Invasive Species in Fisheries
Biodiversity in fish species provides people with multiple benefits, including food, recreation, culture, employment and income. In most aquatic ecosystems, these benefits are threatened by invasive or nuisance fish species, who compete with native species for food and habitat. The establishment of non-native species can disrupt native fish communities and challenge management objectives of states and the federal government (Young, 2009). Invasive species (both plants and animals) are common throughout the Northeast United States, especially in the connecting waterways to Lake Champlain. The St. Larwence River has 87, the Great Lakes have 184 and the Hudson River has 91, while Lake Champlain has only 48 (State of the Lake, 2008).
In Lake Champlain, invasive species are causing problems for the native fisheries and ecosystems of the lake. Of the 88 fish species in the lake, 15 are non-native (Young, 2009), some of which are not problematic. Others, such as alewife and white perch, are particularly damaging because they alter the whole food web from plankton to large sportfish like salmon and trout (State of the Lake, 2008). There are various state and non-profit organizations working to stop the introduction of more invasive species and reduce reduce the impact of invasive and neuisance species. The Strategic Plan for Lake Champlain Fisheries, a report by state (VT and NY) and federal agencies, has the main goal of increasing native species for the purpose of sport fishing (Young, 2009).
Various human activities are to blame for the introduction and prevelance of invasive fish species in the lake. The disturbance, fragmentation, and alteration of both in-stream aquatic and riparian habitats coupled with the introduction of non-native species (generally through shipping channels) negatively affects fish and wildlife resources and the economy of the Lake Champlain basin (Modley, 2005). For example, white perch and alewife prey on eggs of other species (reducing populations), compete with native fish for food and may cause algal blooms (State of the Lake, 2008). The main methods used to control invasive and neusiance species are stocking programs, chemical controls and physical barriers at breeding grounds.
The number of invasive species in Lake Champlain has been steadily increasing over the past 100 years, increasingly impacting the ecosystems and economics of the basin. It is difficult to quantify the benefits of biodiversity and healthy ecosystems in the lake, but the clear economic benefit is sport fishing. Controlling invasive species in order to sustain the angling industry is a major goal of lake advocates because fishing derbies are important to many lakeside communities. The Lake Champlain fishery is based on angling (the only source of commercial sales) of walleye, yellow perch, basses, smelt, and pikes (Young, 2009). An estimate from 1991 found that between 200,000 to 750,000 lbs of fish were sold (Young, 2009)
Invasive fish species have huge economic impacts, both in terms of spending on controls and lost potential revenue. They cost state and federal agencies millions of dollars every year to manage (Modley, 2005). Sea lamprey is especially troublesome because of a large population that preys on healthy fish. Sea lamprey control methods cost approximately $850,000 per year (Lake Champlain Basin Program, 2005). More staggering is the cost of fishermen fishing somewhere else due to the impacts of sea lamprey, an estimated $29.4 million anually (Vermont Fish and Wildlife, 2008). Since even more invasive species are living in connected waterways of Lake Champlain, a rapid response and prevention plan to new introductions has a potential to save a significant amount of money (Modley, 2005).
Modely, Margaret D. (2008). Aquatic invasive species rapid response planning partnerships in the Lake Champlain basin: Bridging international, political, social, and economic gaps. Water SA, 34(4), 476-480. Retrieved from http://www.wrc.org.za/Knowledge%20Hub%20Documents/Water%20SA%20Journals/Manuscripts/2008/05/WaterSA_2008_05_Paper%209.pdf.
State of the Lake. (2008). Lake Champlain Basin Program. Retrieved from http://www.lcbp.org/PDFs/SOL2008-web.pdf.
Young, B. A., Bouffard, W.R., & Chipman, B.D. (2000). Strategic Plan for Lake Champlain Fisheries. Fisheries Technical Committee of the Lake Champlain Fish and Wildlife Management Cooperative, Retrieved from http://www.vtfishandwildlife.com/library/Reports_and_Documents/Fisheries/Strategic_Plan_for_Lake_Champlain_Fisheries.pdf.