A multicohort stock production model

Jerald S. Ault, Donald B. Olson

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


An age structured production model of multicohort fish population dynamics based on the mean metabolic state of individuals and the average abundance of year-classes is proposed. The model allows variations in life stage basal metabolic rates by parameterizing their effects on total population abundance through a mortality function which itself depends upon an individual's status relative to an optimal metabolic state. The metabolic equations are derived in terms of age-specific individual weight. The interaction of individual status and intraspecific competition is allowed by coupling the metabolic equations for growth to those for population abundance. This coupling yields a second-order nonlinear equation in abundance or biomass. In model simulations, (1) increased numbers of cohorts decreased the stability of population biomass, (2) numerically 'strong' year- classes damped and sometimes caused collapse of proximal age-classes, (3) exploitation reduced competitive interactions and increased model stability, and (4) increases in natural mortality introduced greater recruitment variability. The transitional and steady state behaviors of the multicohort model are explored and compared to traditional fishery management models for a small pelagic species, northern anchovy Engraulis mordax.

Original languageEnglish (US)
Pages (from-to)343-363
Number of pages21
JournalTransactions of the American Fisheries Society
Issue number3
StatePublished - May 1996

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science


Dive into the research topics of 'A multicohort stock production model'. Together they form a unique fingerprint.

Cite this