Around a month ago I promised a whistle-stop tour of all ocean sunfish species, but as always, the best laid plans frequently go astray! The recent stranding events proved irresistible for blogging… but today is the day we get back on track!! Today’s star is the sharp-tailed Mola, less commonly known as Masturus lanceolatus.
The sharp-tail is a strange beastie, like an over-inflated rugby ball. It has a more rounded outline in comparison to the more commonly known Mola mola, until you reach the clavus that is (the rudder-like, reduced tail fin). The ‘sharp-tail’ has just that… a strange pointed projection half way along the clavus. The function of this funny fin is not yet understood, but if I had to guess, I would suggest it may have something to do with reducing drag and improving the hydrodynamics of swimming. Definitely a fishy feature that would be really interesting to investigate further!
The species is suggested to live in tropical and subtropical waters, diving to depths of nearly 1000m deep, with the largest specimen measuring over 3.3m long and weighing 2 tons! Sharp-tails are suggested to be widely distributed but relatively rarely seen, and a study in 2009 suggested that individuals may live to be 105 years old! Although the market for sunfish as a food source is fairly limited, there is a target fishery for the species in Taiwan, where the fishery takes up to 494 tonnes of sunfish each year (90% Masturus lanceolatus, 10% Mola mola). Traditionally, only the internal organs were eaten (intestines and reproductive organs -yum!) and the muscle tissue was discarded. However, a recent sunfish food festival promoted eating the meaty muscles of the sharp-tail too, which has led to higher catch rates of this fish (sold at approximately $9 per kg) as a cheap source of protein.
The IUCN currently lists the species as of ‘Least Concern’, but notes that the impacts of the increasing target fishery should be assessed. Further research efforts might also like to consider genetic analyses for stock assessment, alongside estimation of population size and distribution, (and if I had my way, an investigation into the benefits of that strange tail would also make the list!)
This species is a little strange -even by sunfish standards- but a magnificent fish none the less and I hope to learn more about the sharp-tail in future. If anyone is currently working on these crazy creatures please do get in touch!
As always, if you would like to ask any questions about PhD life, fishy science or if you spot a sunfish (esp. a stranded specimen) please get in touch using the comments section or via Twitter: @SunfishResearch or email: firstname.lastname@example.org