In order to understand the affects of fishing regulations, you need to understand fish populations. As such, I am going to give you a high level overview of what a typical fish population might look like. Using a simple “tiered pyramid” model, we can show specific size-classes. The number of fish per tier goes down as the size goes up (one fish lays many eggs and fish are removed from the system at each stage by predators, disease, etc., leaving fewer of the larger ones)

Notes:

• The example provided above is intended to represent a “wild” fishery (not stocked).
• For the sake of argument, let’s assume that each tier represents a year-class.
• Also assume that the dark line denotes the size where fish reach sexually maturity.

 

The model above will be used throughout the article to show how a specific type of regulation effects a given population of fish (shaded areas will represent “legal” fish). It is important to note however, that the lengths used are just examples and do not necessarily represent a specific body of water. In addition, factors other than angling can contribute to the loss of fish at any stage of the pyramid (weather, natural predation, habitat degradation, etc.)

It is also critical that you understand that the size, depth, accessibility, and recruitment (i.e., spawning conditions) have a lot to do with how a given regulation will affect a specific body of water. Here in Maine, our waters are not very fertile and our fish per acre (lakes and ponds) or mile (rivers and streams) is very low. For example, a typical less than 30 acre trout pond may hold from just a few hundred to only a couple of thousand fish at any given time.

While clearly behind the times in regard to regulations, the DIF&W is trying to make up for what took other departments 20+ years of trial and error to learn in just a few short years. In addition, due to the historic reluctance on the part of the department to protect large fish, I expect that we will experiment with less restrictive regulations than is ideal. As such, I expect to see a number of false starts. However, it is critical that we work this out sooner than later.

The options…

1. Minimum Length Limits.

The simplest and most common form of regulations is “minimum length limits”. In this case, anglers may keep one or more fish over a certain length. Implemented properly, this type of regulation can prevent a fish population from collapsing while still allowing some level of harvest. These are best suited for put-and-take fisheries and wild populations in large lakes and rivers. However, many states (including Maine) have used these as their standard for years.

The example below assumes a minimum length limit of 12 inches. In this case, any fish over 12 inches may be harvested. The minimum length limit of 12 inches was chosen to ensure the protection of at least two year classes of sexually mature fish (which is unfortunately not always the case). I believe that this is critical in regard to assuring the long-term stability of the fishery. Less than two years is risky as you need new recruitment to keep the number of fish stable.

The bad news is that in this case no fish over 12 inches is protected. As such, it is purely the luck of the draw that determines whether any fish will ever make it to a decent size. We see the results of this all the time in water managed in this manner; i.e., very few large fish. While pushing up the minimum length limit to something like 18 inches can produce larger fish, studies show that it will only go so far. Specifically, very few fish over 18 inches will be caught.

Example: Minimum Length Limit (12”)

2. Maximum Length Limits.

Another simple albeit less common form of regulation is “maximum length limits”. In this case, the angler may keep one or more fish under a certain length limit. My primary concern with this type of regulation is that no pre-spawn fish are protected and as such, there is no guarantee that any (or enough) fish will reach sexual maturity to ensure the health of the fishery. This is especially risky in small waters that are vulnerable to over harvest (typical Maine brookie pond!).

The good news is that any fish which makes it to 12 inches is protected indefinitely. As such, these fish can potentially reach trophy size. This type of regulations is best suited for very large lakes that can sustain a high level of harvest and where the likelihood of harvesting all pre-spawn fish is low. The best case I have seen for this is Yellowstone Lake which is massive, deep, partially closed to motors, has a very short season, and does not allow ice fishing.

Example: Maximum Length Limit (12”)

 

 

A few words on Slot Limits…

If you read any fishing publications, you will hear a lot in regard to “slot limits”. Slot limits by definition use ranges of inches (i.e., slots) to determine what fish you can and cannot harvest. While they may seem complicated, they are actually quite simple and often quite effective. Originally designed as an alternative to traditional minimum length limits and C&R, slot limits “attempt” to provide the angler with the best of both worlds; i.e., harvest and quality fishing.

3. Open Slot Limits.

By far the most common form of slot limits in Maine, “Open” slot limits (those which allow the harvest of fish from both within and above the slot) are of questionable value. While viewed as restrictive by many Maine anglers, these are in my opinion just glorified minimum length limits. In fact, I see these as ineffective “feel good” regulations that attempt to satisfy everyone and in the end, satisfy only those desiring to harvest a trophy if they catch one (and that is a big “if”).

For example, while many anglers consider “2 fish; 12 inch minimum, only one fish may exceed 14 inches” restrictive, they would not say the same about “1 fish, 14 inch minimum”. However, the latter is in fact more restrictive as it allows only one fish. This is a case where complexity takes on the guise of restrictive. While this type of regulation will in fact slow down the harvest of large fish, it does not stop it. In the end, it catches up with you as I believe it has caught up with us.

This is not to say that this type of slot does not have its place in Maine. In fact, by imposing these types of regulations in the mid 1990’s, former DIF&W commissioner Bucky Owen most likely saved our brook trout fisheries from total collapse. However, while the regulations did slow down the harvest of large fish, increased pressure due to improved access has at this point brought us back to where we were. Going forward this type of slot limit must be used with caution.

 

Example: Open Slot Limit (Minimum length limit 12”, only one fish may exceed 14”)

4. Harvest Slot Limits.

What I personally believe to be the most effective form of slot limit, “Harvest” slot limits (e.g., those which allow the harvest of fish from within the slot only) are usually your best bet. While allowing some level of harvest, this type of slot limit provides protection for large fish. However, like maximum length limits this assumes that a reasonable number of fish make it beyond the slot which is not always the case (especially in small waters that are vulnerable to over harvest).

To be effective, the lower end of the slot should be set using the same logic that is used to define effective minimum length limits (so as to protect at least two year classes of sexually mature fish). The upper end of the slot limit should be set to a length that provides protection for those fish that have demonstrated an ability to get large (as stated earlier, fish are lost all through the pyramid for a number of reasons). This would vary by water and species.

Another major consideration is in regard to the size of the slot. The size of the slot should be in direct correlation to the size of the water. Specifically, the smaller the body of water (or the lower the fish densities), the shorter the slot should be. In most cases, I feel that a slot of 2 inches is most effective. By opening up the slot anymore, you by default allow more fish to be harvested and reduce the likelihood of any fish making it through the slot (it starts acting like a minimum).

Lastly, the number of fish allowed is critical in regard to establishing an effective slot limit. While two fish may be acceptable for minimum and maximum length limits, and open slots, the whole objective of harvest slots is to allow some level of fish to make it through the slot and to a true trophy size. As such, a bag limit of one fish is the best option for a harvest slot. Like I stated in regard to the size of the slot, if too many fish are harvested you defeat the purpose.

Example: Harvest Slot Limit (Minimum length limit 12”, no fish may exceed 14”)

 

5. Protective Slot Limits.

The last type of slot limit is what is called a “Protective” slot limit. In this case, you can only harvest fish from below and above the slot. On paper, this is supposed to create a fishery with a lot of fish between “x” and “y” inches long. However, there are many too many “ifs” in this concept to make me comfortable. Like maximum length limits, there is no guarantee that any fish will survive to reach sexual maturity. In addition, there is no protection for large fish.

This type of slot limit should be limited to large bodies of water or those with very high fish counts that are not likely to be over harvested. Having struggled to find the true benefit of this type of regulation (e.g., all the negatives of minimum/maximum length limits with the complication of a slot limit), I do not feel that they should be used beyond the “experimental” stage to see if in fact it can alter the outcome where minimum and maximum length limits were used in the past.

Example: Protective Slot Limit (All fish below 12” and above 14” must be released)

 

6. Catch-and-Release

Last but not least is catch-and-release (C&R). While receiving very little support from the DIF&W, C&R has worked for the pro bass circuit, native cutthroat trout in Yellowstone Park, numerous famous western tailwaters, and in fact right here in Maine in regard to the Rapid River and the several small ponds it has been tried on. While there are those who routinely say that it “does not work”, I know of no case where C&R did not make the fishing “better”?

Conclusion…

The bottom line is that the mere fact we fish alters the outcome. Even with our best efforts we all accidentally kill fish. In addition, when we do choose to harvest fish, we are altering the natural balance. When we kill pre-spawn fish, we reduce recruitment. When we kill large fish, we eliminate a key predator and a genetically superior specimen. As such, regulations must be implemented with a complete understand of our goals and our options.

If maintaining stable numbers of “decent size” fish is your goal, implement a minimum length limit that protects two years of sexually mature fish (12” would work on most small brookie ponds). If your goal is to create a fishery with a good number of “decent” fish and the chance to catch a large one, impose a harvest slot limit (12-14” would work well on most small brookie ponds). If you want a real opportunity to catch large fish on a fairly regular basis, then go with C&R.

Beyond this, I view the rest of the options as risky at best. While maximums, protective slots, and open slots can work in some cases, these are the exceptions and not the rules. As such, I recommend that we use them sparingly if at all. What often happens is that fisheries managers try to manage anglers and not fish. In doing so, they often impose regulations that in theory (but rarely reality) offer the best of both worlds; i.e., quality fishing and liberal harvest.

The protection of at least two year classes of fish is critical in my opinion. However, this is often not the case here in Maine. With no effective way to control or predict angler harvest and natural mortality, we need to ensure that we have a stable level of recruitment each year. If we harvest too many sexually mature fish in a given season (or lose them to natural causes such as drought, disease, or a deep freeze), we will by default have less recruitment the following year.

If the over harvest of sexually mature fish goes on for more than a year, the population can decrease significantly. Unlike game animals such as deer, we have no easy way to adjust the harvest from one year to the next (the system can’t move that quickly!) In addition, we have absolutely no control over weather, predators (a family of loons or otters can wreak havoc), etc. As such, when it comes to fisheries we need to be much more cautious than we often are.

In regard to large fish, you do not get them by accident. Unless access is real restricted, without effective regulations large fish are a rarity (and I feel that this is the case today – large fish are now “newsworthy” in Maine!). The only management tools we have in this regard are high minimum length limits (18” and up), harvest slots, and C&R. Trying to accomplish this any other way is a noble, but in my opinion, futile effort (especially in small or pressured waters).

If the water in question is stocked, the rules are the same with the exception of the concerns pertaining to the protection of sexually mature fish. A good idea however is to set the minimum or lower end a the slot to allow for the protection of at least one year class as it gives the fish a chance to acclimate to the water. Where applicable (i.e., where fish can hold over), this will greatly reduce the number of fish harvested (put-and-grow!)

What we do know is that we have done a fine job of growing “small” fish and creating fisheries with low fish counts (much lower than what I believe we could have). Like growing large fish, this is no accident and is in fact a direct result of what I feel is flawed management practices implemented by those in charge of the resource. The reality is that we still harvest way too many fish (up to 50% caught in some areas) and we harvest the wrong fish (large ones).

In closing, all we can do is wait and hope that our fisheries managers are focused on fish and not fishermen this time. While we can and should support all levels of fishing (there is room for everyone), this current strategy of “Managing for Mediocrity” (low minimums, open slots, etc.) is not a sound one. It is time that the DIF&W embraces true slots and C&R while avoiding suspect practices such as maximums and protective slots. Remember, good fishing is no accident!