title: Trap-shyness subsidence is a threshold function of mark-recapture interval in brown mudfish Neochanna apoda populations.
abstract: The influence of capture interval on trap shyness, and temperature, rainfall and drought on capture probability (p) in 827 brown mudfish Neochanna apoda was quantified using mark-recapture models. In particular, it was hypothesized that the loss of trapping memory in marked N. apoda would lead to a capture-interval threshold required to minimize trap shyness. Neochanna apoda trap shyness approximated a threshold response to capture interval, declining rapidly with increasing capture intervals up to 16.5 days, after which p remained constant. Tests for detecting trap-dependent capture probability in Cormack-Jolly-Seber models failed to detect trap shyness in N. apoda capture histories with capture intervals averaging 16 days. This confirmed the applicability of the 16 day capture-interval threshold for mark-recapture studies. Instead, N. apoda p was positively influenced by water temperature and rainfall during capture. These results imply that a threshold capture interval is required to minimize the trade-off between the competing assumptions of population closure and p homogeneity between capture occasions in closed mark-recapture models. Moreover, environmental factors that influence behaviour could potentially confound abundance indices, and consequently abundance trends should be interpreted with caution in the face of long-term climate change, such as with global warming.
authors.affiliation: School of Biological Sciences, University of Canterbury, Christchurch, 8140, New Zealand.
authors.forename: R S A
authors.initials: RS
authors.lastname: White
authors.affiliation: Department of Watershed Sciences, Utah State University, Logan, UT, 84321, U.S.A.
authors.forename: P A
authors.initials: PA
authors.lastname: McHugh
authors.affiliation: School of Biological Sciences, University of Canterbury, Christchurch, 8140, New Zealand.
authors.forename: C N
authors.initials: CN
authors.lastname: Glover
authors.affiliation: School of Biological Sciences, University of Canterbury, Christchurch, 8140, New Zealand.
authors.forename: A R
authors.initials: AR
authors.lastname: McIntosh
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D002980:Climate; D005399:Fishes / Q000502:physiology*; D008954:Models, Biological; D011336:Probability; D013312:Stress, Physiological
keywords: capture probability; catchability; climate; temperature; trap awareness; trap dependence