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Agribusiness And Atlantic Salmon: The Effects
3/29/2006
News Release
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Executive Summary
Historically, Atlantic salmon (Salmo salar) populations ranged throughout the New England states, south to Long Island Sound, and Atlantic Canada. In the United States, salmon runs were divided into three Distinct Population Segments (DPSs), or populations that would interbreed when mature (USFWS/ NMFS, 2000). These DPS regions were delineated to include the Long Island Sound, Central New England, and Gulf of Maine Distinct Population Segments. The first two populations have been extirpated and no longer exist. The final existing population, the Gulf of Maine DPS, originally extended down to the Androscoggin River. The Androscoggin no longer supports Atlantic salmon runs, but the remaining rivers in the Gulf of Maine DPS still have “functioning wild salmon populations, although at substantially reduced abundance levels” (USFWS/NMFS, 2000).
Located in the Downeast region of Maine, these rivers include the Dennys, East Machias, Machias, Pleasant, Narraguagus, Ducktrap and Sheepscot Rivers, and Cove Brook. Acknowledging the declining Atlantic salmon populations, the National Marine Fisheries Service and the U.S. Fish and Wildlife Service decided to classify the Atlantic salmon in this DPS as endangered, with the full protection under the Endangered Species Act (ESA). At the time of the listing, members of industry and some in the scientific community expressed concern about the classification of Atlantic salmon as endangered due to the effects of stocking and aquaculture on the population’s genetic distinctness (USFWS/NMFS, 2000). Additionally, many other stakeholders expressed apprehension regarding the listing because of the potential affect on agriculture and other land use in the Atlantic salmon’s habitat. Thus the stage was set for a formal state-wide review of the relative importance of wildlife preservation versus human agriculture interests.
The Endangered Species Act (ESA), aside from making it illegal to harm or kill endangered species (both directly and indirectly), also mandates federal, state, and local agencies to ensure that their actions do not harm these species, or negatively impact their recovery (USFWS, 2001). With the listing of Atlantic salmon, regulation of pesticides, pesticide use, water withdrawal and water pollution by federal, state and local agencies was required to conform to ESA standards. Two of Downeast Maine’s prominent industries, agriculture and forestry, threaten various aspects of Atlantic salmon survival and have been under greater scrutiny following the listing. A recent report released by the Maine Environmental Policy Institute detailed the impacts of the forestry industry on Atlantic salmon (Lansky, 2004). This report will explore the effects of blueberry cultivation on Atlantic salmon in the endangered DPS.
Agencies cite a number of issues that should be addressed for Atlantic salmon recovery. For example, the National Academy of Sciences (2004) listed dams as the largest threat to Atlantic salmon, but stressed the importance of monitoring water quality and stream flow. Project SHARE (Salmon Habitat and River Enhancement) emphasizes the importance of monitoring non-point source pollution (NRWC, 2003). Additionally, the recovery plan for Atlantic salmon drafted by the USFWS and NMFS (2004) listed water withdrawals and acidified water as two critical threats to their survival. Common agricultural practices of blueberry cultivation can affect all of these factors in Atlantic salmon recovery. This report will address the potential threats to the Atlantic salmon caused by the blueberry industry, specifically sedimentation, nutrient loading, pesticide contamination, water withdrawal, wastewater discharge, and acidification. The report’s findings include:
• Sedimentation from low-maintenance roads throughout fields near Downeast rivers create increased problems with sedimentation of gravel beds, which are important Atlantic salmon egg and alevin habitat;
• Nutrient loading is not extensive, but there is some potential for fertilizer application to fields to cause algal blooms and decreased dissolved oxygen in nearby streams and rivers;
• Pesticides used on blueberry fields have limited acute toxicity to Atlantic salmon, but indirect and chronic effects may be severe;
• Hexazinone- this oft-used herbicide is likely in concentrations from drift, runoff and groundwater seep high enough to change aquatic organismal communities, decreasing fitness of fry and parr;
• Malathion and azinphos-methyl may have direct, acute effects on Atlantic salmon physiology and survival, even in low concentrations;
• Water withdrawal can dramatically affect Atlantic salmon and the entire aquatic ecosystem, particularly in the late summer and early fall;
• Discharges from processing plants and other wastewater may have adverse effects on water temperature and dissolved oxygen in rivers, but is limited to small portions of Atlantic salmon habitat;
• Sulfur applications to increase acidic soil conditions are infrequent and sporadic, yet may be of concern for all life stages of Atlantic salmon.
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