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.

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.

Predicting the recruitment strength of an annual squid stock: Loligo gahi around the Falkland Islands

2000 ◽  
Vol 57 (12) ◽  
pp. 2479-2487 ◽  
Author(s):  
David J Agnew ◽  
Simeon Hill ◽  
John R Beddington
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Negative Relationship ◽  
Sea Surface ◽  
Falkland Islands ◽  
Factors Affecting ◽  
Model Combining ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Faster Development

Two cohorts of Loligo gahi recruit to the fishery around the Falkland Islands, the first in summer and the second in autumn-winter. We investigated factors affecting recruitment to these cohorts using 13 years of data (1987-1999). The first evidence for density-dependent effects on recruitment in a squid population is reported, with very high spawning stock biomass leading to a reduction in recruitment in both cohorts. October sea surface temperature was negatively correlated with recruitment to the second cohort 6 months later, and a linear model explained 66% of the variance in recruitment strength. A model combining sea surface temperature and spawning stock size explained 77% of the variance. Thus, low October temperatures and moderate stock sizes lead to higher recruitment the following year than high October temperatures and high stock sizes. A strong negative relationship was also found between sea surface temperature in May and the timing of recruitment to the first cohort the following January-February, suggesting that higher temperatures lead to faster development of embryos or paralarvae and earlier recruitment to the fishery. A predictive model of recruitment size and timing should enable better management of L. gahi.

scholarly journals Incorporation of optimal environmental signals in the prediction of fish recruitment using random forest algorithms

2019 ◽  
Vol 76 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Szymon Smoliński
Keyword(s):  
Random Forest ◽  
Environmental Factors ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Baltic Sea ◽  
Time Window ◽  
Clupea Harengus ◽  
Sea Surface ◽  
Optimal Time ◽  
Fish Recruitment

The drivers of recruitment of selected Baltic sprat (Sprattus sprattus) and herring (Clupea harengus) stocks were investigated. Data on the interaction dynamics among fish species, the biological characteristics of the stocks, the biomass of the main predators, and the hydroclimatic environmental factors (Baltic Sea Index and sea surface temperature) were used in the analysis. The combination of random forest (Boruta algorithm) and “sliding window” approaches was tested on the simulated data and then used for the selection of relevant predictors and the optimal time window for real environmental variables. Sea surface temperature had a significant positive effect on the recruitment processes. Moreover, contrasting effects were observed in the mean Baltic Sea Index from two different time windows. The same environmental variable generated contrasting short-term and long-term effects on fish recruitment. This paper highlights the potential benefits of random forest and data mining applications for the incorporation of environmental factors in the assessment of stocks. The proposed analytical approach may be valuable for the investigations of complex environmental impacts in a broad range of ecological studies.

Life History Characteristics, Reproductive Value, and Resilience of Pacific Herring (Clupea harengus pallasi)

1985 ◽  
Vol 42 (S1) ◽  
pp. s127-s139 ◽  
Author(s):  
D. M. Ware
Keyword(s):  
Body Weight ◽  
Environmental Changes ◽  
The Body ◽  
Clupea Harengus ◽  
Reproductive Value ◽  
Female Size ◽  
Pacific Herring ◽  
Egg Weight ◽  
Surplus Energy ◽  
Clupea Harengus Pallasi

The energy supply available for growth and reproduction (surplus energy), fecundity, and egg size increase with female size in British Columbia stocks of Pacific herring (Clupea harengus pallasi). Fecundity is directly proportional to body weight, whereas egg weight is a curvilinear function with a weight exponent of about 0.2. The reproductive rate, defined as the product of fecundity and egg weight, is, therefore, proportional to the 1.2 power of the body weight. In 1974, 1978, and 1980 the size-dependent fecundity and reproductive rates were remarkably constant among management divisions along the coast. There is no evidence at present that these rates respond significantly to natural variations in stock abundance or marine climate, in contrast, there were interannual and regional differences in surplus energy that appeared as differences in the growth rate. Cluster analysis of the average length at ages 3–7 indicated that herring returning to the same division to spawn were more alike than those between divisions. An approximate reproductive value was calculated for the Queen Charlotte Island stock from the foregoing information, assuming that the population was momentarily at equilibrium. For the suspected natural mortality rate (M = 0.45), the maximum reproductive value occurred quite late in the life span: between ages 9 and 10. in other stocks of Pacific and Atlantic herring (Clupea harengus harengus), with adequate time series, the growth rates and hence weight-at-age have increased by as much as 50% in response to a combination of fishing and adverse environmental changes which reduced population size. Concurrently the age at first maturity fell by as much as 2 yr. It is argued that the maximum growth response of a herring population roughly defines its ability to stabilize itself. If the maximum compensatory response is a 50% increase in weight at age, the population should be able to sustain an annual exploitation rate between 0.2 and 0.3. In principle, at this level of harvesting the population will be as resilient to a short run of unfavorable conditions as an unexploited stock

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.

A semiparametric model to examine stock–recruitment relationships incorporating environmental data

2001 ◽  
Vol 58 (6) ◽  
pp. 1178-1186 ◽  
Author(s):  
D G Chen ◽  
J R Irvine
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Semiparametric Model ◽  
Clupea Harengus ◽  
Environmental Data ◽  
Sea Surface ◽  
Parameter Estimates ◽  
Model Parameters ◽  
Ricker Model ◽  
Stock Recruitment

A novel semiparametric model that can incorporate environmental and fishery data is developed to analyze stock–recruitment relationships. Unlike traditional stock–recruitment models that assume a log-linear relationship between recruitment and environmental and fishery variables, the new model uses a nonparametric smoothing algorithm, which helps quantify the underlying empirical relationships and enables more accurate parameter estimates. Bootstrap resampling is used to evaluate uncertainties in the model parameters. Distribution plots can be produced for stock–recruitment productivity and capacity parameters. This approach is applied to southeast Alaska pink salmon (Oncorhynchus gorbuscha) with sea surface temperature as the environmental variable and West Coast Vancouver Island herring (Clupea harengus) with sea surface temperature and hake biomass as two environmental variables. Results from diagnostic tests indicate that our model performed better than the traditional Ricker model and a Ricker model that was extended to include environmental effects.

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.

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.

Potential Secondary Production from Herring Spawning in the Strait of Georgia

1983 ◽  
Vol 40 (2) ◽  
pp. 109-113 ◽  
Author(s):  
D. E. Hay ◽  
J. Fulton
Keyword(s):  
Primary Production ◽  
Primary Productivity ◽  
Secondary Production ◽  
Clupea Harengus ◽  
Strait Of Georgia ◽  
Clupea Harengus Pallasi ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Larval Emergence ◽  
Carbon Contribution

About 22% of the total herring spawning stock biomass is released annually as milt and eggs. The carbon contribution from herring spawning products to the Strait of Georgia is small in comparison with estimates of annual primary productivity. However, when the carbon contribution is calculated over the ~ 50-d period of spawning, egg incubation and larval emergence for the areas of herring spawning, the estimate of 6.92 g C∙m−2∙d−1 is substantially higher than maximum estimates of primary productivity. Even allowing for considerable dilution and dispersion of spawning products, the estimate of carbon contribution is high relative to primary production. We propose that this material may be a source of energy to promote secondary production, particularly in the form of microzooplankton, such as protozoa, copepod nauplii, or larvae of benthic animals all of which could serve as food for emerging herring larvae.Key words: Clupea harengus pallasi, herring spawning, secondary production, primary production, microzooplankton

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