In order test the accuracy of the BF-RSM, a quantitative validation test was performed by comparing the colonization sequence of the USGS database records to that of the BF-RSM. This test was executed by dividing the colonized area into a grid consisting of 500 km × 500 km cells. Each cell was assigned a column and row number. The sequence of colonization for both the BF-RSM and USGS database records was then recorded according to first occurrences in each of the 24 grid cells containing lionfish. The two sequences were then compared as a series of steps. If the two cells (one from the BF-RSM and one from the USGS database records) for each step were an exact match or one of the 8 surrounding cells, a value of 1 was given indicating a good fit; otherwise the step was given a value of 0. The total value of all steps was then tallied, divided by the total possible score of 24, and multiplied by 100 to give a correlation fit percentage value.
Colonized cells within the depth and temperature parameter corridor, defined in this study as an area where one or more of the parameters (temperature, depth, salinity) being analyzed had a value that fell within the study range of tolerance for lionfish, were indicated with a darker colored dot in the RSM map-output. These indicate high likelihood of adult lionfish survivorship. Areas outside of this corridor were colored with a light colored dot, representing larval transport areas with adult survivorship unlikely due to intolerable temperature and/or depth. Salinity was least likely to be a limiting factor and not considered in this BF-RSM as lionfish have been collected at or near lower and upper salinity limits in the study area indicating a wide tolerance to this parameter (Whitfield et al., 2002).