Kremer Lake has been managed for stream trout since 1927 when trout were first stocked on top of natural populations of warm water fish species. The lake was chemically reclaimed in 1958 and again in 1974 to eliminate warm water species that would compete with stream trout. Rainbow trout, a species popular with anglers, were stocked annually with fingerlings and/or yearlings. Growth and survival of rainbow trout was adversely affected by the resurgence of white suckers and largemouth bass, due to competition for a limited food supply in a lake with very low fertility. It was noted in the 1993 population assessment that many of the rainbow trout did not appear as plump as fish in other area lakes. Subsequently, it was decided to introduce splake and brown trout, which are considered more piscivorous at larger sizes to prey on the increasingly abundant undesirable fish species. Each species was stocked as yearlings in separate years at recommended rates of 50 fish/acre.
This is the third population assessment to evaluate the performance of splake and brown trout and determine if the long range goal of the 2005 management plan was being achieved. The long range goal was to maintain a stream trout fishery capable of producing quality sized (>16 inches) splake and brown trout and to maintain a population that yields a fall trap net catch of at least 1.5 trout per net with 20% of the catch exceeding 16 inches. The combined catch rate for this assessment, 0.70 trout/trap net (0.5 for brown trout, 0.2 for splake), fell short of the long range goal for the third consecutive assessment. However the proportion of quality-sized fish greater than 16 inches was achieved in this assessment as forty (40%) percent of the trap netted brown trout (N=10 trout) and forty-two (42%) percent of the gill netted brown trout (N=14) exceeded 16 inches. Also the mean length of all brown trout from trap nets was 16.0 inches and 16.1 inches for one gill net set. This was the second consecutive assessment where the size structure goal was met or exceeded.
Four splake were sampled in this assessment and they were all captured in trap nets. The three splake in the 13.00-13.99-length group were most likely from the stocked yearlings this spring (2008), and the larger splake from the 16.0-16.99-length group was most likely stocked as a yearling the previous year (2007).
Scale samples were collected from gill net captured brown trout and ages were determined from 13 of the 14 fish. All brown trout were either age-2 or age-3. The fish came from yearling stocked in the springs of 2006 and 2007 therefore they had survived either one and one half or two and one half years in the lake. The age-2 brown trout ranged from 14.1 to 17.9 inches while the age-3 fish ranged from 14.3 to 16.7 inches indicating good growth for the first year and one half in the lake but slowed dramatically the second year. All brown trout were gravid with either eggs or sperm indicating they had attained sexual maturity. Temperature and dissolved oxygen levels were measured in mid-August and revealed a thermocline occurred between 21 and 41 feet where water temperatures dropped rapidly from 71.4 to 43.3 degrees F. Dissolved oxygen levels above 5.0 ppm that is deemed the minimum to sustain stream trout occurred down to a water depth of 41 feet.
Additional undesirable fish species that have repopulated the lake since the last reclamation and captured in this assessment included white suckers and largemouth bass. Gill nets and trap nets captured 10 largemouth bass ranging from 5.0 to 13.8 inches and 16 white suckers ranging from 16.8 to 22.6 inches. This was the third consecutive assessment where golden shiners were absent which correlates with the introduction of brown trout and splake.
Two minnow trap sets yielded no fish.