A population assessment was conducted at Betty Lake in 2012 to monitor the fish population. Submergent vegetation was noted as being moderate to dense around much of the shoreline in 2012. In contrast, the 2007 point/transect vegetation sampling that was conducted ranked every species as being rare. This showed that submergent aquatic vegetation density can be highly variable in Betty Lake. In 2012, a total of 12 species, plus hybrid sunfish, were sampled in the gill nets and trap nets. Betty Lake is primarily managed for northern pike and black crappie, while walleye, bluegill, largemouth bass, and channel catfish are listed as secondary species in the lake management plan. The notation (n=13) refers to the number of times the lake was netted over the stated time period, and catch rates were calculated.
Gill nets sampled low numbers (20) of northern pike for a catch rate of 3.3/net, which was within the normal range for this type of lake. This catch rate indicated that recruitment was low, in 2012. The 2007 catch rate was 10.5/net. Catch rates from 1951 to 2012 (n=13) were variable ranging from 0.7 to 10.5/net with an average of 4.2. Northern pike were 17.7 to 36.1 inches long with an average of 21.5. Northern pike were last stocked in 1993 and the current population is entirely maintained by natural reproduction. Two-out-of-three of the highest catch rates ever measured at Betty Lake occurred in 2002 and 2007, long after stocking had ceased.
Trap nets sampled low numbers (25) of black crappie for a catch rate of 2.8/net, which was within the normal range for this type of lake. The 2007 catch rate was 10.0/net. Catch rates from 1951 to 2012 (n=13) were highly variable ranging from 2.8 to 299.7/net with an average of 33.5 and median (middle most catch rate) of 8.0. Trap netted black crappie were 4.6 to 12.5 inches long with an average of 9.3. Approximately 46% of the trap net catch was 10.5 inches or longer. Gill nets also sampled low numbers (8) of black crappie for a catch rate of 1.3/net, which was below the normal range for this type of lake and the second lowest catch rate ever measured at Betty. Gill netted black crappie were 7.3 to 12.0 inches long with two of the fish reaching 12 inches in length. These quality sized fish should appeal to anglers.
Gill nets sampled low numbers (2) of walleye for a catch rate of 0.3/net, which was below the normal range for this type of lake. The last time the catch rate was this low was 1994 (0.3/net). The 2007 catch rate was 1.7/net. Catch rates from 1951 to 2012 (n=13) were generally low, ranging from 0.0 to 6.3/net with an average of 2.1. The gill netted walleye were 18.9 and 20.9 inches long. Walleye were last stocked in 1992. Catch rates from 1994 to 2012 (n=5) ranged from 0.3 to 3.8/net with an average of 1.4, with three of those catch rates being below the normal range. The last three assessments indicated a decreasing trend in walleye catch rates at Betty Lake.
Gill nets sampled high numbers (77) of channel catfish for a catch rate of 12.8/net. Channel catfish were introduced into Betty Lake in 1983 and catch rates (n=7) have been increasing since they were first sampled in 1986. In 2012, channel catfish were 14.9 to 24.1 inches long with an average of 19.3. Almost 99% of the gill net catch was 17 inches or longer. The trap net catch rate was also high (8.2/net). Trap net sampled channel catfish ranged from 9.1 to 23.9 inches in length with an average of 18.2. Channel catfish were the most abundant fish sampled in both gill and trap nets. High numbers and quality sized fish should appeal to catfish anglers.
Trap nets sampled low numbers (29) of bluegill for a catch rate of 3.2/net which was below the normal range for this type of lake. The 2007 catch rate was similar at 2.4/net. Catch rates from 1951 to 2012 (n=13) ranged from 0.8 to 88.7/net, with an average of13.9 and median of 4.1. In 2012, trap netted bluegill were 3.3 to 6.6 inches long with an average of 5.6. Although gill nets were not the standard gear for sampling bluegill, the catch (8.2/net) was impressive. Gill netted bluegill were 5.3 to 9.7 inches long with an average of 7.9. A total of 43 fish were 7 inches or longer, 28 fish were 8 inches or longer and 3 fish were 9 inches or longer. The 2012 survey and several past assessments (1951, 1982, 1983, 1986, and 1989) showed that Betty was capable of producing bluegill that were 8 inches or longer. The 2002 assessment showed that moderate numbers of 7 inch bluegill were trap netted. This data indicated that Betty Lake was, at least occasionally, capable of producing a quality bluegill population.
Trap nets sampled low numbers (3) of largemouth bass for a catch rate of 0.3/net, which was within the normal range for this type of lake. Largemouth bass were 4.1 to 18.2 inches long and it was likely that three different year-classes were present. Spring night-time electrofishing, the standard sampling method for largemouth bass, was not conducted in 2012.
Gill nets sampled low numbers (2) of yellow perch for a catch rate of 0.3/net, which was below the normal range for this type of lake. The 2007 catch rate was identical at 0.3/net. Catch rates from 1951 to 2012 (n=13) were all low, ranging from 0.0 to 13.8/net with an average of 3.5. Both yellow perch were 6.1 inches long.
Gill nets (1 fish) and trap nets (4 fish) sampled low numbers of carp, in 2012. Gill net and trap net catch rates, from 1997 to 2012 (n=4), both showed decreasing trends for carp. In 2012, low numbers of black bullhead were gill netted (55 fish) and trap netted (15 fish). Gill net catch rates for the last three assessments (2002, 2007, and 2012) showed a decreasing trend for black bullhead. Additional species sampled in the standard gear included white sucker, bowfin, hybrid sunfish, pumpkinseed sunfish, and yellow bullhead.