Northern Pike, (Esox lucius) and Smallmouth Bass, (Micropterus dolomieu) – Management Strategy

Written by: Lindsay Bagg, Trevor Vanderkooy, Victor Del Dotto, Joe Atkinson and Brianna Grieves

Legal Factors

Lindsay, ON exists within Zone 17 as described by the Ontario Fishing Regulations. In Zone 17 there are currently few limitations set for fishing northern pike and smallmouth bass. The open season for northern pike exists all year long and opens the 3rd Saturday in June and ends December 15th for smallmouth bass. There are no size restrictions for either species but there are catch limits based upon the type of license the fisherman possesses of either 6 or 2 for each species. It is important to remember that these restrictions are only those for Zone 17, there are zones within Ontario in which Pike and Bass do have size restrictions. With 20 different zones in total there is a lot of variation. Legal implications exist for anyone who does not abide by these regulations (MNRF, 2017).

Management Strategy

Of course prevention is the most effective invasive management strategy, because once an aquatic invader establishes itself within the ecosystem, range expansion is almost inevitable and elimination is rarely a viable option (Zanden, Olden, Thorne, & Mandrak, 2004). Advocacy for responsible angling and education will be extremely important moving forward in the prevention of the further spread of northern pike and smallmouth bass. Unfortunately, with northern pike and smallmouth bass we are past the point of prevention in many areas. Establishing a set of laws and regulations that may allow angling and physical removal to be a viable method of control for populations of northern pike and smallmouth bass could be a long process of trial and error. Action could be taken by having the season for northern pike and bass open all year long in all zones where they appear as an invasive species and with no size restrictions. Limiting catch and release would be another important step towards effective management.

If laws and regulations were to be changed to allow for physical removal predicting which systems are likely to be impacted would be an important management goal. Few studies up until this point have been able to make quantitative predictions of aquatic invader impacts (Zanden et al., 2004). Though there are many studies that suggest a negative impact, further research is needed to determine whether or not invasive northern pike and smallmouth bass are truly a concern and detriment to their new ecosystems.

Potential Challenges and Solutions

As with many legal issues, making changes to laws and regulations can take time. Hoping for an overnight solution by means of angling would be misguided, to say the least. Many of the other more immediate methods of control can have a more negative impact on the system than beneficial. The huge challenge in the management of northern pike and smallmouth bass is finding the balance between negatively impacting an entire system and controlling the invasive populations. For this reason, angling seems to be the most viable option of management until more quantifiable research can be conducted regarding the impacts of these invasive species.

 Conclusion

As long as affected ecosystems are remaining stable, angling offers the best and least controversial method of management for the northern pike and smallmouth bass. Fishing selectively for northern pike and smallmouth bass has the lowest possible negative impact on the native species in the ecosystem and targets only the invasive. A re-evaluation of laws and regulations regarding the northern pike and smallmouth bass may be beneficial for complete removal but is not necessarily essential for management. Further studies regarding prediction of impact will be essential in the management of invasive aquatic species such as the northern pike and smallmouth bass. Predictions of impact will indicate which systems are most vulnerable and where to focus time and resources.

References

Zanden, M., Olden, J. D., Thorne, J. H., & Mandrak, N. E. (2004). Predicting occurrences and impacts of smallmouth bass introductions in north temperate lakes. Ecological Applications, 14(1), 132-148.

Northern Pike (Esox lucius) & Smallmouth Bass (Micropterus dolomieu) – Historical Profile

Written By: Joe Atkinson, Lindsay Bagg, Victor Del Dotto, Brianna Grieves, Trevor Vanderkooy

Historical Profile
Northern Pike (Esox lucius) and Smallmouth Bass (Micropterus dolomieu) have a long history of being a very popular game fish with anglers. Recreational angling is undoubtedly the number one reason for the introduction of northern pike and smallmouth bass outside their native range. One of the earliest documented introductions of northern pike occurred in Ireland during the 16th century (Harvey, 2009). Similarly, with Smallmouth bass, the species was introduced into several locations across Canada and the United States. They were first introduced into the eastern United States in the late 1800’s and in California in 1874. (Brown, et al. 2009). In Canada, they were introduced by individuals acting by their own volition, into Lake Winnipeg in Manitoba during the early 1900’s followed by Saskatchewan and Alberta as well as in British Columbia where they now reside in the southern Okanagan lakes, Vancouver Island and in the Kootenays (Brown, et al. 2009). Legally they were introduced into Nova Scotia and New Brunswick between 1942 and 1953 (Brown, et al. 2009).

This practice of stocking northern pike and smallmouth bass for recreational fishing has continued to the 21st century and is increasing in popularity. Especially regarding smallmouth bass which is prized as one the most popular sport fish in North America. Large recreational fisheries host tournaments with large prizes offered. In British Columbia alone, the freshwater sport fishery attracts over 400,000 licensed anglers and contributes $233 million to the BC economy and creates 8900 jobs (Harvey, 2009).

Ecological Connections
When considering eradication methods for Northern pike and smallmouth bass its important to note that both species have vastly different behaviours and tendencies towards particular dispositions. Northern pike for instance is a r-strategist, which quickly spawns and provides no parental care to its young and the fingerlings grow quickly and begin to devour whatever they can. Comparatively, Smallmouth bass are a k-strategist which provides dutiful attention to its young and are capable of producing many offspring because of this.

When Northern pike are introduced into a new environment, they quickly become the dominant predators with no sources of predation on the species besides humans (Craig, 2008). This can be detrimental towards other species such as the Atlantic salmon. If northern pike are introduced into a river where Atlantic salmon spawn, they can quickly decimate a population of young fry (Harvey, 2009). Smallmouth bass are also top predators which pose a threat to both native fish as well as macroinvertebrate diversity as juveniles (Brown, et al. 2009).  The introduction of smallmouth bass into areas where they aren’t native caused a shift in prey community structure which indirectly changed the flora and fauna of the system and behaviour of other fish species. (Brown, et al. 2009). In Ontario, smallmouth bass introductions into non-native habitat reduced abundance, altered habitat use and extirpated several minnow and dace species (Brown, et al. 2009).

Critical Assessment of Management Options
Northern pike and smallmouth bass have both successfully established into environments where they have been introduced. This success has caused impacts on other key species such as salmon in the case of both smallmouth bass and northern pike (Carey, et al. 2011). Three primary options are considered for both species. These options are; do nothing, extirpate through use of piscicide and reduce through increased angling.

Firstly, while doing nothing is certainly option for both northern pike and smallmouth bass it is a highly ill advised decision to make, especially in the case of northern pike. As previously discussed, northern pike are an extremely gluttonous species that will consume all available prey and then move onto cannibalism when available resources become short.  Similarly, smallmouth bass will also extirpate other species such as minnows, dace and salmon populations among others. (Carey, et al. 2011). If the goal of managing both of these species is to protect other native species, then doing nothing should not be an option.

Extirpation through piscicides is an option. Northern pike have been successfully eliminated in certain Alaska lakes through the use of a naturally occurring ketone; rotenone (Dunker, et al. 2016).  Rotenone is an effective agent to be used as a piscicide as well as pesticide in organic farming. This is due to rotenone’s low to moderate mobility in soil and sediment, low potential for bioaccumulating in aquatic organisms and is unstable in the natural environment. With a hydrolysis and photolysis half-lives measured in days and hours (Finlayson, et al. 2014).  In a study conducted in Oregon, USA where rotenone was used to effectively eradicate tui chub, rotenone concentrations were found to have decreased by 75% after just 2 days (Finlayson, et al. 2014). Despite all this, the use of rotenone in an aquatic environment poses a significant challenge due to its effects on non-target organisms such as amphibians and macroinvertebrates (Dalu, et al. 2015).  Effects on other non-target species could range from 100% mortality to no effect but while it is known to affect numerous aquatic species, there are few studies that have assessed the total impacts and its ramifications on many species remains unknown (Dalu, et al. 2015).

Finally, the option of reducing through increased angling is a possible management option. With regards to northern pike this is possibly the best option. Northern pike are easily hooked and generally bite throughout the entire day. (Margenau, et al. 2008). According to the Department of Natural Resources of Michigan, a lake stocked with 68 adult northern pike caught 31% (22 pike) within 2 hours of angling per acre in one day (Williams, Jacobs. 1971). While this method won’t entirely guarantee eradication of the species it does provide a good potential source tourism and income from anglers. Northern pike and smallmouth bass are two of the most popular sport fish and complete eradication of the species in certain areas could cause a public outcry. Top this with the fact that the reason these species have spread so far is because of illegal introductions from anglers, guaranteeing that they will not be re-introduced after a total extirpation is hard if not impossible to prevent.

Figure 3: This infographic displays the individual benefits and factors for each of the three management strategies discussed. Least effective strategy would be to do nothing. Extirpation is the most effective method but piscicide will have unknown effects on non-target species. Increasing angling and encouraging catch and keep can reduce populations but other species will still be effected.

management-strategy

References:

Brown, T.G., Runciman B., Pollard, S., Grant, A.D.A., Bradford, M.J. (2009) Biological synopsis of  smallmouth bass (Micropterus dolomieu). Canadian Manuscript Report of Fisheries and Aquatic Sciences 2887: v + 50 p. Retrieved from http://www.dfo             mpo.gc.ca/Library/337846.pdf

Carey, M. P., Sanderson, B. L., Friesen, T. A., Barnas, K. A., & Olden, J. D. (2011). Smallmouth       Bass in the Pacific Northwest: A Threat to Native Species; a Benefit for Anglers. Reviews In Fisheries Science, 19(3), 305-315. doi:10.1080/10641262.2011.598584 retrieved from http://ra.ocls.ca/ra/login.aspx inst=sandford&url=http://search.ebscohost.com.eztest.       cls.ca/l gin.aspx?direct=true&db=eih&AN=78279541&site=eds-live&scope=site

Dalu, T., Wasserman, R. J., Jordaan, M., Froneman, W. P., & Weyl, O. F. (2015). An Assessment    of the Effect of Rotenone on Selected Non-Target Aquatic Fauna. Plos ONE, 10(10), 1-13. doi:10.1371/journal.pone.0142140

Dunker, K. J., Sepulveda, A. J., Massengill, R. L., Olsen, J. B., Russ, O. L., Wenburg, J. K., & Antonovich, A. (2016). Potential of Environmental DNA to Evaluate Northern Pike (Esox    lucius) Eradication Efforts: An Experimental Test and Case Study. Plos ONE, 11(9), 1-21.    doi:10.1371/journal.pone.0162277

Finlayson, B. J., Eilers, J. M., & Huchko, H. A. (2014). Fate and behavior of rotenone in Diamond  Lake, Oregon, USA following invasive tui chub eradication. Environmental Toxicology & Chemistry, 33(7), 1650-1655. doi:10.1002/etc.2608

Harvey, B. (2009) A biological Synopsis of Northern Pike (Esox Lucius). Canadian Manuscript        Report of Fisheries and Aquatic Sciences 2885: v + 31 p. Retrieved from            http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.482.2048&rep=rep1&type     pdf

Margenau, T., AveLallemant, S., Giehtbrock, D., & Schram, S. (2008). Ecology and management of northern pike in Wisconsin. Hydrobiologia, 601(1), 111-123. doi:10.1007/s10750-0079258-z Retrieved from http://ra.ocls.ca/ra/login.aspx?inst=sandford&url=http://search.ebscohost.com.eztest.    cls.ca/login.aspx?direct=true&db=aph&AN=29546883&site=eds-live&scope=site

 

Northern Pike (Esox lucius) & Smallmouth Bass (Micropterus dolomieu)- Ecological Profile

Written by: Lindsay Bagg, Victor Del Dotto, Joe Atkinson, Brianna Grieves, Trevor Vanderkooy.

Distribution: Both the northern pike, Esox lucius and smallmouth bass, Micropterus dolomieu are quite widely distributed both globally and within Canada. Currently the ‘distribution of northern pike is circumpolar in North America and Eurasia, the widest of all species in the genus’ (Harvey, 2009). Similarly, the smallmouth bass can be found throughout Africa, Europe, Russia, and across North America (Brown et al. 2009). Figure 1 illustrates the distribution of northern pike within the province of Ontario while Figure 2 illustrates the distribution of smallmouth bass within the province of Ontario

https://i1.wp.com/dnr.wi.gov/topic/fishing/images/species/northernpike1.jpg
Northern Pike (Esox lucius) Image credit: Vermont Fish & Wildlife Department 2015.

Habitat: Though northern pike and smallmouth bass occupy a very similar range they do differ slightly in habitat requirements. Northern pike prefer mesotrophic to borderline eutrophic lakes with shallow, moderately productive, vegetated waters that are less than 4 metres deep. Northern pike are often found near the shore zone and in areas with an abundance of aquatic plants as they are critical for the fish in each stage of life (Harvey, 2009). Smallmouth bass on the other hand prefer mesotrophic lakes that are clean and clear, an average of 9 metres deep with more shallow, rocky shoals. Smallmouth bass are often found in the area of littoral drop off. Unlike the northern pike, smallmouth bass are rarely associated with abundant aquatic vegetation. Smallmouth bass prefer cover such as docks, submerged logs and over hanging shore vegetation (Brown et al. 2009). Though both species are most commonly found in lakes both have occasionally been known to inhabit rivers. Both species also seek out more shallow waters with cover in the form of aquatic vegetation for northern pike and fallen trees, and boulders for smallmouth bass as spawning habitat.

https://i2.wp.com/petitcodiacwatershed.org/wp-content/uploads/2014/04/smallmouth-bass.png
Smallmouth Bass (Micropterus dolomieu) Image credit: Petit Codiac 2017.

Potential for Infestation: Northern pike and smallmouth bass exhibit the typical reproductive strategy of r-strategists. Short gestation periods, numerous offspring, and relatively short lifespans means that r-selected species thrive in disturbed habitats. Key elements of northern pike and smallmouth bass biology that support their classification as r-strategists are summarized in Table 1.

Table 1: Summary of the reproductive characteristics of the northern pike, Esox Lucius and smallmouth bass, Micropterus dolomieu. Note that both species align best with the reproductive characteristics of r-strategists.

Characteristic r-strategist K-strategist Northern Pike Smallmouth Bass
Mortality Variable and unpredictable More constant and predictable Early life mortality Early life mortality
Lifespan Short Long Short Short
Clutch Size Large Small 32 000 per female – large 14 000 per female – large
Parental Investment/Care Very little if any Required Very little if any Male responsibility for approx. 3 weeks – little
Frequency of Reproduction Once to multiple times over short time period Multiple times but over a prolonged period Multiple times but over a prolonged period Multiple times but over a prolonged period
Additional Factors Most reproductively mature individuals reproduce successfully Few reproductively mature individuals or only some reproduce successfully Fecundity is highly variable, depending not only on size of the female, but also on temperature, food availability, social interactions and density

Survivorship: Both northern pike and smallmouth bass lay thousands eggs each year, many of which may not survive or reach sexual maturity, this designates them as a species with a Type III survivorship curve. The success and survivorship of individuals depends heavily on the environment they find themselves in. Since relatively little parental care is invested in each individual, producing a large number of offspring is important to increase the potential number of survivors.

Dispersal and Vectors:

Northern pike and smallmouth bass are both known to participate in seasonal spawning migrations. Both species will travel up to hundreds of kilometres to tributary streams or rivers to spawn. Outside of this, dispersal is often at the hands of humans. Northern pike and smallmouth bass are often introduced outside of their native range by humans, very often illegally.

Special Considerations: Both northern pike and smallmouth bass can have a dramatic effect on fish community structure and behaviour of other fish species upon introduction to a new ecosystem. Both top predators, once they are established in a new ecosystem both species will rapidly dominate. Northern pike in particular are an opportunistic feeder and will compete with existing predators for food and habitat (Harvey, 2009). There is concern that both northern pike and smallmouth bass prey on salmonids though the ultimate effect on salmonid populations is not clear.

References:

Brown, T. G., Runciman, B., Pollard, S., Grant, A. D. A., & Bradford, M. J. (2009). Biological synopsis of smallmouth bass (Micropterus dolomieu). Canadian Manuscript Report of Fisheries and Aquatic Sciences, 2887, 50.

Casselman, J. M., & Lewis, C. A. (1996). Habitat requirements of northern pike (Esox lucius). Canadian Journal of Fisheries and Aquatic Sciences, 53(S1), 161-174.

Harvey, B. 2009. A biological synopsis of northern pike (Esox lucius). Can. Manuscr. Rep. Fish. Aquat. Sci. 2885: v + 31 p.

Loppnow, G. L., Vascotto, K., & Venturelli, P. A. (2013). Invasive smallmouth bass (Micropterus dolomieu): history, impacts, and control. Management of Biological Invasions, 4(3), 191-206.

Ontario Fish Species. (n.d.). Retrieved January 27, 2017, from http://www.ontariofishspecies.com/index.html

Rafferty, J. P. (2014, January 08). R-selected species. Retrieved January 27, 2017, from https://www.britannica.com/science/r-selected-species

Rauschert, E. (2010) Survivorship Curves. Nature Education Knowledge 3(10):18

Zanden, M., Olden, J. D., Thorne, J. H., & Mandrak, N. E. (2004). Predicting occurrences and impacts of smallmouth bass introductions in north temperate lakes. Ecological Applications, 14(1), 132-148.