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Journal ArticleDOI

Modelling fish spatial dynamics and local density-dependence relationships: detection of patterns at a global scale

01 Sep 1998-Aquatic Living Resources (EDP Sciences)-Vol. 11, Iss: 5, pp 305-314

AbstractA model is used to explore whether local density-dependent recruitment relationships can be observed when considering a larger scale. A virtual population of spawners is tracked within an artificial environment composed of cells. Spawners can move from one cell to another on a spatial grid defined as a square lattice (lattice scale) made of 20 x 20 jointed hexagonal cells (local scale). Five spawner's behaviours are experimented successively: i) spawners stay in the same cell to spawn; ii) they move randomly towards one of the neighbouring cells; iii) they move towards the least populated neighbouring cell; iv) they move towards the most populated neighbouring cell; and v) they move randomly towards a neighbouring cell and then move towards the most populated neighbouring cell. When the migration of spawners is achieved, spawners reproduce only once, recruitment takes place and then they disappear. The recruitment is an event which occurs at a local scale: at the scale of the cell. Using Ricker's stock-recruitment relationship, in each cell the number of recruits is a function of the spawners. Random migrations and migrations towards the less populated cell allow a homogeneous distribution of the spawners throughout the lattice. Whereas in the three other cases, this distribution is not homogenised. The homogenisation of the lattice allows synchrony between local populations and then a stock-recruitment relationship is observable at the lattice scale. Simulations show that local density-dependence is not always detectable when considering large spatial scale. This result strengthens the idea that the choice of spatial scale is essential when studying stockrecruitment relationship.

Topics: Population (51%)

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Citations
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Journal ArticleDOI
TL;DR: This work considers modelling and other applications, including the role of nearest neighbourhood in experimental design, the representation of connectivity in maps, and a new method for performing field surveys using hexagonal grids, which was demonstrated on montane heath vegetation.
Abstract: Regular grids or lattices are frequently used to study ecosystems, for observations, experiments and simulations. The regular rectangular or square grid is used more often than the hexagonal grid, but their relative merits have been little discussed. Here we compare rectangular and hexagonal grids for ecological applications. We focus on the reasons some researchers have preferred hexagonal grids and methods to facilitate the use of hexagonal grids. We consider modelling and other applications, including the role of nearest neighbourhood in experimental design, the representation of connectivity in maps, and a new method for performing field surveys using hexagonal grids, which was demonstrated on montane heath vegetation. The rectangular grid is generally preferred because of its symmetrical, orthogonal co-ordinate system and the frequent use of rasters from Geographic Information Systems. Cells in a rectangular grid can also easily be combined to produce new grids with lower resolutions. However, efficient co-ordinate systems and multi-resolution partitions using the hexagonal grid are available. The nearest neighbourhood in a hexagonal grid is simpler and less ambiguous than in a rectangular grid. When nearest neighbourhood, movement paths or connectivity are important, the rectangular grid may not be suitable. We also investigate important differences between visualizations using hexagonal and rectangular grids. A survey of recent uses of grids in Ecological Modelling suggested that hexagonal grids are rarely used, even in applications for which they are more suitable than rectangular grids, e.g. connectivity and movement paths. Researchers should consider their choice of grid at an early stage in project development, and authors should explain the reasons for their choices.

298 citations


Book
01 Jan 2002
TL;DR: The Human Dimension of Fisheries Science: (P. J. Reynolds, N. Dulvy And C. Roberts) uncovers the human dimension of fisheries science as well as the science and management of fisheries, and some of the aspects of management and ecology that have changed over time.
Abstract: Volume 1: Fish Biology. 1. Banishing Ignorance: Underpinning Fisheries with Basic Biology (P. J. B. Hart and J. D. Reynolds). 2. Phylogeny and Systematics of Fishes (A. C. Gill and R.D. Mooi). 3. Historical Biogeography of Fishes (R. D. Mooi and A. C. Gill). 4. The Physiology of Living in Water (O. Brix). 5. Environmental Factors and Rates of Development and Growth (M. Jobling). 6. Recruitment: Understanding Density--dependence in Fish Populations (R. A. Myers). 7. Life Histories of Fish (J. A. Hutchings). 8. Migration (J. Metcalfe, G. Arnold and R. McDowall). 9. Genetics of Fish Populations (R. D. Ward). 10. Behavioural Ecology of Reproduction in Fish (E. Forsgren, J. D. Reynolds and A. Berglund). 11. Fish Foraging and Habitat Choice: A Theoretical Perspective (G. G. Mittelbach). 12. Feeding Ecology of Piscivorous Fishes (F. Juanes, J. A. Buckel and F. S. Scharf). 13. Fish as Prey (J. Krause, E. M. A. Hensor and G. D. Ruxton). 14. Trophic Ecology and the Structure of Marine Food Webs (N. V.C. Polunin and J.K. Pinnegar). 15. Community Ecology of Freshwater Fishes (L. Persson). 16. Comparative Ecology of Marine Fish Communities (K. Martha M. Jones, D. G. Fitzgerald and P. F. Sale). 17. Interactions Between Fish, Parasites and Disease (I. Barber and R. Poulin). Volume 2: Fisheries. 1. The Human Dimension Of Fisheries Science: (P. J. B. Hart And J. D. Reynolds). 2. Fish Capture Devices In Industrial And Artisanal Fisheries And Their Influence On Management (O. A. Misund, J. Kolding and P. Freon). 3. Marketing Fish (J. A. Young And J. F. Muir). 4. A History Of Fisheries And Their Science And Management (T. D. Smith). 5. Gathering Data For Resource Monitoring And Fisheries Management (D. Evans and R. Grainger). 6. Surplus Production Models (J. T. Schnute And L. Richards). 7. Dynamic Pool Models I: Interpreting The Past Using Virtual Population Analysis (J. G. Shepherd And J. G. Pope). 8. Dynamic Pool Models II: Short--Term And Long--Term Forecasts Of Catch And Biomass (J. G. Shepherd And J. G. Pope). 9. A Bumpy Old Road: Size--Based Methods In Fisheries Assessment (T. J. Pitcher). 10. Ecosystem Models (D. Pauly And V. Christensen). 11. Individual--Based Models (G. Huse, J. Giske And A. G. V. Salvanes). 12. The Economics Of Fisheries (R. Hannesson). 13. Choosing The Best Model For Fisheries Assessment (P. Sparre And P. J. B. Hart). 14. Marine Protected Areas, Fish And Fisheries (N. V. C. Polunin). 15. Exploitation And Other Threats To Fish Conservation (J. D. Reynolds, N. K. Dulvy And C. M. Roberts). 16. Ecosystem Effects Of Fishing (M. J. Kaiser And S. Jennings). 17. Recreational Fishing (I. G. Cowx)

236 citations


Book ChapterDOI
10 Mar 2008

54 citations


Journal ArticleDOI
TL;DR: This work presents the individual-based model Piscator, which describes a multi-species fish community and demonstrates techniques to deal with the inherent complexity of such a model, and proposes a novel procedure for calibration and analysis, in which the complexity of the model is increased step-by-step.
Abstract: Unraveling the mechanisms that drive dynamics of multi-species fish communities is notoriously difficult. Not only are the interactions between fish populations complex, but also the functional niche of individual animals changes profoundly as they grow, making variation in size within populations and even within cohorts highly important to consider. Not surprisingly, traditional aggregated populations models have proved limited in their capacity to describe the dynamics of interacting fish species, and individual-based models have become popular for modeling fish populations. Nonetheless, the majority of the individual-based models describes either a single species or focus entirely on a certain life stage. We present the individual-based model Piscator, which describes a multi-species fish community and demonstrates techniques to deal with the inherent complexity of such a model. We propose a novel procedure for calibration and analysis, in which the complexity of the model is increased step-by-step. We also illustrate the use of a special Monte-Carlo sensitivity analysis to identify clusters of parameters that have roughly the same effects on the model results. As an example, we use the model to analyze a fishery experiment in the Frisian Lakes (The Netherlands). Despite high bream catches (40–50 kg ha−1 per year), it was observed that the seine fishery had unexpected little effect on the bream population. Our simulation results suggest that if one takes community feedbacks and climatic variability into account, this effect can be explained. The main cause was, besides a reduction of piscivory due to a simultaneous gill-net fishery, a coincidental strong year-class just before the fishery started. The strong development of this year-class could be explained by 3 subsequent warm years, whereas yearly variations in recruitment were less important. We also suggest that this relatively realistic model could play a role in ecological theory. It can be used to analyze the conditions for multi-year cycles and chaotic dynamics, phenomena that are usually predicted only from simple abstract models.

47 citations


Journal ArticleDOI
TL;DR: Two individual-based models for the movement of elvers in the French river ‘Adour’ are built and a set of stochastic differential equations and a partial differential equation for the elvers’ density are rigorously obtained.
Abstract: The aim of this paper is to introduce a method of verification of individual-based modeling through a relevant example. We build two individual-based models for the movement of elvers in the French river ‘Adour’. We rigorously obtain a set of stochastic differential equations and a partial differential equation for the elvers’ density, both of which describe the same phenomenon. We solve the partial differential equation numerically and compare statistically the results of both methods, concluding that they are equivalent. This approach constitutes a verification and a protocol of analysis of our individual-based models.

25 citations


References
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Book
30 Jun 1993
Abstract: Series foreword AJ Pitcher Foreword D Pauly Part One: Fundamentals of the theory of fishing, illustrated by analysis of a trawl factoy Introduction:- theoretical methods in the study of fishery dynamics The basis of a theoretical model of an exploited fish population and definition of the primary factors Mathematical representation of the four primary factors Recruitment Natural mortality Fishing mortality Growth A simple model giving the annual yield in weight from a fishery in a steady state Adaptation of the simple model to give other characteristics of the catch and population Part Two: Some extensions of the simple theory of fishing Recruitment and egg-production Natural mortality Fishing mortality and effort Growth and feeding Spatial variation in the values of parameters movement of fish within the exploited area Mixed populations:- the analysis of community dynamics Part Three: Estimation of parameters Relative fishing power of vessels and standardisation of commercial statistics of fishing effort Estimation of the total mortality coefficient (F + M), and the maximum age, t* Seperate estimation of fishing and natural mortality coefficients Recruitment and egg-production Growth and feeding Part Four: The use of theoretical models in a study of the dynamics and reaction to exploitation of fish populations Application of population models of part one Application of population models of part two Principles and methods of fishery regulation Requirements for the regulation of the North Sea Demersal fisheries Appendices Bibliography and author index Subject index List of amendments compiled by the American Fisheries Society

4,358 citations


Journal ArticleDOI
Abstract: This example is provided so that non-theorists may see actual applications of the theory previously described. The Dickcissel sex ratio is employed as an indirect index of suitability. A sex ratio index was found to be correlated positively with density. This is consistent with the hypothesis that territorial behavior in the males of this species limits their density. This study provides a valid example of how the problem can be approached and offers a first step in the eventual identification of the role of territorial behavior in the habitat distribution of a common species.

4,081 citations


Journal ArticleDOI
TL;DR: Plotting net reproduction (reproductive potential of the adults obtained) against the density of stock which produced them, for a number of fish and invertebrate populations, gives a domed curve whose apex lies above the line representing replacement reproduction.
Abstract: Plotting net reproduction (reproductive potential of the adults obtained) against the density of stock which produced them, for a number of fish and invertebrate populations, gives a domed curve wh...

2,853 citations


Book
07 Nov 1996
Abstract: One-Dimensional Maps.- Two-Dimensional Maps.- Chaos.- Fractals.- Chaos in Two-Dimensional Maps.- Chaotic Attractors.- Differential Equations.- Periodic Orbits and Limit Sets.- Chaos in Differential Equations.- Stable Manifolds and Crises.- Bifurcations.- Cascades.- State Reconstruction from Data.

1,861 citations


Journal ArticleDOI
Abstract: We review the early development of metapopulation ideas, which culminated in the well-known model by Levins in 1969. We present a survey of metapopulation terminology and outline the kinds of studies that have been conducted on single-species and multispecies metapopulations. Metapopulation studies have important conceptual links with the equilibrium theory of island biogeography and with studies on the dynamics of species living in patchy environments. Metapopulation ideas play an increasingly important role in landscape ecology and conservation biology.

1,470 citations