Biota of Lakes and Reservoirs - Hydro-Environmental Analysis: Freshwater Environments - page 443

Petromyzon marinus
Map created on 11/8/2011. United States Geological Survey
FIGURE 15.32 Sea lamprey distribution. (From Fuller, P., Nico, L., Maynard, E., Larson, J., and Fusaro, A.,
USGS Nonindigenous Aquatic Species Database, Gainesville, FL, 2012, Available at http://nas.er.usgs.gov/
queries/factsheet.aspx?SpeciesID = 836 Revision Date: 12/22/2011.).
(Fuller et al. 2012). For example, lake trout catch in Lake Huron fell from 3.4 million pounds in
1937 to virtual failure in 1947, while in Lake Michigan the U.S. catch fell from 5.5 million pounds
in 1946 to 402 pounds in 1953 (Scott and Crossman 1973; Fuller et al. 2012). Removing these large
predators also allowed another nonindigenous species, the alewife, to invade. Alewifes are a prob-
lem species in many freshwater lakes, and the presence of the alewife could restructure a lake's food
web, leaving less food for the native species. In the Great Lakes, alewife populations exploded, also
contributing to large additional changes in species composition (Smith and Tibbles 1980).
The continued presence of sea lampreys in the Great Lakes has also impacted attempted restock-
ing programs. As a result, a number of programs are in place that are designed to control lamprey
populations, such as lampricides, barrier dams, and trapping. Traps are intended to remove the adult
lamprey before they can spawn, while barrier dams prevent the adults from reaching spawning areas
in tributaries to the Great Lakes. The lampricides typically target the larval sea lamprey, killing them
before they can transform into their parasitic adult form. Although the number of sea lamprey in the
Great Lakes has been reduced, they still kill substantial numbers of lake trout in some areas and thus
are impeding the rebuilding of established populations (Schneider et al. 1996; Fuller et al. 2012).
15.4.2.4 Geese
Geese are not necessarily an invasive species, in that they are native. But, by the deinition cited
earlier by the Nature Conservancy, they could be considered so. For example, historically, Canada
geese migrated through a number of lyways from northern nesting areas to the south. Increasingly
though, populations of nonmigratory geese have taken up residence in or near many waterbodies,
both creating a nuisance and contributing to water quality problems. Canada geese may be large
(20 or more pounds) and live a relatively long time (20 or more years). A goose can convert about
4 lb. of grass per day to 3 lb. of fecal matter, which could be composed of about 76% carbon, 4.4%
nitrogen, and 1.3% phosphorus (NHDES 2012). One old saying with considerable justiication refers
to speed or acting quickly being “like crap through a goose.” So, for example, as a result, geese may
contribute substantial quantities of coliform bacteria to a lake as well as nutrients and organic mat-
ter. Management strategies include removal (e.g., destroying), discouraging feeding, and changing
landscape practices to reduce feeding and nesting habitats.