Can you eat crayfish from the North Saskatchewan River?

In Canada they are called crayfish, in the USA crawfish or crawdads, and in Australia yabbies.

Whatever you call them, the lobster-like freshwater crayfish may be closer than you think. These animals scurry and spread throughout Alberta’s waters – and have even taken up residence in the North Saskatchewan River in recent years.

CBCs Edmonton AM I checked with Heather Proctor, a biologist at the University of Alberta, to find out more about the arrival of lobsters in Edmonton’s waters.

This interview has been edited for length and clarity.

Are there crayfish in the North Saskatchewan River?

Yes, there really is. And that was a surprise for me when I saw them there for the first time.

The history of crayfish in Alberta is complicated. Until 1991, crayfish were restricted to the Beaver River basin northeast of Edmonton. And even then, there were concerns that the crayfish species, Faxonius viriliscould actually become extinct in Alberta because its habitat was so restricted.

When I returned after about a decade of absence and found them in northern Saskatchewan, I was completely surprised.

What was their ability to survive and spread throughout the system? How did this happen?

Well, it’s still partly a mystery.

Every body of standing water, including many of Edmonton’s stormwater retention basins, has had crayfish end up there because people have released them there, either intentionally because people like crayfish – they’re kind of cute and possibly edible – or perhaps because of the movement of bank reinforcements that may have just accidentally carried them around.

Heather Proctor is a biologist and science professor at the University of Alberta. (Therese Kehler/CBC)

But in northern Saskatchewan and also in the Battle River drainage system, they seem to have migrated up on their own for some reason.

Obviously some species are native to the province and others are not. What is the risk of more crayfish being found in more waters?

This is certainly a major concern for fish and wildlife authorities and other ecological and environmental organizations.

The only species we have in Alberta that is technically native is Faxonius virilis – the northern crayfish – and it is also native to Saskatchewan, Manitoba, Ontario and probably Quebec.

The species is also native to the northeastern United States, so it could reasonably be found in Alberta, although not in as many waters as it currently does due to human migration.

Other species, the rusty crayfish or Faxonius sylvaticaand with many pet species that you may be able to purchase at pet stores, there is concern that they will escape or be deliberately planted in certain locations.

And you may be wondering why: Crayfish are very voracious omnivores. They can eat plants and animals. They like to eat trout eggs that they find on the bottom. And when they eat aquatic plants, they can make a body of water quite muddy.

If people want to catch crayfish or something similar, are there any rules about that?

Basically, wildlife fishing regulations state that you can catch crayfish without a permit if you just use a net or grapple to catch them. You need a permit if you use a baited hook.

However, it is not permitted to take crayfish alive away from the place of capture; they must be killed on site and not relocated.

So how do you kill them?

If you have an amazing ability to boil water at your fishing spot, that would be the quickest and most humane method. Like almost all invertebrates, they have a ventral nerve cord, so you could probably stab them in the chest and kill them instantly that way.

Can we eat the crayfish in the North Saskatchewan River?

Yes, they are edible, but I wouldn’t recommend making a bouillabaisse out of them straight away, as they are of course completely covered in all kinds of slime and also have their intestinal contents – and who knows what they have eaten.

If you want to cook them, people who live in real crayfish territory in the southeastern United States recommend what they call a purgative cure. You put them in cold salt water, which makes them empty their bowels and vomit. And then when they start to purge themselves that way, you can use a kind of bouillabaisse method.

Or you can just cook them, crack them open and eat them like regular lobster meat. And that’s probably the safest method.