Credit River Fisheries Management Plan

Draft Species Specific Management Objectives Update – November 2013


Fish Species Management Objectives provide direction for species mix and partitioning, protection, restoration and recreational uses within the respective Fisheries Management Zones of the Credit River




Brook trout are highly valued as an environmental indicator and sport fish. Brook trout and Atlantic salmon are native and co-existed in the Credit River until Atlantic salmon were extirpated from the Lake Ontario watershed in the late 1800s (Dymond 1965). Today in the Credit River watershed, brook trout are found in the upper portions above Inglewood, in Silver and Black Creeks, Rogers Creek, East and West Credit Rivers and a few other smaller tributaries along the Niagara Escarpment.


During the creation of the Credit River FMP in 2002, concerns were raised for the protection of existing brook trout populations from Atlantic salmon, but more so from rainbow trout. Recent information suggests there is less concern with the impact that Atlantic salmon may have on brook trout populations due to the historical co-existence. It should also be noted that brown trout are known to compete with brook trout and Atlantic salmon and are now considered an invasive species in some areas of North America ( If rainbow trout are allowed access into the middle Credit River, there are concerns that competition between young rainbow trout and brook trout and Atlantic salmon will have negative impacts on these native species.


Management Objective: Protect and restore brook trout populations above the Niagara Escarpment, in the main Credit River upstream of Old Baseline Road in Inglewood, including the East Credit River, West Credit River and in Rogers Creek, upper Black and Silver Creeks through:

  1. prevention of competition with introduced species such as rainbow and brown trout;
  2. instream barrier mitigation;
  3. protective water quality operations criteria for Brook Trout at Wastewater Pollution Control Plants located in Orangeville and Acton;
  4. Protective water quality and quantity design criteria for proposed stormwater management facilities discharging into sub-watersheds supporting the species;
  5. Application of SiltSmart1 protocol for large construction sites in subwatersheds supporting the species; and
  6. Continue monitoring the species e.g. through various monitoring programs.


1. SiltSmart is an erosion and sediment control effectiveness monitoring and rapid response protocol for large urban

development sites.



Atlantic salmon play a valued ecological role in both Lake Ontario and the Credit River as a top predator. Atlantic salmon are considered one of the most valuable game fish and economic resources worldwide. Since the last glaciers retreated approximately 10,000 years ago, Atlantic salmon co-existed with brook trout in the Credit River until they were extirpated in the mid 1800s (Dymond 1965; Department of Planning and Development 1956). Atlantic salmon existed below the Escarpment (Cataract) in the main branch of the Credit River watershed, and most likely had access above the Escarpment toward Erin and Hillsburgh in the West Credit River before the construction of dams as Southern Ontario was settled.


Management Objective:Protect and restore Atlantic salmon, a natural heritage species, in the main Credit River below Cataract Falls downstream to Norval, including the East Credit River, West Credit River, small coldwater Escarpment tributaries, Black Creek upstream of Stewarttown and Silver Creek through:


  1. Stocking of appropriate life stages and strains associated with the broader Lake Ontario Atlantic Salmon Restoration Program;
  2. prevention of competition with introduced species such as rainbow and brown trout;
  3. instream barrier mitigation and habitat rehabilitation;
  4. protective water quality operations criteria for Atlantic salmon at Wastewater Pollution Control Plants located in Orangeville and Acton;
  5. Protective water quality and quantity design criteria for proposed stormwater management facilities discharging into sub-watersheds supporting the species;
  6. Application of SiltSmart protocol for large construction sites in sub-watersheds supporting the species; and
  7. Continue monitoring the species restoration efforts through operation of fishways, operation of rotary screw trap, fall parr assessment and CVC’s watershed monitoring program.




Concerns have been identified relating to northern pike in the Credit River watershed including:


1) presence of northern pike in Island Lake and their potential impact on the largemouth bass population; and


2) downstream migration of pike from Island Lake into the main Credit River and their potential predation on brook trout and Atlantic salmon


Northern pike have become established in the main Credit River above the Niagara Escarpment to Orangeville due to a large population in Island Lake. In the reservoir, northern pike do provide angling opportunities in the summer and also in the winter through a popular ice-fishing program. A screen has been placed over the discharge pipe to try to eliminate the fish escaping the reservoir and potentially harming the native brook trout populations downstream.


Largemouth bass are also found in Island Lake. While both northern pike and

largemouth bass can successfully co-habit the same reservoir, the largemouth bass population may be reduced and the fish may become stunted if the pike population is not controlled. The greatest impact observed from northern pike in the reservoir to date has been the decline of yellow perch.


Management Objective:Control northern pike populations through promotion of harvest and removal above the Niagara Escarpment. In other areas of the watershed, northern pike are managed as part of a naturally self sustaining fishery (e.g., Fairy Lake, lower Credit, off-line ponds, etc.).




Brown trout were introduced into Ontario, in part, for their tolerance of degraded

conditions and because they are highly valued as a sport fish. In fact, the first specially regulated waters and landowner agreements to manage trout and their habitat in the Credit River watershed was established by Trout Unlimited, in the historically stocked waters above Inglewood.


Migratory brown trout also enter the Credit River in the fall from Lake Ontario and are commonly captured through the operation of the Streetsville Fishway. Most of the brown trout caught at this location are not fin clipped indicating a wild origin. Once collected at the fishway, the fish are released upstream of the dam.


Brown trout are known to negatively compete with native brook trout. More recently, this species has been considered as invasive in the province of British Columbia and states of New York and California.1


1 Kerr, S.J. and R.E. Grant. 2000. Ecological Impacts of Fish Introductions: Evaluating the Risk. Fish and Wildlife Branch, Ontario Ministry of Natural Resources., Peterborough, Ontario. 473 p.




Management Objective: Permit and encourage harvest of brown trout, with no size restrictions, in the middle and upper Credit River where this species overlaps with brook trout and Atlantic salmon range. Continue to pass brown trout above the Streetsville Fishway and restrict further access beyond the Norval Dam all year round. Supplemental stocking of brown trout in the main Credit River below Norval is supported unless range overlap with resident species-at-risk, such as Redside Dace, is discovered. Should this situation arise, supplemental brown trout stocking will be discontinued. Monitoring should be continued through operation of fishways and CVC’s watershed monitoring program.




Currently, the majority of Pacific salmon (primarily Chinook and Coho salmon) are stopped at the Streetsville dam to support the provincial fish culture egg collections for the continued stocking program that supports the Lake Ontario fishery. However, some fish do pass through the fishway during the late summer Atlantic salmon migration period. Chinook and Coho salmon are subsequently stopped at the Norval dam.


Management Objective:Continue to stock Pacific salmon (Chinook and Coho), at the rates set by the Lake Ontario Management Unit. Stop the upstream migration of adult fish at the Streetsville Dam, following the late summer run of Atlantic salmon, in order to support the provincial fish culture egg collection for the Lake Ontario fishery. Should alternative locations be used to facilitate wild egg collections, Chinook and Coho salmon could be allowed to pass through the Streetsville fishway and be stopped at Norval.




One of the most discussed and controversial issues during development of the Credit River FMP was expanding access of migratory rainbow trout above the Norval dam into the middle watershed to increase natural reproduction in support of establishing a self-sustaining population. Concerns were raised that if rainbow trout were given access above Norval, there may be competition with the native fish community and naturalized brown trout populations resulting in impacts on the quality of those existing self-sustaining fisheries. More recently, concerns with providing further access of rainbow trout above Norval include impacts to Atlantic salmon restoration and the decline of resident brook trout populations in some areas where there overlaps with rainbow trout.


It appears that strong spawning runs of rainbow trout have been achieved through the efforts of transferring a limited number of adult spawning pairs into Black and Silver Creeks as well as through natural reproduction that is occurring in other areas of the watershed. To address the potential negative impacts associated with rainbow trout access and distribution upstream of Norval on resident brook trout and Atlantic salmon, it is recommended that access and natural reproduction upstream of Norval be limited to adult fish transfers to portions of Black Creek only.

This is a fundamental change to the previous management objective of the Credit River Fisheries Management Plan in that the following actions are no longer required:

  1. Annual stocking of up to 190,000 rainbow trout fry and fingerlings into Black Creek, Silver Creek and the Credit River directly downstream of Papermill Dam; and,
  2. Conduct a feasibility study of a new barrier for the management of rainbow trout upstream of the Norval Dam


Illegal stocking and accidental introductions through escapes from stocked ponds and aquaculture facilities have also resulted in the presence of domestic strains of this species in the watershed.


Management Objective:Protect and maintain the established self-sustaining rainbow trout population and promote the high quality sport fishery that has been established. Continue to allow open access for the species through the Streetsville Fishway and maintain the Norval Dam as the active partition barrier. Wild origin adult rainbow trout transfers and stocking of wild origin fish will be limited to:

1) the transfer of 300 pairs of adult fish in the spring from Norval Fishway to Black Creek between Eighth Line and Stewarttown Dam, Town of Halton Hills;

2) supplemental stocking of fry, fingerlings and yearlings produced by volunteers from 50,000 green eggs collected from wild fish at the Norval Fishway. Stocking is to take place downstream of Norval in the main river unless there is found to be a detrimental range overlap with resident species-at-risk, such as Redside Dace. Should this situation arise, supplemental rainbow trout stocking will be limited to Levi Creek and Mullet Creek tributaries;

3) Continue monitoring through operation of fishways, operation of rotary screw trap and CVC’s watershed monitoring program; and

4) Permit and encourage harvest and removal of the species where it is found overlapping with brook trout range.


If the Norval Dam no longer continues to function as a barrier to rainbow trout migration upstream, the Streetsville Dam will be maintained as the species partition barrier and specific objectives related to adult transfers and stocking will be re-visited.





Largemouth bass can be found in Island Lake, the ponds in Ken Whillans Conservation Area, Fairy Lake, ponds at Erin Stanley Park, Lake Aquitaine, Wolf Lake, Roman Lake, Hillsburgh ponds and several private ponds within the watershed. Although occasionally caught in the river as fish move downstream from ponds and reservoirs, largemouth bass populations are not self sustaining in most of the river, likely due to habitat requirement limitations such as warmer, slow flowing waters. They can be found in Port Credit Marshes and near the mouth of the Credit River.


Management Objective: Maintain current distribution of largemouth bass in reservoirs, isolated ponds and lakes. Stocking largemouth bass in new locations connected to public waterways is discouraged unless associated with the control of non-native invasive fish species in stormwater management ponds.






Historically, smallmouth bass were found in Lake Ontario and had access to the Credit River. Currently, smallmouth bass can be found in Lake Aquitaine and, more recently, in the main river below the Norval Dam.


Management Objective: Protect and improve the smallmouth bass fishery from the mouth of the Credit River to the Norval Dam. Continue to transfer adult smallmouth bass above Streetsville Dam as resources allow. Investigate opportunities to improve the Streetsville Fishway to accommodate passage for smallmouth bass. Continue monitoring through operation of fishways and CVC’s watershed monitoring program.




Redside dace are listed as endangered on the Species at Risk in Ontario (SARO) list and are protected under the Endangered Species Act (ESA), 2007. It is one of several species-at-risk fishes found in the Credit River watershed.


Lake sturgeon and American eel are also designated species-at-risk that either occur now or historically occurred. Lake sturgeon are designated as threatened and American eel are designated as endangered. The last record of lake sturgeon for the watershed was collected in 1936 off the river mouth. Anecdotal reports of occasional sturgeon being caught at the river mouth by anglers have occurred since 1990. American eel are caught more frequently with the last record of capture being at the Norval Fishway in the summer of 2011.


Management Objective: Protect and recover species-at-risk in accordance with species-specific Government Response Statements and Recovery Strategies. Species-at-risk protection and recovery takes precedence over management objectives for non-native and naturalized species such as brown trout, rainbow trout and largemouth bass.




Despite control efforts such as the lamprey barrier at the Streetsville dam and semi-annual lampricide applications by the Department of Fisheries and Oceans, sea lamprey continue to remain as a pest species in Lake Ontario. Sea lamprey pose a significant threat to lake trout restoration in Lake Ontario. Without the continued management of the Streetsville dam as a lamprey barrier and lampricide applications in the Credit River system, the sea lamprey population would increase and have a significant negative impact on migratory salmon and trout fisheries.


Management Objective:Prevent the upstream migration of sea lamprey past Streetsville Dam. Ensure Streetsville Fishway is operated in a manner that prevents sea lamprey from getting upstream. Continue the conservative use of lampricide in the watershed to control sea lamprey production while preventing negative impacts on aquatic species-at-risk.