Critical pollutant indicators

Critical pollutants in off-shore waters

Objective - Critical pollutants in open waters should not pose a threat to human, animal, and aquatic life.
Measure - Concentration of critical pollutants in off-shore waters.
Purpose - To measure priority toxic chemicals in off-shore waters and to assess the potential impacts of toxic chemicals on human health and the aquatic ecosystem and the progress of contaminant reduction efforts.
Target - Concentrations of critical pollutants in off-shore waters are below standards and criteria designed to protect the health of human, animal, and aquatic life.

Critical pollutants in young-of-the-year fish

Objective - Critical pollutants chemicals should not pose risk to fish-eating wildlife.
Measure - Concentration of critical pollutants chemicals in young-of-the-year fish (YoY).
Purpose - To measure persistent toxic chemicals in young-of-the-year fish and to evaluate measure potential harm to fish-eating wildlife.
Target - Concentrations of critical pollutants chemicals in YoY are below standards and criteria designed to protect fish eating wildlife.

Critical pollutants in herring gull eggs

Objective - The health and reproductive success of water birds will not be impaired by contaminants present in the aquatic food web.
Measure - Annual concentrations of persistent toxic chemicals in Herring Gull eggs.
Purpose - To measure critical pollutants in herring gull eggs from colonies that reflect general lakewide conditions and compare contaminant concentrations to criteria designed to protect water birds.
Target - Contaminant levels in colonial nesting water birds are similar to those of unaffected reference sites or are below existing standards or criteria designed to protect colonial water birds.

Critical pollutants in lake trout tissue

Objective - Consumption of fish should not be restricted due to contaminants of human origin.
Measure - Concentrations of pollutants in edible fish tissue responsible for advisories.
Purpose - To measure critical pollutants in fish and to evaluate the potential exposure of humans to these substances through fish consumption.
Target - Contaminants in fish tissue are below existing standards and criteria designed to protect human health as evidenced by the elimination of fish advisories

Lower food web indicators

Nutrients in open waters

Objective - Nutrient levels should be sufficient to support aquatic life without causing persistent water quality problems (e.g., dissolved oxygen depletion of bottom waters, nuisance algal blooms or accumulations, and decreased water clarity).
Measure - Total spring phosphorus levels (µg/L), chlorophyll-a, water clarity.
Purpose - to follow trends in open lake nutrients.
Target - nutrient levels allow attainment of fishery manager objectives without exceeding the GLWQA target of 10 µg/L for Lake Ontario.

Zooplankton populations

Objective - Zooplankton populations will be sufficient to support a healthy and diverse fishery.
Measures - (1) Mean individual size. (2) Biomass.
- To measure directly changes in mean individual size and biomass of zooplankton populations to inmeasure directly changes in food-web dynamics due to changes in vertebrate or invertebrate predation, and changes in system productivity; the type and intensity of predation; and energy transfer within a system.
Targets - Zooplankton populations are sufficient to maintain prey and predator fish at levels consistent with existing binational fishery objectives. Mean individual size of approximately 0.8 mm is generally considered an optimal size when the water column is sampled with a 153 micron mesh net.

Prey fish

Objective - A diverse array of prey fish populations will be sufficient to support healthy, productive populations of predator fishes.
Measure - Abundance, age and size distribution, of prey fish species (deep-water ciscoes, sculpins, lake herring, rainbow smelt, and alewives).
Purpose - To measure directly abundance and diversity of prey fish populations and to inmeasure directly the stability of predator species necessary to maintain biological integrity.
Target - Given the rapid changes that have occurred in the Lake Ontario food web a specific target in terms of average annual biomass cannot be set at this time. A specific target will be set once fishery managers have a better understanding of prey fish dynamics.

Upper food web indicators

Herring gull

Objective - Lake Ontario will support healthy populations of colonial water birds.
Measure - Total number of active herring gull nests counted per year (additional species as necessary).
Purpose - To measure directly numbers of breeding gulls on Lake Ontario to detect changes in population status that may reflect stresses due to contaminants, disease or insufficient food supply.
Target - Reproduction and fledging rates of herring gulls are normal (similar to unaffected background areas).

Lake trout

Objective - Lake trout populations are sustained through natural reproduction.
Measure - Abundance of naturally produced fish. Number of mature females. Number Harvested.
Purpose - To measure progress and identify obstacles to the successful rehabilitation of naturally reproducing populations of lake trout.
Targets - Abundance of at least 2.0 mature female lake trout >3000 grams per standard gillnet; Abundance of naturally produced mature females >0.2 in US, and 0.1 in Canadian waters per standard gillnet; harvest not to exceed 30,000 fish per nation and; abundance of naturally produce age 2 fish: at least 26 juveniles from July bottom trawls in US waters; increase over current levels in Canadian waters.

Mink and river otter

Objective - Naturally reproducing populations of river otter populations are established throughout the Lake Ontario Basin.
Measure - Number of tributaries and wetlands with established mink & river otter populations.
Purpose - To evaluate mink and otter populations in the Lake Ontario Basin.
Targets - All suitable habitats have established, healthy, naturally reproducing populations.

Bald eagle

Objective - Shoreline and inland bald eagle nesting territories are established and sustained through natural reproduction throughout the basin.
Measures - (1) Total number of established bald eagle nesting territories within the Lake Ontario Basin. (2) Total number of established shoreline nesting territories. (3) Average number of eaglets/nest successfully produced.
Purpose - to measure trends in the recovery and re-establishment of bald eagles within the Basin.
Target - All suitable habitat for bald eagle nesting is successfully utilized. Average fledging rates are 1.4 or greater. Shoreline nesting territories are defined as those less than 7 km from the Lake.