Lower section of river the harvest has ranged be- able for this fishery. There are few published data
tween 1 and 46 fish year–1. Average annual harvest on exploitation rates on lake sturgeon fisheries. In
in this section has been 20.2 fish at an average the Saint Laurent River in Quebec, exploitation
weight of 16.6 kg and an average weight of all stur- rates ranged from 10 to 20% on different sections
geon harvested of 3.37 kg hectare^1 year^1. All har- (Dumont et al.^5 ). Exploitation rates of 15 to 20% in
vest estimates were calculated based on the annual the Lac Saint-Pierre section of the Saint Laurent
average harvest between 1983 and 1993. impacted the average length. weight and age of this
Average annual exploitation rates on lake stur- stock (Fortin et al. 1993). The exploitation rate for
geon from the three sections of river were: Lower the Lake Winnebago sturgeon population. between
section 18.7%, Grand Rapids section, 12%, and 1976 and 1983, has averaged 2.5% and between
White Rapids section,8.5%. 1953 and 1959 it averaged 4.3% (Folz & Meyers
The lake sturgeon population in the Menominee 1985). The adult sturgeon stock in Lake Winnebago
River is fragmented by numerous hydroelectric has more than doubled over the past thirty years un
dams. Tagging studies showed that there is little der that type of exploitation.
movement of juvenile or adult fish from one section Table 5 indicates an increasing annual harvest of
of river to another. Dams create a barrier to all up- sturgeon in this section of river. This probably re-
stream movement and very few marked fish sults from anincreased number of anglers and the
showed any inclination to move downstream. We greater number of legal size sturgeon available in
have not tagged lake sturgeon less than 25 cm TL, so the White Rapids section. It appears that the cur-
if downstream movement and dispersal occur, it rent harvest regulations are maintaining the stur-
may take place at sizes > 25 cm TL. Lack of easy geon stock in this section of the Menominee River.
movement by adults between the three sections of however if exploitation rates increase much over
river necessitates that they be managed as distinct the present level, then further restrictions will have
stocks. to be applied. Continual monitoring of this stock is
recommended.
White Rapids sectionThe sturgeon stock in the White Rapids section re-
sponded positively to regulation changes over the
past nineteen years. Although population size in
this section has not increased markedly since the
1970 estimate, its size structure has improved. The
number of sturgeon over the minimum size of 127
cm has more than doubled since1970, while the
number of undersized fish has shown a slight in-
crease. There is no statistical difference (p< 0.05) in
the mean length of sturgeon harvested when com-
paring data from the first six years of the registra-
tion system (1983–1988) with data from the last five
years (I 989–1 993).
The exploitation rate of 8.5%, is the lowest of the
three sections of river studied and it is lower than
previously reported. Priegel^2 calculated exploita-
tion rates of 13% in 1969 and 17% in 1970 for stur-Grand Rapids sectionStanding stock of lake sturgeon in this section of riv-
er is lower than in either of the other two sections.
Although the 1990 estimate of the population is
similar to the 1979 estimate. the number of legal size
sturgeon (> 127 cm) decreased by 27%. The average
exploitation rate was 12% for the 1983 through I993
period. There is no statistical difference (p< 0.05) in
the mean length of sturgeon harvested when com-
paring the first six years of registration data (1983–
1988)with the last five years (1989–1993). Table 5
shows the annual harvest of sturgeon froin this sec-
tion has been fairly stable over the period of the reg-(^5) Dumont, P., R. Fortin G. Desjardins & M. Bernard. 1987. Biol-
ogy and exploitation of lake sturgeon (Acipenser fulvescens)in
the Quebee waters of the Saint-Laurent River pp. 37–76. In:
geon(Acipenser fulvescens).Ontario Fisheries Tech. Rep. Ser.
C.H. Olver (ed.) Proceedings of a Workshop on the LakeStur-
geon in this section, and he suggested that exploita-
tion rates no higher than 5% would be more desir- No. 23.