We've been doing general exploration for Crayfish distribution & natural history in Ontario for the past 35 years, and much of the knowledge of the distribution of Crayfish in Ontario is due to our efforts.

To prototype next year's "Thirty Years Later" expedition, we plan to set off on 10 September 2009 in a survey of places where we've found or suspected the Crayfish Orconectes immunis in the past.

This species, historically known only from southwest of Kingston, has begun showing up in eastern Ontario (fide Eric Snyder), where, as a burrowing species, it has the potential, to displace local populations of O. virilis in intermittant streams in the flat portions of eastern Ontario, where they occupy what is O. immunis' habitat elsewhere.

These O. virilis have what seem to be local adaptations to deal with dry years in temporary streams (shallow burrowing and mass aggregations under flat rocks), so they may be rapidly displaced if O. immunis, with their whole repertoire of burrowing and dried-out adaptations, spread widely from the sites where they are have recently been found. Or maybe not...

It seems timely to revisit places where we and others have previously found Orconectes immunis beyond its contiguous range, and to survey intervening sites to see if it can be found elsewhere.

Frederick W. Schueler & Aleta Karstad
Bishops Mills Natural History Centre

Contact us by phone at (613)258-3107
or e-mail bckcdb@istar.ca last update - 5 Aug 2009 - fws.

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Thirty Years Later:

Revisiting Orconectes immunis localities Thirty Years Later.

Frederick W. Schueler, Adam Zieleman & Aleta Karstad - Bishops Mills Natural History Centre

[Aleta's painting of Orconectes immunis]

Orconectes immunis, the Papershell or Calico Crayfish, is a small to medium- sized crayfish that is slender and fragile looking. It is distinguished from other Ontario Orconectes by a notch at the base of the inner side of the dactyl of the chela. Colouring is olive- green to brown with characteristic dorsal mottled pattern and no colour bands on tips of chelae. It is found in slow moving streams, ponds and lakes, marshes and roadside ditches. It can construct deep burrows and as a result is able to survive in temporary waters. Its contiguous distribution in central Canada is Ontario south of a line between Kingston and the Bruce Peninsula, but scattered records north of there may be either due to a poorly documented natural distribution, or introductions by bait fishermen. (modified from Premek Hamr's account of the species).

[northern records of Orconectes immunis]

This map shows northern sites where we or others have found Orconectes immunis. The truncations of locality names are our records, the "QUE_" ones are from the Québec database (from Jean Dubé), the "L_" lakes are from Brie Edwards and Keith Somers lake surveys, and the "PH_" sites are from Premek Hamr.

Our planned route for our revisits is to go north from Ottawa to Parc de la Vérendrye, where we (unwittingly) took the species in 1974 before it was "known" from Québec, to other Québec sites supplied by Jean Dubé, and then to the Ottawa River near Thorne, Ontario, and Témiscaming, Québec, and to Crab Lake, south of Cartier, where we've found O. immunis in the past. We'll then come across Mantoulin and down the Bruce Peninsula, or home by some other route, depending on the time things have taken, the weather, and other considerations.

Crews from South Nation Conservation will be surveying the Moose Creek (MOOSEC) site. If anyone has extralimital records of O. immunis that they'd like to have checked out, we'd be glad to add them to our list of candidate sites.

[Aleta's painting of Orconectes immunis]