Broad-scale climate influences on cod (Gadus morhua) recruitment on Georges Bank

AbstractGröger, J. P., and Fogarty, M. J. 2011. Broad-scale climate influences on cod (Gadus morhua) recruitment on Georges Bank. – ICES Journal of Marine Science, 68: . Climatic influences on Georges Bank cod recruitment were investigated using the North Atlantic Oscillation (NAO) as an index of atmospheric variability and the Atlantic Multidecadal Oscillation (AMO) as an index of sea surface temperature. A quantitative approach based on a simple Cushing-type stock–recruitment model was developed and extended to include climate influences using the technique of generalized transfer functions (ARIMAX modelling). This allowed the autoregressive nature of the interacting exogenous and endogenous processes to be taken into account. Based on two information criteria, the resulting best transfer function contains winter NAO with a lag of 3 years, annual AMO with a lag of 1 year (both as exogenous climate factors), loge(spawning-stock biomass) as a structural model component, plus two autoregressive parameters. The model is characterized by the smallest information criteria, 92% of explained recruitment variation (vs. 55% from the simple Cushing-type model), excellent forecasting behaviour, and all model assumptions being fulfilled. It is proposed that the model's recruitment hindcasts (ex post forecasts) and forecasts be incorporated into stock and risk assessments as well as management strategy evaluations, either as a climate-induced recruitment index for projections or as real forecasts to establish sustainable cod fisheries on Georges Bank conditioned by climate as a forcing factor.

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The association between Northern Hemisphere climate patterns and interannual variability in Canadian wildfire activity

Canadian Journal of Forest Research ◽

10.1139/x11-131 ◽

2011 ◽

Vol 41 (11) ◽

pp. 2193-2201 ◽

Cited By ~ 13

Author(s):

J.L. Beverly ◽

M.D. Flannigan ◽

B.J. Stocks ◽

P. Bothwell

Keyword(s):

Northern Hemisphere ◽

Arctic Oscillation ◽

Fire Suppression ◽

Atlantic Multidecadal Oscillation ◽

Area Burned ◽

Regression Modelling ◽

Climate Patterns ◽

Large Fires ◽

Climate Influences ◽

Broad Scale

Wildfire impacts on ecological and socioeconomic systems are regulated, in part, by climate. Association between hemispheric-scale climate patterns and annual wildfire activity can be obscured by local factors that also control the initiation and spread of fires. Vegetation, topography, and fire suppression can be expected to influence conventional measures of annual wildfire activity such as area burned, effectively concealing evidence of broad-scale climate influences. This study investigates alternatives to area-burned statistics for quantifying annual wildfire activity in Canada in relation to Northern Hemisphere climate variability represented by the Atlantic Multidecadal Oscillation (AMO). We depart from conventional approaches by including socioeconomic measures of wildfire activity and by assessing spatially referenced wildfire data over units of observation chosen explicitly to diminish variability caused by factors unrelated to broad-scale climate. Our data-centred approach, combined with linear regression modelling, revealed that the AMO was positively correlated with national time series of very large fires (≥10 000 ha), wildfire-related evacuations, and fire suppression expenditures over the period 1975–2007. The AMO and wildfire activity were most closely coupled during a period of predominantly positive-phase Arctic Oscillation (AO) and Pacific Decadal Oscillation (PDO) between 1989 and 2001. Positive correlation between maximum evacuation wind speed and the AMO suggests that wind may be a causal factor in the AMO–wildfire relationship.

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Fractal and Fractional Derivative Modelling of Material Phase Change

Fractal and Fractional ◽

10.3390/fractalfract4030046 ◽

2020 ◽

Vol 4 (3) ◽

pp. 46

Author(s):

Harry Esmonde

Keyword(s):

Transfer Functions ◽

Type Model ◽

Material Structure ◽

Iterative Approach ◽

Response Functions ◽

Physical Processes ◽

Ethyl Vinyl ◽

Solid Models ◽

Liquid Type ◽

Model Phase

An iterative approach is taken to develop a fractal topology that can describe the material structure of phase changing materials. Transfer functions and frequency response functions based on fractional calculus are used to describe this topology and then applied to model phase transformations in liquid/solid transitions in physical processes. Three types of transformation are tested experimentally, whipping of cream (rheopexy), solidification of gelatine and melting of ethyl vinyl acetate (EVA). A liquid-type model is used throughout the cream whipping process while liquid and solid models are required for gelatine and EVA to capture the yield characteristic of these materials.

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Ex post and ex ante prediction of unobserved multivariate time series: a structural-model based approach

Journal of Forecasting ◽

10.1002/for.1017 ◽

2007 ◽

Vol 26 (1) ◽

pp. 53-76 ◽

Cited By ~ 2

Author(s):

Fabio H. Nieto

Keyword(s):

Time Series ◽

Structural Model ◽

Multivariate Time Series ◽

Model Based ◽

Ex Post ◽

Ex Ante

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Risk Assessment of Ex-Post Transaction Cost in Construction Projects Using Structural Equation Modeling

Sustainability ◽

10.3390/su10114017 ◽

2018 ◽

Vol 10 (11) ◽

pp. 4017 ◽

Cited By ~ 5

Author(s):

Zaigham Ali ◽

Fangwei Zhu ◽

Shahid Hussain

Keyword(s):

Structural Equation Modeling ◽

Life Cycle ◽

Transaction Cost ◽

Life Cycle Cost ◽

Structural Equation ◽

Construction Projects ◽

Structural Model ◽

Equation Modeling ◽

Ex Post ◽

Industry Professionals

The transaction cost (TC) escalation is the pervasive problem in the construction industry, which is continuously a threat to maintaining the life cycle cost of projects. Researchers have described the reality of risk for economic transactions. This study has taken the risk as a phenomenon to explore its influence on ex-post TC in construction projects. A questionnaire survey was undertaken from industry professionals to assess the risk of ex-post TC escalation in public-sector construction projects. In total, 475 surveys were conducted in Pakistan and used in the analysis. The data were analyzed using structural equation modeling (SEM) and the measurement and structural model was validated to determine the influence of risk on ex-post TC. The final SEM results show that internal and external risk, including sub hypothesized risks, positively influence TC. The weight of relative importance shows technical risk (23.82%) and environmental risk (22.88%) as significant sub-contributors from internal and external sources, respectively. This study recommends substantial investment in human capacity development to reduce the deficiencies in the ex-ante phase of the projects that help to reduce the risk of ex-post TC escalation. It also suggests the adoption of strict policies on contingency claims, and recommends nontraditional ways of monitoring to overcome the risk of ex-post TC. This study’s results provide valuable information for industry professionals and practitioners to maintain life cycle costs as a contribution to sustainable construction.

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Recent Growth, Biochemical Composition and Prey Field of Larval Haddock (Melanogrammus aeglefinus) and Atlantic Cod (Gadus morhua) on Georges Bank

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f87-003 ◽

1987 ◽

Vol 44 (1) ◽

pp. 14-25 ◽

Cited By ~ 100

Author(s):

L. J. Buckley ◽

R. G. Lough

Keyword(s):

Gadus Morhua ◽

Atlantic Cod ◽

Dry Weight ◽

Melanogrammus Aeglefinus ◽

Good Growth ◽

Georges Bank ◽

Larval Population ◽

Prey Biomass ◽

Recent Growth ◽

Haddock Melanogrammus Aeglefinus

A transect across southern Georges Bank in May 1983 showed higher levels of available prey for haddock (Melanogrammus aeglefinus) and cod (Gadus morhua) larvae at two stratified sites than at a well-mixed site. At the stratified sites, prey biomass was high (30–300 μg dry wt∙L−1) near the surface above the thermocline; values were lower and more uniform with depth (10–30 μg dry wt∙L−1) at the well-mixed site. Larval population centers generally coincided with prey biomass vertically. Recent growth in dry weight of haddock larvae as estimated by RNA–DNA ratio analysis was higher at the stratified sites (8–13%∙d−1) than at the well-mixed site (7%∙d−1). Larvae appeared to be in excellent condition at the stratified sites, but up to 50% of haddock larvae from the well-mixed site had RNA–DNA ratios in the range observed for starved larvae in the laboratory. Cod collected at the same site were in better condition and growing faster than haddock. The data support the hypotheses that (1) stratified conditions in the spring favor good growth and survival of haddock larvae and (2) cod larvae are better adapted to grow and survive in well-mixed waters at lower levels of available food than haddock larvae.

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All the species seen during broad-scale cruises from the US-GLOBEC Georges Bank Program

Biological and Chemical Oceanography Data Management Office ◽

10.1575/1912/bco-dmo.2292.1 ◽

2004 ◽

Author(s):

Edward Durbin

Keyword(s):

Georges Bank ◽

The Us ◽

Broad Scale

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Small-scale temporal and spatial variation in Atlantic cod (Gadus morhua) life history

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f03-090 ◽

2003 ◽

Vol 60 (9) ◽

pp. 1111-1121 ◽

Cited By ~ 44

Author(s):

Tara M McIntyre ◽

Jeffrey A Hutchings

Keyword(s):

Body Mass ◽

Life Histories ◽

Gadus Morhua ◽

Atlantic Cod ◽

Spatial Scales ◽

Gonadosomatic Index ◽

Small Scale ◽

Hepatosomatic Index ◽

Georges Bank ◽

High Fecundity

Life histories of Atlantic cod (Gadus morhua) from the Gulf of St. Lawrence south to Georges Bank differ significantly through time and space. Within the Southern Gulf, fecundity per unit body mass differed by more than 40% over short (2 years) and long (4245 years) periods of time. Significant variation in size-specific fecundity is also evident among populations: Southern Gulf cod produce almost 30% more eggs per unit body mass than those on Georges Bank, whereas fecundity of Scotian Shelf cod is almost half that of cod in Sydney Bight. Compared with those on Georges Bank, Southern Gulf cod life histories are characterized by high fecundity, late maturity, high gonadosomatic index, and large eggs. Relative to the influence of body size, neither temporal nor spatial differences in fecundity can be attributed to physiological condition, as reflected by liver weight, hepatosomatic index, and Fulton's K. Delayed maturity and higher reproductive allotment among Southern Gulf cod can be explained as selection responses to slower growth, higher prereproductive mortality, and fewer lifetime reproductive events. Patterns of covariation in heritable, fitness-related traits suggest the existence of adaptive variation and evolutionarily significant units at spatial scales considerably smaller than the species range in the Northwest Atlantic.

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