History and present status of fisheries for marine fishes and invertebrates in the Strait of Georgia, British Columbia

1983 ◽  
Vol 40 (7) ◽  
pp. 1095-1119 ◽  
Author(s):  
K. S. Ketchen ◽  
N. Bourne ◽  
T. H. Butler
Keyword(s):  
Clupea Harengus ◽  
Pacific Cod ◽  
Cancer Magister ◽  
Strait Of Georgia ◽  
Merluccius Productus ◽  
Management Measures ◽  
Clupea Harengus Pallasi ◽  
Protothaca Staminea ◽  
Dungeness Crabs ◽  
Parophrys Vetulus

An historical account is given of the development of Strait of Georgia commercial fisheries (other than salmon) from their beginnings in the middle to late 19th century to the 1980s. Where possible, attempts were made to explain past fluctuation in abundance, especially to distinguish natural effects from those of fishing or socioeconomic origin. The review deals with commercial exploitation of herring (Clupea harengus pallasi), dogfish (Squalus acanthias), lingcod (Ophiodon elongatus), Pacific cod (Gadus macrocephalus), English sole (Parophrys vetulus), pollock (Theragra chalcogramma), hake (Merluccius productus), Dungeness crab (Cancer magister), shrimps (Pandalopsis dispar, Pandalus platyceros, P. jordani, P. hypsinotus and P. danae), oyster (Crassostrea gigas), butter clams (Saxidomus giganteus), little neck clams (Protothaca staminea), Manila clams (Tapes phillipinarum), geoduck clams (Panope generosa), and other invertebrates. Lingcod and the various shellfish species are also the object of recreational fisheries. Commercial landings in 1980 totalled 25 575 t with a landed value of over 20 million dollars. Over 57% of the weight landed and 70% of its landed value consisted of herring. Oysters, geoduck clams, Pacific cod, and Dungeness crabs were next in importance. We conclude that the future of the fishery will depend on policy regarding the coexistence of commercial and recreational components, the effectiveness of management measures, and probably on the success of controlling domestic and industrial pollution.

Alternative Harvest Strategies for Pacific Herring (Clupea harengus pallasi)

1988 ◽  
Vol 45 (5) ◽  
pp. 888-897 ◽  
Author(s):  
D. L. Hall ◽  
R. Hilborn ◽  
M. Stocker ◽  
C. J. Walters
Keyword(s):  
Management Strategies ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Harvest Rate ◽  
Strait Of Georgia ◽  
Clupea Harengus Pallasi ◽  
Current Management Strategy ◽  
Stock Recruitment ◽  
Spawning Biomass ◽  
Constant Escapement

A simulated Pacific herring (Clupea harengus pallasi) population is used to evaluate alternative management strategies of constant escapement versus constant harvest rate for a roe herring fishery. The biological parameters of the model are derived from data on the Strait of Georgia herring stock. The management strategies are evaluated using three criteria: average catch, catch variance, and risk. The constant escapement strategy provides highest average catches, but at the expense of increased catch variance. The harvest rate strategy is favored for its reduced variance in catch and only a slight decrease in mean catch relative to the fixed escapement strategy. The analysis is extended to include the effects of persistent recruitment patterns. Stock–recruitment analysis suggests that recruitment deviations are autocorrelated. Correlated deviations may cause bias in regression estimates of stock–recruitment parameters (overestimation of stock productivity) and increase in variation of spawning stock biomass. The latter effect favors the constant escapement strategy, which fully uses persistent positive recruitment fluctuations. Mean catch is depressed for the harvest rate strategy, since the spawning biomass is less often located in the productive region of the stock–recruitment relationship. The model is used to evaluate the current management strategy for Strait of Georgia herring. The strategy of maintaining a minimum spawning biomass reserve combines the safety of the constant escapement strategy and the catch variance reducing features of the harvest rate strategy.

Environmental Variation and Recruitment of Pacific Herring (Clupea harengus pallasi) in the Strait of Georgia

1985 ◽  
Vol 42 (S1) ◽  
pp. s174-s180 ◽  
Author(s):  
Max Stocker ◽  
Vivian Haist ◽  
David Fournier
Keyword(s):  
Environmental Variables ◽  
River Discharge ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Strait Of Georgia ◽  
Clupea Harengus Pallasi ◽  
Age Structured ◽  
Age Structured Model ◽  
The Relationship ◽  
Spawning Success

We used an age-structured model to estimate recruitment for the Strait of Georgia Pacific herring (Clupea harengus pallasi) population. The model used for herring is a version of the model described in Fournier and Archibald (1982. Can. J. Fish. Aquat. Sci. 39: 1195–1207), modified to include spawn survey information. Three structural assumptions are made to include the spawn data: (1) the form of the relationship between the actual spawn and the observed spawn, (2) the form of the relationship between escapement and actual spawn, and (3) the existence of a Ricker spawn–recruitment relationship, with a multiplicative environmental component. In order to determine which environmental factors had a significant effect on recruitment, we attempted to explain the residual variation from the Ricker curve with the environmental variables using exploratory correlations. Temperature, river discharge, sea level, and sunlight were examined. A multiplicative, environmental-dependent Ricker spawn–recruitment model was used to identify significant environmental variables. The model suggests a significant dome-shaped relationship between temperature and spawning success with an optimal temperature during larval stages resulting in maximum production of recruits. Also, increased spawning success is associated with increased summer river discharge. The significant environmental variables were included in the age-structured model in a stock–environment–recruitment relationship, and all model parameters were reestimated. The overall model fit improved only marginally with the inclusion of environmental variables, as indicated by the objective function value. However, the S–R component of the objective function dropped by 23% when environmental variables were included.

Spawning and Feeding Behavior of Captive Pacific Herring, Clupea harengus pallasi

1982 ◽  
Vol 39 (3) ◽  
pp. 489-498 ◽  
Author(s):  
N. E. Stacey ◽  
A. S. Hourston
Keyword(s):  
Gonadal Development ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Spawning Behavior ◽  
Sexual Pheromone ◽  
Behavioral Interactions ◽  
Merluccius Productus ◽  
Clupea Harengus Pallasi ◽  
Gadus Macrocephalus ◽  
The Common

Laboratory observations indicate that spawning of Pacific herring (Clupea harengus pallasi) involves very similar if not identical behavior in males and females, and no identifiable behavioral interactions between the sexes. The presence of a sexual pheromone in herring milt is indicated because spawning behavior is rapidly initiated in ripe (ovulated and spermiated) herring of either sex following exposure either to herring milt or to a filtrate of ripe herring testes. Exposure to herring eggs or to filtrates of hake (Merluccius productus) or Pacific cod (Gadus macrocephalus) testes did not elicit such responses. Four components of spawning behavior induced by herring testis filtrate are identified and described: rising and milling, papilla extension, substrate testing, and substrate spawning. Testis filtrates also elicited rising and milling in spent, developing, and mature (unovulated and unspermiated) fish but rising was not followed by papilla extension, substrate testing, or substrate spawning in fish at these earlier stages of gonadal development. Herring at all stages of maturity also displayed rising and milling in response to an olfactory stimulus (filtrate of crushed euphausiids). This feeding response was weakest in the mature and ripe stages, when fish under natural conditions are reported not to feed, and was strongest in the spent stage, when wild fish resume feeding. In terms of the common components of the response to testis and euphausid filtrates (increased swimming speed, rising, and milling), differential responses to these two stimuli were seen only in ripe fish, suggesting herring at other stages of gonadal development may simply perceive milt as a food stimulus.Key words: Clupea harengus pallasi, spawning behavior, pheromone, feeding

Growth and Maturation of Pacific Herring (Clupea harengus pallasi) in the Strait of Georgia

1985 ◽  
Vol 42 (S1) ◽  
pp. s138-s146 ◽  
Author(s):  
V. Haist ◽  
M. Stocker
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Clupea Harengus ◽  
Sea Surface ◽  
Pacific Herring ◽  
Juvenile Growth ◽  
Strait Of Georgia ◽  
Surplus Energy ◽  
Clupea Harengus Pallasi ◽  
Stock Biomass

Juvenile growth rate, adult surplus energy, and the maturation schedule for the Strait of Georgia Pacific herring (Clupea harengus pallasi) stock were investigated over the period 1950–81. The variance in weight at age 2 is largely accounted for by juvenile abundance and sea surface temperature, indicating density-dependent juvenile growth moderated by environmental factors. Density and environmental factors have been equally important in moderating juvenile growth. Yearly variation in maturation of 3-yr-old herring is related to their average length; however, in two of the eight years studied the 3-yr-olds matured at considerably smaller sizes. The variance in adult surplus energy (growth plus gonad production) was largely accounted for by body weight, adult biomass, and sea surface temperature. A dome-shaped relationship between surplus energy and biomass was indicated, suggesting that over a broad range of population size, adult surplus energy is not density dependent. The relationship of sea surface temperature to both juvenile growth and adult surplus energy was quadratic with an optimum value. Recruitment biomass has been a relatively larger component than adult production of total stock growth, particularly during the period of high fishing intensity. This resulted in large fluctuations in stock biomass; in recent years, with lower fishing intensity, adult production has been a larger component of stock growth, and the stock biomass has become more stable.

Modeling of Recruitment Patterns in Pacific Cod (Gadus macrocephalus) in Hecate Strait, British Columbia

1991 ◽  
Vol 48 (11) ◽  
pp. 2240-2249 ◽  
Author(s):  
A. V. Tyler ◽  
W. R. Crawford
Keyword(s):  
Response Surface ◽  
Clupea Harengus ◽  
Data Series ◽  
Pacific Cod ◽  
Modeling Framework ◽  
Pacific Cod Gadus Macrocephalus ◽  
Period 2 ◽  
Clupea Harengus Pallasi ◽  
Gadus Macrocephalus ◽  
Prediction Test

We combined published recruitment hypotheses into a single modeling framework and explored the relative contributions of the hypothesis factors to recruitment variation in Pacific cod (Gadus macrocephalus). Our five hypotheses were (1) recruitment decreased with increasing transport during the larval period; (2) recruitment was related to percentage hatching success as a dome-shaped curve with a peak between 4.0 and 5.0 °C; (3) recruitment was positively related to abundance of age-0 juvenile Pacific herring (Clupea harengus pallasi) hatched in the same year as the cod; (4) recruitment was positively related to abundance of age-0 and age-1 herring in the year prior to spawning; and (5) a dome-shaped curve related recruitment to adult stock size. We used new records for temperature, and a new index of advection based on measures of current in Hecate Strait. For fitting a response surface with age-3 cod recruitment as the independent variable, we used a 20-yr data series of variables from 1962 to 1981 inclusive and reserved data for the years 1982–85 for a prediction test. Only hypotheses 1 and 5 were supported by both the response surface fit and prediction tests. The stock–recruitment curve can be fitted only when the transport curve is fitted simultaneously.

Parasitism on Juvenile Pacific Salmon (Oncorhynchus) and Pacific Herring (Clupea harengus pallasi) in the Strait of Georgia by the River Lamprey (Lampetra ayresi)

1973 ◽  
Vol 30 (4) ◽  
pp. 565-570 ◽  
Author(s):  
J. F. Roos ◽  
P. Gilhousen ◽  
S. R. Killick ◽  
E. R. Zyblut
Keyword(s):  
Size Range ◽  
Pacific Salmon ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Strait Of Georgia ◽  
Clupea Harengus Pallasi ◽  
River Lamprey ◽  
Juvenile Pacific Salmon ◽  
Healing Wounds ◽  
Narrow Size Range

River lamprey (Lampetra ayresi) were found to parasitize the young of five species of Pacific salmon (Oncorhynchus) and Pacific herring (Clupea harengus pallasi) in the Strait of Georgia, B.C. The dorsal attachment of the river lamprey is in sharp contrast to the usually ventral attachment of other species of lampreys that parasitize salmonids. Up to 1.9% of young salmon showed evidence of lamprey marks, and marked fish were generally restricted to a narrow size-range. Some of the fish exhibited severe wounds. Evidence from healing wounds on fingerlings and scars on adults indicates that some juvenile salmon survive the attacks of the river lamprey.

Soft-Bodied Zooplankton Predators and Competitors of Larval Herring (Clupea harengus pallasi) at Herring Spawning Grounds in British Columbia

1990 ◽  
Vol 47 (3) ◽  
pp. 505-515 ◽  
Author(s):  
Jennifer E. Purcell
Keyword(s):  
British Columbia ◽  
Larval Survival ◽  
Clupea Harengus ◽  
Dietary Overlap ◽  
Spawning Grounds ◽  
Predator Species ◽  
Strait Of Georgia ◽  
Barkley Sound ◽  
Clupea Harengus Pallasi ◽  
Important Predator

The soft-bodied zooplankton predators and the microzooplankton foods of herring larvae were collected at 28 herring spawning grounds in British Columbia in April 1984, when herring larvae (Clupea harengus pallasi) hatched. The same predator species were found throughout coastal B.C., but total densities varied over three orders of magnitude. Barkley Sound had the highest densities, and bays in northern B.C. and the Strait of Georgia had higher densities than open shorelines in both regions. Eight of 18 species of soft-bodied predators contained herring larvae. The hydromedusan Aequorea victoria was the most important predator, and consumed 0.4% of the herring larvae∙d−1 in Fanny Bay, and 12.5, 3.9, and 0%∙d−1 over three consecutive days in Kulleet Bay as larval densities decreased. Herring larvae ate copepod nauplii (84.4%) and other microzooplankton. Densities of these prey varied between 0.8 and 37∙L−1 among 21 locations sampled. Only three species of hydromedusae showed extensive dietary overlap (90–100%) with larval herring. Soft-bodied predators consumed < 1%∙d−1 of the microzooplankton in 17 locations, and could have affected densities in only one of the 21 locations. The ratios of microzooplankton to predator densities varied over 1000-fold, suggesting great differences in the chances for herring larval survival among various locations.

An Evaluation of Morphometrics and Meristics for Stock Separation of Pacific Herring (Clupea harengus pallasi)

1984 ◽  
Vol 41 (3) ◽  
pp. 414-422 ◽  
Author(s):  
Hans Jürg Meng ◽  
Max Stocker
Keyword(s):  
British Columbia ◽  
Large Scale ◽  
Function Analysis ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Geographic Scale ◽  
Meristic Characters ◽  
Morphometric Characters ◽  
Strait Of Georgia ◽  
Clupea Harengus Pallasi

We conducted an analysis to determine if Pacific herring (Clupea harengus pallasi) stocks occurring in different localities in British Columbia waters could be separated using morphometric and meristic characters. Discriminant function analysis was applied to morphometric and meristic characters taken from food herring samples. Herring found in northern British Columbia waters were detectably different from those found in the Strait of Georgia. We recommend using meristic characters for separation on a broad geographic scale and using "best" morphometric characters for finer resolution within the established broader groups. We defined a set of 12 best morphometric characters for further large-scale studies.

Interaction between Pacific Cod (Gadus macrocephalus) and Herring (Clupea harengus pallasi) in the Hecate Strait, British Columbia

1986 ◽  
Vol 43 (4) ◽  
pp. 830-837 ◽  
Author(s):  
Carl J. Walters ◽  
M. Stocker ◽  
A. V. Tyler ◽  
S. J. Westrheim
Keyword(s):  
British Columbia ◽  
Historical Data ◽  
Stomach Contents ◽  
Clupea Harengus ◽  
Regression Analyses ◽  
Pacific Cod ◽  
Predator Prey ◽  
Pacific Cod Gadus Macrocephalus ◽  
Clupea Harengus Pallasi ◽  
Gadus Macrocephalus

Pacific cod (Gadus macrocephalus) and herring (Clupea harengus pallasi) in the Hecate Strait have shown fluctuations consistent with the hypothesis that herring recruitment rates are strongly influenced by cod predation. Regression analyses of herring juvenile survival, as measured by log recruits per herring spawner, on Pacific cod abundance indicate that the cod may cause a total instantaneous mortality rate averaging around 0.75∙yr−1 with each cod consuming several hundred herring. Somewhat lower estimates of herring consumption per cod were expected on the basis of stomach contents data, but the discrepancy may well be due to systematic underestimates of cod abundance. Cod recruitment rates are positively correlated with herring abundance, but it is impossible to determine from historical data whether this correlation reflects predator–prey interdependence or the impacts of older cod on their own offspring, since cod and herring abundances are inversely correlated. Peak cod abundances in northern British Columbia during the late 1950's may be partly responsible for the collapse of the herring reduction fishery of the 1960's, and management of the two species should be coordinated to reflect the possibility of similar events in the future.

Biological Basis of Maturation and Spawning Waves in Pacific Herring (Clupea harengus pallasi)

1989 ◽  
Vol 46 (10) ◽  
pp. 1776-1784 ◽  
Author(s):  
D. M. Ware ◽  
R. W. Tanasichuk
Keyword(s):  
Interannual Variation ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Sea Temperature ◽  
Instantaneous Rate ◽  
Strait Of Georgia ◽  
Clupea Harengus Pallasi ◽  
Maturation Rate ◽  
Spawning Time ◽  
Timing Of Spawning

Maturation rates (measured as the change in the gonosomatic index (GSI) with time) over the last month of the annual maturation cycle were estimated for male and female herring in British Columbia, between 1982–87. The data were analyzed to determine interannual and interregional differences in the maturation rate and its influence on spawning time. The data also indicated that in some areas herring spawned in discrete waves — the largest fish tended to spawn first and the smaller fish in subsequent waves. Each spawning wave lasted about 5–6 d and the interwave interval varied from 8–26 d in the Strait of Georgia. General equations were developed to describe gonadal growth over the entire maturation cycle. These equations accounted for the observed differences in: (1) the maturation rates between the sexes (males initially mature faster), (2) the interregional and interannual variation in the timing of spawning (herring tend to spawn later at higher latitudes, and earlier than normal when its warmer), and (3) provide an explanation for spawning waves. All of these phenomena derive from the fact that the instantaneous rate at which the gonad grows during the maturation cycle in both sexes depends on the weight of the fish, and the daily sea temperature.

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