Gravel Chub (Erimystax x-punctatus): COSEWIC rapid review of classification 2019

Official title: COSEWIC Rapid Review of Classification on the Gravel Chub Erimystax x-punctatus in Canada 2019

Committee on the Status of Endangered Wildlife in Canada (COSEWIC)
Extirpated 2019

COSEWIC assessment summary

Assessment summary – May 2019

Common name: Gravel Chub

Scientific name: Erimystax x-punctatus

Status: Extirpated

Reason for designation: The historical Canadian range of this small minnow was originally a single watershed in southern Ontario. The most recent record for this species was in 1958 despite extensive, repeated sampling at known sites and other areas of suitable habitat over the last 60 years. Natural recolonization by the species is not possible because there are no adjacent populations in the Great Lakes watershed.

Occurrence: Ontario

Status history: Last recorded in Thames River drainage, Ontario in 1958. Designated endangered in April 1985. Status re-examined and designated extirpated in April 1987. Status re-examined and confirmed in May 2000, April 2008, and May 2019.

COSEWIC rapid review of classification

Preview

Gravel Chub (Erimystax x-punctatus) is a small stream-dwelling cyprinid. This species is extirpated in Canada, with the last observations of Gravel Chub in the wild being in 1958. Despite substantial targeted sampling over the past six decades, no additional captures have been made. The EOO and IAO for this species each remain at 0 km².

Most recently, the Ontario Ministry of Natural Resources and Forestry (OMNRF) Lake Erie Management Unit initiated a gear-comparison study in the Thames River to determine the best gears to sample the small-bodied fish community. They used small-mesh gill nets, Siamese benthic trawls, and boat electrofishing. The Thames River was extensively sampled, including the areas where Gravel Chub was last known to occur. Despite this effort, as of September 2018, no Gravel Chub had been encountered (Thorn personal communication 2018). Additionally, Department of Frisheries and Oceans (DFO) has conducted extensive small-bodied fish sampling in the Lower Thames River since the last assessment but not at, or near, the area where Gravel Chub was last observed. No Gravel Chub were captured during these surveys (Barnucz personal communication 2018; Drake personal communication 2018). DFO believes that targeted trawling surveys around Muncey (last known occurrence of this species) would be useful to confirm that Gravel Chub is extirpated (Barnucz personal communication 2018).

This species was listed as “Schedule 1 – Extirpated” under the Species at Risk Act (SARA) in 2003. No changes to the effective protection of Gravel Chub under SARA have occurred since the last assessment. The Fisheries Act was revised in 2012, with a change from protecting fishes and fish habitat for all fishes, to just those fishes supporting commercial, Aboriginal, and recreational (CAR) fisheries. If Gravel Chub was present in Canada today, it would not be part of a CAR fishery. In 2008, changes to the Ontario Fishery Regulations increased protection to Gravel Chub by removing species at risk fishes from the list of eligible baitfish species (DFO 2016).

A recovery strategy for Gravel Chub has been published (Edwards et al. 2007). The goal of the recovery strategy is to search for Gravel Chub, while improving habitat within the Thames River to be more suitable for the species, and considering reintroduction. With considerable effort in environmental stewardship, restoration, and public-education initiatives, progress has been made in improving the habitat of Gravel Chub. Water quality has improved with positive effects on instream biota (DFO 2016).

Updated map: Not required

Explanation / updated map provided

Not required.

Gravel Chub is extirpated from Canada. It was known from only two sites in the Thames River in southwestern Ontario. It was last observed 60 years ago and, despite extensive survey efforts every decade since then, no Gravel Chub has been captured. Gravel Chub is a searchable species in the Ontario Natural Heritage Information Centre database of the Ontario Ministry of Natural Resources and Forestry, in which there are no records since 1958.

Technical summary

Scientific name: Erimystax x-punctatus

English name: Gravel Chub

French name: Gravelier

Range of occurrence in Canada (province/territory/ocean): Ontario (Thames River)

Demographic information

Generation time (usually average age of parents in the population; indicate if another method of estimating generation time indicated in the IUCN guidelines (2011) is being used):

2-3 y (estimated)

Is there an [observed, inferred, or projected] continuing decline in number of mature individuals?:

Not applicable

Estimated percent of continuing decline in total number of mature individuals within [5 years or 2 generations]:

Not applicable

[Observed, estimated, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over the last [10 years, or 3 generations]:

Not applicable

[Projected or suspected] percent [reduction or increase] in total number of mature individuals over the next [10 years, or 3 generations]:

Not applicable

[Observed, estimated, inferred, or suspected] percent [reduction or increase] in total number of mature individuals over any [10 years, or 3 generations] period, over a time period including both the past and the future:

Not applicable

Are the causes of the decline a) clearly reversible and b) understood and c) ceased?:

a. unknown
b. no
c. unknown

Are there extreme fluctuations in number of mature individuals?:

No

Extent and occupancy information

Estimated extent of occurrence (EOO):

0 km²

Index of area of occupancy (IAO) (Always report 2x2 grid value):

0 km²

Is the population “severely fragmented” i.e., is >50% of its total area of occupancy in habitat patches that are (a) smaller than would be required to support a viable population, and (b) separated from other habitat patches by a distance larger than the species can be expected to disperse?:

a. Not applicable
b. Not applicable

Number of “locations”^* (use plausible range to reflect uncertainty if appropriate):

0

Is there an [observed, inferred, or projected] decline in extent of occurrence?

Not applicable

Is there an [observed, inferred, or projected] decline in index of area of occupancy?:

Not applicable

Is there an [observed, inferred, or projected] decline in number of subpopulations?:

Not applicable

Is there an [observed, inferred, or projected] decline in number of “locations”*?:

No

Is there an [observed, inferred, or projected] decline in [area, extent and/or quality] of habitat?:

No, water quality has improved.

Are there extreme fluctuations in number of subpopulations?:

Not applicable

Are there extreme fluctuations in number of “locations”?:

Not applicable

Are there extreme fluctuations in extent of occurrence?:

Not applicable

Are there extreme fluctuations in index of area of occupancy?:

Not applicable

^* See definitions and abbreviations on COSEWIC website and International Union for Conservation of Nature (IUCN) (Feb 2014) for more information on this term.

Number of mature individuals (in each subpopulation)

Subpopulations (give plausible ranges) total: Not applicable

N Mature Individuals total: 0

Quantitative analysis

Probability of extinction in the wild is at least [20% within 20 years or 5 generations, or 10% within 100 years]: Not applicable

Threats (direct, from highest impact to least, as per IUCN Threats Calculator)

Was a threats calculator completed for this species? No

Turbidity and sedimentation as a result of watershed land uses, primarily agriculture, are suspected to have been the greatest threat to Gravel Chub. Restoration and environmental stewardship activities are underway and have improved habitat, particularly water quality. Protection has been given to species at risk in baitfish fisheries. Education programs have been initiated to help limit the accidental capture of species at risk during baitfish harvest (DFO 2016).

What additional limiting factors are relevant? Not applicable

Rescue effect (immigration from outside Canada)

Status of outside population(s)? Note that in Great Lakes states in which it is not imperiled, it only occurs outside of the Great Lakes basin.

PA: S1 (critically imperilled)
OH: S4 (apparently secure)
NY: (possibly extirpated)

Is immigration known or possible?

No

Would immigrants be adapted to survive in Canada?

Unknown

Is there sufficient habitat for immigrants in Canada?

Unknown

Are conditions deteriorating in Canada?⁺

Unknown

Are conditions for the source population deteriorating?⁺

Unknown

Is the Canadian population considered to be a sink?⁺

Unknown

Is rescue from outside populations likely?

No

⁺ See table 3 (Guidelines for modifying status assessment based on rescue effect).

Data-sensitive species

Is this a data sensitive species? No

Status history

COSEWIC: Last recorded in Thames River drainage, Ontario in 1958. Designated endangered in April 1985. Status re-examined and designated extirpated in April 1987. Status re-examined and confirmed in May 2000, April 2008, and May 2019.

Status and reasons for designation

Status: Extirpated

Alpha-numeric codes: Not applicable

Reasons for designation: The historical Canadian range of this small minnow was originally a single watershed in southern Ontario. The most recent record for this species was in 1958 despite extensive, repeated sampling at known sites and other areas of suitable habitat over the last 60 years. Natural recolonization by the species is not possible because there are no adjacent populations in the Great Lakes watershed.

Applicability of criteria

Criterion A (Decline in Total Number of Mature Individuals): Not applicable.

Criterion B (Small Distribution Range and Decline or Fluctuation): Not applicable.

Criterion C (Small and Declining Number of Mature Individuals): Not applicable.

Criterion D (Very Small or Restricted Population): Not applicable.

Criterion E (Quantitative Analysis): Not applicable.

Acknowledgements

The report writer would like to thank all of the experts contacted for their willingness to share information, as well as Jenny Wu and Marie-France Noel of the COSEWIC Secretariat, and Nick Mandrak, the Freshwater Fishes Subcommittee Co-chair, for their advice and guidance with the development of this review of classification document.

Authorities contacted

Nick Mandrak, University of Toronto

Scott Reid, Ontario Ministry of Natural Resources and Forestry, Species at Risk

Donald Sutherland, Ontario Ministry of Natural Resources and Forestry, Natural Heritage Information Centre

Erling Holm, Royal Ontario Museum

Andrew Drake, Fisheries and Oceans Canada, Great Lakes Laboratory for Fisheries and Aquatic Sciences

Emily Slavik, Ontario Ministry of Natural Resources and Forestry, Lake Erie Assessment Unit

Michael Thorn, Ontario Ministry of Natural Resources and Forestry - Lake Erie Assessment Unit

Jason Barnucz, Fisheries and Oceans Canada, Great Lakes Laboratory for Fisheries and Aquatic Sciences

Vicki McKay, Lower Thames Valley Conservation Authority

Information sources

Barnucz, J. Email correspondence to P. Cott. 2018. Fisheries and Oceans Canada, Great Lakes Laboratory for Fisheries and Aquatic Sciences, Burlington, ON.

COSEWIC 2008. COSEWIC Assessment and Update Status Report on the Gravel Chub Erimystax x-punctatus in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. 27 pp.

DFO. 2016. Report on the progress of recovery strategy implementation for the Gravel Chub (Erimystax x-punctatus) in Canada for the period 2008-2015. Species at Risk Act Recovery Strategy Report Series. Fisheries and Oceans Canada, Ottawa. ii + 9 pp.

Drake, D.A.R. Email correspondence to P. Cott. 2018. Fisheries and Oceans Canada, Great Lakes Laboratory for Fisheries and Aquatic Sciences, Burlington, ON.

Edwards, A.L., S.M. Reid, and B. Cudmore. 2007. Recovery strategy for gravel chub (Erimystax x-punctatus) in Canada. Species at Risk Act Recovery Strategy Series, Fisheries and Oceans Canada, Ottawa. viii +19 pp.

NatureServe. 2018. [accessed 19 October 2018].

Thorn, M. Email correspondence to P. Cott. 2018. Ontario Ministry of Natural Resources and Forestry, Lake Erie Assessment Unit, Wheatley, ON.

Writer of rapid review of classification

Pete Cott is a biologist based in Yellowknife NWT, and is a member of the Freshwater Fishes Specialist Subcommittee for COSEWIC. His PhD research focused on the reproductive ecology of Burbot.

COSEWIC history

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions (2019)

Wildlife species

A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.

Extinct (X)

A wildlife species that no longer exists.

Extirpated (XT)

A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)

A wildlife species facing imminent extirpation or extinction.

Threatened (T)

A wildlife species likely to become endangered if limiting factors are not reversed.

Special concern (SC)
(Note: Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.)

A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Not at risk (NAR)
(Note: Formerly described as “Not In Any Category”, or “No Designation Required.”)

A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data deficient (DD)
(Note: Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” [insufficient scientific information on which to base a designation] prior to 1994. Definition of the [DD] category revised in 2006.)

A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.

The Canadian Wildlife Service, Environment and Climate Change Canada, provides full administrative and financial support to the COSEWIC Secretariat.