For some years the Vancouver Aquarium in Vancouver, BC has been breeding fish and other aquatic animals for conservation and research purposes. Now the popular facility is looking at rockfish and wolf eels as potential species for aquaculture, and so far so good.
According to Shannon Balfry, Director of the aquarium’s aquatic-animal breeding program, the program started when she was studying aquaculture at the University of British Columbia and working with the aquarium’s research personnel through the federal Department of Fisheries and Oceans’ Centre for Aquaculture and Environmental Research (CAER) West Vancouver laboratory.
She said that wolf eels are still held at the West Van Lab, while the rockfish are kept – until spawning time at least – in regular display or exhibit tanks at the aquarium. The aquarium has its own special breeding and research laboratory that contains 2,000-litre tanks and a dozen or so smaller 200-litre ones.
Apart from their shape, says Balfry, there are some notable differences between the two species, both of which are cold-water marine fish that grow to maturity comparatively slowly, taking between five and seven years to start to spawn.
Balfry said that the rockfish larvae are fed live feed grown on-site – enriched rotifers and artemia, and some copepods. They are fed three times daily – twice during the day and in the middle of the night when an automatic feeder provides their feed.
“The wolf eels take to pellets right away, so feeding them is relatively simple in comparison with the rockfish,” Balfry said. They are fed twice a day.
Balfry also said that the two types of fish behave very differently. The wolf eels cluster together in the bottom of their lidded tanks, until someone takes the lid off the tank to feed them and they come charging to the surface. They don’t need a second call for dinner.
“It can be quite startling at first,” Balfry said. But despite their sharp teeth wolf eels are not aggressive.
Belfry’s favorite is an easy-going, affectionate two-meter long wolf eel named Oscar which has been held for about 20 years. She added that the aquarium now has a broodstock of about 65 pairs of wolf eels.
Balfry also said she’s been pleased with the growth rates for both wolf eels and rockfish in the aquarium’s studies using different diets. When the rockfish went out to a fish farm for on-growing assessment, they grew from about 20-30 grams to around 200 in just over a year.
She said she noted that in some of the local Chinese supermarkets customers can buy eels live from tanks, at around 250 grams.
The aquarium has been successful growing black and China rockfish, and recently sent over 100 copper rockfish to Totem Sea Farms for ocean study.
– Quentin Dodd