Photo Steve Ryan
July 11, 2011
By Dr. Rob Neumann
Fishing quality
Fishing quality isn't so much difficult to define as it is to measure, because there are so many factors that go into each fishing experience. Fishery researchers dealing in social sciences find that fishing quality is affected by a host of variables such as personal values, environmental setting, facilities, habitat, weather, and companionship. More obvious is the catch — species, size, and numbers. Harvest also is important for many anglers.
Fish quality, however, is but a component of fishing quality. When we see photos of giant muskies and pike in this magazine, we appreciate the size of the catch — the fish-quality aspect. Trophy mounts hang in Northwoods taverns as icons of fish quality, although they can also go beyond the catch by conjuring up memories of high-quality fishing experiences. An important distinction between fish quality and fishing quality is that fish quality can be measured more easily using direct measurements of fish size.
In the 1970s, Dr. Richard Anderson, considered a pioneer of modern recreational fishery management, along with his graduate student Dr. Steve Weithman, developed a fish-quality index using length and weight. The length component was scored based on how a fish's length compared to the world-record length for that species. At about 20 percent of world-record length, for example, a fish begins to offer recreational value, which then climbs steeply before leveling off at about 75-percent of world-record length.
Fish quality gives fishery biologists benchmarks for assessing sportfish populations. They can calculate what proportion of a population is composed of fish of certain lengths and compare that to what is considered desirable. In the 1970s, early applications of these ideas were proposed for largemouth bass and bluegill by Dr. Anderson. The term "stock" length was coined for the minimum length at which fish start to provide recreational value, 20 to 26 percent of world-record length, according to Weithman's curve. "Quality" length was assigned to fish at 36 to 41 percent of world-record length. Anderson and Weithman also defined stock and quality lengths for several coolwater fishes, including pike and muskie.
In the 1980s, Don Gabelhouse, then Kansas fishery researcher and now fish chief in Nebraska, also a contributor to In-Fisherman publications, expanded on Anderson's ideas by defining lengths for "preferred," "memorable," and "trophy" length designations. He chose the point on the curve at which it climbs most steeply (40 to 55 percent of world record length) as the preferred length. Memorable is where the curve begins to level off (59 to 64 percent), and trophy is where the curve barely rises once fish reach a certain length (74 to 80 percent). Gabelhouse proposed stock, quality, preferred, memorable, and trophy lengths, for numerous species, and more species have been added over the years by others.
Throughout the development of these length definitions, quality has referred to the minimum length of fish that most anglers like to catch. Most anglers prefer to catch something a bit bigger, hence the name "preferred." Most anglers remember catching an individual memorable-sized fish, and trophy is a size worthy of widespread acknowledgement.
Included here are length designations that have been defined for pike, muskie, and chain pickerel. If you were assigning lengths you might have come up with something different, depending on the growth potential of these species where you fish and how you personally value fish quality.
What lengths would you assign to stock and quality sizes? What size do you prefer to catch? What length makes an individual pike or muskie memorable to you?
