Website and Document Search
Loading

Ausable Bayfield Conservation Authority

Fish Species at Risk

Fish Species at Risk

The following information focuses on fish species at risk in the Ausable River watersheds:

Introduction

Since the summer of 2002, the Ausable River Recovery Team has spent considerable time documenting the species at risk in the Ausable River watershed. 

Extensive fish surveys have been conducted resulting in the discovery of two new fish species in the Ausable River (Black Redhorse and Bigmouth Buffalo).

In all, the Ausable River is home to 20 species at risk, including six (6) fishes, six (6) mussels and eight (8) reptiles.  

 


Fish Species

Six species of fish in the Ausable River are listed as species at risk and their decline can be linked to: siltation/turbidity, habitat destruction and poor water quality.

Pugnose Shiner
(Notropis anogenus)
The Pugnose Shiner is a globally rare, small (up to 6 cm), silvery olive-yellow member of the minnow family. A distinguishing feature of the Pugnose Shiner is its small upturned, almost vertical, mouth. This species prefers marshy areas of sandy-bottomed lakes and streams that have abundant aquatic vegetation and clear, still water.
*ENDANGERED*  (Last examined by COSEWIC in 2002)    Photo: J. Barnucz, DFO

Reason for Designation: The pugnose shiner has a limited, fragmented Canadian distribution, being found only in Ontario where it is subject to declining habitat quality. The isolated nature of its preferred habitat may prevent connectivity of fragmented populations and may prevent gene flow between existing populations and inhibit re-colonization of other suitable habitats.

Status History: Designated Special Concern in April 1985. Status re-examined and designated Endangered in November 2002.

Black Redhorse
(Moxostoma duquesnei)
The Black Redhorse is a small (up to 50 cm), gray-brown sucker that can be distinguished from other redhorses by several features such as its slate-coloured tail and small scales. This species favours riffle and pool areas of clear flowing waters that have sand/gravel/bedrock bottoms. The Black Redhorse was first discovered in the Little Ausable River in 2002.
*THREATENED*  (Last examined by COSEWIC in 2005)Photo: S. Staton, DFO

Reason for Designation: A freshwater fish with a very small, highly fragmented distribution and area of occupancy, as well as restricted spawning habitat preferences. Native populations are found in only 5 Ontario watersheds in areas heavily impacted by urbanization and agriculture. It is at risk of habitat loss and degradation as a result of increased siltation and  turbidity. Dams may adversely affect flow regimes and have fragmented populations in the two major rivers where this species occurs.

Status History: Designated Threatened in April 1988. Status re-examined and confirmed in May 2005.

 

 

Lake Chubsucker
(Erimyzon sucetta)
The Lake Chubsucker is a small (up to 40 cm), olive-coloured deep-bodied member of the sucker family. Habitat preferences are limited to sandy-bottomed lakes and marshes with clear, still water and ample aquatic vegetation. This species only occurs in a few places in southwestern Ontario. In the Ausable River, the Lake Chubsucker population appears to be stable.
*ENDANGERED*  (Last examined by COSEWIC in 2008)

                                                                                                                           Photo: S. Staton, DFO

Reason for Designation: A species with a restricted geographic Canadian range with small extant populations having very specific and narrow habitat preferences, which are under continued stress.  It is extremely susceptible to habitat change driven by urban, industrial and agricultural practices resulting in increased turbidity.  Two populations have been lost, and of the 11 extant populations, 3 are in serious decline as a result of the continuing and increasing threats posed by agricultural, industrial and urban development that are expected to impact the remaining populations of Lakes Erie and St. Clair.

Status History: Designated Special Concern in April 1994. Status re-examined and designated Threatened in November 2001. Status re-examined and designated Endangered in November 2008.

 

Eastern Sand Darter
(Ammocrypta pellucida)
The Eastern Sand Darter is a globally rare, long and slender (up to 8 cm), olive-gold member of the perch family with a distinctively translucent body. This species favours sandy-bottomed streams. The Eastern Sand Darter is known to bury itself completely in the substrate. This species was not found in the 2002 or 2007 surveys and is thought to be extirpated from the Ausable River.
*THREATENED*  (Last examined by COSEWIC in 2009)   

                                                                                                            Picture: Joseph R. Tomelleri, NYSDC

Reason for Designation: This species prefers sand bottom areas of lakes and streams in which it burrows. There is continuing decline in the already small and fragmented populations; four (of 11) have probably been extirpated.  The extent of occurrence of this species in Ontario is approximately half of what it was in the 1970s as a result of habitat loss and degradation from increasing urban and agricultural development, stream channelization and competition with invasive alien species.

Status History: The species was considered a single unit and designated Threatened in April 1994 and November 2000. When the species was split into separate units in November 2009, the "Ontario populations" unit was designated Threatened.

River Redhorse
(Moxostoma carinatum)
The River Redhorse is a large (up to 75 cm), thick-bodied sucker with a prominent, slightly overhung snout and red tail. This species inhabits fast-flowing, clear rivers with rocky pools and runs. River Redhorse populations are scattered throughout Ontario and Quebec and are geographically isolated from U.S. populations. The River Redhorse was historically found in the Ausable River but has not been seen in over 70 years.
*SPECIAL CONCERN*  (Last examined by COSEWIC in 2006)

                                                                                                            Picture: Joseph R. Tomelleri, NYSDC

Reason for Designation: This freshwater fish species occurs in Ontario and Quebec and although it has been collected at new locations in both provinces, sometimes in large numbers, this is thought to reflect the use of more effective sampling techniques such as boat electrofishing. It has likely disappeared historically from the Ausable, Chateauguay and Yamaska rivers, since the use of boat electrofishing has failed to collect it recently. Threats to the species include habitat degradation (pollution, siltation), stream regulation that affects water flow (dams) and habitat fragmentation (dams). The Canadian range is highly fragmented and rescue effect is improbable because of the precarious conservation status in adjoining US States.

Status History: Designated Special Concern in April 1983. Status re-examined and confirmed in April 1987 and in April 2006. 

 

Grass Pickerel 
(Esox americanus vermiculatus) 
Within Canada, these fish are only found in a limited number of locations in Ontario and Quebec.  Numbers have declined due to habitat degredation and loss.  The Grass Pickerel prefers shallow water with an abundance of vegetation.    
*SPECIAL CONCERN*  (Last examined by COSEWIC in 2005)

 

                                                                                                                                Photo: J. Barnucz, D

Reason for Designation: A subspecies known from 10 locations between Lake St.Louis, Quebec and Lake Huron, Ontario. Its usual habitat is shallow water with abundance of aquatic vegetation. An overall decline of approximately 22% in the area of occupancy has been observed. This decline appears to be related to degradation and loss of habitat due to channelization and dredging operations in wetland habitats where this species occurs.

Status History: Designated Special Concern in May 2005.

 

Greenside Darter                                                                                                                         (Etheostoma blennioides)               The Greenside Darter is a small (up to 11cm), olive-green member of the perch family.  This species is identifiable by the 5-8 green V- or W- shaped marks on its side.  The Greenside Darter is a bottom dweller and is usually found in clear, fast-flowing, gravelly bottomed riffle areas of streams and rivers.  In Canada, this species is limited to southwestern Ontario.

*NOT AT RISK*  (Last examined by COSEWIC in 2006)

Reason for Designation: Recent surveys have shown that the species is widespread and abundant in the Ausable, Sydenham and Thames rivers as well as Lake St. Clair. The total Canadian population has also increased through the recent colonization of the Bayfield River, Big Otter Creek, Detroit River and Grand River.  Rescue of greenside darter populations in Canada is possible from Michigan populations.

Status History: Designated Special Concern in April 1990. Status re-examined and designated Not at Risk in November 2006.

 

Bigmouth Buffalo 
(Ictiobus cyprinellus) 
The Bigmouth Buffalo is a large (up to 1 m) member of the sucker family that resembles a common carp.  The species is olive brown in colour and it favours river habitat that is slow flowing, warm, muddy and highly enriched.  The range of the Bigmouth Buffalo appears to be expanding in southern Ontario and it was found for the first time in the Ausable River in 2002.    
*NOT AT RISK*  (Last examined by COSEWIC in 2008)

Reason for Designation: Populations in Ontario appear to be doing well and there are no immediate threats to its continued survival; the area of occupancy appears to have increased and it has been found at 8 new locations since last assessed in 1989.

Status History: The species was considered a single unit and designated Special Concern in April 1989. Split into two populations in April 2008 to allow a separate designation of the Bigmouth Buffalo (Great Lakes - Upper St. Lawrence populations).  The Bigmouth Buffalo (Great Lakes - Upper St. Lawrence populations) was designated Not at Risk in April 2008.

Mussel Species at Risk in the Ausable River

Reptile Species at Risk in the Ausable River