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MICHIGAN DEPARTMENT OF NATURAL RESOURCES
Fisheries Division
EVALUATION OF THE 1971 SPLAKE INTRODUCTION
COPPER HARBOR, LAKE SUPERIOR
Barry R. Miller
Fisheries Biologist
SUMMARY
In the spring of 1971, F splake (13,199 with an average length
of 7.4 inches) were stocked in Copper Harbor, Lake Superior to
compare their growth, survival, and migratory tendencies with
brook trout which had been stocked there previously.
In July, 1972, the splake plant was evaluated with gill nets
set in eleven locations along the northern and southern shores
of the Keweenaw Peninsula. A total of 75 splake (average
length 12.5 inches) were captured; 64% of them inside Copper
Harbor. Growth and survival of splake was closely comparable
to the previously stocked brook trout. Significant numbers of
straying splake were found in only one location (Agate Harbor)
outside of Copper Harbor.
Technical Report: 73-1
Submitted for publication March, 1973.
EVALUATION OF THE 1971 SPLAKE INTRODUCTION
COPPER HARBOR, LAKE SUPERIOR
Barry R. Miller, Fisheries Biologist
INTRODUCT ION
An attempt was made to establish a "coaster" fishery in Copper
Harbor with the release of 25,000 yearling brook trout in 1967 and 10,000
yearlings in 1968. Although their growth rate was good (4.5 to 5.5 inches
in one year), they tended to migrate from the harbor or die within one
and one half years after their release making their availability to the
local fishery rather limited.
In the spring of 1971, 13,199 F, splake (average length 7.4 inches)
were stocked in Copper Harbor in an attempt to co-ipare their growth and
migratory tendencies to that of the Michigan hatchery brook trout in Lake
Superior. It was felt that this longer-lived species, which is similar
in appearance to the true "coaster," might be less migratory and provide
a better fishery in the harbor.
In July, 1972, the first evaluation netting was conducted. This
report summarizes the netting results and discusses the success of the
program to date.
METHODS AND MATERIALS
Lookout
Copper
Harbor (2 sets)
i~2 zE--hoe,Harbor
Agate
Eagle
Cat Harbor
Harbor - I
Great
Sand
Bay
Eagle
River
KEWEENAW
PEN INS U LA
Keystone
Bay
River
FIGURE 1: 1972 SPLAKE EVALUATION GILL NETTING SITES
Evaluation of the 1971 Splake Introduction
Copper Harbor, Lake Superior Page 2
The sampling was done with 900 foot gangs of variable mesh gill
net. One gang, made up of 300 feet of 1 1/2 inch (stretch) mesh, 300
feet of 2 1/2 inch mesh, and 300 feet of 4 1/2 inch mesh, was fished at
each sampling site. Each gang was fished for approximately 24 ho'rs.
Fhe average water depth fished at each site was six to thirty feet.
All gamefish were individually measured (in inches) and weighed
(in pounds). A length-frequencv and total weight was obtained from
non -galm efis h species.
RESULTS
The numbers of each species of fish captured at each netting site
is shown in Table 1. A length-frequency distrj'ution for all species
is presented in Table 2.
Splake were captured at all sites except in Cat Harbor and by the
Lookout Tower. Of the 75 splake captured during the survey, 48 were
taken in the two sets within Copper Harbor. Agate Harbor was the only
site wnere significant numbers of straying splake were found (13 fish
caught). Four or less splake were captured in all other sites outside
of Copper Harbor.
The splake ranged in size from 9.5 to 16.4 inches in length with
the exception of a 21.7 inch, 4.8 pound individual which probably was
a stray out of Lake Fanny Hooe. The average splake was 12.5 inches
long and weighed 0.75 pounds.
Lake trout was the dominant salmonid captured (113 total). From
one to twenty fish were taken at eachl site. The following data on
TABLE 1
COPPER HARBOR SPLAKE EVALUATION
(Number of each fish species caught at each gill netting site)
Fish Species
Splake trout
Eagle
River
Great
Sand Bay
Cat Eagle Agate Lookout Copper Harbor Copper Harbor Horseshoe Keystone Montreal
Harbor Harbor Harbor Tower (near Is.) (Fanny Hooe Cr) Harbor Bay River
TOTI
t v it 11 Of t
1
3
4I
13
21
27
3
1
2
Lake Trout
Brook Trout
Brown Trout
Rainbow Trout
I 4 3- 1- 1 t 1-- 4 -t -1- 4
1
10
13
20
10
9
3
4
17
3
23
11:
If 2
f - 1 2 -
1
1
3
1
2
2
1
-* I * t- 4 4- -4-- 4- - 4 4 1 --4'
1
1
2
3
1
3- -t - 3- -
1I
1
1
1
i --
Coho Salmon
Whitefish
2
1
1
5
1
1
5
i a i q I - # - - -4- - m
Menominee
5
1
22
4
36
11
1
46
17
7
45
27
22
Smelt
Alewife 8 3 6 4 2
1
7 -1
I - 4- 4 ____
Yellow Perch
1
4
1
Walleye
Northern Pike
Buroot
L. N. Sucker
White Sucker
N. Lk" Chub
1
43
0
i ~
56
5
4
-- --- T
31
31
29
13
9
19
1
15
6
15
7
21
1
1
2
57
11
22
18
13
2
67
20
1
85
38
11
6
29
34
21
8
TA B LE 2
LENGTH DISTRIBUTION (IN %) OF THE FISH MEASURED
Fish Species
Length (inch groups)
~~B~T F110
i)121 13)141 15116)-17118) 19 )20 121 )22
1 23
24 1 25
I
26
Splake-Trout
Lake Trout
Brook Trout
9
9
1
18
161
18
2 7
36
241
7
-r- I I I I
5
3
9
Brown Trout
Rainbow Trout
Coho Salmon
White fish
Menomine e
Smelt
Alewife
Yellow jPerch
Walleve -
Northern 'Pike
Burbo0t
L. N: Sucker
1,Thite Sucker
~.L'. Chub
13
25
125
16~
52
17
251~381
Jlo
132
2
2 2
1100i
20
34
131
26
13
10
6
2
13
25
26
13
25
13
4
42
8
128
13
14
9
13
20
I
1l3
14
11
-f
I
I
I
I
I
-i
I.1
{
f
II.
V
27
13
-t
I
ii
-i
-I
4
-I
V
I"I.Li
1~
1~
28
ii
-I
-t
71
4
-V.
-IF-.
1 -1---
I
29
-I
7'
-I.
~1
---1
--I
~1
-U
I--
F
-I--
j1-.~
1 -I
I--
30
31
i 4--
2
ý-- 4
I
I
I - - - -
13
17
1100
13
2
7----
1
50
50
I
- j
j
1-----~
I--- --
- -I ---- I
l~ Ij
1
-i--f
7
10
+- i i i t--4 -
13
23
3
26
17
13
4
'13
13 3
f t -- --+- - i i-- i
4115
ý42 If
2
11
12
9
3
10
22j 13J
--4 -
Evaluation of the 1971 Splake Introduction
Copper Harbor, Lake Superior Page 3
lamprey scarring was obtained: 17-20 inch fish, 12.5% scarred; 21-24
inch fish, 23.8% scarred; fish 29 inches and up, 66.7% scarred. A total
of 5.6% of the lake trout between 25 and 28 inches long bore fresh lamprey
wounds.
Lake trout ranged in length from 14.4 to 31.9 inches. Nearly
60% of the lake trout were between 24.0 and 27.9 inches long.
All other gamefish species (except menominees) were taken in small
numbers in scattered locations. A total of 221 menominees were caught
(1 to 45 in each set).
DISCUSSION
Based on the results of the 1972 evaluation netting, it is
apparent that splake survival for the first year after stocking is closely
comparable to previous y nrs brook trout survival. Similar numbers of
each species were captured with about the same amount of gill netting
effort.
Splake in the 10 to 14 inch size range appear to be readily
catchable. Angler reports from the 1972 season indicate large numbers
of splake were caught throughout Copper Harbor.
The growth rate of splake for one season in Copper Harbor is
nearly identical to the brook trout's. Brook trout released in 1967
added 5.4 inches in length in one year. Brook trout released in 1968
added 4.4 inches by the following year. The splake stocked in 1971
increased in length by 5.1 inches in one year. The only noticeable
difference in growth was that for their length, splake weighed less
Evaluation of the 1971 Splake Introduction
Copper Harbor, Lake Superior Page 4
than brook trout. Splake reached 1 pound in weight at about 14 inches
while the brook trout reached 1 pound between 12.5 and 13.5 inches.
In conclusion, to date there appears to be little difference in
the success of stocking either brook trout or splake in Copper Harbor.
Both species exhibit similar growth and abundance patterns. It appears
that splake will migrate out of the harbor as did the brook trout
previously stocked but the extent of their migratory tendency is unknown
at this time.
In June or July of 1973, another evaluation netting should be
scheduled to check the abundance and growth of the splake in the harbor.
If there appears to be less migration from the splake stocking than from
the brook trout stocking and the splake's growth rate continues to be good,
Copper Harbor should be managed for splake. However, if the carry-over
of splake is in the same magnitude as the brook trout carry-over, brook
trout management would provide a heavier and more attractive fish.
2/28/73
smc