TRU researcher has hopes that the species can make a comeback
Through the 70s and 80s, northern abalone were a prized delicacy from the sea. People were willing to pay a premium price to have the exotic sea snails on their dinner plates. By 2003, however, abalone had been overharvested and the Canadian federal government declared them an endangered species, protected under the Species at Risk Act.
“They’ve put on that endangered list and the harvesting stopped, but the populations still have not rebounded,” marine biologist Louis Gosselin explained.
Gosselin is a TRU professor who specializes in marine invertebrate species like sea stars, crabs and snails. He has been studying the northern abalone for years and, by the end of this decade, he hopes to discover a viable strategy for restoring their population among Canada’s Pacific coast.
“Abalone are part of the natural ecosystem, and if we’re protecting abalone, we’re protecting all the other species that depend on them as well,” Gosselin said.
“The abalone population densities are so low right now that on average there’s about one abalone per five or six square meters. When the population numbers are low, males and females do not meet each other, and you need them meeting each other for them to breed.”
In an attempt to repopulate the abalone populations, one potential strategy researchers have considered is a practice known as “outplanting.”
“Some people think that if the populations in the wild aren’t doing too well, then maybe what we could do is bring them into a hatchery, breed them in a hatchery artificially, and then put them back into nature after a certain age,” Gosselin explained.
He put this idea to the test, conducting a study from the Bamfield Marine Sciences Centre on Vancouver Island. The study used scuba divers to take adult abalone from the wild, bring them into a laboratory and get them to spawn. The resulting offspring were then raised in the lab, in some cases for as long as two to three years. During this time, humans fed the lab-bred abalone a diet consisting of algae, seaweeds and kelp.
When the time came to introduce the abalone to the wild, scuba divers marked and tracked individual abalone to study their progress over time. Gosselin concluded that, while outplanting makes sense in theory, the figures in his research said otherwise. About 60 per cent of the outplanted abalone he studied died within their first two weeks in the wild.
“Within a year, you’re lucky to find one per cent still surviving,” he said.
In comparison, he said wild abalone in similar conditions would lose less than one percent of their population within the same two-week span, and over the course of the year 60 to 70 per cent of the population would survive.
“There is still mortality, but the [wild abalone] population can persist and sustain itself.”
Gosselin then conducted studies to examine why this was the case. He found that the lab-bred abalone never learned to detect or defend themselves against the kinds of predators they would encounter in the wild.
“They’ve lived in an environment where there are no threats or predators,” he explained. “Whenever there’s something moving around them it’s a person coming to feed them.”
“In the wild they’ve been exposed to odours and contact with predators. They don’t get fed, so movement to them is a bad thing, not a good thing. They hide, clamp onto rocks, and avoid predators, so their survivorship is much better.”
“We found that the ones coming from the lab stay out in the open. They don’t hide if there’s a shadow or if something touches them.”
Gosselin suggested that outplanting could still be a viable solution if researchers could somehow train the lab-bred abalone to do a better job recognizing and responding to threats. Researching the viability of this concept is one of his upcoming research projects.
“This might mean having tanks that contain abalone next to tanks that contain predators like sea stars and octopi,” he explained. “Or, if we could have them in the same tank, but with a separator, then abalone could learn smell the predators. Abalone don’t see very well but they can detect predators by smell.”
“One of the tricky things is that to keep the abalone in the lab, you have to feed them, and when you’re feeding them that creates shadows and disturbances in the water.”
To work around this problem, he said researchers could stress the abalone on occasion to help make them uncomfortable with shadows, but Gosselin said that it might take a few more years to know exactly how to do this.
Gosselin hopes that one day, a sustainable harvesting practice might once again be possible.
“At the very least, it would be nice to let the First Nations bring abalone back into their traditions. It’s actually a species that’s been used extensively among the First Nations in the past. They used the insides of abalone shells [mother of pearl] in jewelry, in decorations and at one point even as a currency. Abalone were also used as food, and they used to be so abundant that, at low tide, First Nations people could just go down to the shores and collect them. You can’t do that anymore, there are no abalone at low tide and you have to go much, much deeper to find them.”
“If we can save the species, it’s a win-win for everyone.”