From today’s Seattle Times:

For more than three decades, scientists have been rounding up harbor seals from Puget Sound, drawing their blood, sampling bits of blubber and running other tests to check for signs of disease.

Their goal: to track how harmful concentrations of toxic chemicals are affecting the animals’ health.

Sounds a bit tough on the seals, perhaps. But biomonitoring—the practice of gauging ecosystem status by looking at actual organisms, rather than at the chemical purity of water or soil—is a very powerful tool that deserves more attention than it gets.

After all, I don’t really care if soil or water are contaminated for the sake of the soil and water itself—I care for the creatures (especially humans, but others too) that are affected by the pollution. And what better way to figure out if pollution is affecting living things than by, well, measuring them.

But what really caught my eye in the article was this:

Statewide, harbor seals number about 32,000. They haven’t always been that numerous. Because fishermen complained that seals took too many fish, the state once paid a bounty to reduce their numbers.

The statewide seal population numbered about 5,000 in 1970, Jeffries said. It began to recover after passage of the Marine Mammal Protection Act, which banned killing.

From the first Earth Day to today, a six-fold increase in the state’s harbor seal population. Obviously, just because harbor seal populations are going up doesn’t mean that aquatic ecosystems are healthy. But it’s encouraging nonetheless.