Monday, January 28, 2013

The Hybrid Conundrum by Moderator Anders Halverson

One of the most vexing problems posed by the widespread introduction of rainbow trout in the American West has been their propensity to hybridize with the natives. Take for example, the westslope cutthroat of the northern Rockies. Once the most widespread cutthroat subspecies, their range has been dramatically reduced in the last century due to the introduction of rainbows. Just how far it has shrunk, though, is a matter of some contention. According to the criteria applied by the U.S. Fish and Wildlife Service, a fish can still be considered a Westslope cutthroat even if it has a small amount of rainbow trout DNA (say from a great-grandparent). Such fish still occupy about 20 percent of their original range.

Westslope cutthroat native range
But if only those fish that have absolutely no rainbows in their family tree can be counted, then that number drops to less than 2 percent. What’s more, most of these purebred fish are restricted to high, isolated, headwater streams. They’re threatened by inbreeding depression and, since all the pure mainstem populations have been compromised, many of the genes that might have adapted the species to larger rivers can probably only be found today in hybrids.

Interbreeding between slightly hybridized westslopes and their unpolluted cousins might alleviate these problems. But it would also create new ones. There are the biological issues, of course—some studies for example suggest hybrid fish are less fit. But maybe more importantly, it raises a host of legal issues.

The Endangered Species Act passed by Congress in 1973 did not include any guidelines on hybrids. Thus, when the issue arose in the 1980s, Department of Interior lawyers concluded that hybrids could not be protected under the act. It seemed a reasonable decision, at least for a few years. But when new technology gave us the ability to sequence DNA, it became apparent that hybridization was far more common than anybody had previously thought. Certain wolves (which had a little coyote DNA) and other listed species were thrown into legal limbo.
A likely hybrid westslope-rainbow trout

After a brief period of struggle, the lawyers threw in the towel. Hybridization would have to be handled on a case-by-case basis, they concluded, since hybridization was “more properly a biological issue than a legal one.”

I wonder whether it isn’t also an issue of human values and psychology. Are we really so concerned about purebred westslope cutthroats because hybrids may be less fit or because biodiversity may be associated with ecosystem stability? Or do untainted westslopes somehow appeal to our thirst for the prelapsarian, the rare, or some other innate urge?

Monday, January 21, 2013

The Technological Fix by Moderator Anders Halverson
Discussion topic:  An Entirely Synthetic Fish: How Rainbow Trout Beguiled America and Overran the World

George Perkins Marsh is primarily known today for his 1864 book, Man and Nature, which is widely credited with ushering the idea of conservation into the national discourse. Seven years earlier, though, Marsh wrote a state-commissioned report on the decline of Vermont’s fisheries that previewed many of the same themes.

In this fascinating document, Marsh drew a connection between the loss of fishing opportunities, “duller,” and “more effeminate,” American men, and a threat to “our rights and our liberties.”

Industrialization, logging, and overfishing had initiated the problem. However, “The unfavorable influences which have been alluded to are, for the most part, of a kind which cannot be removed or controlled,” he wrote. “We cannot destroy our dams, or provide artificial water-ways for the migration of fish, which shall fully supply the place of the natural channels; we cannot wholly prevent the discharge of deleterious substances from our industrial establishments into our running waters.”

What to do? Marsh advised artificially propagating and stocking fish into the public waterways. Boys would go fishing again. Democracy would be safe.

George Perkins Marsh
Flash forward to the present day. After hearing me talk about the ecological impacts of fish stocking, people often describe the joy they found as children fishing for what they now realize were probably hatchery rainbows. They connect these experiences to their present love of the out-of-doors and the natural world. And they propose that if stocking fish creates a constituency for such things, perhaps it’s worth any harm it may cause, especially in ecosystems that have already been so dramatically altered by humans.

Perhaps. But I think we should also consider what happens when we try to solve our problems with a technological fix rather than addressing the root of the problem.

On the one hand, history has shown the effectiveness of the technological approach over and over again. For just one example, take the famous 1980 bet between ecologist Paul Ehrlich and economist Julian Simon. Ehrlich believed that overpopulation and overconsumption would lead to a catastrophic depletion of resources unless we tackled both. Simon countered that human ingenuity would mitigate any scarcity issues. They agreed to use the price of certain commodities as an indicator, with Ehrlich betting prices on these items would rise over the next ten years, Simon that they would decline.

Simon won.

Colorado's Crystal River Hatchery
On the other hand, there may be some things that can’t be measured by such simple proxies. Fisheries biologist Ray Hilborn laments that the public in the Pacific Northwest seems to believe that the region’s salmon runs depend entirely on hatcheries. “This belief is particularly pernicious because it inexorably leads to the acceptance of hatcheries as a mitigative measure for further habitat loss and dam construction,” he concludes (full article here).

And when I was researching this book, I had the opportunity to talk to long-time Montana fisheries manager Dick Vincent. He believes that his state’s decision to eliminate most fish stocking has generated an unparalleled river conservation ethic. Because the technological fix is off the table, he maintains, Montanans fight like no others to conserve such things as clean water and spawning habitat.

I’m not a purist, and I don’t have the answers. But I do believe that relying on technological fixes for things like fisheries management can have widespread ripple effects. I wonder, for example, whether our unwillingness to address the root causes of climate change can in some small way be traced back to a hatchery rainbow stocked many years ago to mitigate the effects of a dam.

Sunday, January 13, 2013

An Entirely Synthetic Fish by Author and WILD READ Moderator Anders Halverson

Thanks all for joining this discussion. I’m looking forward to your insights.

I’ll start by giving some background on how I came to write An Entirely Synthetic Fish. About ten years ago, I was working on a Ph.D. in which I used molecular tools like DNA fingerprinting to study ecology, evolution, and conservation. More specifically, I was working with amphibians, mostly wood frogs, addressing questions about inbreeding, kin selection, and microevolution.

I continue to find this field quite fascinating. Nevertheless, there’s nothing like an unfinished dissertation or the thought of all the samples in the lab that still need to be processed to smack you awake in the middle of the night and set you to thinking. And among other things, my late night thoughts focused on the purpose of my labors. So many of the most important debates in society are framed in terms of science. And yet, too often, advocates on all sides seem to use science not to illuminate or question, but rather to justify. Positions are based on value systems that usually remain hidden from scrutiny or discussion, and the resultant debates are therefore fruitless.

The upshot: I decided to leave the lab when I finished my dissertation and examine the issues from a different perspective. I obtained funding from the National Science Foundation to research and write a historical and journalistic narrative that is nominally about rainbow trout but is really, I like to think, about the way we have related to the natural world over the last 150 years.

Fish on Creatine
A group at the University of Missouri is
studying the  effects of the body-
building supplement creatine on
rainbow trout. Photo by Steve Morse
But why rainbow trout? They're frequently the subject of high-profile debates about aquatic ecosystems, for one thing. More importantly, though, I grew up in Colorado and spent many of my happiest hours trying to catch them. For me, as for most anglers, fishing was a way to escape civilization and technology and get back to the natural world. At some point in my late teens, though,  I stopped. I didn’t really think about why, or even notice that I had quit. I just ceased to pick up my rod. It wasn’t until years later (probably late at night) that I began to question it. And it occurred to me that there is a fundamental paradox inherent in recreational fishing, especially in freshwater. Because while it may seem like an escape, fishing is in many ways a product of technology and the industrialized world.

State and federal agencies currently stock more than 40 million pounds of fish in the freshwaters of the United States, almost half of which are catchable sized rainbow trout (more). And often even the fish that didn’t come straight from the hatchery are nonnatives introduced by fisheries managers and zealous anglers many years ago. Rainbows have been introduced to every state in the country and every continent but Antarctica (more). Two out of every three fish swimming in Colorado are nonnative. And I haven’t even mentioned genetic and chromosomal engineering and other ongoing experiments like the one pictured on the right (more).

A Worldwide Fish
Originally native to a narrow band around the Pacific from
Mexico to Kamchatka, rainbow trout can now be found
all over the world (countries in dark gray).
Let’s just say that a stocked rainbow on the end of a fly line is the embodiment of a pretty serious contradiction, at least in my mind. And while it was initially enough of a turnoff to make me quit the sport, it later became a fascinating conundrum that demanded further research.

Of course fish introductions and stocking programs have had some serious consequences for native fauna and ecosystems. Amphibians and freshwater fishes rank #1 and #2 as the most seriously threatened vertebrates in the world. And much of the blame can be laid on the introduction of nonnative fishes. But I’d like to hold off on that for future discussions.

Here I hope to initiate a discussion on the role that science plays in debate and policymaking in conservation and natural resource management. How should it be used? How is it used in fact? I’d very much value your insights in the comments, since if you’re reading this blog you are probably interested or perhaps professionally involved in these fields.

Of course if you've already read the book and have some questions or topics you'd like to discuss or have me discuss in a future post, please mention them. 

Finally, if you are interested in learning more about the book, seeing some cool old photos from the early days of fisheries management, or more photos and figures like those inserted here, please visit

Friday, January 4, 2013

Anders Halverson, Author of An Entirely Synthetic Fish, Moderates WILD READ January 13-February 17, 2013

About Anders Halverson:

Anders Halverson is an award-winning writer with a Ph.D. in ecology from Yale University. He wrote this book, An Entirely Synthetic Fish: How Rainbow Trout Beguiled America and Overran the World,  as a research associate at the University of Colorado’s Center of the American West with a grant from the National Science Foundation.

About the Book:

Suppose that more than a century ago, U.S. government officials became concerned democracy itself was at risk because men seemed to be less virile.  Suppose that to reverse this trend they decided to populate streams, rivers, and lakes with “an entirely ‘synthetic’ fish”—quarry with which Americans could rediscover their abilities to capture and kill animals. And suppose that, up to the present, these creatures were still being produced and distributed on a massive scale, sometimes even being trained like gladiators and pumped full of the same supplements as the best human athletes so that they would provide a better fight.

Such is the true story of the rainbow trout. Sometimes vilified for their devastating effects on the native fauna, sometimes glorified as the preeminent sport fish, the rainbow trout is the repository of more than a century of America's often contradictory philosophies about the natural world. Exhaustively researched and grippingly rendered by award-winning journalist, aquatic ecologist, and lifelong fisherman Anders Halverson, this book chronicles the discovery of rainbow trout, their artificial propagation and distribution, and why they are being eradicated in some waters yet are still the most commonly stocked fish in the United States.