Merv Cooper's motto is "a house is not a home without a hermit crab".
Surrounded by thousands of "chirping" crabs inside his Rockingham store, south of Perth, Mr Cooper says people line up to get their hands on the quirky "low-maintenance" pet.
"They're a bit noisy; some of them chirp, mainly at night-time," he said.
"[We've got] about 5,000 crabs in stock, which will change hands over the next three or four weeks, and then we'll get some more."
The former pearl diver has been collecting and exporting the popular Australian land hermit crabs for the pet industry for more than 40 years and holds Western Australia's only license to export the crabs overseas to Hong Kong, the United States and Korea.
He also supplies up to 50 pet shops in Western Australia and about 20 pet shops in the eastern states.
Mr Cooper, who has one of only five crab collecting licences in WA, gathers thousands of the crabs in their shells from the wild on the state's northern beaches near Exmouth where this species of hermit crab — Coenobita variabilis — is endemic.
He registered the name Crazy Crabs nearly 40 years ago, popularising the creatures as attractive and unusual minimal maintenance pets.
Mr Cooper said the low price, about $5 for a small crab, made them an ideal first pet for children and families.
"They're not hard to look after, they're educational," he said.
Mr Cooper said some crabs he had sold to families had survived for up to five years.
"They nip every now and then to keep the kids on their toes, you might say, and you can have five or six in a small tank that we supply."
Concerns about pet's 'disposable' nature
But there are concerns that because they are considered "quirky", hermit crab pets are not taken seriously.
WA Museum curator of crustacea Andrew Hosie said sometimes the pet was seen as expendable.
"They certainly are quirky [but] there's the perception they are a simple species to keep as a pet," Mr Hosie said.
He said people did not realise that in the wild the crab could expect to have quite a long life.
"They can live for more than 10 years when kept well, but people don't expect them to live for that long either.
"People will generally expect they may last a couple of years, and because they're not necessarily that invested in the animal, then the animal's death isn't necessarily seen as a big problem.
"But around Perth, if you're not careful in the winter, you may find that the temperatures drop a little bit too low for them, which can certainly result in them becoming very sluggish.
"And they may try and bury themselves in the sand and kind of insulate themselves. And then you do run the risk of them getting too cold and dying."
Mr Hosie also said overcrowding in a single tank could also be problematic for the animal.
Need for hermit crab rescue service
Pet shop worker Clare Fullston started an online hermit crab rescue group when she noticed customers had a lack of knowledge about what the crabs required to survive.
Ms Fullston said people often surrendered crabs they could no longer look after.
"They're a hands-off pet. Kids end up finding them boring because they aren't supposed to handle them, and they tend to bury themselves down in the sand.
"Kids want pets that they can have out on their lap and hold, but doing that suffocates and stresses them because they've got modified gills.
"It's really like having a scorpion, a fish or a tarantula as a pet. You look at them and enjoy them but you don't really handle them.
"I mean, you don't get a fish out and start patting it — but they are very interesting to watch."
Crabs abundant in the wild
According to WA Fisheries, about 80,000 crabs were collected by two active operators in 2020.
While the value of a hermit crab licence was difficult to estimate directly, Fisheries estimates it is between $1 million and $5 million.
Mr Cooper said collecting crabs could be quite hard work.
"[I collect crabs] at 12 o'clock at night. The tide is out, there's no rain and no wind when it's very hot," he said.
"As the tide goes out further you start falling into 150 millimetres of sand and you start walking around with buckets to pick these crabs up. It gets very heavy," he said.
"So you know you've worked when you've done five or six hours.
"We only go to our spots once or twice a year so [the population] gets a chance to build up."
Hermit crabs lay their eggs in the ocean so are unable to be bred in captivity.
Tim Nicholas from the WA Department of Primary Industries and Regional Development said the number of individual land hermit crabs taken had decreased since the early to mid-2000s, when catches were about 100,000 crabs per year.
He said despite the number of crabs collected from the wild, the species was abundant.
"Given the large area in which the species is distributed, their early maturation and long life, the biomass of the land hermit crab is unlikely to be impaired by the current level of fishing," Mr Nicholas said.
But Ms Fullston said people should do their research before taking on a wild-caught crab.
She said people were often shocked to hear the crabs needed a more complex tank set-up than the small plastic boxes they were sold in at pet stores but the correct information was available online.
"People are realising actually these little creatures do need more care than they think," she said.
"I want to make a point that no animal is a throwaway pet."
