A review of factors limiting recovery of Pacific herring stocks in Canada

AbstractSchweigert, J. F., Boldt, J. L., Flostrand, L., and Cleary, J. S. 2010. A review of factors limiting recovery of Pacific herring stocks in Canada. – ICES Journal of Marine Science, 67: 1903–1913. On the west coast of Canada, Pacific herring (Clupea pallasi) supported an intensive reduction fishery from the early 1930s until the collapse of all five major stocks in the late 1960s, which then recovered rapidly following a fishery closure. Despite conservative harvests, abundance has declined again recently, with little evidence of recovery. We investigated the effect of bottom-up forcing by zooplankton abundance, top-down forcing by fish and mammal predators, and the effects of sardine abundance as potential competitors on the natural mortality of the herring stock on the west coast of Vancouver Island. Herring mortality was positively related to Thysanoessa spinifera and southern chaetognaths and negatively to pteropod abundance. Estimated predation on herring decreased significantly during the years 1973–2008, with the main consumers changing from fish to mammals. However, the correlation with herring mortality was negative, whereas there was a significant positive relationship with sardine abundance. Population recovery is expected to be facilitated by a combination of factors, including adequate food supply, limited or reduced predation (including fishing), and limited competition particularly for wasp–waist systems, where different forage species may occupy similar niches.

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Recruitment prediction for Pacific herring (Clupea pallasi) on the west coast of Vancouver Island, Canada

Ecological Informatics ◽

10.1016/j.ecoinf.2008.02.003 ◽

2008 ◽

Vol 3 (2) ◽

pp. 202-206 ◽

Cited By ~ 7

Author(s):

Michel Dreyfus-León ◽

Jake Schweigert

Keyword(s):

West Coast ◽

Vancouver Island ◽

Pacific Herring ◽

The West ◽

Clupea Pallasi

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Variability of Pacific herring (Clupea pallasii) spawn abundance under climate change off the West Coast of Canada over the past six decades

Journal of Marine Systems ◽

10.1016/j.jmarsys.2019.103229 ◽

2019 ◽

Vol 200 ◽

pp. 103229 ◽

Cited By ~ 1

Author(s):

Yi Xu ◽

Caihong Fu ◽

Angelica Peña ◽

Roy Hourston ◽

Richard Thomson ◽

...

Keyword(s):

Climate Change ◽

West Coast ◽

Pacific Herring ◽

The West ◽

Clupea Pallasii ◽

The Past

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Feeding by grey seals on endangered stocks of Atlantic cod and white hake

ICES Journal of Marine Science ◽

10.1093/icesjms/fsu123 ◽

2014 ◽

Vol 71 (6) ◽

pp. 1332-1341 ◽

Cited By ~ 24

Author(s):

M.O. Hammill ◽

G.B. Stenson ◽

D.P. Swain ◽

H.P. Benoît

Keyword(s):

High Mortality ◽

West Coast ◽

Atlantic Cod ◽

Stomach Contents ◽

Natural Mortality ◽

The West ◽

Cape Breton Island ◽

Cape Breton ◽

The Mean ◽

Overwintering Area

High natural mortality is preventing the recovery of collapsed stocks of Atlantic cod and white hake in the southern Gulf of St Lawrence, Canada. Predation by grey seals has been proposed as an important cause of this high mortality. We determined the contribution of cod and hake to the diet of grey seals collected along the west coast of Cape Breton Island and in the Cabot Strait, an area where overwintering cod aggregate. Along the coast of Cape Breton Island, the contribution of hake and cod to the diet was 30 and 17%, respectively, by weight using stomach contents and 13 and 9%, respectively, based on intestine contents. In the Cabot Strait, when overwintering aggregations of cod were present, cod accounted for 68% (range 57–80%) of the male diet from stomachs, and 46% (range: 31–64%) of the diet determined from intestines. Among females, cod represented 14% (range: 0–34%) and 9% (range: 3–54%) of the diet from stomachs and intestines, respectively. In Cabot Strait, white hake accounted for up to 17% of the diet by weight from stomachs, and up to 6% of the diet determined from intestines. The mean length of cod consumed by seals was 28 cm (SD = 8.6) along the coast of Cape Breton Island, and 39 cm (SD = 5.7) in Cabot Strait. The mean length of hake consumed by seals was 29 cm (SD = 7.0) along the coast of Cape Breton Island, and 35 cm (SD = 5.6) in Cabot Strait. Cod and hake are more important to the diet of males than that of females. The contribution of cod to the diet of grey seals foraging in the cod overwintering area is much greater than has been reported elsewhere.

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

Journal of the Fisheries Research Board of Canada ◽

10.1139/f55-030 ◽

1955 ◽

Vol 12 (4) ◽

pp. 571-592 ◽

Cited By ~ 21

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.

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Erratum: Age-specific natural mortality rates of adult Pacific herring (Clupea pallasi) from southern British Columbia

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f01-206 ◽

2002 ◽

Vol 59 (1) ◽

pp. 196

Author(s):

R W Tanasichuk

Keyword(s):

British Columbia ◽

Mortality Rates ◽

Pacific Herring ◽

Natural Mortality ◽

Clupea Pallasi

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Natural mortality estimates of juvenile Pacific herring (Clupea pallasi) in Prince William Sound, Alaska

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f02-017 ◽

2002 ◽

Vol 59 (3) ◽

pp. 416-423 ◽

Cited By ~ 8

Author(s):

Kevin DE Stokesbury ◽

Jay Kirsch ◽

E Vincent Patrick ◽

Brenda L Norcross

Keyword(s):

Size Structure ◽

Mortality Rates ◽

Pacific Herring ◽

Natural Mortality ◽

Prince William Sound ◽

Clupea Pallasi ◽

Northern Latitudes ◽

Primary Literature ◽

Acoustic Surveys ◽

Young Of The Year

The densities of young-of-the-year and 1-year-old Pacific herring, Clupea pallasi, in Prince William Sound, Alaska, were estimated using acoustic surveys from June 1996 to March 1998. Four bays were surveyed with acoustic transects that were repeated three times in 24 h. Species composition and size structure were determined from net collections. Averaging over the 24-h period allowed the best use of all data, as observations between the three replicates were similar but sporadic, possibly resulting from the different seasonal daynight cycle in these northern latitudes. The average instantaneous natural mortality rates for young-of-the-year Pacific herring were 0.009 (standard deviation (SD) = 0.002) and 0.016 (SD = 0.012) for the 1996 and 1997 cohorts, respectively. The average instantaneous natural mortality rates for 1-year-old Pacific herring were 0.003 (SD = 0.007) and 0.008 (SD = 0.005) for the 1995 and 1996 cohorts, respectively. Combining our estimates with those in the primary literature for other life history phases of Pacific herring indicated a progressive decrease in instantaneous natural mortality with age. This study presents the first direct estimates of natural mortality for juvenile herring.

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Age-specific natural mortality rates of adult Pacific herring (Clupea pallasi) from southern British Columbia

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f00-205 ◽

2000 ◽

Vol 57 (11) ◽

pp. 2258-2266 ◽

Cited By ~ 11

Author(s):

R W Tanasichuk

Keyword(s):

British Columbia ◽

Mortality Rate ◽

Sampling Bias ◽

Mortality Rates ◽

Energy Requirements ◽

Pacific Herring ◽

Natural Mortality ◽

Clupea Pallasi ◽

Surplus Energy ◽

Using Data

I used data for over 665 000 Pacific herring (Clupea pallasi) seined or gillnetted in southern British Columbia between 1951 and 1998 to estimate age- and year-specific adult natural mortality rates. Apparent sampling bias precluded using data collected before 1980. The instantaneous natural mortality rate is an increasing exponential function of age. Surplus energy requirements for gonad recrudescence appear to cause the death of adult herring.

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