Tuesday, October 28, 2008

Fight over dams fueled by new study

It's a shocker, a new study that claims dams make no difference to salmon survival. But don't start planning new dams just yet...the study has serious flaws and the conclusions are overstated.

Think about it...if one new study came out saying smoking doesn't cause cancer, would you be ready to change your mind after years of studies to the contrary?

The journal that publised the study heralded the findings with a stupid press release that claimed: "Dams make no damn difference to salmon survival." Now that's adding gasoline to a fire, with a ridiculously overstatement of the study's results. Thankfully, this title was quickly removed from the press release.

How did we get into this mess? What's up with PLoS Biology, the online journal that published the study and pushed the findings with a sensational press release? I'll pose the question to PLoS's online community manager and get back to you with the answer.

Here's what happened. Researchers compared survival of young salmon moving downstream to the ocean in two different rivers, one with dams (Columbia River) and one without (Fraser River). They survived equally well, or I should say equally poorly.

From this, a conclusion that dams don't matter? A better conclusion is to report that salmon survived poorly in both rivers, so they both have problems. One (Columbia) has a dam problem, and the other (Fraser) has a non-dam problem.

This study is more reasonable than the press release, but it still invites foolish interpretations with some of the language in uses to describe the results.

4 comments:

c said...

I too am skeptical of the study, though I'm just hearing of it today. I'm curious if you know what a healthy survival rate would be?

Mark Powell said...

I don't know the answer, what survival rate to hope for in rivers this big. It seems extreme to lose most of the fish in a life stage that is so short (one to a few months), but I don't know if that's a reasonable view.

tres_arboles said...

Well you identified the source of the problem with the study in your own post (the publisher, not the study or its authors), but it's worth emphasizing.

Both rivers represent survival struggles for salmon, just different sources of struggle. It's my understanding that the study authors were far more reticent regarding the meaning of the study results than the press release would suggest.

I guess even scientific journals are sold by the same techniques that newspapers are these days. That fricken' press release was a joke.

David, Seattle

Mark Powell said...

thanks tres. the authors were not entirely blameless, but the publishers were the real culprits in the bad hype. Here's an answer from a PLoS spokesperson, brought to you by blogfish:

"the authors have just added a note to the paper explaining that they did not see the press release before it went out, and we've added an apology from the biology editors."

a bit lame, but better than nothing. they ought to match the original hype in the hype retraction. oh well.