INDIVIDUAL-BASED MODEL OF YOUNG-OF-THE-YEAR STRIPED BASS POPULATION-DYNAMICS .1. MODEL DESCRIPTION AND BASE-LINE SIMULATIONS

Authored by Kenneth A Rose, JH Cowan

Date Published: 1993

DOI: 10.1577/1548-8659(1993)122<0415:ibmoyo>2.3.co;2

Sponsors: United States Department of Energy (DOE) Electric Power Research Institute (EPRI)

Platforms: No platforms listed

Model Documentation: Other Narrative Flow charts Mathematical description

Model Code URLs: Model code not found

Abstract

An individual-based model of population dynamics of age-0 striped bass Morone saxatilis is described and model predictions are analyzed. The model begins with spawning and simulates the daily growth and mortality of the progeny from each egg clutch as the fish develop through the life stages of egg, yolk-sac larva, feeding larva, and juvenile during their first year of life in a single, well-mixed compartment. Day of spawning and development rates of eggs and yolk-sac larvae depend on temperature. Daily growth of feeding individuals is represented by a bioenergetics equation, for which consumption is based on random encounters by individuals with different types of prey. Larvae feed on four zooplankton types and juveniles feed exclusively on size-classes of four benthic types. Mortality of eggs and yolk-sac larvae has both temperature-dependent and constant terms; mortality of feeding larvae and juveniles depends on an individual's weight and length. Most of the computations in the simulation involve determining the daily number of each prey type eaten by each striped bass. Model predictions of larval and juvenile densities, growth rates, and mortality rates were similar to values observed in the Potomac River. Larger mothers produce more and larger eggs, which lead to larger larvae at first feeding. Increasing first-feeding size from 5.0 to 5.5 mm caused a 4.5-fold increase in survival to age 1. Average growth rates during the first 15 d of feeding for larvae that would survive to age 1 were about 0.1 mm/d higher than the average of all larvae. Juveniles in the model appeared to die at random because both the rate and the degree of size-selective mortality decreased rapidly during the juvenile stage. The model represents feeding in detail: additional model refinements and analyses should focus on incorporating behavioral and phenotypic differences among individuals, spatial and temporal variability in temperature and prey, and further model corroboration.

Tags

Mortality growth Temperature Size Smallmouth bass Reactive distance Larval fish Bluegill lepomis-macrochirus Morone-saxatilis Potomac estuary