The early life-history dynamics of Northeast Arctic cod: levels of natural mortality and abundance during the first 3 years of life

2016 ◽  
Vol 73 (2) ◽  
pp. 246-256 ◽  
Author(s):  
Bjarte Bogstad ◽  
Natalia A. Yaragina ◽  
Richard D.M. Nash
Keyword(s):  
Life History ◽  
Early Life ◽  
Egg Production ◽  
Gadus Morhua ◽  
Early Life History ◽  
Natural Mortality ◽  
Arctic Cod ◽  
Stock Assessments ◽  
Class Strength ◽  
New Generation

Recruitment at age 3 of the Northeast Arctic cod (Gadus morhua) is highly variable. It has generally been believed that year-class strength for this stock is determined prior to settlement to the bottom after about 6 months. However, newer observations indicate that year-class strength may change considerably between settlement and recruitment at age 3. Our analyses cover the 1983–2009 year classes where comprehensive data from total egg production (TEP), surveys, and stock assessments were available for a thorough examination of these cohorts. On average, only 6 out of 1 million of a new generation at the TEP stage reaches the age of recruitment to the fishery. The between-cohort variability in abundance is greatest at the ages 0–1 stage. Although the mortality is highest during the first months of life, the year-class strength can also be affected considerably by processes taking place between the 0-group stage (∼6 months) and age 3. The mortality in this period of life seems to be strongly density-dependent, and cannibalism is an important source of mortality.

Spatially dynamic maternal control of migratory fish recruitment pulses triggered by shifting seasonal cues

2018 ◽  
Vol 69 (6) ◽  
pp. 942 ◽  
Author(s):  
Daisuke Goto ◽  
Martin J. Hamel ◽  
Mark A. Pegg ◽  
Jeremy J. Hammen ◽  
Matthew L. Rugg ◽  
...  
Keyword(s):  
Life History ◽  
Early Life ◽  
Life Histories ◽  
Egg Production ◽  
Local Density ◽  
Early Life History ◽  
Biophysical Model ◽  
Larval Stages ◽  
Predation Mortality ◽  
Stability And Resilience

Environmental regimes set the timing and location of early life-history events of migratory species with synchronised reproduction. However, modified habitats in human-dominated landscapes may amplify uncertainty in predicting recruitment pulses, impeding efforts to restore habitats invaluable to endemic species. The present study assessed how environmental and spawner influences modulate recruitment variability and persistence of the Missouri River shovelnose sturgeon (Scaphirhynchus platorynchus) under modified seasonal spawning and nursery habitat conditions. Using a spatially explicit individual-based biophysical model, spawning cycle, early life-history processes (dispersal, energetics and survival) and prey production were simulated under incrementally perturbed flow (from –10 to –30%) and temperature (+1 and +2°C) regimes over 50 years. Simulated flow reduction and warming synergistically contracted spring spawning habitats (by up to 51%) and periods (by 19%). Under these conditions, fewer mature females entered a reproductive cycle, and more females skipped spawning, reducing spawning biomass by 20–50%. Many spawners migrated further to avoid increasingly unfavourable habitats, intensifying local density dependence in larval stages and, in turn, increasing size-dependent predation mortality. Diminished egg production (by 20–97%) and weakened recruitment pulses (by 46–95%) ultimately reduced population size by 21–74%. These simulations illustrate that environmentally amplified maternal influences on early life histories can lower sturgeon population stability and resilience to ever-increasing perturbations.

Paternal effects on early life history traits in Northwest Atlantic cod, Gadus morhua

2013 ◽  
Vol 29 (3) ◽  
pp. 623-629 ◽  
Author(s):  
M.-M. Kroll ◽  
M. A. Peck ◽  
I. A. E. Butts ◽  
E. A. Trippel
Keyword(s):  
Life History ◽  
Early Life ◽  
Gadus Morhua ◽  
Life History Traits ◽  
Atlantic Cod ◽  
Early Life History ◽  
Paternal Effects ◽  
Northwest Atlantic

Factors Influencing Year-Class Strength of Percids: A Summary and a Model of Temperature Effects

1977 ◽  
Vol 34 (10) ◽  
pp. 1900-1909 ◽  
Author(s):  
J. F. Koonce ◽  
T. B. Bagenal ◽  
R. F. Carline ◽  
K. E. F. Hokanson ◽  
M. Nagięć
Keyword(s):  
Life History ◽  
Temperature Regime ◽  
Early Life ◽  
Yellow Perch ◽  
Lake Erie ◽  
Perca Flavescens ◽  
Early Life History ◽  
Direct Effects ◽  
Factors Influencing ◽  
Class Strength

Factors regulating year-class strength in the percid genera Stizostedion and Perca are summarized. Some index of water temperature regime correlates significantly with year-class strength of percids in many water bodies. Moderate synchrony of year-class strength is noted for walleye (Stizostedion vitreum vitreum) in several lakes in North America. A probablistic model is proposed to explain the basis of temperature dependence of year-class strength in percids, but tests of the model using Lake Erie data indicated that observed correlations between temperature and year-class strength of yellow perch (Perca flavescens) and walleye may not be the result of direct effects of the temperature regime on survivorship of early life-history phases. Key words: Percidae, year-class strength, temperature, probalistic model, early life history

scholarly journals Factors Regulating Early Life History Dispersal of Atlantic Cod (Gadus morhua) from Coastal Newfoundland

PLoS ONE ◽  
2013 ◽  
Vol 8 (9) ◽  
pp. e75889 ◽  
Author(s):  
Ryan R. E. Stanley ◽  
Brad deYoung ◽  
Paul V. R. Snelgrove ◽  
Robert S. Gregory
Keyword(s):  
Life History ◽  
Early Life ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Early Life History

Prey tell: what quillback rockfish early life history traits reveal about their survival in encounters with juvenile coho salmon

2020 ◽  
Vol 650 ◽  
pp. 7-18 ◽  
Author(s):  
HW Fennie ◽  
S Sponaugle ◽  
EA Daly ◽  
RD Brodeur
Keyword(s):  
Life History ◽  
Early Life ◽  
Life History Traits ◽  
Direct Evidence ◽  
Coho Salmon ◽  
Larval Fish ◽  
Early Life History ◽  
In The Wild ◽  
Otolith Microstructure Analysis ◽  
Pelagic Juvenile

Predation is a major source of mortality in the early life stages of fishes and a driving force in shaping fish populations. Theoretical, modeling, and laboratory studies have generated hypotheses that larval fish size, age, growth rate, and development rate affect their susceptibility to predation. Empirical data on predator selection in the wild are challenging to obtain, and most selective mortality studies must repeatedly sample populations of survivors to indirectly examine survivorship. While valuable on a population scale, these approaches can obscure selection by particular predators. In May 2018, along the coast of Washington, USA, we simultaneously collected juvenile quillback rockfish Sebastes maliger from both the environment and the stomachs of juvenile coho salmon Oncorhynchus kisutch. We used otolith microstructure analysis to examine whether juvenile coho salmon were age-, size-, and/or growth-selective predators of juvenile quillback rockfish. Our results indicate that juvenile rockfish consumed by salmon were significantly smaller, slower growing at capture, and younger than surviving (unconsumed) juvenile rockfish, providing direct evidence that juvenile coho salmon are selective predators on juvenile quillback rockfish. These differences in early life history traits between consumed and surviving rockfish are related to timing of parturition and the environmental conditions larval rockfish experienced, suggesting that maternal effects may substantially influence survival at this stage. Our results demonstrate that variability in timing of parturition and sea surface temperature leads to tradeoffs in early life history traits between growth in the larval stage and survival when encountering predators in the pelagic juvenile stage.

scholarly journals Early life history responses and phenotypic shifts in a rare endemic plant responding to climate change

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Daniel E Winkler ◽  
Michelle Yu-Chan Lin ◽  
José Delgadillo ◽  
Kenneth J Chapin ◽  
Travis E Huxman
Keyword(s):  
Climate Change ◽  
Life History ◽  
Phenotypic Variation ◽  
Early Life ◽  
Early Life History ◽  
Interactive Effects ◽  
Endemic Plant ◽  
Cushion Plant ◽  
Rare Endemic

We studied how a rare, endemic alpine cushion plant responds to the interactive effects of warming and drought. Overall, we found that both drought and warming negatively influenced the species growth but that existing levels of phenotypic variation may be enough to at least temporarily buffer populations.

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