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How the Hatchery’s Robust Sampling and Monitoring Process helped them Manage a Problem in 2017

One of the legacies of the Consent Agreement is the water monitoring system at the Hatchery. Dr. Ray Canale, the court appointed Master for the Agreement developed a sophisticated model that allows Hatchery Biologist, Mr. Paul Stowe, to stay on top of what’s happening in terms of phosphorus discharge. That model worked perfectly in spring 2017 when the Hatchery exceeded the court appointed limits.

For nine years the Hatchery has been raising Atlantic Salmon from the eyed egg stage to yearlings (approx. 6.5 inches) for release in Lake Huron. Atlantic Salmon are considerably more difficult to raise than other salmon. In the fall of 2016, a number of the fish were getting sick and needed treatment with both antibiotics and a topical treatment.  The treatment, together with the cooler winter temperatures, enabled the Atlantic Salmon to recover.

But the problem did not end there.

Water the diseased Atlantic Salmon had swum in had to be reused with the Coho Salmon.  By December the Coho were coming down with Bacterial Coldwater Disease, which required another course of treatment. Problem?  The antibiotic was not available in the low-phosphorus feed normally used. A high phosphorus feed had to be used daily for ten days as opposed to the two or three times a week normally at that time of year. Platte Lake now had two problems floating downstream from the Hatchery—high phosphorus feed and heavier feeding rates.  In March, the fish required another course of treatment.

Fortunately, the fish recovered, but what about the Lake?

Sampling results confirmed there was a problem and Paul began tweaking his processes where he could. He discontinued feeding yearling fish and reduced feed rates for Coho and Chinook.  Three weeks later, when the phosphorus had worked its way into the Lake, the net result was a “violation”—a discharge in excess of allowed limits of one pound in March and two pounds in April. There have been no violations since 2017.

The good news? Because the sampling from the Hatchery is constantly updated in their database and shared with the PLIA (it is reviewed by the board and posted on our web site for everyone who wants to see it) no one was surprised. The PLIA had been in touch with Paul and knew he was on top of solving the problem.

Since 2017, Paul has identified a new supplier who can provide low phosphorus medicated feed. This will allow much more rapid treatment if similar problem arises in the future.

Most importantly, this example demonstrates the importance of a strong and healthy partnership between the PLIA and the Hatchery. In the past, without the internal monitoring of the Hatchery and vigilant people like Paul, this problem would have gone unnoticed and Platte Lake would have been the recipient of more phosphorus pollution.

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