Table 4. Estimated number of lake sturgeon in the Lower section
of the Menominee River, by size group.
TL (cm) 1991 survey
< 107 456
107 437
108
140 29
152 0
165 0
~
from the most recent population estimates (1990
and 1991).
Results and discussionVarious studies report sturgeon lengths in either
fork length or total length, but not in both measure-
ments. This makes it difficult to compare age and
growth information between studies. In this study
the relationship between these two measurements
was calculated. We measured both FL and TL for
1839 lake sturgeon, between 25 and 175 cm TL. The
relationship between these variables for lake stur-
geon in the Menominee River is:TL = 3.52688 + 1.05682 FL;
N = 1839; r = 0.998.All population estimates satisfied the requirements
to insure unbiased estimates (MC -4N) (Robson &
Regier 1964). Lake sturgeon population estimates
for sections of the Menominee River with 95 % con-
fidence limits are given in Table 1. The estimated
number of sturgeon over selected sizes in the three
sections of river are shown in Tables 2, 3 and 4.
Standing stock estimates for lake sturgeon from the
different sections of river were calculated from the
1990 and 1991 estimates. The Lower section had the
highest standing stock of 67.8 kg hectare-1, followed
by the White Rapids section at 23.8 kg hectare-1,
and then the Grand Rapids section at 15.6 kg hec-
tare-1.
Nearly 5000 lake sturgeon have been tagged in
the different sections of the Menominee River since- In various surveys and through the registra-
tion process, 255 tagged sturgeon have been recap-
tured. Most of these fish were recaptured in the
same section of river in which they were tagged. Of
194 recaptured sturgeon originally tagged in the
White Rapids section of the river, only four fish or
2% were found to have moved, and they moved
downstream into the Grand Rapids section. Sixty
one sturgeon originally tagged in the Grand Rapids
section of the river were recaptured and only 1 or
1.6%, was recovered in the Lower section.
Table 5 shows the annual harvest of lake sturgeon
from the Menominee River since the inception of
the registration system in 1983. Between 1500 and
2000 anglers participate in the sturgeon fishery on
the Menominee River each year. The number of an-
glers has increased steadily since the inception of
the registration system. Roughly five percent of an-
glers successfully harvested a legal sturgeon. In the
White Rapids section of the river the harvest has
ranged from 8 to 33 fish annually, with an average of
just under 19 fish year-1. The average weight of an
individual fish taken in this section was 16.1 kg, and
the average weight of all sturgeon harvested was
0.50 kg hectare-1year-1. In the Grand Rapids sec-
tion of the river the average annual harvest has
been 10.9 fish, with a range of 1 to 28 fish taken an-
nually. These fish had an average weight of 15.8 kg
and the average weight of all sturgeon harvested
from the section was 0.35 kg hectare-1 year-1. In theTable 5. Annual harvest of lake sturgeon from the three sections
of the Menominee River.Year White Rapids Grand Rapids Lower section Total
section section1983 9 9 1 19
1984 8 4 1 13
1985 12 1 2 15
1986 13 10 12 35
1987 20 15 23 58
1988 21 14 22 57
1989 32 28 20 80
1990 18 13 22 53
1991 19 9 33 61(^1992233) 46 72
1993 33 14 40 87
Total 208 120 222 550
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