The Voyages of The Largest Fish in the World – oceanbites

Gallimore, C. G., Walton, C., Nugent, R., Fradkin, M., Poppell, L., Schreiber, C., Coco, C., Grober, M., Carlson, B., Dove, A. D. M., & Black, M. P. (2024). A longitudinal behavioral evaluation of aquarium whale sharks (Rhincodon typus): Insights into anticipatory cues, particular person variation, and social interplay. Frontiers in Marine Science, 11, 1418002. https://doi.org/10.3389/fmars.2024.1418002

Male whale shark at Georgia Aquarium Image credit: Zac Wolf through Wikimedia Commons 

The Largest Fish in the World

The whale shark, scientific title Rhincodon typus, is the largest residing fish species, making it uncommon to seek out in aquaria. 

In the wild, the whale shark is susceptible to a quantity of human threats, equivalent to boat strikes and fishing, and is due to this fact categorised as endangered on the IUCN Red List.

Whale sharks are filter feeders, that means they eat by straining food from the water as they go by it. They additionally eat vertically, that means that they flip into a vertical place and assault their prey from beneath, mostly capturing crab and fish larvae, mollusks, and different crustaceans. 

Only 10 aquaria in the world have ever hosted whale sharks. The Georgia Aquarium is home to the Ocean Voyager exhibit, which homes a number of whale sharks and gives guests the alternative to swim with them. In this examine, researchers use the Georgia Aquarium’s 6.3 million gallon whale shark tank to look at the whale sharks’ behavioral patterns, assessing metrics equivalent to depth, swim velocity, lead-follow interactions, and diver presence in order to higher perceive their conduct and social construction and evaluate their outcomes to wild whale shark conduct.

The Sharks in the Unbelievable Ocean Voyager Exhibit

Researchers carried out examinations of the whale sharks in the Ocean Voyager tank each six months, in which they measured the weight of every animal and the size of numerous physique components and fins.

Whale sharks have been fed twice a day with krill, silverside fish, squid, and vitamin dietary supplements. 

Over a 4 yr period (2008-2012), volunteers and interns logged over thirty thousand observations of metrics equivalent to depth, swimming velocity/direction, and lead-follow interplay (social exercise in which one whale shark leads or follows one other). Simultaneous recordings taken by totally different observers have been in contrast to make sure that their notes have been constant.

Swimming velocity was measured based mostly on the quantity of time the shark took to go a quantity of four-foot panels. Swimming direction was categorised as clockwise or counter-clockwise. Lead-follow interactions have been categorized relying on the distance between the two sharks concerned, their positioning, and whether or not they have been main or following.

The Voyages of the Whale Sharks

Each of the 4 whale sharks exhibited their own distinctive conduct patterns, with totally different swimming velocity averages. One shark strongly most well-liked clockwise swimming, two sharks mildly most well-liked clockwise swimming, and one swam in each instructions virtually equally. 

All 4 sharks tended to increase their velocity roughly half-hour earlier than feeding instances. They additionally all frequented the high depths of the tank far more than the backside depths. Interestingly, nonetheless, every particular person differed vastly from the others in their depth frequency. 

In phrases of lead-follow interactions, one shark led more than it adopted. Three of the sharks confirmed patterns in their interactions, whereas one shark’s lead-follow patterns didn’t differ from random, suggesting that he might not have had important interactions or relationships with the others. 

Finally, the researchers discovered that whale shark swimming speeds elevated when diving guests weren’t in the tank. 

Greater Cleveland Aquarium 01-22-2015 – Shark Tank Diver 5. Image credit: David Ellis through Flickr Creative Commons 

How Does the Ocean Voyager Represent the Real Ocean?

While this examine gives novel insights into the behavioral patterns of whale sharks, it’s important to notice that an aquarium setting may be very totally different from the wild. An extra limitation in this examine is that observations have been solely made in the day time. 

Still, the swim velocity of the whale sharks in this examine was per the world average. Wild whale sharks, like the sharks in this examine, are additionally discovered to stay close to the floor of the water round 50% of the time. 

The increase in swim speeds of whale sharks previous to feeding instances is probably going a consequence of classical conditioning (when a stimulus results in a discovered response), since the feeding of different members of the Ocean Voyager exhibit have been fed at this time, and the sharks due to this fact knew to anticipate their food coming. This kind of studying conduct, together with a highly effective sense of scent, has been noticed in a quantity of shark species, growing the probability of such a connection between swimming velocity and feeding instances. 

Whale shark encounter off Caribbean coast of Panama. Image credit: NOAA Photo Library through Flickr Creative Commons 

So What?

Better understanding of the whale shark’s behavioral patterns is essential for informing management choices for the endangered species. Additionally, the insight into their social interactions supplied by this examine can information choices relating to their humane remedy in aquaria globally. In explicit, the conclusion that the presence of divers in the tank solely influences swim velocity, which is suspected to lower in an avoidance try by the sharks, might trigger marine biologists to rethink the determination to permit divers into the tank in any respect.

In normal, studying more about a species can solely help scientists and policymakers make good conservation choices and educate the public about how their interactions with wildlife can have an effect on the ecosystem.