Across the Midwest, walleye anglers will encounter a variety of regulations when it comes to walleye management. One of these regulations is a closed season, which is present in states such as Minnesota, Wisconsin, and northwest Iowa. Other states including South Dakota, North Dakota, and Nebraska will remain open for walleye fishing year-round. The reason for these closures is to “protect the spawners”, but is that really necessary?
Spring fishing in South Dakota, particularly the Missouri River reservoirs, can be fantastic. The water is warming, fish are moving into predictable areas, and there is often significantly decreased prey availability within a waterbody. All of these conditions set up for a very good bite, and successful anglers.
This excellent fishing often results in anglers harvesting fish, visiting the cleaning station, and sharing stringers of their catch on social media. Combine this with the fact that spring fishing can produce very quality walleyes as well, and calls to “protect the spawners” and close the season will begin.
The main reason behind this thought process is to allow larger, female walleyes to carry through their spawning rituals that occur every springtime without being harvested. Arguments are made that by closing the season, more eggs will be laid, and more fish will be produced.
Before diving too deep into this discussion it’s important to remember the three most important elements of fisheries management: recruitment, growth, and mortality. Recruitment is new fish entering a system. Growth is how they increase to catchable and preferred sizes as they age. Mortality is a fish exiting a system.
Recruitment is the first component of this, and this is where requests to close the season will originate. The thought process is that the more female walleyes that spawn, the more fish there will be in the coming months and years.
It’s important to note that walleye populations in South Dakota are rarely limited by the total number of fish available for spawning. Female walleyes are incredibly proficient, and the more significant impact on recruitment is environmental factors and not the total number of fish spawning.
Walleyes are broadcast spawners, they provide no parental care once eggs have been laid, and both the eggs and subsequent fry are at the mercy of their environment. Current, runoff, wind conditions, temperature, and precipitation all have an impact on how many eggs ultimately survive and hatch. Beyond that, life for a fry is just as difficult as they avoid predators and find food for themselves to grow.
It’s also important to note that a female walleye, while not full of eggs in the summer, continues to be exactly that – a female walleye. Anglers that claim these fish need to be protected and released in the springtime will not hesitate to keep one of these fish in the summer months, and because neither eggs nor sperm are present would be unable to identify the sex of the fish either way.
Once a fish is harvested, whether it is in March or July, that fish is no longer in the population. It no longer provides an opportunity for anglers to catch, and it no longer will contribute to natural recruitment within the system. No matter the date when it happens, this fish has experienced the final element of fisheries management – mortality.
Statistically speaking, the bulk of that harvest mortality is going to take place between April and July. Specifically, May and June see the most usage and harvest. Weather conditions in the early spring can be difficult, and fishing conditions can be too. The majority of anglers’ use and harvest will occur in the early to mid-summer.
It is also important to note that in the spring the bulk of the fish both caught and harvested are going to be males. This is because the males are more aggressive, actively patrolling the spawning areas looking for meals, while larger female walleye will be staging in the deeper water adjacent to this area and less active overall.
The fact of the matter is the greatest regulation on early spring walleye fishing, and in turn walleye harvest, is Mother Nature. While warm years with minimal snowfall will provide anglers opportunities to access the water earlier, other years with colder temperatures and heavy snowpack may limit access until the middle of March or even into April. Spring snowstorms may even further complicate access.
To further expand on this, the greatest factor on spawning success and recruitment is going to be Mother Nature as well. When environmental conditions are right, year-classes are going to be very strong. When weather conditions are not, the year-classes will reflect this as well.
This all ties into the type of the fishery itself. The most consistent walleye producing reservoirs in South Dakota are Lake Sharpe and Lake Francis Case. These reservoirs annually produce a quality year-class of walleyes, maintaining the high abundance and catch rates these fisheries are known for. Lake Oahe, while more of a boom or bust fishery, also produces walleye each season.
Larger waterbodies in eastern South Dakota such as Bitter Lake, Waubay Lake, Lake Poinsett, Lake Thompson, 81 Ponds, and Lake Sinai also often produce year-classes of fish each year. These fisheries, as well as others, may be supplemented by stockings conducted by South Dakota Game, Fish and Parks (GFP) biologists.
These stockings are determined annually, and based on lake survey data from previous years to further improve walleye recruitment. The supplemental stocking helps fill the gap where environmental conditions may limit natural recruitment.
The ultimate regulator of both walleye seasons and recruitment is Mother Nature. Extended winters, cooler springs, and above average precipitation can all limit angler usage and in turn harvest. Conversely, short winters and warm springs can allow for increased angling participation in the spring.
The same factors that impact anglers taking to the water, will also impact the ultimate success of walleye recruitment. While closed seasons are a regulation option, it’s often a social regulation and the true biological impact is determined by Mother Nature.
