Pike Spawning Habitat Near Pewaukee Lake

BIO-380

Jeremy Smith

Dan Tilly

Stephen Vandenberg

Wisconsin Lutheran College

Introduction

The pike population is controlled by the annual urge to spawn. The spawning of pike in wetland areas is an annual occurrence controlled by the changing weather from spring into summer. Typical spawning takes place between mid-March and mid-April. In order for the pike to spawn water temperatures must stay cold, typical spawning temperature is 6˚ C (Frost and Kipling 1967). Flooding is another important aspect for pike spawning runs because it allows adult pike to swim into a wetland area and lay their eggs. The adult pike mate and the females lay their eggs in the murky wetland waters. The eggs must then stick to plant leaves in order to stay off the bottom out of anoxic conditions (Casselman and Lewis 1996, Minns et al 1996). During this time the eggs are small, sticky, and brown, then hatch into alevin and fall to the bottom where they will continue to grow feeding on large isopods. These alevin pike will move in and out of the silty substrate in order to maintain oxygen levels in their bodies until they reach 4-8 cm in length which is when most begin to feed on other small fish. At this time they are called fry, and stay in the wetland area. However, they will move throughout the sedges and cattails. Survival is very low for fry pike at about 5 percent. Therefore it is extremely important to protect the fry in order to develop a sustainable adult population. After this stage the pike begin to exhibit adult characteristics including territorialism, aggression, and solitary behavior and begin to move into the lake setting. From there the pike begin the spawning process with in a 2-3 year window continuing the constant flow between its spawning habitat and its lake habitat (Williamson 1942, Frost and Kipling 1967).

The area planned for the development of a pike spawning bed is the Meadowbrook prairie bordering Pewaukee Lake. It is a wetland area connected by a stream to the lake. This stream creates a way for the pike to move in and out of the lake. Pike generally breed and live in sluggish waters that include lakes and slow moving streams. Also, pike lay their eggs in shallow water, usually by the water’s edge, and attach them to the leaves distributing 5-60 of them per plant. Grasses, rushes, and sedges are the most common plants to which eggs attach (Alldridge 1980). During this period there is a high level of cannibalization of fellow pike young. Protecting the pike from intraspecific competition is important throughout this stage. Consequently, the area in which a pike spawning bed is constructed must exhibit slow moving waters, plenty of aquatic grasses and sedges, and good protection in order to assure a high level of reproduction (Frost and Kipling 1967, Minns et al 1996).

The importance of the water quality is extremely important to pike spawning as well. However, the overall clarity does not play as important of a role as was once thought. A minimum depth of 10 inches is required for adult pike to swim into a spawning area, but that level shouldn’t reach a level over 20 inches (Clark 1950). It also has been observed that where the pike were seen spawning, the water was very clear and the eggs could easily be located to show that spawning has occurred. Contrary to having clear water in Lake Erie, spawning was observed in a section of Nettle Lake with a Secchi disk reading of 2 inches. This being said, such low transparencies in the water of Nettle Lake probably did not affect the spawning act. These waters appeared as light brown in bog-like bays to the heavily silt-laden flood waters along lesser protected shores. The pH of the waters at Nettle Lake that favored pike spawning varied from 6.8 to 8.2 (Clark 1950).  It seems that the water clarity is not extremely important to pike spawning; however the depth and pH play an important role in constituting a spawning habitat.

The type of bottom over which spawning occurs varies greatly, however; a soft silt filled with decaying vegetation is preferred (Schindler 1946). Spawning also occurred in a hatchery pond over coarse, stone rip-rap when large amounts of cat-tail debris and quiet waters were present. It has also been reported that northern pike were seen to spawn in shallow waters of rivers, lakes, and inundated meadows and swamps in Europe. The substrate associated with spawning is used as a hiding place for young pike and is therefore very important in the production of a spawning site (Schindler 1946).

This project presents an important stepping stone in improving the overall quality of Pewaukee Lake. While Pewaukee Lake already has a population of pike living there, this spawning habitat has the potential to increase the population (Pewaukee lake memorandum. With the high level of fisherman, an ever present need for a higher quality and quantity of northern pike has been created. Along with addressing this issue the addition of more pike to the lake, this project could greatly influence the overall diversity of the lake. Pike act as a natural predator in the lake and could help control populations of smaller fish. Finally, this spawning habitat could serve as a standard for future spawning efforts in Wisconsin. Consequently, the development of this spawning habitat would be an improvement to the Pewaukee Lake environment.

Pike are prevalent in the upper part of Wisconsin and Michigan due to the high amount of quality spawning habitats. The purpose of this study is to understand the many important aspects involved with pike spawning and compile the information into a recommendation for the Lake Pewaukee Sanitary District.
Methods
On September 23rd, 2011 the group of WLC students met with Department of Natural Resources agents as well as Lake Pewaukee Sewage District agents in order to walk the wetland area and understand the layout of the Meadowbrook prairie. Along with this meeting a tour of the area was completed while noting species located in the area. Next, an intensive search of primary literature regarding pike spawning was completed in order to understand the best way to provide a habitat for pike spawning in the marsh area near Lake Pewaukee. The literature search also consisted of looking for any similar studies completed on pike spawning habitat creation or restoration. Through this research a recommendation was formed for the Lake Pewaukee Sanitary District manager.
Results
There were many scientific papers that were useful while researching the necessities of a pike spawning bed. The paper Observations of spawning habits of the northern pike in northwestern Ohio was useful for understanding the actions involved with adult spawning pike as well as preferred conditions for spawning (Clark 1950). This is important because once the favorable spawning conditions of the water and land are known, a design of a pike spawning bed can be constructed to yield the highest number of pike. Another article that stood out in regards to pike spawning was Observations on the spawning habits of the northern pike, Esox lucius, in northwestern Ohio (Williamson 1942). This paper gave additional insight on pike spawning habits. It focused on where pike eggs were most commonly found. The final paper that was extremely helpful was titled, Northern pike (Esox Lucius) habitat enhancement in the Northwest territories (Cott 2004). This paper focused on a restoration site and the effects the restoration had on the pike population. When constructing a pike spawning bed, it is extremely important to understand the process of pike spawning as well as process that have worked in the past.

A trip to the wetland area in the fall of 2011 included a tour of the area where a list of plant species that inhabit the area was created. The Pewaukee lake marsh is filled with many different types of species of plants.

Table 1. Plant species found in the wetland area near Pewaukee Lake.

Family	Number of species	Family	Number of Species
Gramineae	2	Violageae	1
Cyperaceae	4	Lythraceae	1
Liliaceae	4	Umbelliferae	2
Amaryllidaceae	1	Boraginaceae	1
Iridaceae	1	Labiatae	4
Orchidageae	1	Scrophulariaceae	1
Salicaceae	2	Rubiaceae	1
Betulaceae	1	Caprifoliaceae	1
Santalaceae	1	Compositae	17
Rununculageae	3	Primulaceae	2
Saxifragageae	1	Gentianaceae	1
Fabaceae	1	Total number of species	56
Rhamnaceae	1	Alien plant species	4
Cornaceae	1	Percent alien species	7.1%

The wetland is located in close proximity to the southern edge of Pewaukee Lake. The space between the lake and the wetland is predominantly residential. The creek flows under the road just before it runs into the lake. A natural spring is located near the northwest corner of the marsh. The natural spring aids with flooding the wetland in the spring and flows from the pond to the creek and then into the lake (Figure 1).

Figure 1. Lake Pewaukee, surrounding residential, and wetland area, taken November 10, 2011. Pewaukee Lake is found on the left of the image and the wetland image is found on the right.

The wetland area includes a river on the southern end which floods the wetland in the spring. Also, a pond surrounded by cattails is found in the middle of the wetland area. The northern part of the area is a steep upland area that is covered in oaks and buckthorn (Figure 2).

Figure 2. Wetland area found near Pewaukee Lake, taken November 10 2011. Stream is found on the bottom left corner of the image. Pond is located in the middle of the image with the steep upland just above it. Natural spring begins near the houses in the top left corner where it meets up with the creek near the bottom left corner of the image.

Discussion

A study done in the Northwest Territories observed the impact of a restoration project to a destroyed pike habitat. The restoration involved expanding the area and creating channels to the area for water flow. After this process was completed the area was left to naturally vegetate. Within two years the area had been completely vegetated and adult pike were observed spawning in the area (Cott 2004). This area contained many of the same characteristics as the Meadowbrook prairie which indicates the possible success of this project.

The wetland area near Pewaukee Lake is an ideal spot for a pike spawning habitat, the observations have been made about the area and the known research scoured for information, it is now important to construct a plan regarding the creation of a pike spawning bed near the Lake.

Pike are dependent on water level and temperature when it comes to their spawning habits. Spawning typically begins when temperatures hit approximately 6˚ C and therefore flooding efforts should be coordinated with this change in water temperature. This flooding should continue from after the temperature change for about four weeks after spawning starts. Another important observation found that pike spawning took place in areas where the water had a depth of 20 inches while most spawning took place at a depth of less than 10 inches (Williamson 1942). In addition, it has been observed that pike spawned in depths ranging from 6 to 18 inches of water (Williamson 1942). These observations are extremely important dimensions that will be taken into consideration for creating a spawning bed. The current wetland area will not be sustainable at a depth of 6-20 inches due to depth changes in periods of drought and rain. It is crucial for the spawning area to receive flood waters from the nearby spring and reach ideal spawning depths. Therefore an extended buffer zone to the wetland area should be added in order to increase the spawning area (Figure 3). An extended buffer zone could be created by digging out the outside edges of the wetland area to increase depth.

Figure 3. Meadowbrook prairie and surrounding areas. Spawning area indicated by dark hash marks near pond, taken August 31, 2011.

Also, multiple smaller paths for water to flow along with pike to move from the creek would be beneficial. Many small rivulets versus one large creek is preferred because it allows pike fry to move out of the area while deterring predators to sit in wait for the small pike (Minns et al 1996). This would create favorable spawning areas around the wetland and would range from approximately 3 to 22 inches of water. Following the addition of rivulets; adding a means to pump water up the southern creek from Pewaukee Lake would be beneficial. Flooding should be conducted from the southern border of the wetland to not only encourage pike to run up the creek but also to discourage runoff on from the northern edge of the wetland. Doing this will allow the pike to have favorable spawning conditions during flooding seasons even when unusually low water levels are present.
Another factor that has been attributed to the success of a pike spawning is the aquatic plants found in the spawning bed (McCarraher 1972). In the center of the proposed area to build the hatchery, there is a cluster of cattails. It has been noticed that spawning occurred in a hatchery that contained large amounts of cat-tail debris and quiet waters (Schindler 1946). The cattails found in the marsh will provide large amounts of debris which enhance pike spawning. Also, the dense live cattails encourage separation between young pike, which decreases cannibalism, as well as limiting adult re-entry into the spawning bed, reducing predation and immature pike die off (Cott 2004). Therefore the cattails in the wetland should be maintained. However, cattails in too dense of a population can cause the eggs to fall into the anoxic substrate. Therefore, the population should be controlled and not allowed to dominate the area. Wetland sedges should be introduced and encouraged to grow in the areas where cattails are prevalent. The sedge Carex spp. has been found in areas of high level of pike spawning and the mats created by its past stems cause a good lower layer for the pike alevin to hatch and grow (Cooper et al. 2005, Pierce et al 2005). Two other species that have been linked to successful spawning is Chara spp. and Calamagrostis canadensis (Mcharaher 1972, Minns et al 1996, Pierce 2005). This is due to the fact that the eggs stick easily to these species which provides an oxygenated place for the eggs to grow (Minns et al 1996). An introduction of this species through planting in the wetland may increase the likelihood of successful spawning runs into the wetland area.
The substrate of the wetland area also needs to be considered in this spawning bed creation process. A silty well oxygenated substrate formed from decaying plant matter has been found to increase spawning activity in a given area (Casselman and Lewis 1996, Minns et al 1996, Pierce et al. 2005).  One tactic to improving the substrate in the spawning area would be to leave as much dead plant matter in the area throughout improvements done to the area. Another possible tactic to improve the substrate quality in the marsh would be to develop a mechanism in which water is pumped from the northern spring under the wetland into the silt creating a lower level of anoxic substrate. Through these methods the substrate could become an inviting place for young pike to grow.

An additional factor that should be taken into consideration when developing this pike spawning area is an effective bordering system. Pike young are susceptible to runoff in the early stages of their life (Hassler 1970, Pierce et al 2007). A natural berm border has the potential to slow down the flow of sediment into spawning areas. This method would be extremely effective on the northern edge of the wetland area due to the steep hill found just north of the area that is bordered with a busy road. A natural effort to increase the number of large plant species such as Sagittaria latifolia, Alisma plantago-aquatica, Sparganium eurycarpum, and Iris versicolor in the upland area, while depleting the population of buckthorn in the area could also be used to decrease the amount of runoff into the spawning area and should be considered (SEWRPC, 2003).

The process of developing this spawning habitat needs to be followed up with further research into the effectiveness found in the spawning process. It is extremely important for this project to not stop just with the formation of the bed. Casselman and Lewis (1996) stress the importance of follow up studies. In the past, projects similar to this have not been well documented or followed up on. This has made it extremely difficult to understand the best possible method for creating a pike spawning habitat. However, through careful follow up research the effectiveness of this project can be quantified (Casselman and Lewis 1996). One method used to track the spawning of pike includes the expulsion of radio transmitters along with eggs. The method includes the implantation of transmitters into female pike prior to the spawning season and then tracking the location where the transmitter is deposited (Pierce et al. 2005). This could present an effective way in the future to determine the efficacy of the project.

Works Cited

Alldridge, N.A., and White, A.M. 1980. Spawning site preferences for northern pike, Esox lucius, in a New York marsh with widely fluctuating water levels. Ohio J. Sci. 80: 57–73.

Brynildson, C. 1958. What’s happening to northern pike spawning grounds? Wis. Conserv. Bull. 23: 1–3.

Casselman, J.M., and Lewis, C.A. 1996. Habitat requirements of northern pike, Esox lucius. Can. J. Fish. Aquat. Sci. 53(Suppl. 1).

Clark, C.F. 1950. Observations on the spawning habits of the northern pike, Esox Lucius, in northwestern Ohio. Copeia, 1950(4): 258-288.

Coble, D.W. 1972. Ecological significance of vegetation to northern pike, Esox lucius, spawning. Trans. Am. Fish. Soc. 101: 560–565.

Cooper, J.E., Mead, J.V., Farrell, J.M. & Werner, R.G. 2008. Potential effects of spawning habitat changes on the segregation of northern pike (Esox lucius) and muskellunge (E masquinongy) in the Upper St. Lawrence River. Hydrobiologia 601: 41-53.

Cott, P. A. 2004. Northern pike (Esox lucius) habitat enhancement in the Northwest Territories. Canadian Technical Report of Fisheries and Aquatic Sciences 2528.

Frost, W. E. & Kipling, C. (1967). A study of reproduction, early life, weight-length relationship and growth of pike Esox bcicrs L. in Windermere. J. Anim. Ecol. 36, 651-693.

Grimm, M.P., and Backx, J.J.G.M. 1990. The restoration of shallow eutrophic lakes, and the role of northern pike, aquatic vegetation and nutrient concentration. Hydrobiologia, 200/201: 557–566.

Hassler, T.J. 1970. Environmental influence on early development and year-class strength of northern pike in Lakes Oahe and Sharpe, South Dakota. Trans. Am. Fish. Soc. 99: 369–375.

McCarraher, D.B., and Thomas, R.E. 1972. Ecological significance of vegetation to northern pike, Esox lucius, spawning. Trans. Am. Fish. Soc. 101: 560–563.

Minns, C.K., Randall, R.G., Moore, J.E., and Cairns, V.W. 1996. A model simulating the impact of habitat supply limits on northern pike, Esox lucius, in Hamilton Harbour, Lake Ontario. Can. J. Fish. Aquat. Sci. 53.

Pierce, R. B., J. A. Younk, and C. M. Tomcko. 2007. Expulsion of miniature radio
transmitters along with eggs of muskellunge and northern pike–a new method for locating critical spawning habitat. Environmental Biology of Fishes 79:99-109.

Schindler, Otto 1946 Concerning the development, habits and the culture of the pike. Allgemeine Fischereizeit, 71(7/8): 13-16; (9/10): 1-6.

Southeastern Wisconsin Regional Planning Commission (SEWRPC). 2003. A Water
Quality Management Plan for Pewaukee Lake, Waukesha County, Wisconsin.
Community Planning Assessment Report No. 58, 2nd edition. Madison, WI.

Williamson, Lyman 0. 1942 Spawning habits of muskellunge, northern pike. Wisconsin Cons. Bull., 7 (5): 10-11.