We recently added a school of 50 new Atlantic bonito to the Save Our Seas Foundation Shark Exhibit at the Two Oceans Aquarium and were asked an interesting question - why don’t the sharks eat the new fish? Good question - let's investigate!
The first thing to consider is our ethical considerations as an aquarium - firstly, we have the ethical responsibility to ensure that the habitats we provide our animals with are safe and suitable (that means not adding fish to an exhibit where we know they will be eaten), and we also have an ethical responsibility to ensure that the natural behaviours and instincts of animals that will be released back into the wild (in other words, we don't "tame" the sharks). With that in mind, here's how we do it:
Ragged-tooth sharks, as with many of the top-level ocean predators, are incredibly efficient hunters - this means they don't waste energy randomly attacking fish unless they are actually in need of a meal and have a good opportunity to feed, particularly in the cover of darkness in the case of ragged-tooth sharks. What this means is that simply by feeding the sharks regularly, keeping track of their eating habits, and monitoring their behaviours and responding accordingly, our aquarists can ensure that the sharks don't need to hunt the fish they share an exhibit with, and won't take advantage of confused newly added fish after a mealtime. In other words, efficient, well-fed predators are too lazy to chase fast-moving fish!
You may have noticed that certain shark species, like ragged-tooth sharks, are actually quite commonly kept in aquariums around the world. We've already spoken about some of the reasons for this, like their ability to breathe without moving, but it also comes down to feeding habits - predators that live in natural habitats like the deep sea or open ocean may not have the luxury of being able to rely on regular feeding opportunities and may be opportunistic hunters - a trait that would be difficult to ethically compensate for in an aquarium environment. For this reason, aquarium's don't simply collect random fish - very careful planning goes into selecting animals that we know are compatible and can thrive in the environment we provide.
Snack time in the Save Our Seas Foundation Shark Exhibit ��
Nom nom nom!!! ��Everyone loves lunchtime at the Save Our Seas Foundation Shark Exhibit, where visitors get to meet and learn all about ragged-tooth sharks - an iconic South African species (and definitely a Two Oceans Aquarium favourite)! Sea you soon! https://www.aquarium.co.za/ ��: Martine ViljoenPosted by Two Oceans Aquarium on Friday, 27 August 2021
Do things ever go wrong? Absolutely! Although every effort is made to accommodate the natural habits of these animals, sometimes something unexpected happens and a fish gets eaten - loadshedding and failed generators plunging the exhibit into darkness the day before mealtime, a confused fish literally swimming into a sharks mouth (it happens), or a shark simply feeling unusually hungry despite our recordkeeping. Our job is to do everything we can to minimise these incidents.
Finally - fish can protect themselves! By carefully selecting animals that naturally share a habitat, we can also be sure that the prey species that are present have natural behaviours, adaptations and instincts that they can use to protect themselves. The giant kob simply grow too big for a ragged-tooth shark to easily eat. Small mullet quickly regroup their shoals into schools and swim away if they feel threatened. And the beautiful new Atlantic bonito use their fast swimming speeds and disruptive camouflage to form schools that are simply too much effort for the ragged-tooth sharks to pursue!
It's a dynamic system, so next time you're at the Two Oceans Aquarium, be sure to stop at the Save Our Seas Foundation Shark Exhibit to see these interesting animal interactions for yourself!