Trap-shyness subsidence is a threshold function of mark-recapture interval in brown mudfish Neochanna apoda populations

R. S.A. White, P. A. Mchugh, C. N. Glover, A. R. Mcintosh

Research output: Contribution to journalJournal Articlepeer-review

8 Citations (Scopus)


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 16·5days, 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 16days. This confirmed the applicability of the 16day 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.

Original languageEnglish
Pages (from-to)967-980
Number of pages14
JournalJournal of Fish Biology
Issue number4
Publication statusPublished - 1 Oct. 2015


  • Capture probability
  • Catchability
  • Climate
  • Temperature
  • Trap awareness
  • Trap dependence


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