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.

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.

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.

Aggregation of euphausiids and Pacific hake (Merluccius productus) along the outer continental shelf off Vancouver Island

1997 ◽  
Vol 54 (9) ◽  
pp. 2080-2096 ◽  
Author(s):  
D.L. Mackas ◽  
R. Kieser ◽  
M. Saunders ◽  
D.R. Yelland ◽  
R.M. Brown ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Vancouver Island ◽  
Outer Continental Shelf ◽  
Merluccius Productus

Downstream and Early Marine Migratory Behaviour of Sockeye Salmon (Oncorhynchus nerka) Smolts Entering Barkley Sound, Vancouver Island

1993 ◽  
Vol 50 (6) ◽  
pp. 1329-1337 ◽  
Author(s):  
Chris C. Wood ◽  
N. Brent Hargreaves ◽  
Dennis T. Rutherford ◽  
Brian T. Emmett
Keyword(s):  
Surface Waters ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Vancouver Island ◽  
Migratory Behaviour ◽  
Merluccius Productus ◽  
Barkley Sound ◽  
Tidal Waters ◽  
Single Night ◽  
Catch Rates

Behaviour of sockeye salmon (Oncorhynchus nerka) smolts was studied during their migration down the Stamp and Somass rivers and through Alberni Inlet and Barkley Sound, Vancouver Island. Emigration from Great Central Lake was typical of other sockeye lakes: smolt abundance peaked in early May and most smolts left the lake at dusk. Migration down the rivers occurred only during twilight or darkness and most smolts made the 25-km journey to tidal waters within a single night. Those that did not held position in tight schools in the surface waters of deep pools during daylight. During downstream migration, ground speed averaged about 2.5 km/h, and smolts did not appear to be especially vulnerable to predation owing to their short residence time, with few smolts remaining in the river during daylight. Catch rates at purse-seine sampling sites throughout Alberni Inlet and Barkley Sound indicated that sockeye smolts migrated more slowly in tidal waters and were sometimes highly vulnerable to predaceous fish (especially Pacific hake, Merluccius productus). Estimated migration speeds through Alberni inlet were 1.9 km/d for smolts entering tidal waters during April and May, and 1.3 km/d for those during June and July; speed through Barkley Sound was 1.6 km/d throughout May–July.

Variation in Pacific Hake (Merluccius productus) Summer Length-at-Age Near Southern Vancouver Island and Its Relationship to Fishing and Oceanography

1990 ◽  
Vol 47 (11) ◽  
pp. 2195-2211 ◽  
Author(s):  
Barry D. Smith ◽  
Gordon A. McFarlane ◽  
Mark W. Saunders
Keyword(s):  
Sea Level ◽  
Coastal Upwelling ◽  
Southern Oscillation ◽  
Vancouver Island ◽  
Relative Strength ◽  
Merluccius Productus ◽  
Enso Events ◽  
Sea Level Anomalies ◽  
General Decline ◽  
Level Height

Male and female Pacific hake (Merluccius productus) sampled in summer off southern Vancouver Island since 1976 show a general decline, plus marked variability, in mean lengths-at-age. Multiple regression analysis related the length-at-age pattern to von Bertalanffy and density-dependent growth, length-selective fishing mortalities, and a suite of oceanographic covariates (sea level height, temperature, and salinity anomalies). Because offshore Pacific hake migrate annually between southern California and British Columbia, with larger fish migrating further north, we deduce that the summer fishery in Canadian waters selectively removes the larger hake each year causing a decline over time in mean lengths-at-age. Apart from the general decline, oceanographic factors explained most interannual variability in mean lengths-at-age. Specifically, mean lengths-at-age were generally smaller in years of above normal sea level height and temperature, and below normal salinity. Sea level anomalies in particular have been associated with the relative strength of the alongshore currents within the coastal upwelling domain; thus, we argue that stronger northward (or weaker southward) flows assist the northward migration of hake. Consequently, in years of higher than normal sea level, such as during major El Niño–Southern Oscillation (ENSO) events, more smaller hake arrive off Vancouver Island in summer resulting in lower mean lengths-at-age.

Inferring the Summer Distribution of Migratory Pacific Hake (Merluccius productus) from Latitudinal Variation in Mean Lengths-at-Age and Length Frequency Distributions

1992 ◽  
Vol 49 (4) ◽  
pp. 708-721 ◽  
Author(s):  
Barry D. Smith ◽  
Gordon A. McFarlane ◽  
Mark W. Saunders
Keyword(s):  
Fish Population ◽  
Vancouver Island ◽  
Length Frequency ◽  
Frequency Distributions ◽  
Merluccius Productus ◽  
The Mean ◽  
Summer Distribution ◽  
The Right ◽  
Mean Variance ◽  
Length Frequency Data

Average summer distribution of abundance and biomass for the migratory population of Pacific hake (Merluccius productus) is described by age, length, and latitude, based on a model proposing that (1) changes in mean length-at-age with latitude and (2) the nonnormal (skewed to the right) appearance of length-at-age distributions near southwest Vancouver Island could be caused by length-dependent migration velocities and changing migration velocity with latitude. Our model uses mean length-at-age data collected annually near four latitudes from California to Vancouver Island, length frequency data collected annually near southern Vancouver Island from 1978 until 1988, and hydroacoustic data collected triennialiy from 1977 until 1986. We conclude that (1) hake slow their northward migration from the spawning grounds off southern California as they approach the productive feeding grounds off southwestern Vancouver Island, (2) older (larger) hake migrate further north than younger (smaller) hake, and (3) older hake are more abundant in Canadian waters than younger hake. Although all three conclusions have previously been partly substantiated, we show that seemingly undramatic patterns in the mean, variance, and distribution of lengths-at-age can be remarkably revealing about the distribution of a migrating fish population.

Two species of Kudoa (Myxosporea: Multivalvulida) parasitic in the flesh of Merluccius productus (Ayres, 1855) (Pisces: Teleostei) in the Canadian Pacific

1981 ◽  
Vol 59 (11) ◽  
pp. 2085-2091 ◽  
Author(s):  
Z. Kabata ◽  
D. J. Whitaker
Keyword(s):  
New Species ◽  
Vancouver Island ◽  
The Other ◽  
Strait Of Georgia ◽  
Merluccius Productus ◽  
Two Samples ◽  
Host Parasite

Two samples of hake, Merluccius productus (Ayres, 1855), one taken SW off Vancouver Island, the other in the Strait of Georgia, were examined for muscle parasites. The offshore hake is infected with two species of Kudoa Meglitsch, 1947 (Myxosporea): K. thyrsitis (Gilchrist, 1924) and K. paniformis sp.nov. Only K. thyrsitis occurs in the Strait of Georgia. The new species is described and illustrated. Host–parasite relationships of both species are discussed and reasons for their differences in this respect are speculated upon.

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.

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