title: Methods for assessment of short-term coral reef fish movements within an acoustic array.
abstract: BACKGROUND
  Arrays of passive receivers are a widely used tool for tracking the movements of acoustically-tagged fish in marine ecosystems; however, the spatial and temporal heterogeneity of coral reef environments pose challenges for the interpretation of tag detection data. To improve this situation for reef fishes, we introduced a novel response variable method that treats signal detections as proportions (i.e., percent transmissions detected or "detection rates") and compared this against prior approaches to examine the influence of array and transmitter performance, signal distance and environmental factors on detection rates. We applied this method to tagged snappers and groupers in the Florida reef ecosystem and controlled range-tests on static targets in Bayboro Harbor, Florida, to provide methodological guidance for the planning and evaluation of passive array studies for coral reef fishes.
  
  
  RESULTS
  Logistic regression analysis indicated detection rates were primarily a non-linear function of tag distance from receiver. A 'model-weighted' function was developed to incorporate the non-linear relationship between detection rate and distance to provide robust positioning estimates and allow for easy extension to tags with different ping rates.
  
  
  CONCLUSIONS
  Optimal acoustic array design requires balancing the interplay between receiver spacing, detection rates, and positioning error. Spacing receivers at twice the distance of the modeled 50% detection rate may be appropriate when quantification of overall space use is a priority, and would provide a minimum of 75% detection rate. However, for research where missing detections within the array is unacceptable or time-at-arrival based fine-scale positioning is needed, tighter receiver spacing may be required to maintain signal detection probability near 100%.
authors.affiliation: Division of Marine Biology and Fisheries, University of Miami, Rosenstiel School for Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149 USA ; NOAA Fisheries, Southeast Regional Office, 263 13th Ave South, Saint Petersburg, FL 33701 USA.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Farmer
authors.affiliation: Division of Marine Biology and Fisheries, University of Miami, Rosenstiel School for Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149 USA.
authors.forename: Jerald S
authors.initials: JS
authors.lastname: Ault
authors.affiliation: Division of Marine Biology and Fisheries, University of Miami, Rosenstiel School for Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149 USA.
authors.forename: Steven G
authors.initials: SG
authors.lastname: Smith
authors.affiliation: School of Ocean and Earth Science and Technology, Hawai'i Institute of Marine Biology, University of Hawai'i at Manoa, PO Box 1346, Kaneohe, HI 96744 USA.
authors.forename: Erik C
authors.initials: EC
authors.lastname: Franklin
keywords: Acoustic array; Acoustic telemetry; Coral reef; Dry Tortugas; Fish movements; Marine reserves; Reef fish