PIERRE PEPIN results 19
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Identifying the Drivers of Newfoundland Capelin Recruitment After a Breakdown in the Environment–Recruitment RelationshipNARA Subscribed
Environment‐recruitment relationships often break down over time. This can occur because of spurious results from testing numerous environmental variables in the original analyses or from relative changes in the importance of specific environmental drivers over time. An environment‐recruitment model was developed for the Newfoundland and Labrador capelin stock, but the relationship first weakened with the addition of new data...
Morphological covariates of the ontogenetic shift from nauplii to copepodite prey in larval fishNARA Subscribed
Larval fish are active planktonic predators, with many species feeding initially on copepod nauplii and gradually shifting their selection to copepodites. This study evaluated whether it is possible to develop a general widely applicable empirical model to describe the transition from feeding on copepod nauplii to copepodites in relation to body length, maxilla length and eye diameter. The study also evaluated whether the swit...
Life in the fast lane: Revisiting the fast growth—High survival paradigm during the early life stages of fishesNARA Subscribed
Early life survival is critical to successful replenishment of fish populations, and hypotheses developed under the Growth‐Survival Paradigm (GSP) have guided investigations of controlling processes. The GSP postulates that recruitment depends on growth and mortality rates during early life stages, as well as their duration, after which the mortality declines substantially. The GSP predicts a shift in the frequency distributio...
Plankton size spectra as an indicator of larval success in Pacific sardine ( Sardinops sagax )NARA Subscribed
Estimating demographic changes in a population requires the measurement of some minimal combination of several vital rates, including the flux of individuals into a population, the population growth rate, individual growth rates and mortality rates. For larval fishes, the ratio of instantaneous mortality to growth (i.e., their ‘recruitment potential’) has been used to make inferences of cohort trajectory where measures of popu...
Incorporating knowledge of changes in climatic, oceanographic and ecological conditions in Canadian stock assessmentsNARA Subscribed
Environmental impacts on fisheries are pervasive, yet methods to account for them in stock assessments and management decisions vary in rigour and quality. The prevalence and efficacy of methods to account for environmental impacts are not well documented, limiting our ability to adequately respond to future environmental and climate changes for adaptive resource management. In Canada, legislation now requires that environment...
Potential impact of climate change on northern shrimp habitats and connectivity on the Newfoundland and Labrador continental shelvesNARA Subscribed
The effect of climate change on ocean circulation and environmental conditions will likely impact important fisheries species which have a limited habitat range and a prolonged larval dispersal phase. Based on projections from a regional scale ice‐ocean model (RCP 8.5 scenario), we investigated the spatial distribution variability of the bentho‐pelagic northern shrimp ( Pandalus borealis ) preferred depth and thermal habitat a...
Response of Scotian Shelf silver hake ( Merluccius bilinearis ) to environmental variabilityNARA Subscribed
Commercially‐exploited fish populations are not only shaped by fishing pressure, but also by the dynamics of their environment. By quantifying the influence of environmental variability, fisheries management advice can be improved and uncertainties reduced. To this end, we developed statistical models of the response of Scotian Shelf silver hake stock metrics to variability in zooplankton community composition and phenology ov...
Assessing connectivity patterns among management units of the Newfoundland and Labrador shrimp populationNARA Subscribed
The Eastern Canadian northern shrimp population, representing one of the most important fisheries in the region, decreased dramatically since the mid‐2000s to a historical low in 2017, but changes were not spatially uniform. Applying a biophysical model within Newfoundland and Labrador ( NL ) management areas, we investigated connectivity processes during the long pelagic larval phase (2–3 months) of Pandalus borealis and key...
Spring larval fish assemblages in the Strait of Georgia (British Columbia, Canada) were characterized for the first time based on three spatially extensive field surveys in late‐April of 2007, 2009 and 2010, a period which spanned both warm and cold environmental conditions. The abundance, diversity and community structure of the assemblages were examined to investigate interannual variability, and responses to environmental f...
Reproductive resilience: a paradigm shift in understanding spawner‐recruit systems in exploited marine fishNARA Subscribed
A close relationship between adult abundance and stock productivity may not exist for many marine fish stocks, resulting in concern that the management goal of maximum sustainable yield is either inefficient or risky. Although reproductive success is tightly coupled with adult abundance and fecundity in many terrestrial animals, in exploited marine fish where and when fish spawn and consequent dispersal dynamics may have a gre...
We investigated the drift of passive particles on the N ewfoundland S helf and western L abrador S ea using numerical simulations to assess the possible sources of plankton collected at a high frequency sampling site (S27; 47.55°N, 52.59°W) located near the coast of N ewfoundland, C anada. We also summarized data detailing the seasonal stage succession of C alanus finmarchicus at that site, as well as along three oceanographic...
Predicting the vertical profiles of anchovy ( Engraulis mordax ) and sardine ( Sardinops sagax ) eggs in the California Current SystemNARA Subscribed
Several published models exist for simulating vertical profiles of pelagic fish eggs, but no one has rigorously assessed their capacity to explain observed variability. In this study, we applied a steady‐state model, with four different formulations for vertical diffusivity, to northern anchovy ( Engraulis mordax ) and Pacific sardine ( Sardinops sagax ) eggs in the California Current region. Vertical mixing profiles, based on...
Fisheries Ecology and ManagementNARA Subscribed
Using patch studies to link mesoscale patterns of feeding and growth in larval fish to environmental variabilityNARA Subscribed
We present results from a series of three patch studies designed to examine links between environmental variability and mesoscale patterns of feeding and growth of larval radiated shanny ( Ulvaria subbifurcata ). We examine the effects of variability in temperature, turbulence and prey concentration on both the mean (i.e. population level) and the variance (i.e. individual level) of larval feeding and growth rates among the th...
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