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| Photo courtesy of Ningaloo Reef Dive - Migration Media 2014 |
These cosmopolitan
gentle giants of the Coral Coast are relatively slow moving cruisers of the
open ocean.
Hence, they
are actually like a moving reef sanctuary!
It is very
rare to see a large wild whale shark without an entourage...
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| Photo courtesy of Ningaloo Reef Dive, by Migration Media 2014 |
This little whale shark came with his own entourage of juvenile golden trevally! This was an amazing day with over 40 whale sharks spotted in the area by Coral Bay's spotter plane!!
Remoras, pilot fish, and juvenile golden trevallies are
often seen “hitching a ride” on or in its wake, even around their mouths. In
these symbiotic relationships are
generally ‘commensalistic’, in which the smaller fish are benefiting while the
whale shark is unaffected. The smaller fish gain protection, in some cases a
free ride, and a meal catching scraps of food. However, the whale sharks may still
gain some benefit if any skin parasites are eaten and [in the case of the footage featured in the previous blog, see below]
the occasional snack out of the shoal themselves. This may be considered as an
example of a ‘trade-off’ for the
protection that the small school of fish receives as a whole. Often larger
pelagic fish (like cobia) will also shadow the whale sharks, including other shark
species such as bronze whalers, which lurk in the depths below, in perchance of
an easy side-meal from its entourage.
Watch: Remoras, Cobias
& Rainbow Runners
As they are
typically thought lead a life of solitude, the whale sharks may actually 'enjoy
the company' out on the open ocean, although, I have found that this may not
always be the case.
Whilst working as a ‘lead swimmer’ guiding on whale shark
swim tours, I have had a tiring experience trying to keep up swimming with a 6m
juvenile whale shark that visibly seemed distressed about all the attention it
was receiving from its entourage. This whale shark was swimming unusually
erratically, seemingly trying to rid itself of the cloud of trevally, pilot
fish and remoras encircling it and clearly ‘getting in its face’.
We left him in peace to deal with his 'frustrations' and to come to terms with his relationship with the remoras that would inevitably "stick around" for a life-long relationship.
We left him in peace to deal with his 'frustrations' and to come to terms with his relationship with the remoras that would inevitably "stick around" for a life-long relationship.
BIBLIOGRAPHY:
Stewart, B. S., & Wilson, S. G. (2005). Threatened
fishes of the world: Rhincodon typus (smith 1828) (rhincodontidae). Environmental
Biology of Fishes, 74(2), 184-185.
Wilson SG, Polovina JJ, Stewart BS, Meekan MG (2006)
Movements of whale sharks (Rhincodon typus) tagged at Ningaloo Reef,
Western Australia. Marine Biology, 148, 1157–1166.
Wolfson, F.H. & Notarbartolo-di-Sciara,
G. (1980) Whale Shark Bibliography. Scripps
Institution of Oceanography Library. UC
San Diego: Scripps Institution of Oceanography Library. Retrieved from: https://escholarship.org/uc/item/4xd5r8q6
This is cool! It's interesting, I wonder if it gets to a point where the number of fish around these sharks becomes more of a parasitic relationship. Like you said, surely it would get annoying and perhaps even hinder the sharks' ability to swim smoothly sometimes.. What's the largest number of fish you've seen swimming around these guys?
ReplyDeleteSo glad you found it interesting too! :)
DeleteThe situation that I had described above would count for the most variable number of species and size of fish that I have witnessed in a whale shark entourage (and would probably qualify as a parasitic relationship in that moment). However, I think the video of the tiny schooling bait-fish would win for the largest number :)
Such a cool story! I am absolutely flabbergasted that it is the dorsal fin that is modified into a sucker, and not the mouth! I didn’t realise that these fish actually attached upside down. Fantastic! Are individual whale sharks identifiable by their entourage or does this entourage change with time? Do you think that the juvenile whale shark was disturbed by all the attention because of its size (i.e. smaller body size with a large entourage = more “parasitic” than “commensalistic”)? Awesome!
ReplyDeleteTheir entourage does change. I have witnessed members of their fishy entourage 'jump ship' and swap to another passing whale shark (or other large objects in the water)! Many times I even had them try to follow me! - Baby pilot fish (the little yellow ones in the above photo) and remoras (a mate was given a mark on his skin from one trying to sucker-on) - but was able to shoo them back to the mother-ship, since I would be getting out of the water, leaving them stranded.
DeleteYes, I do think that the mentioned juvenile whale shark was disturbed in more of a 'parasitic' nature, due to his seemingly stressed and erratic behaviour.There were also quite a lot of large trevally in the hindering school of fish, so it may not have been just amount of attention. Being a juvenile, it may have also been a bit inexperienced in with dealing with such attention when it migrated within close proximity to the outer reef (so we left him in peace and located a more relaxed whale shark to swim with). :) I'm glad you enjoyed my blog post :)
Great article with excellent idea! I appreciate your post. Thanks so much and let keep on sharing your stuffs keep it up.
ReplyDeleteningaloo reef fishing