These create the opportunity for photo-identifying individual sharks and have enabled non-invasive population, movement, and growth studies on the species in the Caribbean region and elsewhere.ĭISTRIBUTION, ABUNDANCE AND CONSERVATION STATUS It feeds on plankton, small squid or fish.Įach whale shark has a characteristic and unique white-spotted pattern on their dorsal surfaces. The whale shark is one of only three known filter-feeding shark species. While they have a large litter with 300 pups, their pups emerge free-swimming at a small ( 50–70 cm TL) size, and are assumed to face a high initial mortality rate. Whale sharks reproductive cycle is likely to be biennial, at a minimum, and probably longer. Longevity is currently unknown, as whale sharks appear to have determinate growth, but the species has been validated to attain at least 50 years old, and maximum age may exceed 100 years. Maturity is attained at 9–10 m TL in females (estimated to be reached at 30–40 years) and 7–9 m in males (estimated at 25 years). Whale sharks are the largest of all fish, with a maximum total length (TL) of 18–20 m. Sci, published online Septemdoi: 10.3389/ : Requin baleine Whaleshark (Rhincodon typus)©Pedro Vieyra Asymptotic Growth of Whale Sharks Suggests Sex-Specific Life-History Strategies. The findings were published in the journal Frontiers in Marine Science.

“This paper has really re-written what we know about whale shark growth.” “Learning that whale sharks plateau in their growth goes against everything scientists previously thought,” Dr. “They gather to exploit an abundance of food so they can maintain their fast growth rates.” “The finding also explains why gatherings of whale sharks in tropical regions are made up almost entirely of young males,” Dr. And that’s a real worry for whale sharks.” “If you’re a very slow-growing animal and it takes you 30 years or more to get to maturity, the chances of disaster striking before you get a chance to breed is probably quite high. “The discovery has huge implications for conservation, with whale sharks threatened by targeted fishing and ships strikes,” he added. “So these giant females are probably getting big because of the need to carry a whole lot of pups.” “That’s a remarkable number, most sharks would only have somewhere between two and a dozen.” Only one pregnant whale shark had ever been found, and she had 300 young inside her.” “For the females, there are huge advantages to being big. “It is the first evidence that males and female whale sharks grow differently,” Dr. The study also included data from whale sharks in aquaria. “It works the same way our eyes do - so you can calibrate the two video recordings and get a very accurate measurement of the shark.” “It’s basically two cameras set up on a frame that you push along when you’re underwater.” Brett Taylor, a marine scientist in the Australian Institute of Marine Science at the University of Western Australia. “We recorded more than 1,000 whale shark measurements using stereo-video cameras,” explained Dr. They tracked 54 whale sharks as they grew - a feat made possible by a unique ‘fingerprint’ of spots on each whale shark that can be used to identify individual fish. Meekan and colleagues collected yearly length measurements of whale sharks at Ningaloo Reef, Western Australia, from 2009 to 2019, during the peak of the annual whale shark aggregation, typically in the first week of May each year. It’s only about 20 or 30 cm (7.9-11.8 inches) a year.” “But even though they’re big, they’re growing very, very slowly. Mark Meekan, a fish biologist in the Australian Institute of Marine Science at the University of Western Australia. That’s absolutely huge - about the size of a bendy bus on a city street,” said Dr. “Whale sharks have been reported up to 18 m long. Image credit: Andre Rereuka / Australian Institute of Marine Science, University of Western Australia. Meekan et al found evidence that male whale sharks ( Rhincodon typus) attain asymptotic sizes of around 8.5-9 m at Ningaloo Reef, which suggests that females are more likely to reach the largest sizes (over 12 m) observed in the species.

Whale shark size