This report summarizes integrated management of sea lamprey activities by the Department of Fisheries and Oceans Canada and the U.S. Fish and Wildlife Service in the Great Lakes in 1995. Lampricide treatments were conducted on 48 tributaries (Table 1). Larval assessment crews surveyed 294 Great Lakes tributaries, inland lakes, and lentic areas to assess TFM treatment or barrier effectiveness, plan future TFM treatments, and establish production capacity of streams. Asessment traps were operated in 73 tributaries and captured 73,415 spawning-phase sea lampreys (Table 2).
Fish community objectives for sea lamprey populations as
set by the Lake Committees are being met in Lakes Superior, Erie, and Ontario.
The uncontrolled population of sea lamprey larvae in the St. Marys River
continues to produce an unacceptably high population of parasitic lampreys
in Lake Huron that are compromising lake trout rehabilitation in that lake.
In addition, parasitic sea lampreys are more abundant in the northern part
of Lake Michigan than in the south and likely are a threat to lake trout
survival in the rehabilitation refuges and zones.
Further progress was achieved in development of an effective
strategy to control sea lampreys in the St. Marys River. The third year
of the larval and habitat mapping was completed with 56 km2 surveyed to
date. Trials with the new granular Bayer formulation showed larval populations
were reduced by 51-86%. Designs for new adult traps were completed and
a rhodamine dye study to predict the effectiveness of a TFM treatment was
planned.
Implementation of the sterile male release technique continued
in Lake Superior and the St. Marys River. The sterilization facility continues
to meet the needs of the program and 23,379 male lampreys were sterilized
and released into streams in 1995. A short-term assessment of the technique
was conducted on four streams indicating the observed ratio of sterile:resident
males in study streams was not significantly different than modelled ratios.
The Barrier Task Force worked on expanding the development
and use of sea lamprey barriers. Presently, 52 barrier dams have been constructed
or modified on Great Lakes tributaries to stop sea lamprey migration. In
1995, three barriers were constructed and one existing dam modified to
prevent passage of spawning sea lampreys.
Studies to monitor the long-term effect of lampricide treatments
on macroinvertebrate communities in index rivers continued. Studies were
also conducted to determine the potential impacts of sea lamprey management
on lake sturgeons in two Lake Superior tributaries. Drift net studies indicated
emigration of fry to Lake Superior occurs before July 1 in the Sturgeon
River.
A total of 708 public outreach activities were conducted,
requiring 224 staff days.
Lake Number Of Streams Discharge m 3/s TFM g1, 2 Bayer 73kg1 Distance km Superior 10 100.7 7,256 51.9 476.6 Michigan 11 59.4 11,570 24.0 679.1 Huron 12 114.2 10,916 89.8 262.6 Erie 1 0.7 188 - 48.3 Ontario 14 47.7 4,675 - 285.7 Total 48 322.7 34,605 165.7 1,752.3 1 Lampricides used are in kg of active ingredient. 2 Includes 726 TFM bars (0.2 kg per bar) applied in 27 streams.
Lake Number of Streams Total Captured Number Sampled Percent Males Mean Lenth (mm) Mean Weight (g)
Males Females Males Females
Superior 21 2,967 552 56 440 433 217 210
Michigan 13 18,729 663 41 466 468 244 247
Huron 16 46,974 811 53 458 472 219 234
Erie 8 504 216 58 489 493 285 287
Ontario 15 4,241 747 54 458 468 216 247
Total 73 73,415