Catch and Keep - Why? Update from history of regulations and fishery response.

wayne gustaveson

Staff member
The smallmouth story is about effective management. There was a time when they were little and scrawny. The population was way too large for existing conditions and available forage. The writings below chronicle how we overcame the tough times by increasing harvest and changing attitudes. Thought you might like to relive the experience:

Catch and Release - Or Keep?

My career as a biologist is unique in that I have spent my whole time on one body of water. I love Lake Powell! It is the second largest reservoir in America and has incredibly diverse fishery dynamics. There has never been time to get tired of doing the same old thing. There are new challenges each day.

I wrote this in the summer of 2001.

"Spent yesterday morning by myself in meditation concerning "my lake" and how to help it. I went to Navajo Canyon fishing for smallmouth and stripers. Found both and really enjoyed it. But my reason for being there was to finally decide what to do about the smallmouth growth slowdown. We need to harvest more fish. Most folks do not keep smallmouth. Only 5-11% of all fish caught get harvested. We have been struggling with increasing the creel limit knowing that if anglers kept 6 fish (current limit) it would help. But if we don't keep 6 fish now how will raising the limit solve the over population problem.

Obviously the question is more about education and less about numbers. So I caught and kept 6 smallmouth. Then I filleted them. It reminded me of the good old days when I filleted crappie. Fillet size and time spent was very reminiscent of crappie. But my little pile of fillets was a few short of a meal. So I caught 6 more fish and filleted them. Caught two fish better than 12 inches and released them. When I added the next batch of fillets to the pile there was just enough for a meal of real prime, thin, bite-sized, eating. Really reminded me of crappie then.

But we are talking about most visitors staying here for 3-5 days. It would be nice to have two meals when you return to CA, AZ, NV, UT or wherever. Not every one is going to keep smallmouth. The problem will still be convincing anyone to keep and fillet small fish. Those that do need to be rewarded and be able to make an impact.

So on my boat in Navajo Canyon, I decided to increase the smallmouth limit to 20 fish per day with 20 in possession. Law enforcement types do not want to separate bag and possession so I will honor their concern.

At the same time we will restrict crappie bag and possession to 10 fish to protect that population until they can find a filling reservoir condition with flooded brush which will allow them to bring off a good year class.

On January 1, 2002 a new regulation was enacted on Lake Powell that allowed anglers to keep 20 smallmouth bass. The number was not important. It could have been 10 or 30. The philosophical statement was the clincher. I wanted anglers to know that it was okay to keep a smallmouth bass. Catch and release was not working at Lake Powell. Catch and keep would help improve the fishery. Anglers responded to the new keeper philosophy by doubling the bass harvest. In 2002 and 2003 about 25% of bass caught were kept.
Fast forward to 2004. After only two years of "keeping bass" the fishery has responded in dramatic fashion. Shad forage is more abundant. Smallmouth bass are bigger and fatter. Bass tournaments held in 2002 saw winning average weights of less than 5 pounds for five 12-inch smallmouth bass. The first two tournaments held in 2004 had winning weights of over 9 pounds for five fish with a "big fish" over 3 pounds. The ratio of bass over 13 inches in the population (RSD) has improved from zero in 2000 to 20% in 2003. The outlook for 2004 is for continued bass growth and better quality fishing.

How does this work? Smallmouth targeted by our catch and keep program, those 9-11 inch bass, are the most aggressive predators. Young bass are naïve, fearless and always hungry. By keeping the smaller, most aggressive bass, more food was made available for the older, wiser fish that were more selective in feeding habits. Keeping the larger bass would have had the opposite effect of leaving the most efficient predators and not freeing up enough additional forage. Anglers were given information about the goal of the bass harvest program and the target size fish to harvest. They responded with enthusiasm. This was a victory for angler education in action.

While it seems impossible for anglers to have any impact on over populated striped bass or smallmouth bass in a lake the size of Powell, the results suggest just the opposite. With over a million angler-hours expended each year, given a direction and purpose, there was enough angler impact to make a difference. By harvesting more fish, anglers played a significant role in changing the population structure of both the bass and striper populations.

The wild card is forage status. Natural cycles often determine good and bad shad production years. The bass harvest program was instituted at a time when shad numbers were low. Shad numbers improved in 2002 and 2003. There may have been improvement in bass growth without any harvest emphasis. But one thing is for sure. There were fewer mouths to feed when the shad population exploded meaning more shad for each predator. Smallmouth bass and striped bass health and growth improved in record time to levels beyond our wildest hopes.

We nailed this one perfectly! Thanks to every angler who kept a 9-inch bass from Lake Powell. Your reward awaits. Make a fishing trip here in 2004 and see what happened!

Creel limits changed in 2002.

Please keep 20 bass of the most common size (9-12 inch). Release larger bass that are large enough to eat smaller bass and will help restore the proper size balance within the smallmouth population.


Largemouth have declined in number due to lack of brushy cover and declined in size due to competition for forage with other game fish. Please release all largemouth which will allow these faster growing bass to represent a larger portion of the bass community.


Decline in flooded brush during spawning season has caused a decline in crappie numbers. The limit has been decreased to still allow some limited harvest but to protect crappie until higher lake levels cover new brush and allow crappie populations to expand.

Details of growth slowdown of smallmouth bass:

Average size of smallmouth bass in lake Powell is smaller now than it was from 1990 to 1997. Proportional Stock Density (PSD) defined in this study, as a ratio of number of smallmouth bass in the population greater than 11 inches has declined from a high of 81% in 1993 to a low of 33% in 2000. Relative Stock Density (RSD-p) which is angler preferred size fish greater than 13.7 inches has declined from 32% in 1992 to 0% in 2000.

Smallmouth are smaller in size for one or all of the following reasons:

Growth has slowed for most fish probably due to competition with each other for limited food. One year old fish caught in 1992-1995 were 8.8 inches long (11.2 inches at age 2). One year old fish caught from 1996-2000 were only 7.2 inches long (8.8 inches at age 2). Lake Powell smallmouth that once entered the "stock" (11 inches) at age 1+ now don't get that big until age 2+. Quality lengths (13.7 inches) once attained at age 3 now requires 5 years growth.

Excessively high reproduction does not appear to be driving average size down. Recent measurement of annual production by electrofishing collection has found less age 0 fish than previous surveys.

Fish physical condition (relative weight) is declining along with growth. One possible problem is the largemouth bass tapeworm which infects most of the population and has since smallmouth were introduced. While the parasite is NOT outwardly visible, and does NOT effect eating quality, it may have a negative effect on reproduction and growth. It is felt that the parasite has a compounding effect during periods of slow growth and intense competition. Parasite effect is worse when food is scarce. Crayfish are the mainstay of the diet and eating the hard shelled crayfish helps purge the adult parasite from the gut. It is only intermediate parasite life stages that live in the organs and tissues that are taxing for the fish.

Anglers at Lake Powell voluntarily released 83% of all smallmouth caught in 1997 and 89% in 2000. Over 573,000 smallmouth were caught and only 63,000 kept. Very few fish already in hand are kept due to angler philosophy, and smaller size of average fish. This voluntary return persisted even when average size of bass was larger.


The obvious response to the problem is that there are too many smallmouth bass with not enough food. With striped bass in similar conditions we have recommended maximum angler harvest to bring predator numbers in balance with forage supplies. That seems to be exactly what is needed to meet this challenge.

Increased harvest is a good step without irreversible ramifications since it is the present nature of the angler not to keep bass. If it turned out that smallmouth populations began to plummet due to harvest and/or natural causes, we could simply say "don't keep smallmouth" and that would happen.

Increasing limits to allow a substantial harvest is a biological statement made to address the growth slow down. The bigger challenge is to educate anglers to keep smallmouth bass and particularly the 9-11 inch smallmouth bass that are so abundant. The limit increase is a message to the angling public that managing agencies recognize a problem and have assigned a regulation to address the problem realizing that a change in angler attitude will ultimate determine the success or failure of the regulation.

Lake Powell Bass Fisheries in 2012 will rival the glory years of the early 60s and 70s

Largemouth fishing won't be quite as good because there will be thousands of anglers fishing for them instead of hundreds. Smallmouth fishing will be 100% better because there weren't any smallmouth in the 70s. We got to this point after recovery from a drought and the regrowth of brush. When flooded that brush provided largemouth with needed cover to increase their population strength and vitality. Now with good forage and habitat both large and smallmouth fisheries are strong with big fish common for both species.
Smallmouth maintain their unprecedented healthy physical condition. Relative weight is at a decade high point.

Largemouth Bass are more numerous and larger than they have been in the past decade.

Crappie are abundant. A new lake/state record 3 pound 5 ounce monster was caught. The 10 fish limit remains restrictive as that population will slowly decline over the next 5 years, now that the shoreline brush has been covered and will decompose.

Theses are the new glory years for the lake. I hope you enjoy them as much as I.

Summary 2018-

Smallmouth were overabundant in 2017 - a year of high water and high forage. Overwinter there was considerable growth of the young bass population. Now in 2018 the fat yearlings have grown to husky two year olds. The entire smallmouth population shows good size and abundance - with one exception. The San Juan arm has always been the smallmouth hangout. While average size of smallmouth increased lakewide overwinter, bass in the San Juan remained slightly stunted. The reason was lack of harvest in this lake area. Anglers should use this information to help us increase smallmouth overall health by harvesting a limit of smallmouth bass (20) on each trip to the San Juan in 2018. We will study the impact of your help as we conduct the annual gill net survey in November 2018. Thanks
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Well-Known Member
I like doing my part to keep fish to help decrease competition. Now I have an excuse to go to the San Juan arm to catch a limit of smallmouth......Thank you!

I think the Glen Canyon Dam tailwater ( Lee's Ferry) is a good example of how 1) a fishery can be destroyed by catch and release and 2) how changing regulations to appease fishing guides and sportsmen groups can literally protect a fishery to death. I have always thought if bag/possession limits were appropriate, there is no need for size and slot limits. Catch and release may be the politically correct thing to do, but it's not always biologically correct. You can always count on me to keep fish and kill coyotes during the denning period too. My middle name should have been, "Harvester."

Wayne, it would take someone having 4 decades of experience on Lake Powell before they would be able to perform at your level. We are fortunate to still have your input in making fish management decisions. Thanks for what you do!