Relief from the dog days of summer is as close as the nearest spring-fed stream. With just a facemask, a snorkel, and an old pair of sneakers, you can observe aquatic life on its own terms — underwater. Snorkeling is a great way to introduce children to the cool side of nature.
First, just a few words of warning. Wherever you snorkel, make safety your top concern. Never snorkel alone. Stay in shallow water. And never explore under large rocks or submerged logs.
Before getting wet, walk a length of stream, and notice it consists of two parts: slow moving pools and rapidly flowing riffles.
Pools may be as small as a birdbath or as large as a swimming pool. When you find an inviting knee-deep pool, put on your mask and snorkel, float face down, and watch. Within a few minutes, curious fish approach. As your body cools, watch for colorful sunfish.
In bigger, darker pools, scan under a tangle of roots or under floating logs. These dark refuges provide excellent cover where larger predatory fish such as trout and bass await passing prey — insects, smaller fish, frogs, and snakes.
Even more interesting are the smaller fish found in the shallow, rapidly flowing riffles. This is the noisy, “gurgling” part of a stream. Here, where the flow rate is often so fast it seems every living thing should be swept away, is where darters live.
Facing upstream, lie down in a riffle to view the darters. Inch into the current and scan the rubble. Notice the small fish darting among the stones.
Darters are suited to life in swift currents. Some anchor themselves near the cover of larger rocks. Others wedge themselves among stones on a tripod consisting of the tail and pelvic fins. Still others bury all but their heads in fine sand or gravel.
Masters of disguise, darters can be drab and difficult to see. Some, though, display almost gaudy patterns of reds, blues, and oranges. Think of brightly colored darters as the butterflies or warblers of the fish world.
Many freshwater invertebrates stay hidden beneath large flat rocks that cover clear stream bottoms. Gravel stream bottoms are home to many species of freshwater clams, mussels, snails, and larval aquatic insects. Flip large flat rocks, let the current clear the sediment, and you’ll observe an impressive diversity of aquatic life.
The flat-bodied creatures that cling tenaciously to the undersides of submerged rocks are stonefly and mayfly larvae. From the tip of the abdomen of stonefly larvae, you’ll notice two tail-like filaments. Larval mayflies have three such tails. The presence of stoneflies and mayflies indicates clean water.
My favorite aquatic insects are caddisfly larvae. If you notice a bundle of tiny pebbles or twigs moving across the stream bottom, watch it closely. Pick one up, and you’ll discover it’s home to an insect. On one end there’s a head and thorax, complete with legs. The soft tissues of the abdomen are protected by the case that surrounds it.
Caddisfly larvae build their own house and carry it on their back. The weight of the case helps anchor the larvae in moving water, and it’s excellent camouflage when the larvae rests. The materials used to make such cases include grains of sand, tiny pebbles, and sometimes plant material. Some of the pebble-users actually build a spiral case that can easily pass for a snail shell.
The biggest surprise in a clear cold clean stream awaits under large flat rocks almost too difficult to move. Hellbenders are huge salamanders that spend their daylight hours under large flat rocks on rocky stream bottoms. At night they emerge to dine on crayfish (about 90% of their diet) and other small aquatic creatures.
Mature hellbenders measure 17 (males) to 21 (females) inches, and the body seems wrapped in flabby folds of skin. The eyes are small, beady, and positioned on top of the head. If you do find a hellbender, be sure to gently return the rock to its original position so it can return to its refuge.
Hot humid weather presents a great opportunity to get wet, stay cool, and learn a little aquatic natural history.