At a time when folks are worried about alien flora and fauna getting accidentally introduced into the area and causing havoc – the dreaded “invasive species” problem, which truly is dreadful – why do we spend lots of money deliberately spreading foreign fish all over the place?

Blame history.

The fish in question is the rainbow trout, which has been bred and distributed throughout rivers of the world for more than a century because it’s a robust sport fish. It’s fun to try catching and fun to eat when you succeed.

We’ve been spreading rainbow trout around our rivers for so long, and we do it so well, that it would be hard to stop now, even as we struggle to contain other alien aquatic species.

As told in the excellent book “An Entirely
Synthetic Fish” by Anders Halverson, fishing in wild rivers was touted in the 19th century by American leaders worried that the Industrial Revolution was breaking our connection to the natural world, particularly the hunter/gatherer connection.

The lively, fast-growing rainbow trout, native to the Pacific Northwest, was seized upon as an ideal fish for luring city folk into America’s wilds. Fisheries management was born.

These days, federal and state agencies in the U.S. release about 2 billion rainbow trout each year, putting quarter-pound-ish “fingerling” fish in rivers everywhere.

We’re not alone. Rainbow trout are now found over much of the planet, from South Africa to the Souhegan River, Malawi to the Merrimack River.

New Hampshire is in the midst of trout-stocking season, which runs from April 1 through mid-July. Rainbow trout, plus another alien species called brown trout as well as native brook trout, are raised and placed in some 300 lakes and rivers each year as a lure to anglers.

Those streams were once full of brook trout (Salvelinus fontinalis), the official state freshwater fish, known to anglers as “brookie.”

Its numbers have fallen due to a variety of environmental issues, most notably development that causes sedimentation, higher water temperatures, and acidity.

The brook trout isn’t endangered, but its range has been so altered over time that a special program has been developed to help preserve it. The existence of rainbows and brown trout complicates those efforts.

Researchers spend time stunning fish in small creeks and rivers with electricity so they can determine the species and see how many brook trout actually exist. (My daughter participated in one such study a couple of summers ago; she said it’s amazing how many fish live in even tiny streams.)

Only a couple of small watersheds in the North Country are said to still have a high percentage of historic habitat with self-sustaining brook trout populations.

Officials are quite aware of potential problems with alien trout, and stock just brook trout in certain places. Recently, for example, brookie fingerlings were taken by helicopter to 48 remote ponds around the state.

Still, it can’t help our state fish that we work so hard to spread competitors to our native trout throughout its habitat. Why do we do it?

Because it’s a big business that accomplishes what it set out to do. Well-stocked rivers draw anglers, who spend money in local restaurants and hotels, and who buy the fishing licenses that help underpin much government wildlife work.

New Hampshire Fish & Game in particular is dependent on hunting and fishing licenses, whose numbers have been stagnant or dwindling. People like me, who hike and canoe but don’t know which end of a fishing rod is which, don’t really pay anything to maintain wild spaces.

Changing the fish-
stocking process could disrupt that system, so I imagine it’s unlikely to change. Better the devil you know, I guess.

Granite Geek appears Mondays in the Telegraph, and online at www.granitegeek.org. David Brooks can be reached at 594-6531 or dbrooks@nashuatelegraph.com.