A federal government invasive species expert believes the Asian crab found Monday in Cootes Paradise must have been deliberately released, possibly for religious reasons, by someone who smuggled the creature into Canada.

Becky Cudmore, of Fisheries and Oceans Canada, says it's the only reasonable explanation for the sudden appearance of the adult Chinese Mitten Crab that was found at the Cootes Paradise Fishway Monday.

In some belief systems, she says, if you release "a very highly valued organism, a long-lived organism or hardy organism into the wild ... it provides points for your karma afterlife."

The live crab was captured at the RBG-operated fishway between Hamilton Harbour and Cootes Paradise, and handed over to Fisheries and Oceans. The fishway is designed to block carp from the ecologically fragile Cootes marsh and allow other native, desirable fish species to pass through.

Cudmore feels the crab could not have been accidentally introduced to Hamilton Harbour through ballast water in a ship, as is sometimes the case with invasive species, because of strict ballast monitoring and the fact that it was an adult.

But Hugh MacIsaac, an invasive species expert from the University of Windsor, disagrees. He believes the crab, as a larva in saltwater, could have been carried by the ship into the freshwater lakes where it was released and grew to its adult size.

The crab is unique in that it lives in saltwater and freshwater at different stages in its life. It will only reproduce in saltwater so there is no risk of offspring in Hamilton Harbour from the crab that was found, he said.

There have been 24 Chinese Mitten Crabs recorded in the Great Lakes between 1965 and 2007, says Cudmore. The one found Monday is the first since 2007 in the Great Lakes and the first ever in Hamilton Harbour.

"It is a very valuable food item in some markets," says Cudmore. However, the Canadian Food Inspection Agency does not allow the crab to be imported out of concern over a parasite it carries that can be harmful to human health.

Cudmore says the crab from the fishway has been preserved and will be used for "educational purposes" to try to dissuade people from placing non-native species in Canadian waters.

- Invasive crab makes strange appearance in Cootes Paradise