60
Paul T. Jacobson
likelihood of escape from aquaculture facilities is sufficiently high that the federal
interagency group, the Aquatic Nuisance Species Task Force, considers eventual
escape virtually guaranteed (OTA 1993).
Introductions have also occurred as a result of removal of natural barriers.
Examples of this class of introduction include the Sea Lamprey (Petromyzon
marinus) and the Alewife (Alosa pseudoharengus) which were able to bypass
Niagara Falls and enter the upper Laurentian Great Lakes following construction
of the Welland Canal. Finally, intercontinental transfers have occurred via ballast
water. For example, the European Ruffe (Gymnocephalus cernuus) invaded the
Laurentian Great Lakes via ballast water originating in Europe.
The consequences and public perceptions of these introductions are as varied as
the means by which the introductions have occurred. The Sea Lamprey contributed to the demise of Lake Trout (Salvelinus namaycush), a large commercially valuable piscivore, and the abundance of non-native Alewife subsequently
exploded in habitat that held few large predators. Alewife reached nuisance levels
and underwent periodic die-offs that created offensive and unhealthy conditions
requiring expensive cleanups. Beginning in 1966, Pacific salmonids were introduced into the upper Great Lakes in large numbers. Between 1966 and 1983, an
average of 2.6 million Coho Salmon (Oncorhynchus kisutch) were stocked annually into Lake Michigan alone. Pacific Salmon have substantially reduced the
abundance of Alewife and are the driving force behind a large recreational fishery
in the Great Lakes. In 1980, the Great Lakes recreational fisheries comprised 54
million angler days and more than $1.7 billion in angler expenditures (Radonski
and Martin 1986). Chemical treatment of streams flowing into the upper Great
Lakes with lamprecide provides short-term control of lamprey abundance but is
costly ($10 million annually for control and related research; OTA 1993). Native
Lake Trout remain at low abundance, and the recreational fishery is maintained by
massive stockings of Pacific salmonids.
The Common Carp was introduced to North America to provide a familiar food
and sport fish for European immigrants (Courtenay and Kohler 1986; Lathrop et
al. 1992). The first introduction occurred in the Hudson River, New York, in 1831;
a second release was into a pond in California in 1872 (Moyle 1976; Courtenay
and Kohler 1986). From 1877 until 1896, the U.S. Commission of Fish and
Fisheries distributed Common Carp for culture and introduction (Courtenay and
Kohler 1986; Lathrop et al. 1992). In 1897, the U.S. Fish Commission stopped
distributing Carp because the species was well established and because of growing complaints by the public (Moyle 1969; Lathrop et al. 1992). Although the
species has historically supported profitable commercial fisheries (Lathrop et al.
1992), the introduction of this species to North America is generally considered a
fisheries management disaster. Adverse effects of this species extend beyond the
lakes in which carp live because they destroy important submerged aquatic vegetation beds in staging lakes used by diving ducks on their annual migrations.
The Brown Trout was introduced from Europe for sport fishing and has become
widely established in North America. It is prized as a sport fish, and widespread
stocking continues. Although some adverse effects on native species have been
Paul T. Jacobson
likelihood of escape from aquaculture facilities is sufficiently high that the federal
interagency group, the Aquatic Nuisance Species Task Force, considers eventual
escape virtually guaranteed (OTA 1993).
Introductions have also occurred as a result of removal of natural barriers.
Examples of this class of introduction include the Sea Lamprey (Petromyzon
marinus) and the Alewife (Alosa pseudoharengus) which were able to bypass
Niagara Falls and enter the upper Laurentian Great Lakes following construction
of the Welland Canal. Finally, intercontinental transfers have occurred via ballast
water. For example, the European Ruffe (Gymnocephalus cernuus) invaded the
Laurentian Great Lakes via ballast water originating in Europe.
The consequences and public perceptions of these introductions are as varied as
the means by which the introductions have occurred. The Sea Lamprey contributed to the demise of Lake Trout (Salvelinus namaycush), a large commercially valuable piscivore, and the abundance of non-native Alewife subsequently
exploded in habitat that held few large predators. Alewife reached nuisance levels
and underwent periodic die-offs that created offensive and unhealthy conditions
requiring expensive cleanups. Beginning in 1966, Pacific salmonids were introduced into the upper Great Lakes in large numbers. Between 1966 and 1983, an
average of 2.6 million Coho Salmon (Oncorhynchus kisutch) were stocked annually into Lake Michigan alone. Pacific Salmon have substantially reduced the
abundance of Alewife and are the driving force behind a large recreational fishery
in the Great Lakes. In 1980, the Great Lakes recreational fisheries comprised 54
million angler days and more than $1.7 billion in angler expenditures (Radonski
and Martin 1986). Chemical treatment of streams flowing into the upper Great
Lakes with lamprecide provides short-term control of lamprey abundance but is
costly ($10 million annually for control and related research; OTA 1993). Native
Lake Trout remain at low abundance, and the recreational fishery is maintained by
massive stockings of Pacific salmonids.
The Common Carp was introduced to North America to provide a familiar food
and sport fish for European immigrants (Courtenay and Kohler 1986; Lathrop et
al. 1992). The first introduction occurred in the Hudson River, New York, in 1831;
a second release was into a pond in California in 1872 (Moyle 1976; Courtenay
and Kohler 1986). From 1877 until 1896, the U.S. Commission of Fish and
Fisheries distributed Common Carp for culture and introduction (Courtenay and
Kohler 1986; Lathrop et al. 1992). In 1897, the U.S. Fish Commission stopped
distributing Carp because the species was well established and because of growing complaints by the public (Moyle 1969; Lathrop et al. 1992). Although the
species has historically supported profitable commercial fisheries (Lathrop et al.
1992), the introduction of this species to North America is generally considered a
fisheries management disaster. Adverse effects of this species extend beyond the
lakes in which carp live because they destroy important submerged aquatic vegetation beds in staging lakes used by diving ducks on their annual migrations.
The Brown Trout was introduced from Europe for sport fishing and has become
widely established in North America. It is prized as a sport fish, and widespread
stocking continues. Although some adverse effects on native species have been