1. GRATIOT LAKE FISHERY Past, Present, Future
Tom Rozich
MDNR Fisheries Biologist
Retired

2. STATUS OF THE FISHERY Environment-physical/chemical description
History-surveys, stockings, and management operations
Current Status-fishery resource
Analysis & Discussion
Management Direction

3. ENVIRONMENT Physical Parameters *1,438 acres
*Max Depth-78’; Ave Depth 25’
*Shoals-30% of area (430 acres) and are 75’ to 1200’ wide
*Four inlets-Eister, Sucker, Nine Hundred Thirty-two Creeks and an unnamed tributary
*One outlet-Little Gratiot River
*Substrate-mostly sand, gravel, rubble, with little organic material (deep areas)

4. ENVIRONMENT-Cont’d Chemical Parameters *pH 6.6 to 7.8
*Methyl Orange Alkalinity-20 to 25
*Secchi Disk-20 feet (average)
*Dissolved Oxygen-excellent above thermocline, very little below

6. HISTORY Stockings 1934-1,200 LMB fingerlings
LMB, 375K WAE (fry),4K YEP, 10K BLG
LMB, 350K WAE, 20K BLG, 6K LAT, 500 SMB
1937-1K LMB, 225K WAE, 25K BLG
LMB, 500K WAE, 25K BLG, 7K LAT
K WAE, 30K BLG, 4K SMB
K WAE

7. HISTORY-Cont’d 1959- 325 adult NOP 1962- 3K MUS 1973- 418 adult NOP
K NOP fry
K TMUS
,750 TMUS

8. HISTORY-Cont’d Modern era walleye stocking
,494; K & 27K RBT
,400 & 15K RBT
K & 15K RBT
K & 15K RBT
,040 & 15K RBT
,741
,986
,358
,148

9. HISTORY-CONT’D Fisheries Surveys
First survey July 28th, August 16th & 17th, 1926 by John Lowe.
Subsequent surveys in 1938, 1953, 1957, 1968, 1977, 1987, 1997, 2005, and 2011

10. HISTORY-Cont’d
*1926 results-Mr Lowe’s words “This lake provides some fine fish, moderately abundant, but very small. Perch, common suckers, and northern pike abundant. Rock bass and smallmouth (black) bass moderately abundant. Whitefish are probably present, but we didn’t get them. A few brook trout. No planting needed, except for crayfish as food for bass.”

11. HISTORY Cont’d
*1938 results-NOP up to 30”, SMB abundant and small. YEP still abundant. No WAE, BLG, LMB, or LAT captured. Minnow species: blunt-nose, Johnny and Iowa darters, muddler (sculpin), log perch, & 9-spine stickleback.
*1953 results-nice YEP (6”-12”), NOP (18”-36”), SMB (10”-17”), RKB (4”-9”), and 50 suckers. No WAE, but anglers report catching them.
*1957 results-very abundant rock bass and suckers. Few NOP, SMB, and YEP. First WAE!

12. HISTORY-Cont’d
*1968 results-strong populations of RKB, YEP, SMB (small), and NOP (avg 22”). No WAE or MUS captured.
*1977 results-large numbers of RKB (4.8”). Good numbers of SMB. Fair YEP. Few NOP. No WAE/MUS.
*1987 results-rock bass and suckers are 81% of biomass! Good YEP & SMB. Good numbers of WAE from 1985 & 1986 stocking.

13. HISTORY-Cont’d
*1997 results-rock bass and suckers 60% of biomass. Few YEP. Good NOP (5>30”). Good WAE (avg 22.2”). SMB abundant, but small. All fish exhibit slow growth! Few smelt captured
*2005 results-good NOP (20%>30”) and SMB (27% legal). Rock bass and suckers still very abundant. Good WAE (24% legal). Few adult perch, but lots of YOY. Two MUS (avg 38”). Smelt runs down.

14. CURRENT STATUS 2011 Survey Results
Goal-obtain a walleye and northern pike population estimate
*316 WAE marked during netting
*343 WAE captured electro fishing
*25 NOP marked during netting
*53 NOP captured electro fishing
*3 MUS marked during netting
*4 MUS captured electro fishing (no recaps)

15. CURRENT STATUS Cont’d Walleye by Inch Class
6” ” ” ”- 2
7” ” ” ”- 2
8” ” ”-30
9” ” ”-11
10” ” ”-11
11” ” ”-10

16. Walleye Inch Class Distribution

17. Northern Pike Inch Class Distribution

18. CURRENT STATUS Cont’d
Other species- YEP: 30 sampled, only four 7” or greater; SMB” 24 sampled, 71% legal; few RKB; 134 common white suckers; and three bullhead (a first).

19. HISTORY-Cont’d
*1947-ninety brush shelters installed on north shoal area at 15 foot contour
* Hoad-type fish shelters were placed in 60 groups of 10 each
*1961 Public Fishing Site purchased and developed

20. ANALYSIS & DISCUSSION GIVENS *low MO-range 20-25-very soft water
*low pH-range 6.6 to 7.8
*lack of vegetation & woody material
*low DO below thermocline
*slow fish growth….all species
*heavy to predator species (now)
*lack of forage fish, except suckers

21. MANAGEMENT DIRECTION OPTIONS *lower NOP size limit to 24”, from 30”
*stock MUS at 2-3 per acre
*cease WAE stocking short term or permanently
*stock small forage……fathead minnows
*reintroduce smelt for forage & fishery
*encourage anglers to target rock bass
*add woody material to shoal areas

22. QUESTIONS-?
Any and all, as there is no unintelligent question………….

23. Thank You, one and all !! May all the fish you catch be so big that you will not need to embellish on their size or weight!!