Generalized fish life-cycle poplulation model and computer program
A generalized fish life-cycle population model and computer program have been prepared to evaluate the long-term effect of changes in mortality in age class 0. The general question concerns what happens to a fishery when density-independent sources of mortality are introduced that act on age class 0, particularly entrainment and impingement at power plants. This paper discusses the model formulation and computer program, including sample results. The population model consists of a system of difference equations involving age-dependent fecundity and survival. The fecundity for each age class is assumed to be a function of both the fraction of females sexually mature and the weight of females as they enter each age class. Natural mortality for age classes 1 and older is assumed to be independent of population size. Fishing mortality is assumed to vary with the number and weight of fish available to the fishery. Age class 0 is divided into six life stages. The probability of survival for age class 0 is estimated considering both density-independent mortality (natural and power plant) and density-dependent mortality for each life stage. Two types of density-dependent mortality are included. These are cannibalism of each life stage by older age classes and intra-life-stage competition.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 5115285
- Report Number(s):
- ORNL/TM-6125; TRN: 12-009247
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
COMPUTER CODES
FISHES
LIFE CYCLE
POPULATION DYNAMICS
AGE DEPENDENCE
ENTRAINMENT
FERTILITY
FORTRAN
IMPINGEMENT
MATHEMATICAL MODELS
MORTALITY
POPULATIONS
SURVIVAL TIME
ANIMALS
AQUATIC ORGANISMS
PROGRAMMING LANGUAGES
VERTEBRATES
520100* - Environment
Aquatic- Basic Studies- (-1989)
550100 - Behavioral Biology