An In-depth look at:
“91-6 MDNR Fisheries Technical Report, Aug 15, 1991

Results of Early Season, Catch-and-Release Bass Fishing at Six Lakes

by James C. Schneider, James R. Waybrant, and Richard P O’Neal”

Part 1 – The MDNR Study – FTR 91-6                              Click here-> [To Part 2 – My Commentary]

91-6 MDNR Fisheries Technical Report, Aug 15, 1991 Results of Early Season, Catch-and-Release Bass Fishing at Six Lakes by James C. Schneider, James R. Waybrant, and Richard P O’Neal”A common problem with many fisheries studies, they don’t get out to the anglers. Following is a detailed report on the Michigan Department of Natural Resources (MDNR) on the early season, catch-and-release bass study on 6 test lakes. I don’t know how many of you really have seen those results from the final measurements that went on before the initial sunset period ended (and has been consistently extended so far).

The study is officially MDNR Fisheries Division Technical Report 91-6, August 15, 1991: Results of Early Season, Catch-and-Release Bass Fishing at Six Lakes by James C. Schneider, James R. Waybrant, and Richard P. O’Neal.

The actual study started in 1988 and has another technical report – 89-2 – that provided results at the end of the initial year. The season runs from April 1 until Memorial Day weekend on Muskegon Lake, Hardy Dam Pond in Newaygo County, and Cass, Kent and Pontiac Lakes in Oakland County. You may legally fish for bass, but you have to immediately release them.

Text from the Abstract:

  • From onsite opinion surveys – 82% of anglers approved of the test and “would approve of extending the concept of preseason catch-and-release fishing to some other lakes, 8% disapproved, and 10% had no opinion.”
  • “Spring bass fishing effort increase approximately 40%, on average.”
  • The bass catch, measured by number of bass caught per hour, was not any higher than the open season.
  • “Recruitment of small bass to these populations did not appear to be harmed by fishing during the spawning period.”
  • “Changes in spring bass fishing effort and catch were smaller than expected, mainly because many anglers (about 44% of all anglers and 69% of the frequent bass anglers) were already in the habit of fishing for bass prior to the normal bass season.”
  • “A large percentage (83%) of all anglers said they usually release most of the legal-length bass they catch during the normal bass season.”
  • They recommended “that the concept of preseason catch-and-release bass fishing be continued on these six lakes and extended to other southern Michigan lakes which have a history of good bass recruitment, ample adult bass populations, light to moderate fishing effort in summer, and no problems with excessive populations of slow-growing panfish. A revision of Fisheries Division policy will be necessary to implement this recommendation.”

Comments from opening explanations:

  • “Some anglers now fish for bass prior to the statewide opening of bass season… They question the need to protect bass populations from preseason catch-and-release fishing in every lake. Likewise, most fisheries managers believe that such fishing would not harm the resources or existing fisheries of many lakes and would generate many hours of additional recreational opportunity.”
  • “Based on previous Michigan studies, and other information, we anticipated that preseason catch-and-release bass fishing likely would have the following effects:
  1. Spring fishing effort would increase by less than 67%…;
  2. Summer bass catch rates and total annual harvest would decline slightly because, of the bass caught in the spring…some would die of hooking mortality and some others would be more wary the rest of the year;
  3. Hooking mortality of fish released immediately would be under 10% and be compensated for by a reduced harvest in summer;
  4. Temporary removal of some male bass from their redds would not significantly reduce bass recruitment for the population as a whole;
  5. Bass population characteristics such as recruitment, growth, total mortality, and standing crop would not be altered significantly; and
  6. Most bass anglers would find preseason catch-and-release fishing to be acceptable.”

Information from the various Methods:

  • It was originally planned to study recruitment and general abundance of bass over a five year period, with comparisons to populations on two lakes just before the study period, and monitoring again in 1988, 1990 and 1992. The additional sampling scheduled for 1992 was canceled “because sufficient results had been obtained” by 1990.
  • “Bass Recruitment Surveys: The relative abundance of small bass in all six test lakes was sampled with DC electrofishing gear in fall 1988 and fall 1990 to monitor reproductive success. If fishing for adult bass during the early season (when they are attempting to spawn) had a significant detrimental effect on bass reproductive success, then it should be reflected in weak and missing year classes beginning in 1988. Little background was available for the study lakes, but the typical pattern for other southern Michigan lakes is a modest amount of recruitment every year. If bass recruitment failed completely in the study lakes for 3 years, then even low sampling effort should detect it. …If bass recruitment were only slightly or sporadically effected, then a much more intensive, long-term study would be required.”
  • “Fall electrofishing surveys in 1988 and 1990 found adequate numbers of small bass in one or both years. This indicates that the early fishing season had not completely disrupted bass spawning success during the first 3 years of study.”
  • Interesting from the angler opinion surveys during the study period, when asked if they were affiliated with a fishing organization, “a surprisingly high fraction, 21%, of all interviewees belonged to fishing clubs… A wide variety of clubs was represented, not simply those concentrating on bass fishing. Thus, the special season did not attract large numbers of organized bass fishermen or bass tournaments.”
  • “Monthly estimates of 1988 fishing effort and catch for Cass Lake and Kent Lake were presented in the prior report (Schneider et al. 1989). They were compared to similar data collected in previous years (1986 and 1987) to determine if there were any changes in these fisheries caused by the early bass season. The comparison indicated that the early bass season had little effect on the fisheries of these two lakes.”
  • “One concern at the beginning of the study was that bass might be very vulnerable to anglers during the early season, especially while nesting. Average catch-per-hour statistics for anglers who were specifically fishing for bass do not substantiate this concern. For 12-inch and larger bass, both species combined, average catch rates were consistently higher after Memorial Day than during the early season.”

From Discussion:

  • “Surprisingly, largemouth bass catch per hour was no better during the early season than during the first couple of months of the normal season. This was unexpected because it is widely believed that (a) bass are vulnerable while guarding nests, (b) they concentrate in warm bays and feed ravenously, and (c) they are more naive after a winter’s rest. However, there was some evidence that smallmouth bass catch rates were slightly higher in spring than during the normal season… Consequently, lakes containing marginal populations of smallmouth bass should be managed cautiously.”
  • “Undoubtedly, the growing ethic of catch-and-release fishing has been of great benefit to bass stocks and fisheries throughout the State. It has helped offset this still-growing demand for bass fishing.”
  • “The most difficult effect of spring fishing to predict is its effect on bass recruitment. The problem consists of two parts: the effect of temporary removal of a guarding male bass on the survival of his young and, more importantly, the cumulative effect of each disturbance on total recruitment of fingerling bass to the population as a whole. The two are not always closely related because usually many more larval fish are produced than the environment can support and only a limited number of fingerling bass can survive.”
  • “The more difficult question to answer is the probability of bass populations declining to a lower level of abundance…because of spring catch-and-release fishing. Arguments suggesting a significant decline is unlikely include:
  1. Other states (mostly to our south) have allowed year-round, almost unrestricted, bass harvest for many years, apparently without ill effect (Latta 1974; Rideout and Oatis 1975).
  2. Michigan has allowed some bass harvest during spawning season for 30 years, apparently without obvious signs of detriment. Prior to 1962, spawning bass were almost completely protected by a closed season from January 1 to June 24. The opening day was advanced to June 1 in 1962, then to Memorial Day weekend (usually the fourth weekend in May) in 1973. Many bass populations, especially in northern Michigan, have not finished spawning by June 1.
  3. Generally, there is no close relationship between the number of adult bass and the number of fingerling recruits they produce (Latta 1974, 1975). Only six adults per acre can produce excessive numbers of fingerlings (Schrouder et al. 1989; Mraz 1964). Environmental variation can cause wide fluctuation in survival of young.
  4. Generally, anglers are unable to catch every bass, or even enough bass to harm recruitment (Bennett 1972).

Counter arguments, that there may be a real risk to some bass populations in Michigan from catch-and-release spring fishing, include:

  1. Michigan bass populations are much smaller than southern bass populations, therefore there is a greater risk of unusual events causing insufficient spawners. In southern Michigan lakes, typical bass populations are about 10 pounds per acre and 10 adults per acre (Schneider 1971). Unproductive northern lakes may have only a few adults per acre (Wagner 1988). By contrast, typical (“balanced”) midwestern ponds to our south contain 40+ pounds per acre and 20+ adults per acre (Reynolds and Babb 1978).
  2. The climate in northern Michigan provides a variable environment for bass reproduction (edge of bass range), with a relatively high risk of reproductive failure. To compensate, broodstocks and nesting success should be maintained at a relatively high level. For both largemouth and smallmouth bass, weather can have a large effect on reproductive success and cause weak year classes (Wagner 1988; Latta 1975).
  3. Sometimes an alarmingly high fraction of a bass population is caught by anglers. Up to 55% of a bass population has been caught in 1 day (Redmond 1972). At Wakeley Lake, Crawford County, Michigan, where catch and release is in effect for all fish, the number of bass caught in 10 weeks exceeded the bass population by a factor of two (J. C. Schneider unpublished data). Most observers would agree that the potential for overexploitation has increased in recent years because of increased fishing for bass and improvements in gear and angling techniques.

We conclude that the greatest risk of reproductive harm is to bass populations which contain few adults (as in small or unproductive lakes), co-occur with excessive panfish populations (as in stunted bluegill lakes), are exploited more easily (as in heavily fished or unproductive lakes), or have variable recruitment (as in northern Michigan lakes). Smallmouth bass should be of greater concern than largemouth bass.”

The study recommendations were:

  1. “From a biological perspective, the special early bass season could be continued at the study lakes. However, their bass populations should be surveyed periodically to confirm that recruitment is adequate.
  2. Likewise, this concept could be extended to other selected southern Michigan lakes. Popular support is essential in the selection process. These lakes should be relatively large, have good populations of bass, have consistent recruitment of bass, and not have stunted panfish problems. Smallmouth bass, if present, should be of special concern.
  3. Spring bass pressure should be maintained at a modest level. High pressure, as might be generated by unrestricted bass fishing tournaments, should not be promoted.

Fisheries Division policy on bass seasons should be reevaluated. Both biological and sociological factors should be considered.”

bass line

Well, there you have it. Most of the relevant parts of our own Michigan study on a spring catch-and-release bass season. There’s more text in the study going into further detail on some of the processes, and several tables showing results of surveys and census. I have read this entire study several times and reviewed the tables. In Part 2 of this document, I continue with explanations of this particular study and the issue it covers based on my interviews of researchers, biologists, and related data.