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Water Quality in Gulf of Maine Atlantic Salmon DPS Watersheds

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The Maine Department of Environmental Protection (DEP) sets water quality standards for the rivers and lakes of the state. It shares water quality monitoring responsibilities in the seven Gulf of Maine Distinct Population Segment or DPS Atlantic salmon rivers with watershed councils, the Department of Agriculture (DAG), the Department of Conservation (DOC), the Atlantic Salmon Commission (ASC) and private companies. In the year 2000, the DEP hired staff and began a focused program to "to see if salmon reproduction or productivity is limited by natural or man-made water quality conditions found in the salmon rivers" and to capture water quality baseline data to gauge trends (Whiting, 2001a). 

The Sheepscot River basin provides a model for cooperative efforts to examine water quality factors that may limit Atlantic salmon recovery. The Sheepscot Valley Conservation Association, the Sheepscot River Watershed Council, the Kennebec Soil and Water Conservation District, Project SHARE and federal and State agencies have combined to perform or fund numerous studies to define temporal and spatial water quality impairment. The data from these studies and the reports themselves are component parts of KRIS Sheepscot and their findings are summarized here in the water quality Background pages and used as the basis for Hypotheses that look for patterns in the data. Charts of the most important data summaries can also be found as Topics in the KRIS database.

Volunteers have helped with water quality data collection on all seven rivers, including during summer baseflow conditions and winter stormwater runoff (Whiting, 2003). The Maine Volunteer Lake Monitoring Program (Williams, 2002; 2003) coordinates hundreds of volunteers who collect thousands of water quality samples from lakes throughout the state, including lakes within some Atlantic salmon river systems. Extensive access to Maine lake water quality data can be obtained at the PEARL website hosted by the University of Maine. The DEP tracks and regulates most water pollutants, but yields authority over pesticides to DAG. The Maine Department of Forestry, which is under DOC, also monitors pesticides. Agencies work closely together in part because of cooperation under the Atlantic Salmon Conservation Plan for Seven Maine Rivers (MASTF, 1997). Many problems identified have been partially remedied because of this strategy and such progress is noted below. Water quality factors discussed here are those with potential to inhibit recovery of the DPS wild Atlantic salmon populations: dissolved oxygen, biological oxygen demand, nutrients, pH and chemical pollutants (Dill et.al., 2002). Temperature and sediment were also identified as threats but are covered on separate pages.

Robinson et al. (2003) note some regional, long-term trends that should be considered because similar trends may be manifest in the DPS rivers: 

"Annual concentrations of sulfate and total phosphorus decreased during the second half of the century, whereas annual concentrations of nitrate, chloride, and residues increased throughout the century....These changes in the water quality probably are related to changing human activities. Most notable is the relation between increasing use of road de-icing salts and chloride concentrations in rivers. In addition, changes in concentrations of nitrate and phosphorus probably are related to agricultural use of nitrogen and phosphorus fertilizers."

Water Quality Standards

The Maine DEP sets water quality standards for various stream "Classes", which are defined according to their condition, location and uses (Table 1) (MDEP, 2002). Criteria are set for some types of measurements such as dissolved oxygen (D.O.) and the bacteria E. coli, but there are no standards for other parameters like temperature. Maine standards for acceptable levels for pesticides, metals and other pollutants sometimes follow national standards set by the U.S. Environmental Protection Agency. Waterbodies that fail to meet water quality standards are placed on the impaired waterbodies list (303d) as required under the Clean Water Act (CWA) (MDEP, 2004).

Table 1. Maine classification of fresh surface waters and criteria for dissolved oxygen and bacteria (38 MRSA §465, MDEP 2001). Taken from Table 2.4.1. (Arter, 2004).

Dissolved Oxygen 

In a report to the Maine Atlantic Salmon Task Force, Dill et al. (2002) noted that summer dissolved oxygen (D.O.) "below 6 mg/L are not suitable for salmonids". The Maine DEP requires levels of 7 ppm and 75% saturation in all except Class C waters (Table 1), which do not occur in DPS rivers. Among the DPS rivers, only the Sheepscot River has a significant D.O. problem (Arter, 2004; Dill et al., 2002). Maine DEP has found D.O. at seven sites to be so impaired they have been added to the Total Maximum Daily Load list, which recommends them for study and ultimate remediation (Arter, 2004). 

Melissa Halsted collects dissolved oxygen data on the Sheepscot River. Photo provided by SVCA.

Problem areas include the West Branch, Dyer River, the mainstem Sheepscot River and Trout, Choate, Meadow and Carlton Brooks. The lower Sheepscot basin has the most problem with D.O., which Dill et al. (2002) ascribed to the accumulation of nutrients from the entire watershed. Halsted (2003) found that the lowest flow periods tended to coincide with the lowest dissolved oxygen levels. The fluctuation of dissolved oxygen nocturnally and diurnally, coupled with high chlorophyll-a levels, suggest that algae blooms may be driving D.O. cycles (Arter, 2004). Dissolved oxygen drops at night due to respiration of algae, while values during the day may sometimes be supersaturated due to photosynthesis. Algae blooms, in turn are stimulated by nutrients (see below) and warm water conditions.

Biological Oxygen Demand

Biological oxygen demand (BOD) in the Gulf of Maine Atlantic salmon DPS watersheds seems to be of little concern, except for one location in the Sheepscot River. Waste from the Palermo Fish Hatchery is spilled into the upper Sheepscot River just below the outlet of Sheepscot Pond. Maine DEP notes that the reach below the hatchery is listed as Class B, but usually only meets Class C criteria with regard to D.O. (Arter et al., 2004). Maine DEP  (2002) macroinvertebrate studies also indicate that conditions are highly enriched and that water treatment of hatchery effluent may be insufficient.

Bacteria  

Both Pugh (2002) and Arter (2004) note that at several locations the Sheepscot River fails to meet Maine DEP water quality standards for Escherichia coli (E. coli). Elevated bacteria levels occurred at four of six impaired sites (Table 2). The same information can be viewed in spatial form in Figure 1, also from Arter (2004). Patterns of impaired values suggest that some problems are tied to point sources while others are more likely from non-point source pollution (NPS). Once again, Halsted (2002) found relationships between low flow and bacteria counts as she had for temperature and D.O. Dill et al. (2002) point out that, although bacteria such as E. coli do not pose a threat of disease to fish, high bacteria counts are often correlated to nutrient inputs from septic systems or farm animals in proximity to streams, which then have ripple impacts on fish and water quality. E. coli is also a concern in the lower Sheepscot because of potential shellfish harvesting. Area closures are often necessary because of high bacteria counts with "approximately 75% of the estuary shoreline below Wiscasset....classified as prohibited, or closed to shellfish harvesting" (Arter, 2004). 

Table 2. This table, from Arter (2004), lists locations of chronic water quality impairment in the Sheepscot River basin and gives water quality summaries and comments regarding needs for additional monitoring.

Figure 1. This map from Arter (2004) shows areas of diminished water quality in Sheepscot River. Codes for each site indicate the types of water quality problems that exist and whether the site is listed under the TMDL. Sites with multiple indications of impairment are usually in lower river locations, consistent with Arter's hypothesis that nutrients are accumulating from NPs throughout the watershed. One exception is the reach immediately below Sheepscot Pond, which is affected by the Palermo Hatchery effluent (Arter, 2004).

Nutrients 

Nutrients are recognized as a threat to DPS Atlantic salmon survival only in the Sheepscot River (Dill et al., 2002). Nutrients impact fish and water quality mainly through side effects of the algae blooms they trigger, including low D.O. Phosphorous (P) is usually the nutrient that limits aquatic plant growth, so total phosphorous (TP) is a useful measurement for assessing the potential for blooms. Nitrogen is also a good indicator of nutrient enrichment and has the potential to stimulate plant growth. It is most available to plants in the form of ammonium ions, but is measured as nitrates in studies of the Sheepscot River. According to Arter (2004): "Nitrates in water generally originate from precipitation, human, and animal waste, residential and agricultural fertilizers and bedrock."

Arter (2004) noted that the Maine Volunteers Lake Monitoring Program data indicated that three lakes in the Sheepscot basin, Clary Lake and Long Pond and Dyer Long Pond, all had elevated levels of phosphorous and high chlorophyll levels indicative of algae blooms and eutrophication. NOAA Fisheries collected pH data in the lower Sheepscot River that showed nocturnal-diurnal fluctuations of pH indicative of algae blooms (Arter, 2004), with day time highs reaching 8.5. One concern about elevated pH is that, in combination with elevated water temperature, it may trigger a shift in available nitrogen from the ammonium ion to dissolved ammonia (Goldman and Horne, 1983), also know as unionized ammonia, which is lethal to fish life at concentrations as low as 0.25 mg/l (U.S. EPA, 1986). 

Table 3. Percent of total ammonia converted to unionized or dissolved ammonia in response to temperature and pH. From Goldman and Horne (1983).

According to MDEP data, the total phosphorous (TP) in the lower mainstem Sheepscot and lower West Branch is highest (max 160 µg/L) during low flow conditions but also shows a smaller peak (max 91 µg/L) during storms (Arter, 2004). Arter (2004) postulated that the concentrations were highest in the lower rivers due to "an accumulation, or downstream, effect" stemming from non-point source pollution. Information on nitrates in the Sheepscot River (Arter, 2004) is consistent with the hypothesis that nutrients are accumulating in the lower river: "Nitrates are generally higher in both the WB and MS than other salmon rivers. The Sheepscot ranges from < 1.0 µeq/L (essentially zero) to 29.9 µeq/L whereas the Narraguagus ranges from < 1.0 to 5.6 µeq/L."  

Diagram of Non-Point Source Pollution assessment and abatement on Maine DPS rivers. From the Maine Dept. of Agriculture (2002).

The Maine Department of Agriculture, in cooperation with other state agencies, helped abate non-point source pollution problems, including nutrients, in DPS rivers in the last few years. (See flow chart at left). The DAG formed a statewide Nutrient Management Board and hired a Nutrient Management Coordinator. Other specialists have been trained in nutrient control throughout the state and 341 nutrient management plans had been certified as of 2002 (MDAG, 2002). Two million dollars were spent on pollution control structures and a ban on winter spreading of manure was implemented. Nutrient abatement is approached as follows (MDAG, 2002): Monitor compliance with nutrient management program Respond to Ag complaints in the Atlantic salmon watersheds Inventory agricultural land use in each watershed Work closely with partners to develop and distribute nutrient, manure and sediment BMPs

pH

As noted above in the Nutrients section, elevated pH can be a concern in rivers that are nutrient enriched, but low pH or acid conditions are a more widespread threat to the health of Atlantic salmon in the DPS Gulf of Maine rivers (Dill et al., 2002; NRC, 2004). Dill et al. (2002) note that "There are episodic declines in pH and increases in aluminum in Maine rivers that are sufficient to adversely affect sensitive life stages of salmon." Exposure to levels of pH under 6.2 is harmful to Atlantic salmon (Kroglund and Staurnes, 1999). Sensitive life history phases include the egg and alevin phase, fry at swim up and onset of feeding, and the smolt phase (Dill et al., 2002).

Smolts may be the most vulnerable because of the challenge posed by transition to salt water. The National Research Council (2004) specifically noted effects on smolts from acid rain as one of the most significant factors limiting Atlantic salmon recovery. "The problem of early mortality as smolts transition from freshwater to the ocean and take up residence as post-smolts needs to be solved" (NRC, 2004). Alkalinity is a useful measurement in judging risk from acid rain because it is an index of a streams buffering capacity (Whiting, 2002).

Whiting (2002) noted that pH was not normally elevated in DPS rivers during summer periods and pH and alkalinity "were moderate (pH range 5.72-8.23, ANC range 25-2,350 ueq/L) and within ranges known to be healthy for Atlantic salmon and other aquatic life. There was no evidence of chronic acidification or extreme nutrient or organic loading." Arter (2004) noted that, although the Sheepscot River did not normally have pH values that pose a threat to Atlantic salmon, the lowest value of 5.7 was registered during high flows such as winter storm events or spring runoff. Several studies have shown patterns of pH problems in Atlantic salmon DPS rivers (Haines and Akielaszek, 1984; Haines et al., 1990; Beland et al., 1995; Whiting, 2002; Arter, 2004). River systems east of the Penobscot have soil and geologic conditions which make them more vulnerable to acid precipitation and runoff (Table 4). "The rivers most vulnerable to acidification are: Narraguagus, Pleasant, Machias, East Machias, and Dennys" (Dill et al., 2002). Tributary basins seem to be more vulnerable than mainstem rivers and the Pleasant River registered the lowest values.

Table 4. Minimum pH levels for various DPS Atlantic salmon rivers from various studies.

There are records of fish mortality and studies indicating levels of impairment of Atlantic salmon in DPS rivers due to acid precipitation and runoff. Haines et al. (1990) found mortality of pre-smolts in the winter of 1986-87 in Sinclair Brook, a tributary of the Narraguagus. While the Tunk Stream is not a listed DPS river, Whiting (2002) documented mortality of alewives in conjunction with a two storm events in October and November 2002: "The cause of death was asphyxiation and is consistent with acid rain toxicity." Magee et al. (2001) showed that river-resident smolts from the Narraguagus River delayed emigration and had inferior osmoregulatory function, when compared to hatchery-reared smolts. Dill et al. (2002) noted that this could indicate inhibition of successful smolting and recommended more studies.

A potential contributor to acid conditions in streams may come from blueberry and cranberry production: "Application of elemental sulfur to low bush blueberry fields to reduce soil pH....to produce a soil pH of 4.2" (Dill et al., 2002). 

Chemical Pollutants

There are many different types of chemicals that may pollute water, including organic chemicals such as pesticides, inorganic chemicals, and petrochemicals. Some of these substances have been more closely studied than others because they are recognized as potential limiting factors for Atlantic salmon in Gulf of Maine DPS rivers (Dill et al., 2002).

Organic Chemicals: Pesticides fall under this category, and some substances used agriculturally in Maine have found their way into the waters of DPS rivers giving rise to concern about effects on Atlantic salmon. Dill et al. (2002) were particularly concerned about organic chemicals because of potential endocrine disruption, which changes sex hormone systems (see more on endocrine disruption). Fish at any life stage can be affected, but and the greatest concern, based on the work of Fairchild et al. (1999) and McGee (2001,) is how endocrine disruption interferes with smolting, . The Maine Atlantic Salmon Technical Advisory Committee (Dill et al., 2002) arrived at the following conclusion: "Given the widespread occurrence of known endocrine disrupting chemicals in Maine Atlantic salmon rivers, the committee concludes that endocrine disrupting chemicals have a high probability of adversely affecting Atlantic salmon restoration." Hexazinone is recognized as a particular problem because it is used widely on low bush blueberries and it has been found in tributaries of the Pleasant and Narraguagus rivers (Beland et al. 1995; Chizmas 1999). 

The ESA listing notice for the DPS Atlantic salmon (USFWS/NOAA, 2000) noted existing and potential impacts to the species from "chronic exposure to insecticides, herbicides, fungicides, and pesticides" and said that "discharging (point and non-point sources) or dumping toxic chemicals, silt, fertilizers, pesticides, heavy metals, oil, organic wastes or other pollutants into waters supporting the DPS" would be a potential "take".

The Maine DAG has worked cooperatively to abate recognized problems related to pesticides in DPS watersheds as part of Atlantic Salmon Conservation Plan for Seven Maine Rivers (MASTF, 1997). Their closest partners in monitoring, not only pesticides but also nutrients and sediment, are the Maine DEP, Soil and Water Conservation Districts and the University of Maine Cooperative extension. Pesticide pollution reduction includes the following steps (MDAG, 2002):

• Identify specific pesticides used in watersheds

• Conduct ground and surface water quality monitoring programs

• Conduct intensive surveillance of blueberry applications

• Conduct environmental risk assessment(s) as needed

• Provide technical expertise and promotion of BMPs

MDAG (2002) noted the following success with regard to Hexazinone: "Studies have shown that Hexazinone decreased in Maine ground water from 1994 to 1999 as a result of a specific plan for this chemical being devised. This is important to Atlantic salmon conservation efforts because these ground waters may be connected to surface waters in some DPS rivers. Stricter regulations were combined with grower education. Practical solutions that worked for growers were 1) lower application rates, 2) switching to granular versus liquid products, switching to less toxic herbicides and skipping application cycles."

Inorganic Pollutants: Aluminum is known to contribute to fish toxicity or stress associated with acid precipitation and runoff (see pH section above). Chlorine can also be a companion problem with acid rain because its toxicity is elevated.

Chlorine: Dill et al. (2002) note the elevated risk of chlorine toxicity in conditions of low pH or increased water temperature. The risk area is a reach of the Narraguagus River where local drainage conditions limit the effectiveness of typical septic systems and where overboard discharge (OBD) systems are used. These alternative wastewater treatment systems use chlorine to kill potentially harmful bacteria but chlorine, if released into streams is highly toxic to fish. Consequently, risk to Narraguagus Atlantic salmon from chlorine in the effected reaches would be elevated during acid runoff conditions or during periods of low flow and elevated temperature. 

References

Arter, B. S., 2004. Sheepscot River Water Quality Monitoring Strategic Plan: A guide for coordinated water quality monitoring efforts in an Atlantic salmon watershed in Maine. Prepared for the Project SHARE: Research and Management Committee. 84 pp. [975kb]

Beland, K., N. Dubé, M. Evers, R. Spencer, S. Thomas, G. Vander Haegen, and E. Baum.1995. Atlantic salmon research addressing issues of concern to the National Marine Fisheries Service and Atlantic Sea Run Salmon Commission. Maine Atlantic Sea Run Salmon Commission Final Project Report NA29FL0131-01.

Chizmas, J. S. 1999. Study of pesticide levels in seven Maine rivers. Maine Board of Pesticides Control. 14 pp [6.2 Mb]

Dill, R., C. Fay, M. Gallagher, D. Kircheis, S. Mierzykowski, M. Whiting, and T. Haines. 2002, Water quality issues as potential limiting factors affecting juvenile Atlantic salmon life stages in Maine rivers. Report to Maine Atlantic Salmon Technical Advisory Committee by the Ad Hoc Committee on Water Quality. Atlantic Salmon Commission. Bangor, ME. 28 pp. [162kb]

Goldman, C.R. and A.J. Horne. 1983. Limnology. McGraw-Hill, Inc. New York . 464 pp.

Halsted, M., 2002. Effects of stream flow on the stream temperature, E. coli concentrations and dissolved oxygen levels in the West Branch of the Sheepscot River. Alna, ME. 15 pp. [450kb]

Haines, T., and J. Akielaszek. 1984. Effects of acidic precipitation on Atlantic salmon rivers in New England. U.S. Fish and Wildlife Service FWS/OBS-80/40.18.

Haines, T., S. Norton, J. Kahl, C. Fay, S. Pauwels, and C. Jagoe. 1990. Intensive studies of stream fish populations in Maine. U.S. Environmental Protection Agency, Office of Acid Deposition, Environmental Monitoring and Quality Assurance, EPA/600/3-90/043.

Kroglund, F., and M. Staurnes. 1999. Water quality requirements of smolting Atlantic salmon (Salmo salar) in limed acid rivers. Can. J. Fish. Aquat. Sci. 56: 2078-2086.

Magee, J. 2001. Agrochemical monitoring and potential effects on Atlantic salmon in eastern Maine rivers. National Marine Fisheries Service Report.

Maine Department of Agriculture. 2002. Report on activities in Atlantic Salmon Conservation Plan Rivers 2002. Maine Dept. of Ag. 

Maine Department of Environmental Protection. 2002. Water quality concerns and effects from state fish hatchery discharges. Unpublished Report. Augusta, ME.

Maine Department of Environmental Protection. 2004. 2002 Section 303(d) Report: Total Maximum Daily Load (TMDL) Waters. Augusta, ME.

National Research Council, 2003. Atlantic Salmon in Maine. The Committee on Atlantic Salmon in Maine, Board on Environmental Studies and Toxicology, Ocean Studies Board, Division on Earth and Life Sciences. National Research Council of the National Academies. National Academy Press. Washington, D.C. 260 pp. [3.5Mb]**

Pugh, L., 2002. Analysis summary of water quality monitoring data, 1994-2001. Sheepscot Valley Conservation Association . Alna, ME. 6 pp. [225kb]

Robinson, K. W., J. P. Campbell, and N. A. Jaworski, 2003. Water quality trends in New England rivers during the 20th century. United States Geologic Service. Water-Resources Investigations Report 03-4012. Pembroke, NH. 29 pp. [950kb]

State of Maine. (1998). Maine Section 303(d) Waters list. http://www.state.me.us/dep/blwq/docmonitoring/303d981.pdf.

U.S. Environmental Protection Agency, 1986. Quality criteria for water 1986: EPA 440/5-86-001. Office of Water Regulations and Standards,  Washington D.C.

U.S. Fish and Wildlife Service and National Oceanic and Atmospheric Administration, 2000. Endangered and Threatened Species; Final Endangered Status for a Distinct Population Segment of Anadromous Atlantic Salmon (Salmo salar) in the Gulf of Maine. Federal Register Notice Vol. 65, No. 223 / Friday, November 17, 2000 / Rules and Regulations. Pages 69459-69483 [225kb]

Whiting, M., 2001a. Year 2000 Progress Report for DEP Water Quality Monitoring Plan - Maine Atlantic salmon rivers. Maine DEP, Bangor Regional Office. Bangor, ME. 4 pp. [25kb]

Whiting, M., 2001b. Progress report: A summary of water quality monitoring results from Spring 2001, Maine Atlantic Salmon Rivers Project. Maine DEP, Bangor Regional Office. Bangor, ME. 6 pp. [775kb]**

Whiting, M., 2002. Maine Salmon rivers water quality monitoring progress report for 2002 field season. Maine DEP, Bangor Regional Office. Bangor, ME. 22 pp. [2.25Mb]**

Williams, S. 2002. Maine Volunteer Lake Monitoring Program Annual Report 2002. Maine Volunteer Lake Monitoring Program, Auburn, Maine. 52pp. [7 Mb] http://www.mainevolunteerlakemonitors.org/.

Williams, S. 2003. Maine Volunteer Lake Monitoring Program Annual Report 2002. Maine Volunteer Lake Monitoring Program, Auburn, Maine. 52 pp. [8 Mb] http://www.mainevolunteerlakemonitors.org/.