Assessing Mink Population and Habitat Requirements in Florida

mink in trap

A mink waiting in a live trap for biologists to take measurements and genetic samples, and then be released.

The American mink (Neovison vison) is a semi-aquatic species in the weasel family that is associated with freshwater and salt marsh habitats in North America. In Florida, there are four different subspecies of mink: the Atlantic salt marsh mink (N. v. lutensis); Gulf salt marsh mink (N. v. halilimnetes); Everglades mink (N. v. evergladensis); common mink (N. v. mink). Each subspecies is restricted to specific regions and habitats within Florida.

Due to their restrictions in range, these subspecies are highly susceptible to local extinction. Concerns of population viability led the Everglades mink to be listed as a threatened species in 1973. Prior to surveys by FWC researchers, little was known about the range, population, and life history of each subspecies. Therefore, a formal evaluation of each subspecies is needed to determine risks and guide management actions. In addition, information on genetic relatedness is required to confirm current salt marsh mink subspecies designation.

Starting October 2013, FWC researchers began using cameras and spotlights to survey mink. Live trapping is also used to collect measurements and genetic samples. The surveys are conducted year-round except during the breeding season.

The survey methods for each subspecies is different. On the Atlantic coast, spotlight and floating camera traps were used to survey for mink in salt marsh habitat. Due to logistics, only floating camera traps were used to survey the Gulf salt marsh habitat. To detect the elusive Everglades mink, researchers are using tracking plates, ground cameras and visual surveys in addition to floating cameras and spotlight surveys.   All surveys have been completed for the Atlantic salt marsh mink. Researchers are still in the process of collecting genetic samples from Gulf salt marsh mink, but have completed camera surveys. Research on the Everglades mink will continue for the remainder of the year, and the common mink surveys began summer 2017. Data analysis is currently underway for all completed surveys.

mink being released from trap

After using a live trap, a biologist releases a mink back into its habitat after taking measurements and genetic samples.

Data analysis on the population status of all mink subspecies will follow the International Union for Conservation of Nature (IUCN) criteria for extent of occurrence, area of occupancy, and total population size. Biologists will then model habitat selection of mink populations and identify critical habitat. The phylogenetic analysis will be completed by Central Connecticut State University, using the hair and tissue samples collected.

Although data is still being analyzed, discoveries have been made. Preliminary findings indicate that the range of the Gulf salt marsh mink is more restricted that previously believed. Original range maps had the subspecies going as far northwest as Ochlockonee Bay; however, biologists did not detect any minks north of Horseshoe Bay.