Individual variability and spatial heterogeneity in fish population models

1994 ◽  
Vol 4 (1) ◽  
pp. 91-123 ◽  
Author(s):  
Jeffrey A. Tyler ◽  
Kenneth A. Rose
Keyword(s):  
Spatial Heterogeneity ◽  
Fish Population ◽  
Individual Variability ◽  
Population Models

Lack of relationship between simulated fish population responses and their life history traits: inadequate models, incorrect analysis, or site-specific factors?

2005 ◽  
Vol 62 (4) ◽  
pp. 886-902 ◽  
Author(s):  
Kenneth A Rose
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Lake Trout ◽  
Fish Population ◽  
Population Models ◽  
Site Specific ◽  
Density Dependent ◽  
Population Responses ◽  
Adult Growth ◽  
Specific Factors

Relationships between fish population responses to changes in their vital rates and commonly available life history traits would be a powerful screening tool to guide management about species vulnerability, to focus future data collection on species and life stages of concern, and to aid in designing effective habitat enhancements. As an extension of previous analyses by others, I analyzed the responses to changes in fecundity and yearling survival of age-structured matrix and individual-based population models of 17 populations comprising 10 species. Simulations of the matrix models showed that the magnitude of population responses, but not the relative order of species sensitivity, depended on the state (sustainable or undergoing excessive removals) of the population. Matrix and individual-based models predicted population responses that appeared to be unrelated to their species-level life history traits when responses were plotted on a three-end-point life history surface. Density-dependent adult growth was added to the lake trout (Salvelinus namaycush) matrix model, and simulations demonstrated the potential importance to predicted responses of density-dependent processes outside the usual spawner–recruit relationship. Four reasons for the lack of relationship between population responses and life history traits related to inadequate population models, incorrect analysis, inappropriate life history model, and important site-specific factors are discussed.

scholarly journals STUDY OF SINGLE-SPECIES POPULATION MODELS

2020 ◽  
pp. 161-166
Author(s):  
Marthak Rutu
Keyword(s):  
Spatial Heterogeneity ◽  
Environmental Effects ◽  
Age Structure ◽  
Single Species ◽  
Research Paper ◽  
Population Models ◽  
Deterministic Models ◽  
One Dimensional ◽  
Species Population ◽  
Single Species Population

In this research paper one dimensional population models developed centuries ago shows that growth and/decay of single homogeneous populations But environmental effects spatial heterogeneity or age-structure deterministic models prevailing single species population models.

The importance of noise in fish population models

1991 ◽  
Vol 11 (3-4) ◽  
pp. 197-223 ◽  
Author(s):  
Jon T. Schnute
Keyword(s):  
Fish Population ◽  
Population Models

scholarly journals Sustainability in single–species population models

2005 ◽  
Vol 360 (1453) ◽  
pp. 147-162 ◽  
Author(s):  
Terrance J. Quinn ◽  
Jeremy S. Collie
Keyword(s):  
Carrying Capacity ◽  
Egg Production ◽  
Single Species ◽  
Fish Population ◽  
Population Models ◽  
Reproductive Value ◽  
Fishing Mortality ◽  
Suitable Alternative ◽  
Trade Offs ◽  
Single Species Population

In this paper, we review the concept of sustainability with regard to a single–species, age–structured fish population with density dependence at some stage of its life history. We trace the development of the view of sustainability through four periods. The classical view of sustainability, prevalent in the 1970s and earlier, developed from deterministic production models, in which equilibrium abundance or biomass is derived as a function of fishing mortality. When there is no fishing mortality, the population equilibrates about its carrying capacity. We show that carrying capacity is the result of reproductive and mortality processes and is not a fixed constant unless these processes are constant. There is usually a fishing mortality, F MSY , which results in MSY, and a higher value, F ext , for which the population is eventually driven to extinction. For each F between 0 and F ext , there is a corresponding sustainable population. From this viewpoint, the primary tool for achieving sustainability is the control of fishing mortality. The neoclassical view of sustainability, developed in the 1980s, involved population models with depensation and stochasticity. This view point is in accord with the perception that a population at a low level is susceptible to collapse or to a lack of rebuilding regardless of fishing. Sustainability occurs in a more restricted range from that in the classical view and includes an abundance th reshold. A variety of studies has suggested that fishing mortality should not let a population drop below a threshold at 10–20% of carrying capacity. The modern view of sustainability in the 1990s moves further in the direction of precaution. The fishing mortality limit is the former target of F MSY (or some proxy), and the target fishing mortality is set lower. This viewpoint further reduces the range of permissible fishing mortalities and resultant desired population sizes. The objective has shifted from optimizing long–term catch to preserving spawning biomass and egg production for the future. The use of discount rates in objective functions involving catch is not a suitable alternative to protecting reproductive value. As we move into the post–modern time period, new definitions of sustainability will attempt to incorporate he economic and social aspects of fisheries and/or ecosystem and habitat requirements. These definitions now involve ‘warm and fuzzy’ notions (healthy ecosystems and fishing communities, the needs of future generations, diverse fish communities) and value judgements of desired outcomes. Additional work is needed to make these definitions operational and to specify quantitative objectives to be achieved. In addition, multiple objectives may be incompatible, so trade–offs in what constitutes sustainability must be made. The advances made under the single–species approach should not be abandoned in the post–modern era, but rather enhanced and combined with new approaches in the multi–species and economic realms.

Integrating Bioavailability of Metals in Fish Population Models

2021 ◽  
Author(s):  
Sharon D. Janssen ◽  
Karel P.J. Viaene ◽  
Patrick Van Sprang ◽  
Karel A.C. De Schamphelaere
Keyword(s):  
Fish Population ◽  
Population Models
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