Vulnerability of larval herring (Clupea harengus pallasi) to capture by the jellyfish Aequorea victoria

1987 ◽  
Vol 94 (2) ◽  
pp. 157-162 ◽  
Author(s):  
J. E. Purcell ◽  
T. D. Siferd ◽  
J. B. Marliave
Keyword(s):  
Clupea Harengus ◽  
Aequorea Victoria ◽  
Clupea Harengus Pallasi

Predation by Medusae on Pacific Herring (Clupea harengus pallasi) Larvae

1982 ◽  
Vol 39 (11) ◽  
pp. 1537-1540 ◽  
Author(s):  
Mary Needler Arai ◽  
Douglas E. Hay
Keyword(s):  
British Columbia ◽  
Coastal Waters ◽  
Laboratory Tests ◽  
Clupea Harengus ◽  
Aurelia Aurita ◽  
Pacific Herring ◽  
Aequorea Victoria ◽  
Clupea Harengus Pallasi

In laboratory tests young Pacific herring (Clupea harengus pallasi) larvae were eaten by several species of hydromedusae common in coastal waters off British Columbia, including the previously controversial Sarsia tubulosa and by the scyphomedusa Aurelia aurita. Field collections and observations confirmed that the distributions of medusae and larvae overlap and that some medusae feed on herring larvae in nature. In coastal waters and bays of British Columbia, the hydromedusae Sarsia tubulosa or Aequorea victoria may be most abundant during the time of peak herring larvae abundance.Key words: herring, larvae, Clupea, Sarsia, Aequorea, predation, medusae

Predation on Fish Larvae and Eggs by the Hydromedusa Aequorea victoria at a Herring Spawning Ground in British Columbia

1989 ◽  
Vol 46 (8) ◽  
pp. 1415-1427 ◽  
Author(s):  
Jennifer E. Purcell
Keyword(s):  
British Columbia ◽  
Fish Larvae ◽  
Clupea Harengus ◽  
Gut Content Analysis ◽  
Gut Content ◽  
Fish Eggs ◽  
Aequorea Victoria ◽  
Clupea Harengus Pallasi ◽  
Pelagic Eggs ◽  
Eggs And Larvae

The importance of soft-bodied zooplankton as predators of fish eggs and larvae was examined during March–June, 1983 in Kulleet Bay, Vancouver Island, British Columbia. The diet of the jellyfish Aequorea victoria was evaluated by gut content analysis of individually collected specimens. Crustacean zooplankters were eaten in lesser proportion, and larvaceans, fish larvae, hydromedusae, and siphonophores were eaten in greater proportion than their presence in the environment. Numerous herring larvae (Clupea harengus pallasi) were consumed, as well as the larvae of fishes in several other families (primarily Pleuronectidae, Cottidae, Scorpaenidae, Stichaeidae, Pholidae, and Gadidae), and the pelagic eggs of flatfish (Family Pleuronectidae). When herring larvae hatched in mid-March, A. victoria medusae in the bay contained an average of 22 herring larvae each, comprising 48% of all ingested prey. The predation rates on herring and other fish larvae were calculated from the numbers of larvae in A. victoria, the digestion times, and the field densities of medusae and larvae. Accordingly, 4 newly-hatched herring larvae∙m−3∙d−1 (0.7%∙d−1) were consumed by A. victoria but few were eaten after April 5–6. Predation on other fish larvae was [Formula: see text] larvae∙m−3∙d−1 during April 5 to May 3, but was not detectable in samples collected during May 9 to June 7. Other soft-bodied predators (ctenophores, chaetognaths, siphonophores, and other hydromedusae) contained few fish larvae.

Fixation Shrinkage of Herring Larvae: Effects of Salinity, Formalin Concentration, and Other Factors

1982 ◽  
Vol 39 (8) ◽  
pp. 1138-1143 ◽  
Author(s):  
D. E. Hay
Keyword(s):  
Clupea Harengus ◽  
Pacific Herring ◽  
Larval Size ◽  
Factors Affecting ◽  
Clupea Harengus Pallasi

The most important factors affecting the degree of larval shrinkage of Pacific herring (Clupea harengus pallasi) larvae during fixation are the salinity and formalin concentrations and initial larval size. In low formalin concentrations (2–5% formalin) shrinkage increased from less than 2% shrinkage at low salinities to about 10% shrinkage in seawater formalin. In high formalin concentrations (20–30% formalin) shrinkage was fairly uniform, ranging from about 3% shrinkage in low salinities to about 5% in seawater. Shrinkage in fixatives stored at 0, 5, 10, 20, and 30 °C was slightly higher (1–2%) at the higher temperatures. Buffering agents and starvation had no effect on shrinkage. Small, young larvae shrank relatively more than larger older larvae.Key words: herring larvae, fixation, shrinkage, formalin, salinity

Chill Stowage and Development of Rancidity in Frozen Pacific Herring, Clupea harengus pallasi

1978 ◽  
Vol 35 (4) ◽  
pp. 473-477 ◽  
Author(s):  
E. Bilinski ◽  
R. E. E. Jonas ◽  
Y. C. Lau
Keyword(s):  
Key Words ◽  
Peroxide Value ◽  
Frozen Storage ◽  
Thiobarbituric Acid ◽  
Acid Number ◽  
Clupea Harengus ◽  
Pacific Herring ◽  
Clupea Harengus Pallasi ◽  
Low Levels

Freshly caught Pacific herring, Clupea harengus pallasi, were stowed in ice or refrigerated seawater (RSW) at −0.8 °C for 0, 2, and 4 d and were then filleted and stored frozen (−28 °C) for up to 11 mo. The development of rancidity was determined using the peroxide value and the thiobarbituric acid number. During the chill stowage before freezing, the lipids from the flesh were not subjected to any significant oxidation. In Cryovac-vacuum-packed fillets the rancidity remained at low levels during the duration of frozen storage. If oxygen was present during frozen storage, chill stowage accelerated the development of rancidity and this effect was more pronounced in the case of RSW than ice, especially after 4 d of stowage. Key words: Pacific herring, Clupea harengus pallasi, rancidity, icing, refrigerated seawater, frozen storage

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.

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