The waters off N.L. are crawling with all kinds of crab — and commercial potential

With 2,322 licensed inshore harvesters hauling in 26,400 tonnes of coveted crustaceans last season, Newfoundland and Labrador's snow crab industry is the most lucrative fishery in the province.

But did you know there are other crab species fished commercially in waters off Newfoundland and Labrador? In fact, the ocean off our coast is quite literally crawling with a wide variety of crab.

Darrell Mullowney, a research scientist with the shellfish section of the Department of Fisheries and Oceans, studies the crab family tree of species.

"Toad crab is a cousin of the snow crab, only smaller," said Mullowney.

Mullowney describes the toad crab has having a darker shell than the orange shell of a snow crab, and its body is longer than it is wide.

"They look like pears. If you took the animal and you were looking at it with the nose up and you kind of squeezed your fingers in around where the bottleneck on a pear would occur, they're kind of shaped like that."

The toad crab fishery started in the early 2000s, possibly because harvesters were looking for other species to fish in the wake of the cod moratorium. From 2001 to 2005 harvesters took 1,200 tonnes of toad crab from the water every year, but its popularity has declined. Since 2015, the average annual catch has been from 200 to 400 tonnes. 

Another species of crab fished commercially in Newfoundland and Labrador is the rock crab, which Mullowney said he considers one of the most unappreciated animals in the province.

"We all recognize them as those those crab shells that are on the beach or walk along basically any beach in Newfoundland and Labrador," he said.

Mullowney says the rock crab has incredible range as it lives in waters as far south as South Carolina, as far north as Iceland, and can be found living along the shoreline or in depths of up to 750 metres. The rock crab can also tolerate an incredible temperature range, from about –2 C to 30 C.

"The colour variance can be quite expansive as well. Kind of yellowish orange to purple-brown tones, depending on the environment that it happens to be living in. So it has a lot of has a lot of traits that are very unique."

In terms of fishing, harvesters catch between 20 to 100 tons of rock crab each year. 

In both the toad crab and rock crab fisheries, the shellfish is caught in the same way as snow crab.

"It's a modified snow crab pot … to get them, basically, with smaller mesh, so there are regulations on the pots. They are male-only fisheries and have a minimum legal landing size," said Mullowney.  

There are just three commercial crab species in Newfoundland and Labrador: snow crab, toad crab and rock crab. 
But Mullowney says there are definitely other species with commercial potential. 

"The southwest part of the Grand Bank is a very special place for crab species in Newfoundland and it's incredibly diverse. It's influenced by the Gulf Stream water and so it's where most of our diversity occurs."

Mullowney says there are 10 to 12 different kinds of crab species living in this area at different depths and temperatures.

"A giant crab would be down there, with perhaps some commercial potential at some point in time."

Mullowney says there's also a species living there that goes by a few different names: northern stone crab, spiny brown crab or brown king crab. 

"It's kind of a slope edge- or a fjord edge-living creature, just like the king crabs that you would see in the Alaskan fishery, only smaller."

Mullowney says there have been several trials to get a commercial fishery going on that particular edge-dwelling crab but there have been difficulties in getting high catch rates. 

Then there's the porcupine crab, which is a variant of a king crab. 

"They've got great big spines on them but, again, trials on fisheries have found it difficult to get suitable catch rates," said Mullowney.

Despite the fact that commercial fisheries haven't been successful yet, Mullowney sees great potential for some of these quirky crawlers in the ecosystem, and observing crab species provide opportunities for tracking climate change.

"This is the stuff for young biologists to look at, the diversity," said Mullowney.

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