Desired Outcome: Fishability
(fish that are safe to eat)

SOLEC Assessment

SOLEC's overall subjective assessment of its indicator Chemical Contaminants in Edible Fish Tissue is "Mixed, Improving." This assessment is described in the SOLEC report as, "The ecosystem component displays both good and degraded features, but overall, conditions are improving toward an acceptable state."⁸

Basis for SOLEC Assessment

SOLEC reported on the results of a study that applied a uniform set of health standards to historical data on polychlorinated biphenyls (PCBs) in coho salmon in the Great Lakes.⁹ The results show a slight decline in PCBs over time. Because of the risks they present and their persistence, PCBs are a frequent basis for health-based fish consumption advisories in the Great Lakes basin, and coho salmon is a popular sport fish.

The indicator for the desired outcome of Fishability is based on the concentration of persistent toxic substances that bioaccumulate in the food chain and can harm the health of humans who eat contaminated fish. Under SOLEC, this is measured by using fish contaminant data and a standardized fish advisory protocol. The Indicators Implementation Task Force concluded that indicators for the desired outcome of Fishability could be measured using trends in the chemical contaminants PCBs, DDT and mercury in selected species of fish, such as walleye, lake trout, coho salmon, smelt and alewife.¹⁰ The Task Force also concluded that trends could be measured by the number of added, altered or lifted advisories where changes in advisories reflected changes in fish tissue concentrations, although not in cases where changes were made based on contaminant concentrations at which advisories were issued.

Commission Assessment

There continue to be restrictions on consumption of sport fish from the Great Lakes, and the desired outcome of Fishability has not been achieved for sport or subsistence fishers. All eight Great Lakes states and the province of Ontario continue to have fish consumption advisories. The analysis of PCBs in coho salmon using a uniform advisory is a good initial effort that provides information over both space and time. However, as recognized by the Parties, a single contaminant in a single species of fish is not sufficient for a thorough assessment of this desired outcome.

The Indicators Implementation Task Force report states that trends detected in fish contaminants could be corroborated by long-term trends of contaminants in fish-eating wildlife species, such as otters, snapping turtles and bald eagles as well as herring gull eggs. Bald eagles had PCB levels that were stable or declining in the last decade, but no trends are apparent for the entire Great Lakes.¹¹ Real declines in the levels of PCBs over the last 20 years are evident from studies of Great Lakes biota, including herring gull eggs, lake trout, coho salmon and bald eagles.

Commission-sponsored studies using several data sets for PCBs in herring gull eggs, and a data set for PCBs in coho salmon, show continuing decline in contaminant levels, but at dramatically slower rates than was observed in the period immediately following controls on manufacturing and point sources (1978-1980), and the rapid declines for the period of 1983-1989. The presence of a plateau effect is possible but unknown. Recent trends for PCB levels in lake trout also show a weak or very slow decline, which also could indicate a plateau, but there is no solid statistical evidence of such. The recent trends for PCBs in bald eagles are unclear because of huge data scatter, but only some pollutants, notably DDE and oxychlorodane show continuing declines in the bald eagle in all Great Lakes locations.¹²

Indicator Challenges

The eight Great Lake states and the province of Ontario have jurisdiction over sampling, measurement and analytical protocols and issue their own advisories. Individually, each jurisdiction has compiled a great deal of information on fish consumption advisories in the Great Lakes.

However, this information is not readily comparable or compatible for analysis.

Using changes in fish consumption advisories as a measure for this indicator would be effective if there were a uniform protocol for advisories in all jurisdictions and the rationale behind any changes to the advisories were clearly stated when issued. Given the number of jurisdictions involved, devising such a uniform advisory is not an easy task.

As outlined later in this Eleventh Biennial Report, studies show injury to human health. This is particularly so in fetuses and young children, and at lower levels of exposure to contaminants in fish than had previously been encountered. Exposure varies by type of fish, the parts of fish consumed and frequency of consumption. Without major new initiatives to reduce the sources of contaminants and ongoing human exposure, the desired outcome of Fishability will not likely be achieved in the foreseeable future.