05 August 2023

Be on the lookout for Marmorkrebs, Ontario! Marmorkrebs finally found in North America

Marbled crayfish recovered from pond in Burlington, OntarioBurlington Today is reporting that Marmorkrebs have been found in Burlington, Ontario.

The details are hazy.


Marbled crayfish – an aquatic invasive species that is prohibited in the province – has been found in the Burlington area.


That’s the extent of actual reporting. The rest of the article is background information.

Edit, 6 August 2023: A Burlington Post article is a little more expansive.  It gives a general location (a city park).

Previously, another marbled crayfish was reported in the area on iNaturalist. (I actually went to where the iNaturalist sighting was to look around, but heard people had already looked and found nothing.) 


This Burlington marbled crayfish sighting is also on iNaturalist, from Premek Hamr, also known as “Dr. Crayfish.” Premek has extensive experience with Ontario crayfish, so it’s not as though this is an Ontario native being misidentified.


On Twitter, Hamr has been sharing pictures of multiple individuals, including juveniles. This indicates there is a breeding population at this location.


Ontario just banned marbled crayfish last year.

While this is a watershed moment in the worldwide invasive status of marbled crayfish, it is something that has been expected for a long time. It’s mostly surprising in that it didn’t happen a few years ago.

The map of Marmorkrebs introductions has been updated.

External links

Marbled crayfish sighting in iNaturalist


Premek Hamr on Twitter: Onetwo , three, four


Be on the lookout for marbled crayfish in the Burlington area (Burlington Today)


‘Capable of cloning’: Invasive crayfish found in Burlington pond (Burlington Post)

‘Capable of cloning’: Invasive crayfish found in Burlington pond (Hamilton Spectator

Ontario Natural Resources and Forestry on Twitter

Related posts

Ontario prohibits Marmorkrebs

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