This was the first of two assessments scheduled for this lake in the 2009 lake management plan to monitor the lake trout population. The next assessment is currently scheduled for 2023.
Lake trout were abundant in Bat Lake in 2013, although most were fairly small. The lake trout gill net catch was the highest seen in this lake to date, easily exceeding the normal range for a lake of this type. No lake trout larger than 20 inches were taken; however, the lack of larger fish was not unusual for a lake of this type, where lake trout are limited to a mostly invertebrate forage base. Several year classes, all naturally produced, contributed to the catch, with none standing out as having been exceptionally strong. Lake trout growth had been slow; fish reached a mean length of just 15.5 inches at the end of their sixth year, compared to a mean of 17.7 inches for similar lakes in this area.
White sucker were still present in Bat Lake in 2013, but were apparently not abundant. None were taken in gill nets in this assessment. Catches in previous assessments have also been very low. Minnow traps used in this assessment marked the first attempt to identify fish species found in nearshore areas of the lake. Minnow traps added Iowa darter, fathead minnow, longnose dace, and northern redbelly dace to the list of fish species observed in this lake, and confirmed the continued presence of white sucker.