Babine Steelhead Weight Estimator [Archive] - Fly Fishing Forum

: Babine Steelhead Weight Estimator


Bob Pauli
12-05-2003, 09:26 PM
December 12, 2003

KEELIN WEIGHT ESTIMATOR FOR BABINE STEELHEAD

A scientist looks at Babine steelhead weight estimates.

This week I had the good fortune to make the acquaintance of Mr. Tom Keelin. Tom is a dedicated S & S [steel & spey] fisherman, with a scientific bent, who spent two years analyzing Babine steelhead length and girth dimensions versus weight.

Tom created his weight estimator based on physical measurements of 56 steelhead caught and released at Silver Hilton Lodge in 2001-2002 as recorded by Mark MacAneeley, the head guide. A soft mesh net was used to gently lift the steelhead from the water to enable accurate weighing prior to release.

Tom discovered that:
• using the traditional formula
length*girth*girth / 800
-gave a weight estimate within 1 lb of actual 7% of the time.
-93% of weights are underestimated by more than 1 lb.

• using the Sturdy formula
length*girth*girth / 750
-gave a weight estimate within 1 lb of actual 33% of the time.
-67% of weights are underestimated by more than 1 lb.

• using the “Keelin Estimator”
length*girth*girth / 690
-gave weight estimates within 1 lb of actual 81% of the time.
-10% of weights are underestimated by more than 1 lb.
-9% of weights are overestimated by more than 1 lb.
- An interesting part of the Keelin estimator is adding 1/4 inch to the measured length of a hen, and deducting 1/4 inch from the measured length of a buck before entering the Keelin table.

The Keelin package consists of two sheets, one graphing data points and lines representing the three formulas described above, and the second a table of weights vs. girth and length.

For copies, send request to KeelinSteelWeigh@aol.com
Specify format: Adobe Acrobat Reader PDF or Microsoft Power Point.

Tom indicated interest in joining this board and welcomes questions and comments. tomk@keelin.com

Bob Pauli
12-07-2003, 12:14 AM
Tom Keelin's formula makes me wonder about weight estimates of Bukley, Kispiox and other upper Skeena fish, being so close to the Babine.

Has anyone on this board measured and weighed such a fish?