Simulated and observed response of the southwest Vancouver Island pelagic ecosystem to oceanic conditions in the 1990s

1999 ◽  
Vol 56 (12) ◽  
pp. 2433-2443 ◽  
Author(s):  
Clifford KL Robinson ◽  
Daniel M Ware
Keyword(s):  
Empirical Data ◽  
Coastal Upwelling ◽  
Condition Factor ◽  
Model Performance ◽  
Ecosystem Model ◽  
Vancouver Island ◽  
Pacific Herring ◽  
Pelagic Ecosystem ◽  
Clupea Pallasi ◽  
The Pacific

In this paper, we discuss changes in the ocean climate around La Perouse Bank off southwestern Vancouver Island, British Columbia, and its influence on the functioning of the pelagic ecosystem. We compare results of a one-dimensional simulation model of plankton and fish production and biomass dynamics with empirical data collected in the 1990s. Comparisons of simulation results with empirical data indicate that the La Perouse model can account for relative interannual changes in copepod biomass, euphausiid biomass and production, the consumption of Pacific herring (Clupea pallasi) by Pacific hake (Merluccius productus), and the growth condition factor of Pacific hake. The model is less successful at capturing changes in spring diatom biomass, the proportion of euphausiids in the Pacific hake diet, and interannual variability in the Pacific herring condition factor. A measure of overall model performance suggests that the La Perouse ecosystem model performs equally well in both strong and weak upwelling periods. The La Perouse ecosystem model has been used to generate an annual index of net phytoplankton and macrozooplankton production for the coastal upwelling region off southwestern Vancouver Island from 1967 to 1998.

Influence of biomass and ocean climate on the growth of Pacific herring (Clupea pallasi) from the southwest coast of Vancouver Island

1997 ◽  
Vol 54 (12) ◽  
pp. 2782-2788 ◽  
Author(s):  
R W Tanasichuk
Keyword(s):  
Growth Rates ◽  
Growing Season ◽  
Vancouver Island ◽  
Pacific Herring ◽  
Daily Growth ◽  
Sea Temperature ◽  
Clupea Pallasi ◽  
Southwest Coast ◽  
Growth Increments ◽  
Adult Growth

I examined the growth of Pacific herring (Clupea pallasi) from the southwest coast of Vancouver Island using data for over 83 000 fish seined between 1975 and 1996. Size-at-age (length, total mass) of recruits (age 3) was negatively related to parental biomass. Length was also negatively related to sea temperature over the first growing season and positively related to salinity later in the third growing season. Prerecruit effects explained variations in mass and length for adult herring ages 4 and 5, respectively. Growth of adults was described as growth increments (growth rates). Seasonal growth in length for adults was assumed to be a linear function of time, and growth in mass an exponential function. Daily growth rates for length were negatively related to initial length. Instantaneous daily growth rates in mass were a negative function of initial mass, adult biomass, and sea temperature in August. Interannual variations in condition suggest that adults grow differently in mass than they do in length. I suggest that length is not synonymous with mass as a measure of adult growth. Consequently, it provides little, if any, information on surplus energy accumulation by adults and therefore adult fish contribution to stock productivity.

scholarly journals Data conflicts in fishery models: incorporating hydroacoustic data into the Prince William Sound Pacific herring assessment model

2007 ◽  
Vol 65 (1) ◽  
pp. 25-43 ◽  
Author(s):  
Peter-John F. Hulson ◽  
Sara E. Miller ◽  
Terrance J. Quinn ◽  
Gary D. Marty ◽  
Steven D. Moffitt ◽  
...  
Keyword(s):  
Large Population ◽  
Population Decline ◽  
Assessment Model ◽  
Pacific Herring ◽  
Prince William Sound ◽  
Clupea Pallasi ◽  
The Pacific ◽  
Age Structured ◽  
Population Indices ◽  
Asa Model

Abstract Hulson, P-J. F., Miller, S. E., Quinn, T. J. II, Marty, G. D., Moffitt, S. D., and Funk, F. 2008. Data conflicts in fishery models: incorporating hydroacoustic data into the Prince William Sound Pacific herring assessment model. – ICES Journal of Marine Science, 65: 25–43. Data conflicts present difficulties in running integrated assessment models as shown by the age-structured assessment (ASA) model for the Pacific herring population in Prince William Sound (PWS), Alaska. After the 1989 “Exxon Valdez” oil spill in PWS, the Pacific herring (Clupea pallasi) ASA model indicated a significant decline in the population, starting in winter 1992. Back-calculated estimates from hydroacoustic abundance surveys that started in 1993 suggested that the ASA model overestimated herring biomass from 1990 to 1992 and that the population decline actually began in 1989. To expose data conflicts, we incorporated the hydroacoustic survey information with all available spawning population indices directly into the age-structured model. In this way, the substantial uncertainty about population parameters from 1989 to 1992 attributable to data conflicts was quantified. Consequently, the magnitude of declines for that period estimated from both linear and ASA models depend on the type of integrated datasets and weighting, particularly with indices of male spawners. Our view is that a major decline started in 1992 when disease affected a large population that was in weakened condition. Other views are consistent with the existing data too.

scholarly journals Two egg-derived molecules in sperm motility initiation and fertilization in the Pacific herring (Clupea pallasi)

2008 ◽  
Vol 52 (5-6) ◽  
pp. 743-752 ◽  
Author(s):  
Gary N. Cherr ◽  
Masaaki Morisawa ◽  
Carol A. Vines ◽  
Kaoru Yoshida ◽  
Edmund H. Smith ◽  
...  
Keyword(s):  
Sperm Motility ◽  
Pacific Herring ◽  
Clupea Pallasi ◽  
The Pacific

Modelling Pelagic Fish and Plankton Trophodynamics off Southwestern Vancouver Island, British Columbia

1994 ◽  
Vol 51 (8) ◽  
pp. 1737-1751 ◽  
Author(s):  
Clifford L. K. Robinson ◽  
Daniel M. Ware
Keyword(s):  
British Columbia ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Coastal Upwelling ◽  
Squalus Acanthias ◽  
Pacific Herring ◽  
Fish Production ◽  
Clupea Pallasi ◽  
Merluccius Productus ◽  
Arrival Timing

A trophodynamics model is used to estimate annual plankton and fish production for the southern British Columbia continental shelf during 1985–89. The model describes the feeding interactions among diatoms, copepods, euphausiids, juvenile and adult Pacific herring (Clupea pallasi), Pacific hake (Merluccius productus), chinook salmon (Oncorhynchus tshawytscha), and spiny dogfish (Squalus acanthias) and is forced by empirical seasonal patterns in upwelling, sea surface temperature, and solar radiation. The most important simulation results are that (1) there is an imbalance between fish consumption and euphausiid production during the summer upwelling season, (2) the biomass and arrival timing of migratory hake significantly influence plankton and fish production, and (3) about 11% of the 332 g C∙m−2∙yr−1 annual diatom production is transferred to copepods and euphausiids and 1.0% of the diatom production to fish, while 27.5% of the 11.9 g C∙m−2∙yr−1 euphausiid production is consumed by herring and hake. The high plankton and fish production on the southern British Columbia shelf is comparable with other productive coastal upwelling regions.

scholarly journals Effects of Salinity on Sperm Motility, Fertilization, and Development in the Pacific Herring, Clupea pallasi

1998 ◽  
Vol 194 (1) ◽  
pp. 25-35 ◽  
Author(s):  
F. J. Griffin ◽  
M. C. Pillai ◽  
C. A. Vines ◽  
J. Kääriä ◽  
T. Hibbard-Robbins ◽  
...  
Keyword(s):  
Sperm Motility ◽  
Pacific Herring ◽  
Clupea Pallasi ◽  
The Pacific
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