Biocomplexity at North Temperate Lakes LTER; Whole Lake Manipulations: Exotic Crayfish Removal 2001 - 2010

As part of a whole-lake experiment to overexploit a rusty crayfish (O. rusticus)
population in Sparkling Lake, Vilas County, Wisconsin, crayfish were intensively trapped and
removed from the lake from early to mid June through late August starting from 2001through
2008. From 2001 to 2004, removal traps were concentrated on the southern and western
shorelines of the lake, where cobble is prevalent and catch rates were highest. Starting in
2005, additional traps were used and trapping effort was spread around the entire perimeter
of the lake. Additional traps (perimeter) were set on standard arrays at 43 sites around the
lake at 1 m deep from 2001 through 2006. In 2001 and 2003, traps (depth transect) were also
set on standard arrays that ranged from 0.5 to 12 m deep. From 2001-2004, trap_site
corresponds to one of the 43 standard sites where the trap was set. For perimeter and depth
transect trapping, one trap is set at a trap site. During the removal trapping, 10 traps are
set at each of the standard trapping sites. The trap_id identifier contains more information
about the spatial location of a removal trap. From 2005-2008, traps were numbered
sequentially moving clockwise around the lake starting at site 1, with no reference to
standard trapping sites from previous years. In 2009, traps were set at the 43 standard
sites. Capture data were recorded in 2009 but crayfish were not removed. Daily catch
statistics: The data table Crayfish Daily Capture Summary provides the number of each
species captured each day in the perimeter and removal traps. Also included are data on the
number of traps pulled on that day and the number of trap_days these traps represent. These
data can be used to calculate capture rates. The data table Crayfish Daily Capture by
Station has daily catch statictics for 2009 at the capture site level. Crayfish length
measurements: Prior to 2005, a crayfish that was measured could be associated with the
specific trap in which it was captured. These length data are included in the Crayfish
Individual data table. Starting in 2005, carapace measurements were only taken on 50
randomly selected O. rusticus individuals each day. The data table Crayfish Carapace Length
contains these data which are not associated with specific traps. Trap site locations: The
data table Sparkling Lake Crayfish Trap Sites contains the location of the 43 standard
crayfish trap sites. See Crayfish Removal Protocol for further explanation of TECHNIQUE and
TRAP_ID fields. Number of sites: 43 trap sites Sampling Frequency: annually during summer