title: Breeding return times and abundance in capture-recapture models.
abstract: For many long-lived animal species, individuals do not breed every year, and are often not accessible during non-breeding periods. Individuals exhibit site fidelity if they return to the same breeding colony or spawning ground when they breed. If capture and recapture is only possible at the breeding site, temporary emigration models are used to allow for only a subset of the animals being present in any given year. Most temporary emigration models require the use of the robust sampling design, and their focus is usually on probabilities of annual survival and of transition between breeding and non-breeding states. We use lake sturgeon (Acipenser fulvescens) data from a closed population where only a simple (one sample per year) sampling scheme is possible, and we also wish to estimate abundance as well as sex-specific survival and breeding return time probabilities. By adding return time parameters to the Schwarz-Arnason version of the Jolly-Seber model, we have developed a new likelihood-based model which yields plausible estimates of abundance, survival, transition and return time parameters. An important new finding from investigation of the model is the overestimation of abundance if a Jolly-Seber model is used when Markovian temporary emigration is present.
authors.affiliation: School of Mathematics, Statistics and Operations Research, Victoria University of Wellington, Wellington 6140, New Zealand.
authors.forename: Shirley
authors.initials: S
authors.lastname: Pledger
authors.forename: Edward
authors.initials: E
authors.lastname: Baker
authors.forename: Kim
authors.initials: K
authors.lastname: Scribner
mesh_terms: D000818:Animals; D001947:Breeding / Q000706:statistics & numerical data*; D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D005260:Female; D005399:Fishes / Q000502:physiology*; D016013:Likelihood Functions; D008297:Male; D015233:Models, Statistical; D011157:Population Dynamics; D011159:Population Surveillance / Q000379:methods*; D012107:Research Design; D018401:Sample Size
keywords: Abundance; Breeding return times; Capture-recapture analysis; Lake sturgeon; Temporary emigration; Unobserved state