The streams are easy to access from hiking trails. The question hikers always ask: “Are there fish in there?”
One of us gives a long discourse on brook trout natural history. Another grunts something like “little ones,” all while thinking, “that’s why I have a rod in my hand.” My answer varies, but I’m often mystified by the very question. How come many people don’t know that there are fish in the stream? Part of my displeasure could be my growing concern about the fate of the fish. With the climate changing, will these cold-water fish be there for long?
David Demarest, a fisheries biologist with the park, told me he’s worried about some of the south-running streams. “They seem to heat up earlier, stay warmer into fall.” However, it can be hard to determine the exact role climate change plays in their warming, as many have also lost tree canopy to gypsy moth, hemlock woolly adelgid and now emerald ash borer. A warming climate may have extended the range of these pests.
Nathaniel Hitt, a fish biologist with the U.S. Geological Survey, said he worried more about the increased rain than heat. He and other biologists worry that the increased rainfall scours the streams during breeding season, washing away eggs and habitat for egg-laying. Trout are spawning now, when the region has seen record rainfall, as much as 500 percent of normal levels.
To gather more information, Hitt has worked on a grant to involve citizens in data collection. He would place a kickboard in the stream with a hole for a camera. The kickboard camera would float over the stream, a roving eye, attached to a rod and line — fishing for information. Through a Google Cardboard viewer, users on land could see below the surface, counting fish and other aquatic life. Would it help provide some baseline data to measure climate or other effects? It isn’t yet, but such a view might expose young people to something they have never seen before.
Citizen scientists help the USA National Phenology Network gather leaf-out data across the United States. These data show great variability from year to year, but the trend is distinct: earlier warmer temperatures and earlier first buds, including among cherry blossoms. Such programs, including Trout Unlimited’s Trout in the Classroom, may spawn a generation of citizen scientists who will keep track of what could be lost. Joni Mitchell was right that you don’t know what you’ve got till it’s gone. But you have to know it in the first place.
There are winners and losers in climate change. Among fish, the native brook trout, here since the last ice age, are being pushed farther upstream. Other fish, such as the banded killifish and the mosquitofish, have expanded their range in the Potomac, also probably an indicator of climate change.
The graphs and hockey stick trend lines show it. But climate change is evident if we use our own eyes, too. Not just in the intensified hurricanes or the record rainfall; anyone who sleds in winter, gardens in spring or fishes in fall notices changes.
Brook trout and the pristine streams they inhabit are indicators of the overall health of the environment. We have taken action before, passing the Clean Water Act in the 1970s and amendments in subsequent decades.
So, are there fish in there? For now.