by Autumn Wang
This summer, I joined the Shaw Centre for the Salish Sea as an Assistant Educator. My favourite part of the job is being able to observe a lot of the animals. The aquarium exhibits can bring animals closer, especially the smaller creatures that are hard to spot in the wild. The acrylic makes observation easier by providing a different angle and perspective (you can see underneath animals!). I also saw some unique behaviours I learned about in my courses. Here are some of the cool things I got to see this summer.
Northern abalone radula
Abalone Eating
Have you seen an abalone eat? They have two rows of teeth on a structure similar to a tongue! This is called a radula. Abalone press their mouth against the surface of rocks and other hard substrates. Then, they scrape the surface with their chain of sharp teeth. What are they eating? Algae! This grazing leaves behind marks that look like two white lines and you can follow the trails to see where the abalones have been. Other animals also have a radula for eating including turban snails, limpets, chitons and many more. On your next visit, take a closer look at the abalones or other animals pressed against the glass and watch the radula moving in and out to graze.
Moon jelly
Moon Jelly Feeding
You might wonder, “How does a jelly eat when they don’t have a mouth?” Jellyfish use small hairs called cilia, located on their tentacles, to move food directly to the stomach. The moon jellies at the aquarium are fed sea monkeys which are microscopic shrimps. The moon jelly first uses the stinging cells in their tentacles to sting and hold onto their prey. Then, the cilia gather the food into a small pile, and move them into the stomach. As you watch, the horseshoe-shaped stomach will gradually fill up, and become the colour of their prey.
Rough keyhole limpet
Limpet Eye Spots
Have you ever seen the eyes of a limpet? When you look closely at the base of their tentacles, you may see small black dots which are their eye spots. They can’t see us with their eye spots. But those eye spots are very important for telling day and night, and for detecting predators. Eye spots can sense the changes in the amount of light. When predators pass by, their shadow casts over the limpet, eyespots sense the sudden light change, and the limpet will hide in its shell until the predator is gone. Try looking for the eye spots of limpets. Can you find other animals that also have eye spots?
Leather star
Underside of Leather star
Have you ever taken a look at the underside of a sea star? If you look closely, you might find smaller creatures that call this place home. Sea fleas and skeleton shrimps are some of the small animals you may find. The sea stars provide shelter for these animals. Some worms also live under the sea star. They use the sea star as a shelter, and will defend the sea star when there are predators around. This commensal relationship is found in many other animals, where both organisms benefit from each other. For example, worms living on shells of shellfish, or sea anemones living on crab’s exoskeleton. When you look into an exhibit next time, can you spot any animals living together?
Basket Star
Have you seen the Centre’s basket stars? They often cling on to the rope in their exhibit and can be hidden out of view. Many visitors will walk by the exhibit without noticing them. Basket stars are related to brittle stars so you might notice some similarities. They have long and skinny arms that are used for locomotion and catching food. Most of the time you might see them curled up on the rope. When the basket stars are feeding, they will extend their arms out, looking like a net or basket, and use their arms to catch food that drifts by. Try looking at some of our exhibits from a different point of view, like the inside of an empty shell, behind a rock, in the corner of an exhibit. Maybe you can find some something you didn’t notice before.
Shrimp Carrying Parasitic Copepod
Is that shrimp carrying eggs? That was what I thought at first. After a closer look, I realized it is carrying a parasitic copepod. Unlike other copepods that live their life floating in the water as a plankton, these copepods will find an animal that will take care of it. They trick the shrimp into thinking they are the eggs, and the shrimp will carry the copepods under their abdomen and provide nutrients for them. Shrimps are not the only animal the copepods target. They will also infect crabs and other decapods.
Our aquarium is home to a lot of fascinating creatures. Some just take a bit more effort to find than the others. When you visit us, or other aquariums, try looking at the exhibits from a different point of view. I’m sure you will have some exciting discoveries. If you are a big marine nerd like me, I strongly recommend bringing a magnifying glass with you, it will open a whole new underwater world.