Species Profile

Oregon Spotted Frog

Scientific Name: Rana pretiosa
Taxonomy Group: Amphibians
COSEWIC Range: British Columbia
COSEWIC Assessment Date and Status Change: May 2011
COSEWIC Status: Endangered
COSEWIC Status Criteria: B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v); C2a(i)
COSEWIC Reason for Designation:

This highly aquatic frog has a small Canadian distribution within the populated and highly modified Fraser River Basin in southwestern British Columbia. It currently occurs at four sites, isolated from one another, and has been extirpated from an additional three sites. One extant population is near extinction, and the remaining populations are small and vulnerable to disturbance and stochastic events. Habitat loss and fragmentation, hydrological alteration, disease, introduced predators, and poor water quality continue to threaten remnant populations.
COSEWIC History of Status Designation: Designated Endangered in an emergency assessment on 13 September 1999. Status re-examined and confirmed in May 2000 and in May 2011.
SARA Status: Schedule 1, Endangered
Date of Listing (yyyy-mm-dd): 2003-06-05

Please note that this information is provided for general information purposes only. For the most up to date and accurate list of species listed under the Species at Risk Act, please see the Justice Laws Website.

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Quick Links: | Photo | Description | Distribution and Population | Habitat | Biology | Threats | Protection | Recovery Initiatives | Recovery Team | National Recovery Program | Documents

Image of Oregon Spotted Frog

Oregon Spotted Frog Photo 1

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Description

The Oregon Spotted Frog, Rana pretiosa, is a member of the family Ranidae, or true frogs. Prior to 1997, the name Rana pretiosa was applied to both R. pretiosa and R. luteiventris (Columbia Spotted Frog) as currently known. Therefore, when interpreting research conducted prior to 1997, a reader must note the geographic location of the study, which will indicate the species in question. The Oregon Spotted Frog is a medium-sized frog with a body length in adults of 60 to 80 mm. The background colour is brown or reddish and becomes more reddish as the frogs age. The common name of the species is in reference to the dark spots with light centres that are present over the head, back, and legs. The underside of the legs and belly of juvenile frogs is white or cream-coloured, changing to orange or red in adults. The distribution of the Oregon Spotted Frogoverlaps with that of the Northern Red-legged Frog (R. aurora), with which it may be confused. The two species can be distinguished by subtle differences in appearance, including lack of green mottling in the groin, shorter legs, and more upturned eyes in the Oregon Spotted Frog. The Oregon and Columbia Spotted Frogs are very similar in appearance but are not found in the same areas. This species is sensitive to contaminants in its environment including nitrates and nitrites, prevalent in run-off from agricultural areas. The Oregon Spotted Frog may serve as a bioindicator of the condition of shallow wetlands that it occupies. (Updated 2017/06/13)

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Distribution and Population

The historical range of the Oregon Spotted Frogextends from the Pit River drainage in California northward to southwestern British Columbia. The species has disappeared from many areas throughout its range, including three of seven known sites in British Columbia, all three known sites in California, 44 sites in Oregon, and 11 sites in Washington State. Its current range extends from extreme southwestern British Columbia southward to the Klamath Basin in Oregon. In Canada, the species is extant at four sites all within the Fraser River Basin of British Columbia: Aldergrove, Maria Slough, Mountain Slough, and Morris Valley. (Updated 2017/06/13)

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Habitat

The Oregon Spotted Frogis usually associated with large (> 4 ha) wetlands with emergent or floating vegetation within forested landscapes. The frogs are highly aquatic and almost always found in or beside water. In spring, egg-laying occurs in shallow warm water in seasonally inundated areas. In summer, the frogs forage in shallow wetlands. In winter, they often over-winter in springs and seepages that do not freeze completely or in low-flow channels or ditches, or they may bury into silty soil or vegetation at such sites. (Updated 2017/06/13)

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Biology

The frogs become active and begin breeding in spring after air temperatures reach approximately 5°C. Males produce a characteristic advertisement call consisting of a rapid series of short, low-pitched clucks, and usually call under water. Egg-laying is temperature-dependent and typically begins in March and continues for 2 to 4 weeks in British Columbia. Egg masses, each with up to 1500 eggs per mass, are laid in communal clusters with the tops of egg masses often exposed to the air. The placement of egg masses in shallows makes them vulnerable to freezing and desiccation caused by wind or receding water levels. In some years, embryonic survivorship can be zero. Survival of tadpoles can also be extremely low due to depredation. Most movements of individual frogs between breeding and wintering habitat are localized, but the frogs are capable of longer movements of up to about 3 km along water courses. (Updated 2017/06/13)

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Threats

The greatest threat to the species in Canada is continuing loss of suitable wetlands and associated terrestrial habitat and accompanying habitat fragmentation and population isolation. Additional threats include alteration of site hydrology, which can adversely affect egg-laying habitat and increase mortality of eggs; pollution affecting embryonic or tadpole survival; diseases such as chytridiomycosis and iridoviruses; and predators or competitors such as introduced American Bullfrogs, Green Frogs, and fish. (Updated 2017/06/13)

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Protection

Federal Protection

The Oregon Spotted Frog is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

The Oregon Spotted Frog is protected by the British Columbia Wildlife Act. Under this Act, it is prohibited to kill, collect, or hold captive any amphibian without a permit.

Provincial and Territorial Protection

To know if this species is protected by provincial or territorial laws, consult the provinces' and territories' websites.

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Recovery Initiatives

Status of Recovery Planning

Recovery Strategies :

Name Recovery Strategy for the Oregon Spotted Frog (Rana pretiosa) in Canada
Status Final posting on SAR registry

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Recovery Team

Oregon Spotted Frog Recovery Team

  • Bob Woods - Chair/Contact - OGD (other federal dept)
    Phone: 613-995-4087  Fax: 613-992-9422  Send Email

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Recovery Progress and Activities

Summary of Progress to Date The Oregon Spotted Frog recovery team aims to increase all three Oregon Spotted Frog populations to self-sustaining levels, as well as reintroduce the frog to historic sites and survey for undetected populations. The team is increasing the habitat quantity and quality at occupied sites and is monitoring the effectiveness of habitat management techniques. Husbandry techniques have been developed allowing the team to rear Oregon Spotted Frogs in captivity for population augmentation or reintroduction. Recovery planning is guided by research that clarifies habitat requirements and threats and that assesses the effectiveness of alternative recovery strategies. Summary of Research/Monitoring Activities Identifying suitable habitat has been a high priority for the recovery team. Radio telemetry projects have provided valuable information on the frog’s habitat use. As the team’s understanding of the frog’s habitat requirements has improved, they have been able to inventory potential breeding habitat at historically occupied sites and nearby existing sites. A demographic sensitivity analysis is being conducted to identify the best developmental stage for frogs to be released into the wild. In order to make this assessment and undertake a population viability analysis, researchers have conducted field studies to determine the reproductive output and survival rates of frogs, the current population size, the sex ratio, and other variables. The Oregon Spotted Frog population increased between 1999 and 2003 at one site. Researchers are assessing whether this increase was due to habitat restoration work or simply a fluctuation of the population. In order to gain a better understanding of the Oregon Spotted Frog’s demographics in Mountain Slough, BC, frogs were trapped during breeding and information on their sex, mass, and length was recorded. Twelve of these frogs, with a mass greater than 22 grams, were selected for transmitter attachment to determine frog movements from breeding locations. The transmitter allows the frogs to be tracked, using a radio receiver, and their position over a 20 week period (the battery life is 20 weeks) was logged using a global positioning system. Summary of Recovery Activities The primary reason for the Oregon Spotted Frog’s decline is the loss of shallow wetlands with stable water levels, which are required for egg-laying. Fluctuating water levels cause egg masses to dry out. One of British Columbia’s Oregon Spotted Frog populations was rapidly declining for this reason. Therefore, since 1999, the recovery team has monitored egg masses at this site and collected egg masses at risk of drying out. These eggs are reared in captivity and the froglets are returned to the wild population. At the same time, a longer term approach is being taken to habitat degradation. Some habitat has been restored since 1999. This includes sites whose hydrology has been managed to provide more stable water levels. For example, a deep-water well was constructed at one site to minimize the effect of droughts on water levels. Furthermore, introduced Bullfrogs are controlled because they exert considerable predation pressure on the Oregon Spotted Frog. Reed Canary Grass, another invasive exotic, degrades the frog’s habitat and is being controlled at some sites. Beavers became numerous over the 1990s at one site and significantly altered the site’s wetland, reducing the amount of shallow wetland edge, which is crucial habitat for the Oregon Spotted Frog. Therefore, Beavers are being removed from this site. A captive breeding program has been successfully established and will provide frogs for future reintroductions. The Vancouver Aquarium Marine Science Center actively participates in this program. They released 140 Oregon Spotted Froglets into marshland on the outskirts of Agassiz in 2002 and will continue with these activities every year until the population has been fully recovered. URL’s: Nature Canada, Endangered Species:http://www.cnf.ca/species/critters/oregon.html BC Frog Watch factsheet:http://wlapwww.gov.bc.ca/wld/documents/oregonspfrog.pdf Vancouver Aquarium Marine Science Center:http://www.vanaqua.org/conservation/oregon-spotted-frogs.html Greater Vancouver Zoo:http://www.gvzoo.com/Codes/oregon.html

Documents

PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.

22 record(s) found.

COSEWIC Status Reports

  • COSEWIC assessment and status report on the Oregon spotted frog Rana pretiosa in Canada (2011-09-09)

    The Oregon spotted frog, Rana pretiosa, is brown to reddish brown with black halos spread over its head and back. Adults have a mottled belly and yellow to salmon colour wash. Egg masses are laid communally in tight groupings. Single egg masses or groups of two or three egg masses are uncommon. Rana pretiosa and the Columbia spotted frog (Rana luteiventris) are sibling species identifiable through protein analysis and differentiated since 1997. Previously, they were collectively known as a single species, Rana pretiosa.

Response Statements

  • Response Statement - Oregon Spotted Frog (2011-12-08)

    This highly aquatic frog has a small Canadian distribution within the populated and highly modified Fraser River Basin in southwestern British Columbia. It currently occurs at four sites, isolated from one another, and has been extirpated from an additional three sites. One extant population is near extinction, and the remaining populations are small and vulnerable to disturbance and stochastic events. Habitat loss and fragmentation, hydrological alteration, disease, introduced predators, and poor water quality continue to threaten remnant populations.

Recovery Strategies

  • Recovery Strategy for the Oregon Spotted Frog (Rana pretiosa) in Canada (2015-12-30)

    The Oregon Spotted Frog, a highly aquatic frog, was listed as Endangered on Schedule 1 of the federal Species at Risk Act (SARA) in 2003. Environment Canada (EC) is the lead federal department under SARA, but the province of British Columbia is the responsible jurisdiction for the management of this species and is the lead for recovery planning under the Accord for the Protection of Species at Risk. A provincial recovery strategy for the species was developed on behalf of province of British Columbia in 2012. EC is adopting the provincial recovery strategy under section 44 of SARA and has included a federal addition to complete the SARA requirements. The federal addition and the provincial recovery strategy constitute the federal recovery strategy for the Oregon Spotted Frog. It has been prepared in cooperation with the province of British Columbia.

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2010 - 2011 (2011-09-09)

    Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to “assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species”. COSEWIC held two Wildlife Species Assessment Meetings during the past year assessing the status or reviewing the classification of a total of 92 wildlife species.

Permits and Related Agreements

  • Explanation for issuing permit(#1), persuant to the provisions of section 73 of SARA (2006-02-03)

    The proponent proposes to conduct an aquatic vertebrate biodiversity study within the Oregon Spotted Frog (OSF) Habitat study area to determine the type and number of species utilizing the habitat and whether the presence of invasive species may be having an impact on Oregon Spotted Frog survival and productivity. From this perspective, the study also examines the regeneration of an invasive grass species and the feeding habits of the bullfrog (Rana catesbeiana), an invasive vertebrate species. GEE minnow traps, fitted with foam floats, will be used to passively capture aquatic vertebrates. Traps will be checked every 12 hours for a total of 3 days, but no trapping will occur during the breeding season of the Oregon Spotted Frog (approximately mid-February to end of April), to avoid any risk of impacts to the population.
  • Explanation for issuing permit(#2), persuant to the provisions of section 73 of SARA (2006-03-06)

    To measure survivorship, 15-25 eggs are sub-sampled from randomly selected wild egg masses and percent survivorship, time to hatching and rate of hatching can be determined. Where possible, eggs will be collected randomly from different locations of the egg mass to ensure samples are taken from both the outside and inside of the egg mass. The egg sub-samples will be transferred into Nytex cages holding cages and egg development will be monitored in situ, within 1-3 m of the wild egg mass. Cages are visited two to three times per week during the three week period of development to hatching.
  • Explanation for issuing permit(#28), persuant to the provisions of section 73 of SARA (2006-06-28)

    The activity involves the presence/non-detected surveys at several sites for a number of species at risk that have been evaluated as having potential for occurrence at these sites. Methodologies proposed for several species do not require a permit due to their primarily observational character. For Oregon Spotted Frog (Rana pretiosa), Sharp-tailed Snake (Contia tenuis) and Oregon Forestsnail (Allogona townsendiana), brief capture (dip-net surveys) or low-intensity harassment (overturning natural cover objects) may be required.
  • Explanation for issuing permit(#3), persuant to the provisions of section 73 of SARA (2006-03-08)

    A physical search of the wetland will be conducted to determine the location of Oregon Spotted Frog (OSF) egg masses. Global positioning system data for egg mass locations will be collected and physical barriers will be erected to protect egg masses from bullfrog and invertebrate predation. A total of 1400 eggs or less than 10% (whichever number is smaller) will be partitioned from OSF egg masses, taking care to take a similar number from each mass. Two to three eggs from each egg mass will be preserved in the appropriate chemical solution to allow for future DNA fingerprinting. Trapping of adult OSF by means of opportunistic dip netting will be conducted in areas surrounding and near egg masses in order to evaluate the success of the captive breeding program. All captures will be examined for markings, and their dorsal surfaces will be photographed. Individuals will be photographed on top of a scale background to facilitate the recording of snout-vent length from photograph records and thereby minimizing handling time. Bullfrog (Rana catesbeiana ) capture will be completed through opportunistic and directed surveys for dip netting bullfrogs. Night time spotlighting will be completed in areas away from known OSF breeding locations. Bullfrogs will be euthanized and preserved for gut content analysis. Dipnetting for bullfrogs will not be conducted within 30 m of known oviposition sites. A visual survey for red-legged frog (Rana aurora) will be conducted throughout the OSF habitat, wetlands to the northwest of the site, and along a river within the site.
  • Explanation for issuing permit(#36), persuant to the provisions of section 73 of SARA (2007-03-05)

    Oregon Spotted Frog (Rana pretiosa). Eggs will be collected and transported to two captive rearing facilities (Greater Vancouver Zoo and Mountain View Conservation and Breeding Society). Metamorphs will be released at the breeding sites in late summer. 250 eggs will be taken from an individual egg mass to the rearing facilities. The number of egg masses sampled will depend on the number of egg masses oviposited at each of the study sites. From historic records, we estimate that at Aldergrove sub samples will be collected from between five and 15 egg masses. At GVZ up to eight tanks are available and at MVCS up to 15 tanks are available for captive rearing of Oregon spotted frogs. The recommended density for captive rearing of tadpoles is 0.26 tadpoles/L (Hawkes, 2006) and densities will be kept at or below this recommendation.
  • Explanation for issuing permit(#37), persuant to the provisions of section 73 of SARA (2007-03-05)

    This research will continue to quantify the embryonic survivorship of the Oregon spotted frog (Rana pretiosa) from early development through to hatching. This will be done by observing egg mass sub-samples using holding cages set up in- situ near the wild egg mass. Only eggs will be used for the research and after hatching the tadpoles are released at the site where the eggs were oviposited. Number of eggs used will depend on the number of egg masses laid. We estimate that 90-180 eggs will be sampled (i.e. 15-30 eggs from an estimate of 6 egg masses).
  • Explanation for issuing permit(#59-04-0403), persuant to the provisions of section 73 of SARA (2004-08-26)

    The activity involves biological salvage and subsequent removal of a stand of invasive reed canary grass (Phalaris arundinacea). Habitat that replicates Oregon Spotted Frog active summer habitat and critical breeding habitat will be constructed. The project area will be completely contained within a silt fence and there will be no impacts to the main wetland. There are no impacts to downstream habitats. Minnow traps will be used to trap aquatic vertebrate and invertebrate fauna, including Oregon Spotted Frog adults and larvae. Traps will be checked daily and all trapped fauna will be trans-located to the main wetland on the outside of the silt fence.
  • Explanation for issuing permit(#59-05-0276), persuant to the provisions of section 73 of SARA (2005-03-01)

    To measure survivorship, 15-25 eggs are sub-sampled from randomly selected wild egg masses and percent survivorship, time to hatching and rate of hatching can be determined. Where possible, eggs will be collected randomly from different locations of the egg mass to ensure samples are taken from both the outside and inside of the egg mass. The egg sub-samples will be transferred into Nytex cages holding cages and egg development will be monitored in situ, within 1-3 m of the wild egg mass. Cages are visited two to three times per week during the three week period of development to hatching.
  • Explanation for issuing permit(#59-05-0277), persuant to the provisions of section 73 of SARA (2005-02-28)

    This activity involves the following components: 1.Trapping of adult and juvenile frogs at or near oviposition sites using a protocol which the Recovery Team has approved. Trapping occurs after egg-laying has ceased and traps are set no less than 5m from egg masses. 2.Release of captive-reared froglets to the site. 3.Protection of wild egg masses via transfer to in situ containers. 4.Partitioning and removal of a subset of the hatchlings for captive rearing (up to 1560 hatchlings). 5.In situ larval 'headstarting' of 100 larvae in pens.
  • Explanation for issuing permit(#SARA-PYR-2007-0044), persuant to the provisions of section 73 of SARA (2007-04-11)

    The proponents will capture adult Oregon Spotted Frogs, using up to 30 live minnow traps at a known oviposition site. Traps will be set overnight, and checked the following morning, reset, and checked the following afternoon. Traps will be set 3 days a week for up to 4 weeks. All amphibians caught, regardless of species, will be weighed and measured (snout-vent length). Oregon Spotted Frogs will be examined for marks (elastomer dye or Soft VI tags) indicating that it was reared in captivity. All animals will then be immediately released. No animals will be marked in this pilot year.
  • Explanation for issuing permit(#SARA-PYR-2008-0072), persuant to the provisions of section 73 of SARA (2008-03-01)

    The proponents will capture adult Oregon Spotted Frogs, using up to 60 live minnow traps at a known oviposition site. Traps will be set overnight, and checked the following morning, reset, and checked the following afternoon. Traps will be set 3 days a week for up to 6 weeks. All amphibians caught, regardless of species, will be weighed and measured (snout-vent length). Oregon Spotted Frogs will be examined for marks (elastomer dye or Soft VI tags) indicating that it was reared in captivity. All animals will then be immediately released.
  • Explanation for issuing permit(#SARA-PYR-2008-0083), persuant to the provisions of section 73 of SARA (2008-05-12)

    The immediate goal of this project is to acquire a natural resource inventory within the DND ASU Chilliwack. The proponent has demonstrated that compared to lethal and more invasive capture and marking techniques, their methods are either non-invasive or identified as the least-invasive alternative.
  • Explanation for issuing permit(#SARA-PYR-2008-0100), persuant to the provisions of section 73 of SARA (2008-08-21)

    The proponent will electro-fish American bullfrogs, an invasive amphibian species, for removal in three wetlands at MDA Aldergrove, which had a historically abundant Oregon Spotted Frog population that is now in decline (no egg masses have been observed in the subject area in the past two years). The proponent has identified that American bullfrog predation on Oregon Spotted Frogs as an impediment to recovery of this species listed as "Endangered" under Schedule 1 of the Species at Risk Act. Any endemic species will be returned to the wetland and in the event that Oregon Spotted Frogs are observed in the study area during the process, electro-fishing will be halted.
  • Explanation for issuing permit(#SARA-PYR-2009-0115), persuant to the provisions of section 73 of SARA (2009-08-17)

    The proponents will conduct ground surveys of species at risk including, amphibian visual encounter surveys, Oregon forestsnail ground searches, Badger burrow searches, Pacific water shrew habitat ratings, Spotted bat roost searches, snake foraging surveys, Monarch surveys (visual searches for larvae and adults), Great basin spadefoot egg mass surveys and Snake den surveys. No traps will be set and animals will only be handled where it is necessary for species identification and photo documentation. All animals will then be immediately released in the habitat where captured. No animals will be marked.
  • Explanation for issuing permit(#SARA-PYR-2009-0120), persuant to the provisions of section 73 of SARA (2009-09-18)

    Radio-telemetry will be used to determine fate of captive reared Oregon Spotted frogs to assess potential success of population augmentation. Transmitters will be attached to the captive reared frogs using established methods and the frogs will be tracked daily. PIT tags will also be inserted under the skin. Precise locations will be recorded using GPS and hand capture of the frogs will only take place if absolutely necessary.
  • Explanation for issuing permit(#SARA-PYR-2010-0130), persuant to the provisions of section 73 of SARA (2010-03-17)

    Oregon Spotted Frog (Rana pretiosa) and Red legged frog (Rana aurora): 1. Maximum of 10 eggs per egg mass of both species can be collected for genetic sampling to differentiate R. pretiosa and R. aurora. 2. Adults of both species may be collected by hand, swabbed on underbelly and legs with Q tip for purposes of disease evaluation. 3. Adults of both species may be captured by hand, held in buckets containing at least 50 mm depth wetland water and vegetation from the animals' resident wetland, for the purposes of identification of the species through extended inspection of the adults.
  • Explanation for issuing permit(#SARA-PYR-2010-0131), persuant to the provisions of section 73 of SARA (2010-03-25)

    Consistent with Section 73 (2) the activity is scientific research relating to the conservation of the species and conducted by qualified persons and the activity benefits the species or is required to enhance its chance of survival in the wild.

Recovery Document Posting Plans

  • Environment and Climate Change Canada's Three-Year Recovery Document Posting Plan (2016-07-06)

    Environment and Climate Change Canada’s Three-Year Recovery Document Posting Plan identifies the species for which recovery documents will be posted each fiscal year starting in 2014-2015. Posting this three year plan on the Species at Risk Public Registry is intended to provide transparency to partners, stakeholders, and the public about Environment and Climate Change Canada’s plan to develop and post these proposed recovery strategies and management plans. However, both the number of documents and the particular species that are posted in a given year may change slightly due to a variety of circumstances. Last update December 2, 2021
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