Fish play diverse and significant roles in our society. Several hundred billion are farmed and caught for food each year around the world. Here in Canada, they are the third most popular pet after cats and dogs, and the third most common research model after mice and birds. Each year, nearly 20 million are caught recreationally in British Columbia, the third highest in the country.
Even though they are widely used, fish are not very well understood — or appreciated. “We have a hard time relating to them,” says Meghann Cant, animal welfare educator for the BC SPCA. “We seem to have so little in common with them that it’s easy for us to believe they’re just primitive, instinct-driven animals.”
However, in recent years, this traditional view of fish as unthinking, unfeeling automatons has been challenged. Thanks to researchers studying fish around the world, we are discovering more about their mental and emotional capacities all the time. Here are just a few examples that speak to the complex abilities found in fish:
Fish have social lives
Bluestreak cleaner wrasses provide a special cleaning service to other fish. The wrasses swim into the gills and mouths of their “clients” to remove and feed on their parasites. “In some cases, their clients are fish who would otherwise eat them,” says Cant. The wrasses can remember more than a hundred individual clients of all different species. They can also recall how well their last interaction with each one went.
Studies have shown that being stroked by cleaner fish is not only a pleasurable feeling for client fish, it also helps them to relieve stress. “It’s like a therapeutic massage,” says Cant.
Fish are great communicators
Elephantfish communicate using electricity. Through unique electrical signals, they can tell each other apart. “These signals say how old they are, how big they are, how far away they are and even whether they’re male or female,” says Cant. Males use them to serenade females, and pairs sing duets together.
Groups of knifefish, another type of electric fish, can even change frequency to avoid jamming each other’s signals. One scientist who studies them, says Cant, has made these signals audible, and likens the adult knifefish to violins and the younger ones to flutes.
Giant moray eels and Red Sea coral groupers often hunt together. First, the groupers make gestures to ask the eels to join them on a hunt — a kind of sign language, says Cant. Then, once out hunting, they adopt complementary roles: the eels can squeeze into crevices too small for the groupers, while the groupers are faster swimmers in open water. Working together, the pair has a better chance of catching something to eat. “Groupers will also ask octopuses to hunt,” says Cant. “Apparently, the octopuses catch on a little quicker than the eels do.”
Do fish really have three-second memories?
At low tide, frillfin gobies stay close to shore in tide pools to feed. When a predator such as a heron comes along, they escape by leaping into an adjacent pool. They are remarkably accurate; missing a jump would mean being stranded on the rocks. Frillfins are able to leap from pool to pool by memorizing the layout of the tide pool while swimming over it at high tide. All it takes is one try to create this mental map — and they can still remember it more than a month later. “The forgetful Dory from the movie Finding Nemo is far from reality,” says Cant. “Fish have excellent memories.”
Daffodil cichlids live in extended family groups. The group is made up of a large male and a large female — the dominant pair who do all the breeding. The rest are smaller helper fish. Many of the helpers are the offspring of the pair. They stay behind to defend the group’s territory and care for their younger brothers and sisters.
Can fish play?
The spontaneous nature of play makes it a difficult behaviour to observe in the wild. However, in captivity, white-spotted cichlids have been seen playing with objects such as floating thermometers, swirling around them and batting at them. “It’s reminiscent of kids playing with those punching bag clowns weighted at the bottom to bounce back,” says Cant.
Fish are good learners
With incredible aim, archerfish can shoot powerful jets of water out of their mouths to knock down insects flying above them. They learn this impressive skill by watching and copying other archerfish.
More recently, it was discovered that archerfish can recognize human faces and tell them apart. “What’s even more impressive,” says Cant, “is the fact that the fish can still identify people when their faces are turned away from them.”
What does this mean for fish welfare?
Given the varied roles they play in our society — as pets, food, entertainment and research subjects — fish are by far the most used vertebrate on Earth. “The scientific evidence is now weighted in favour of fish as thinking, feeling creatures,” says Cant. “Perhaps it’s time we put the debate to rest and turn our attention instead to how we can improve their lives.”
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