM Berger ◽  
...  
Keyword(s):  
Life History ◽  
Environmental Effects ◽  
Environmental Conditions ◽  
Vancouver Island ◽  
Additive Models ◽  
Life History Stage ◽  
Fish Stocks ◽  
Merluccius Productus ◽  
Multiple Dimensions ◽  
Effects Of Temperature

Environmental conditions can have spatially complex effects on the dynamics of marine fish stocks that change across life-history stages. Yet the potential for non-stationary environmental effects across multiple dimensions, e.g. space and ontogeny, are rarely considered. In this study, we examined the evidence for spatial and ontogenetic non-stationary temperature effects on Pacific hake Merluccius productus biomass along the west coast of North America. Specifically, we used Bayesian additive models to estimate the effects of temperature on Pacific hake biomass distribution and whether the effects change across space or life-history stage. We found latitudinal differences in the effects of temperature on mature Pacific hake distribution (i.e. age 3 and older); warmer than average subsurface temperatures were associated with higher biomass north of Vancouver Island, but lower biomass offshore of Washington and southern Vancouver Island. In contrast, immature Pacific hake distribution (i.e. age 2) was better explained by a nonlinear temperature effect; cooler than average temperatures were associated with higher biomass coastwide. Together, our results suggest that Pacific hake distribution is driven by interactions between age composition and environmental conditions and highlight the importance of accounting for varying environmental effects across multiple dimensions.

Integrated geophysical modelling of terranes and other structural features along the western Canadian margin

1992 ◽  
Vol 29 (7) ◽  
pp. 1492-1508 ◽  
Author(s):  
S. A. Dehler ◽  
R. M. Clowes
Keyword(s):  
Seismic Refraction ◽  
Vancouver Island ◽  
Structural Features ◽  
Pacific Rim ◽  
Data Set ◽  
Reflection Seismic ◽  
Barkley Sound ◽  
The Pacific ◽  
Wrangellia Terrane ◽  
Lower Crustal

An integrated geophysical data set has been used to develop structural models across the continental margin west of Vancouver Island, Canada. A modern accretionary complex underlies the continental slope and shelf and rests against and below the allochthonous Crescent and Pacific Rim terranes. These terranes in turn abut against the pre-Tertiary Wrangellia terrane that constitutes most of the island. Gravity and magnetic anomaly data, constrained by seismic reflection, seismic refraction, and other data, were interpreted to determine the offshore positions of these terranes and related features. Iterative 2.5-dimensional forward models of anomaly profiles were stepped laterally along the margin to extend areal coverage over a 70 km wide swath oriented normal to the tectonic features. An average model was then developed to represent this part of the margin. The Pacific Rim terrane appears to be continuous and close to the coastline along the length of Vancouver Island, consistent with emplacement by strike-slip motion along the margin. The Westcoast fault, the boundary between the Pacific Rim and Wrangellia terranes, is interpreted to be 15 km farther seaward than in previous interpretations in the region of Barkley Sound. The Crescent terrane forms a thin landward-dipping slab along the southern half of the Vancouver Island margin, and cannot be confirmed along the northern part. Model results suggest the slab has buckled into an anticline beneath southern Vancouver Island and Juan de Fuca Strait, uplifting high-density lower crustal or upper mantle material close to the surface to produce the observed intense positive gravity anomaly. This geometry is consistent with emplacement of the Crescent terrane by oblique subduction.

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.

Aporocotyle margolisi n.sp. (Digenea: Aporocotylidae) from Merluccius productus

1967 ◽  
Vol 24 (8) ◽  
pp. 1763-1773 ◽  
Author(s):  
John W. Smith
Keyword(s):  
Vancouver Island ◽  
Merluccius Productus ◽  
Bulbus Arteriosus

Aporocotyle margolisi n.sp., from the bulbus arteriosus of Merluccius productus (Ayres) caught off Vancouver Island, is described and figured. Records of Aporocotyle from other hosts are discussed.

The Dellwood knolls and their role in triple junction tectonics off northern Vancouver Island

1980 ◽  
Vol 17 (5) ◽  
pp. 577-593 ◽  
Author(s):  
R. P. Riddihough ◽  
R. G. Currie ◽  
R. D. Hyndman
Keyword(s):  
Triple Junction ◽  
Plate Tectonics ◽  
Vancouver Island ◽  
Ocean Bottom ◽  
Ocean Bottom Seismometer ◽  
Geological Evidence ◽  
Topographic Features ◽  
Narrow Valley ◽  
The Pacific ◽  
Geophysical Surveys

The Dellwood knolls are two small topographic features on the ocean floor off northern Vancouver Island. They have been proposed as a spreading centre connecting the Explorer ridge to the Queen Charlotte fault and the location of a triple junction between the Pacific, American, and Juan de Fuca plate systems.Detailed geophysical surveys and ocean-bottom seismometer deployments confirm that they are the site of active seismicity and recent volcanism. Modelling of the magnetic anomaly field shows that it is almost entirely produced by normally magnetized material, supporting geological evidence that the knolls are probably less than 1 Ma old. Although the two knolls are separated by a narrow valley with some downfaulting, they do not form a clearly linear spreading rift.Assessment of their role in the plate tectonics of the region suggests that spreading at the knolls was initiated around 1 Ma ago in crust now 4.5 Ma old as part of a complex, northwesterly ridge migration process at the northern end of the Explorer ridge. Reconstruction of this process, which involves asymmetric spreading and ridge jumping, provides an explanation for the creation of the associated Paul Revere and Winona ridges.

A Statistical Examination of Anisakis Larvae (Nematoda) in Herring (Clupea pallasi) of the British Columbia Coast

1955 ◽  
Vol 12 (4) ◽  
pp. 571-592 ◽  
Author(s):  
Yvonne M. M. Bishop ◽  
Leo Margolis
Keyword(s):  
British Columbia ◽  
West Coast ◽  
Maximum Level ◽  
Vancouver Island ◽  
First Year ◽  
Intensity Of Infection ◽  
The West ◽  
Strait Of Georgia ◽  
Clupea Pallasi ◽  
First Year Of Life

The presence of larval Anisakis in British Columbia herring was examined during the winter fisheries of 1950–51 and 1951–52. In the commercial catches in the Strait of Georgia the incidence was found to be between 80 and 90%. In Hecate Strait, on the west coast of Vancouver Island and in the mainland coastal area of Queen Charlotte Sound it was between 90 and 100%. The intensity of infection varied greatly in different fishing areas (i.e. in different herring populations). Generally, the maximum level of infection occurred in the Queen Charlotte Sound coastal regions, and decreased both north and south of this area. Fish on the west coast of Vancouver Island were more heavily infected than those on the east coast (Strait of Georgia). The level of infection increased with age, I-year fish (i.e. fish in their first year of life) being uninfected. The intensity of infection remained constant throughout the winter for any particular age and area and was the same for both sexes. In most areas the level of infection was a little lower in 1951–52 than in 1950–51.

A New Species of Bradyidius (Copepoda: Calanoida) from the Pacific Coast of North America

1966 ◽  
Vol 23 (6) ◽  
pp. 805-811 ◽  
Author(s):  
Tai Soo Park
Keyword(s):  
British Columbia ◽  
New Species ◽  
North America ◽  
Pacific Coast ◽  
Vancouver Island ◽  
Saanich Inlet ◽  
The Pacific ◽  
A New Species

A new species Bradyidius saanichi from Saanich Inlet, Vancouver Island, British Columbia, Canada, is described and illustrated in detail. This species is closely related to B. pacificus (Brodsky, 1950) among the six previously known species in the genus, but can be readily distinguished from the latter by the strongly divergent rostral rami in addition to some other differences.

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