Friday, 28 October 2016

WALLEYE Rehabilitation Efforts

WALLEYE Rehabilitation Efforts

From The Status of Walleye in Nipigon Bay Area of Concern: 2012

Prepared for Environment Canada

By Terry Marshall, Marshall Consulting

March 313, 2013

In 1991, the historic loss and continued low abundance of walleye in Nipigon Bay was identified as a Beneficial Use Impairment [BUI] in the Nipigon Bay Remedial Action Plan [RAP] Stage 1 document [Cullis et al 1991].  Through the RAP process, multiple actions were identified and implemented in an effort to restore walleye in the Nipigon River including the stocking of adult walleye [Cullis et al 1995]. The Nipigon River walleye stock was later recognized as one of 14 priority areas for walleye rehabilitation around Lake Superior in “ A Rehabilitation Plan for Walleye Populations and Habitats in Lake Superior” [Hoff 2002].


A stocking plan was initiated in 1978 as an approach to rehabilitate the walleye population of Nipigon Bay and continued until 1992 [Wilson 1991]. Initially eggs were stocked, then fingerlings and fry, and finally adult walleye were transferred into the bay.

The source of eggs for the stocking program varied through the years, but included Current River, Onaman Lake, and Lake Nipigon.  Stocking sites included Jackfish River, Condon Island and three sites on the Nipigon River: the Lake Helen access, the highway bridge, and the river mouth.

An adult stocking program began in 1986, with 2,686 fish transferred from Savanne Lake over a four year period.  A further 12,100 fish were obtained from Lac des Mille Lac, Georgia Lake and Lake Nipigon and stocked in the bay from 1990 to 1992 [Wilson et al 2007]. ( and Trapnarrows Lake )



There has been considerable progress in addressing environmental concerns in the Nipigon Bay AOC.  This has included the development of a bioengineered marina at  Red Rock, which features armour stone breakwalls that provide public access and fish and wildlife habitat; the development and implementation of the Nipigon River Water Management Plan, which has provided a workable solution to water use conflicts arising from regulated flows;  and the realignment of Clearwater Creek and Kama Creek, which restored valuable brook trout habitat in the AOC.  The “historic” spawning grounds and the “Old Mill Site” wetland on the lower river were rehabilitated through removal of logs, pilings and debris.  Domtar Packaging Ltd. Upgraded its treatment technology in 1995 to improve the quality of wastewater discharged to Nipigon Bay ( and ceased operation in 2006).  In 2012, the township of Nipigon incorporated secondary treatment to its water pollution control plant.

In 2004, Environment Canada completed an assessment of the sediment contaminants in Nipigon Bay.  The findings suggest that the soil contamination near the vicinity of the pulp and paper mill have reduced to a point that the concentrations are suspected to have no or limited impact on the benthos [Richman 2004].

A recent inventory of benthic macroinvertebrate communities in the Nipigon system suggests a high quality habitat indicative of a highly oxygenated, unimpaired environment [Deacon 2011].

Thursday, 27 October 2016

WALLEYE Decline - the Sea Lamprey Control Factor

From The Status of Walleye in Nipigon Bay Area of Concern: 2012

Prepared for Environment Canada
By: Terry Marshall, Marshall Consulting
March 31, 2013

Sea Lamprey Control


An electric barrier on the Jackfish River was operated by the Sea Lamprey Control Center for three years beginning in 1959.  Besides restricting walleye and other fish from moving up the river, it also caused direct mortality with an estimate of 700 walleye killed during its first year of operation alone [R. Ryder pers. Comm., cited in Wilson 1991]

It is unknown how the use of lampricide in later years affected walleye, although there were reports of significant mortality of many different species of fish in the Nipigon and Jackfish rivers following lampricide treatments in the 1960s and 1970s [Wilson 1991]. While early life stages of walleye are thought to be considerably more resistant than sea lamprey ammocoetes to TFM lampricide [Seelye et al 1987]. Recent kills of post spawning adult walleye have been reported following TFM treatment [McChesney 2008; Preddice 2009].

WALLEYE - Habitat degradation

WALLEYE – Habitat Degradation factor

From The Status of Walleye in Nipigon Bay Area of Concern: 2012

Prepared for Environment Canada  by Terry Marshall  Marshall Consulting  March 31,2013

Factors related to the Walleye decline in Nipigon Bay

Habitat degradation

In a historical review of Nipigon Bay Walleye, Wilson[1991] detailed the many habitat alterations that affected this population.  The logging industry contributed through damming, deforestation, sedimentation, the accumulation of wood fibre, bark, and other organic matter from historic log drives, and DDT contamination.  The creation of hydroelectric generating stations segmented the Nipigon River isolating fish populations and the altered flow regimes affected stream bank stability, sediment load and the quality of fish and wildlife habitat.  Effluent discharges from municipal sewage treatment plants and a kraft pulp and paper mill were also implicated in the demise of the walleye fishery [Ryder 1968]

WALLEYE : suggested factors for decline

WALLEYE, Factors suggested for Decline

From: The Status of Walleye in Nipigon Bay Area of Concern: 2012

Prepared for: Environment Canada

By: Terry Marshall

March 31, 2013

There has been much debate over what was responsible for the dramatic decline in the walleye population in Nipigon Bay.

A number of factors have been suggested, including overfishing and habitat degradation [Ryder 1968, Wilson et al 2007].  Sea Lamprey control may also have played a role.  Kelso and Cullis [1996] provide a detailed timeline of these various perturbations.


At the time of collapse of the walleye population in Nipigon Bay, less was understood about the dangers of overfishing, with the feeling that fish populations were able to compensate for large reductions in their abundance.  In 1956, in a review of walleye dynamics in the Nipigon River during the peak of commercial harvest, Ryder [1956] reported “… the commercial catch has increased immensely over the past two years, thus reducing the competitive factor among pickerel themselves.  The drastic reduction of Lake Trout … removes a competitive factor making more food available to the pickerel.  It might be concluded then, that the present rate of exploitation is far below the maximum catch that could be taken to improve the quality of  the population… the harvest has not yet approached the point where optimal benefits to the pickerel population and subsequently to the angler are received.”

This proved to be false, as the walleye population rapidly declined over the next few years.

In Nipigon Bay, the commercial harvest was a classic example of fishing a stock down to insignificance.

Within this Bay, walleye were very concentrated post-spawn, and gillnet and poundnet operations targeted them very effectively.  The gillnet catch-per-unit-effort [CUE] remained extremely high through the latter period [1959-63] of reduced abundance, revealing the efficiency of the fishermen as they became more attuned to the fish’s seasonal movements [Ryder 1968]. In addition , a substantial angling fishery also existed [Schram et al 1991]

The walleye catch in Nipigon Bay from all commercial gear during the eight peak years of harvest prior to the collapse [1951-1959, 1956 excluded]  totalled 97,245 kg.  The average weight of walleye in the catch can be assumed to be similar to that reported for the Black Bay harvest , which was 0.87kg [P. Addison, pers. Comm.].  This then translates into an annual harvest of about 14,000 walleye which when related to the estimated population size of 41,000 mature fish [Ryder 1968] implies an annual exploitation rate of 34% [or higher, including the angling harvest].  While this high of an exploitation rate may arguably be sustainable in more southern locales [ Schmalz et al 2011], it has never proven to be the case in the colder waters of Ontario [Baccante and Colby 1996]

Nipigon Bay and the Nipigon River were closed to commercial fishing for walleye in 1984 and to angling in 1989, along with the Jackfish River.



From the Status of Walleye in Nipigon Bay Area of Concern: 2012

Prepared for: Environment Canada by: Terry Marshall, Marshall Consulting,

 March 31, 2013


Nipigon Bay was designated an Area of Concern (AOC) in 1987 under the Canada-United States Great Lakes Water Quality Agreement.

The degradation of fish populations and the loss of fish habitat were beneficial use impairments (BUI) identified in Stage One of the Remedial Action Plan (RAP).

One of the fish populations that had been greatly reduced in numbers is that of Walleye (Sander vitreus).  Overharvesting, degraded habitat, pollution and the construction of dams have been identified as possible factors.

There have been a number of research and assessment studies in recent years supported by the RAP process to learn more about Walleye and their use of existing habitat and to monitor their population recovery.  Ontario Ministry of Natural Resources (OMNR) Nipigon District, OMNR Upper Great Lakes Management Unit, OMNR Aquatic Research and Development Section, Anishinabek/Ontario Fisheries Resource Centre and the Red Rock Indian Band have all contributed to this field work.

A Brief Overview of the Walleye Stocks in Lake Superior

The Walleye populations of Lake Superior have always been relatively small and widely scattered due to limited amounts of available habitat [Schneider and Leach 1977].  Within this lake they are confined to shallow embayments and the estuaries of moderate to large rivers which afford suitable conditions for spawning and the protection of juvenile fish.

Historically, the three largest stocks of walleye were found in Black Bay and Nipigon Bay, Ontario, and in the St. Louis River at Duluth, Minnesota [MacCallum and Selgeby 1987].

Smaller populations occur elsewhere around the lake, where smaller rivers and protected bays provide appropriate habitat.

Exploitation has been an ongoing source of stress to these walleye populations, with commercial harvest records going back to about 1870.  In the early years, most of the harvest came from Michigan and Wisconsin waters, but from about 1920 onward harvest was largely from Ontario, with Black Bay contributing about 90% of the yield until the collapse of its walleye fishery in 1968 [Schneider and Leach 1977; Schram et al 1991]. In Nipigon Bay, an increase in the commercial walleye harvest occurred in the late 1940s as lake trout stocks declined through overexploitation and sea lamprey predation [Lawrie and Rahrer 1972].

Following a number of years of high harvest in the 1950s, the walleye population declined catastrophically with no harvest reported from 1966 onward.  The Whitefish Bay stocks were also fished commercially at the Goulais River and in Batchewana Bay until their decline in the early 1970s [Schram et al 1991].

As a result of these intense fisheries, along with pervasive habitat degradation, walleye fisheries declined across Canada at this time.  Country-wide, the annual catch of walleye fell from 9,090,909 kg in 1955 to about 2,954,500 kg in 1971 [Hartman 2009]

The populations that persisted all lacked a commercial fishery.  This included the smaller Thunder Bay populations near the mouths of the Current, Kaministiquia, Pine and Pigeon rivers.  Schram et al [1991] reported these to have been only lightly fished by anglers with all populations appearing stable, although habitat loss has subsequently been identified as an issue [ Solec 2012].  The St. Louis population was the only large stock of walleye to survive this period and continue to be one of the healthiest stocks in the lake [Solec 2012]. Interestingly, it too was not commercially fished as the walleye had an objectionable flavour attributed to chlorophenolic products released from upstream paper mills [Margenau and Schram 1982; MacCallum and Selgeby 1987].