By Hand, or By Net?

By Hand, or By Net?

Plus finding the right Spey-casting lines, and more weighty matters.

A couple seasons ago, I stopped using a landing net because I'd heard nets harm trout. However, I still see lots of guides using them. Which is better, using a landing net or releasing the fish by hand? Also, which type of net material is best for the fish?
The jury is still out on this one, as there has been little scientific research done on the effect landing techniques and net materials have on fish mortality. Anecdotally, however, landing a trout by hand is generally considered the least-harmful technique; if you do use a landing net, consider one that's made of knotless rubber or mesh material.

The only study we found that examined this question involved measuring the effect various net materials had on bluegills. The study found that "all net types resulted in heightened injury and mortality with the knotted mesh types being more injurious than the rubber or knotless mesh." However, all fish landed by hand as part of the study survived with no ill effects. Dr. Cory Suski, one of the study's authors, was quick to point out that the results of this study cannot be applied across all fish species and situations as there are too many variables, the most important being scale size and water temperature. Nevertheless, there are situations where nets just make sense: fishing from a boat (which is why you've seen lots of guides using them), if you're expecting to catch large fish or if you're fishing in fast water. Whether you land a trout by hand or with a knotless net, here are a couple things to keep in mind:
  1. Always wet your hand or the net bag before grabbing the fish
  2. Keep the fish in the water as much as possible.
  3. Release the fish as quickly as possible.
-Jim Reilly

In Spey-casting, how necessary is it to use a double-taper or level line, given that you're doing a glorified "roll-casting" cast? And is a Spey rod softer (more flexible) than stiffer (fast)?
Since my Spey-casting experience is limited-and has been compared to pitching hay onto a wagon-I can think of no better person to whom to defer than Rio Products' Simon Gawesworth. Spey-caster and angler extraordinaire, and author of the newly released second edition of Spey Casting (, Simon says:

"The perfect line design for Spey-casting has weight in the rear end and a long, fine taper to a light front end. The light front end is most useful because this is usually the part of the fly line that is sitting on the water at the start of the forward cast. In both Spey- and roll-casting, the more line drag there is at this point, the more energy is lost in the cast as the line tries to break out of the surface film. A thinner front end helps this a lot. Also, the D-loop is what loads the rod, so it is important that the D-loop has the weight, particularly in the section closest to the rod tip. Take a look at this PDF file and in particular the end of page 3 and the first part of page 4. Click here to download the PDF.

About rod action he says: "Traditional Spey styles have deeper flexing blanks than the norm and 'dredger' (Skagit) style rods even greater flex. Scandinavian style rods are faster and quick in the tip. In truth, I usually tell people to use a similar action of Spey rod to a single-handed rod, as they have the correct stop and casting acceleration built in (their muscle memory). Personally, I really like the faster action rods for all styles of Spey-casting."
-Buzz Bryson

More About Calculating Weight

Your article in the April issue ("Ask FR&R") piqued my curiosity on the source of the fish-weight formula.weight = (girth2 x length)/800
I wrote Dr. Jerry Ault at the University of Miami, who does a lot of the research for Bonefish& Tarpon Unlimited, and he jumped on the case.
Sandy Moret
Islamorada, FL

Dr. Ault's response: I have uncovered the full story. Tom Gibson of Texas pointed me in the right direction. The concept for the weight estimator that you mentioned is actually attributed to a guy named William W. Wood, who was one of the pioneers of fishing for tarpon in Cuba. The reference to the idea is found in a book (Salt Water Fishing) by Van Campen Heilner (1953). The full derivation of the formula for estimating the weight of a fish…is based on the idea of placing two wedges base-to-base and assuming the cubic volume is of similar consistency to fish flesh. The idea was pretty novel for its day! A general note is that, by and large, I find that this estimator is 12 to 15 percent low for the cursory range of data that I have evaluated. Its value is in the idea that it is quick.

Click here to download Dr. Ault's complete research paper on this subject.

I don't know if this is germane to the question posed in your April 2008 issue in regard to the formula to determine the weight of a fish from its length and girth measurements, but are you familiar with Sturdy's formula for determining the weight of steelhead (and I understand Atlantic salmon, too)? I believe the formula is: weight = (4/3 x girth2 x length)/1000. A short time ago I tried to find more information about this formula on the Internet, with little or no luck. I would be interested to know more about who Mr. Sturdy is or was, and about his formula (and/or the similar formula described in your recent issue) in a future issue of Fly Rod& Reel.
Doug Finney
Scottsdale, AZ

We found Sturdy's formula to be weight = .00133 x girth2 x length. A note from a reader added yet another layer to this question: Kurt Iverson of Juneau, AK, sent us a copy of an article published in Salmon& Steelhead Journal in which the weight formula is weight = (girth2 x length)/800. This article also cites a new and improved steelhead-weight-estimate formula originated by Lewis Lum of the University of Portland: weight = .0007 x girth2 x length.