Fishy trivia 2): secrets of the sharp-tailed sunfish!

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!

2The 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.

3The 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:


The spoils of war! Mass Portuguese Man O’War wash up (*with video!)


Only last week I was writing about an unusual ocean sunfish stranding in Cornwall, but following directly on its’ (purely proverbial) heels we are now in the midst of a mass stranding of Portuguese Man O’War!! You would be forgiven for thinking these stunning stingers were jellyfish, but in fact they are actually a colony of tiny individual siphonophores that lump together to form one working “individual” that cannot survive without each other.

These amazing creatures divide up the duties of daily life, with cells specialising into one of four differing types:

1) The pneumatophore: these cells form the blue/pink float that acts a buoyancy aid and sail. The float can either be left or right handed, with its fate decided by the wind so if one half of the population runs aground, the other half should be sent back out to safety at sea! Its vague resemblance to an actual warship gives the PMoW its distinctive name.

2) The dactylozooids: these form the long strings of stingy tentacles! Up to 50m long, they trail in the water column providing the colony with plenty of food, trapping fishes with paralysing venom and passing them up to the digestive team. The mechanism for injecting venom is mechanical meaning that even when washed up dead on the beach, it can still sting!

Poking is not recommended (at least not with your fingers) and if stings are unavoidable, don’t use vinegar or fresh water and for goodness sake don’t pee on it! Just like bee and wasp stings are treated differently, jellyfish and siphonophores are different beasties. The best you can hope for is to remove tentacles (carefully) with tweezers and wash well with seawater.

3) The gastrozooids: these cells form bag-like structures under the float to digest prey and distribute the goodies throughout the colony. Yum!

4) The gonozooids: these are the reproductive cells and either male or female for each colony. The gametes are shed into the sea to join with other gametes from other colonies, but the PMoW can also reproduce by asexual budding! Neat.

We believe the sudden influx of these exotic creatures is off the back of the recent hurricanes over in the Western Atlantic so keep your eyes peeled on UK beaches. The photos from Cornwall (more below) show just how many were washing up last week! The pictures also show just how easy it would be for a hungry predator (like a leatherback turtle) to mistake a balloon for a siphonophore or jellyfish…


Aside from being fascinating creatures in their own right, I was particularly interested in this happening so close to our stranded sunfish… and I was lucky enough to have some samples posted to me by the Friends of Portheras Cove (a wonderful marine conservation group)! These arrived safe and sound thanks to the lovely Jan and Delia (who also provided these stunning photos) and I was able to prepare and dry samples of each for later stable isotope analysis to see if the sunfish might include them in their diet! Maybe our sunfish was snacking on Man O’War when it stranded… watch this space! To show a little bit of what we do in the labs here at Queen’s University, I made a short silly video (in the style of the ever-popular Tasty recipe mini clips) of this process… so let me know what you think!

In the meantime if you spot a dead sunfish please do get in touch (esp. if you are happy to take a little snip from the fin) or if you have any questions about research, marine life etc. then please drop me a line below in the comments or email me at: or tweet me @SunfishResearch

Holiday blog special! Beach combing for bodies: sun, sand… & a stranded sunfish!

Today is a special holiday blog! I know, I know, we’ve all seen so many Instagram perfect pictures of sunny beaches and tropical skies sometimes it’s hard to take as autumn settles in but please bear with me as this holiday involves beach combing for bodies… you’ve guessed it –we had a sunfish stranding!

To cut a long story short, I tried to have a holiday this past week in Cornwall, leaving my sunfishy stuff behind me, locked in the office and not to be thought of at all. But while I was happily munching through mountains of scones with real Cornish clotted cream (yum!) life had other plans… The Cornish Wildlife Trust sent me an email, of all the beaches in all the world, a sunfish had just stranded dead near Newquay, less than 40 minutes from where I was staying!


Needless to say, I jumped in the car (accompanied by my boyfriend, mum and dog) and headed over to the site where it had last been seen stranded partially up a river estuary. We waited for low tide, expectations low, in case the recent storm surge had dragged it back to sea… but after an hour of searching the sand we spotted a large grey shape! After battling the dog to reach it first, it turned out that the sunfish was in great condition (the birds had only been able to steal the upturned eye and a quick peck at the less armoured ‘openings’ of the fish) so minus a few oozings, it was really fresh. Infact so fresh, that when we cut it open to collect our tissue samples, it still felt warm! Amazing and disgusting all in one, ah the life of a marine biologist.


I am so grateful for the alert from the Wildlife Trust as although stranded fish like this are a sad sight, they provide vital data for our research. Using our scrambled dissection kit, including my mum’s best steak knife and an old teaspoon (don’t worry we washed them first!) we were able to collect samples of skin, muscle, vertebrae, teeth and the other eye! Yes we tea-spooned out an eyeball, (turns out my mum didn’t want the spoon back so it’s now in my regular dissection kit). Over the last few days I have been preserving these samples for future analyses so please watch this space!

If anyone else spots a dead sunfish please do get in touch and if you are happy to take a little snip from the fin (or any more adventurous samples) then please please drop me a line below in the comments or email me at: or tweet me @SunfishResearch

Sunfish in flight! From London to Belfast safe and sound


Fishy trivia 1): the slender sunfish

So a few blog posts back, eagle-eyed readers might remember I mentioned plans to write detailed overviews about each sunfish species… but then an entirely new species was discovered, so of course I got carried away with a shiny new sunfish and neglected my original plans! So please accept my apologies and prepare for some sunfish trivia!!

Image result for slender sunfish

Today’s star is the slender sunfish, less commonly known as Ranzania laevis. The slender sunfish is a beautiful creature, the colourful cousin of our favourite Mola mola, and easily identified by its more elegant, elongated shape, typically with stunning stripes and spots along the silvery body. The species was first described in 1776 by Thomas Pennant, a Welsh naturalist and explorer whose works influenced other important figures of the time, including Georges Cuvier and Samuel Johnson, who said he was “the best traveller I ever read”. Praise indeed!

The species was later moved to the taxonomic group ‘Ranzania’, which forms a genus all Image result for slender sunfishof its own, named in 1840, after the famous Italian priest and naturalist Camillo Ranzani who was director of the Museum of Natural History in Bologna from 1803 to 1841. As with the other sunfish species, very little is known about the slender sunfish’s life history. It is suggested to occur in subtropical regions, up to 140m deep, with the largest specimen to date reaching 1m in length. The IUCN currently lists the species as of ‘Least Concern’ due to its broad distribution, high abundance in parts of its range and no known major threats. Of course this sounds like great news for Ranzania, but after working with Mola I have learned to be cautious… the extensive bycatch of sunfish species across the world is likely to affect other species and I would be really interested to learn if there is mass bycatch of Ranzania in areas where it is thought to be abundant, (as there is with Molas).

Image result for ranzania laevis

The IUCN recommends genetic analyses of Ranzania, and after the recent discovery of a third Mola species (with suggested further cryptic species!), I would love to know more about their population genetics to see if the species Ranzania laevis is actually made up of one homologous group, discreet stocks or potentially new species…

As it stands, I believe it is fair to say that this species could benefit from further research, and as I have had a few emails over the last couple of months from keen students looking for advice on interesting sunfish studies… this could be a great place to start!

Related image

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:


Hoodwinked by a 2 ton fish! The discovery of a new sunfish species

It’s not often that new megafaunal species are discovered these days, but for the first time in 130 years we have a new sunfish on the block! Introducing Mola tecta, to be commonly known as the hoodwinker sunfish, identified by Marianne Nyegaard.


M. tecta in the wild (photo credit César Villarroel, ExploraSub)

Only a few weeks back I wrote a blog about the differing sunfish species and how scientists from several different labs had suggested there was at least one other Mola species out there in the big blue. Now thanks to Marianne and her collaborators, we have a formal description of a species entirely new to science which means it can be officially added to the sunfish ranks! Following four years of painstaking work, Marianne has amassed considerable data on this new species, including genetic and morphological data, which means it can now be easily identified.

The simplest method to tell a hoodwinker sunfish from any other sunfish species is to look at its reduced tail fin, the clavus. The hoodwinker’s clavus has a small fold in the middle that appears to divide the clavus into two lobes (see Marianne’s diagram below). This is a feature that only hoodwinkers seem to have, and now they are being noted all over the southern hemisphere including off New Zealand, Tasmania, Australia, South Africa and Chile!

tecta 3

Scaled line diagram of M. tecta by diver (illustration by Michelle Freeborn, Wellington Museum Te Papa Tangarewa)

This wonderful piece of detective work has led Marianne all over the world collecting data, and is also testament to the kindness and enthusiasm of the public, sending in samples from remote areas. After hiding in plain sight among the tangled taxonomy of sunfishes, this species finally has a name, a type specimen for reference and a genetic signature so it can be clearly identified.

tecta 2

New display specimen at the Otago Museum

However, now the Hoodwinker has been established, we have many more mysteries to solve: how many are there? how far can they range? are they, like other sunfishes, subject to high fisheries pressures? The research questions (already numerous enough with the current number of sunfish species) are stacking up rapidly! It could be that the Hoodwinker has been identified only to discover that it too is vulnerable in our changing oceans.

As with many marine species, we will need to learn more about these strange creatures to ensure they are sustainably managed; to safeguard their habitat, to understand their role in local ecosystems and to keep the environment in balance for it’s own sake and for future generations to admire.

It seems this exciting new discovery is just the beginning…. !

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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 channels below:

Comments section on this blog

Twitter: @SunfishResearch


Summer, seminars & sunfish! The FSBI 2017 conference

The sun is out and for a few glorious days it really feels like summer in the UK!! For first and second year PhD students this is great time to get into the field to collect data followed by the peace and quiet of universities during undergrad holidays for analysis and writing up. But for those of us in third year, with fieldwork now (mostly!) completed, this time of year provides exciting, nerve-wracking chances to present our new findings at conferences!

As my PhD is generously supported by the Fisheries Society of the British Isles (the FSBI), 20170707_091756I was delighted to finally have the opportunity to attend one of their legendary conferences! Several hundred scientists from all over the world converged (or should that be shoaled?) at Exeter University for a week long foray into the incredible world of fish!

35593512252_6c2a5cb0b5_z I was presenting two elements of my research: a poster on my first sunfish study ‘Seeking the sun in deep, dark places: Mesopelagic sightings of ocean sunfishes’ and a 12 minute presentation of my latest work ‘Applying species distribution models to a data poor, pelagic fish complex: The ocean sunfishes’ and so it was with a heady mixture of nerves and excitement that I hiked up the hill from Exeter train station and breathlessly entered the enormous glass entrance hall at the Forum. I needn’t have worried, without exception biologists are incredibly relaxed, friendly people and within 10 minutes I had my poster up, conference goody bag in hand and was chatting fish with incredible scientists.

The FSBI attracts researchers from all over the world and I loved the jam-packed program with presentations, speed talks and posters which kept us busy from 8.30am till 7pm, interspersed by cream teas, socials and sports and followed every night by music, quizzes and dinners. I met such an incredible array of inspirations scientists, my notebook is now full of papers to read, tweeps to follow and ideas to try! As if this wasn’t enough already, I was delighted to be awarded second prize in the student talks and I found more researchers interested in sunfish ecology with collaborative plans already taking shape. If you are interested in any aspect of aquatic biology I cannot recommend this conference enough!

Many thanks to the FSBI for putting on such a great event (& for putting the photos online, many of which have been borrowed for this blog!) and here’s looking forward to #FSBI18, hope to see you there!

Any questions about PhD life, sunfish science or just fancy a fish chat? Use the comment box below or get in touch through my twitter @SunfishResearch

Taxonomic Troubles: When is a sunfish not a sunfish?

When is a sunfish a sunfish or not? The riddle of speciation and how we define which animals belong to which taxonomic group is a long and tangled tale (and is by no means solved in modern biology!)


Sunfish having an existential crises: what am I?

To consider ‘what is an ocean sunfish’, really we need to be thinking about what makes a species? How do we define types of creature? Typically at school we are taught that a species is a group of living organisms which are capable of breeding or exchanging genes and producing viable, fertile offspring. However, as is often the case in life, things are rarely as simple as they first seem… so bring on the fun!

Speciation occurs when new environmental opportunities pop up and creatures start to take advantage! Of course some individuals may have traits that make them better suited to the new way of living than others and if they can become more successful at feeding or finding breeding sites etc. then they can produce more successful offspring with those traits and the group slowly evolves to perfectly make the most of the niche presented. This can occur through several pathways:

1) Physical division of a population i.e. by formation of a mountain range or river (known as allopatric speciation)

fig 1

2) When small groups break away from a larger population and become isolated (peripatric speciation) enabling traits within the smaller group to become more distinguished

fig 2

3) If a population becomes increasingly spread out over a large area they may form regional groups (parapatric speciation) where although mixing between groups is possible, it becomes less likely and each group adapts to local conditions

fig 3

4) Or when new niches occur and some groups find new advantages such as different food sources to take advantage of, and despite the lack of physical barriers or distance, begin to diverge from the original species (sympatric speciation)

fig 4

To make matters more complex, hybridisation between certain closely related groups is sometimes possible. An interesting example of this is occurring currently in Alaska and parts of Canada where polar bears and grizzly bears (two differing species) are suddenly coming into close contact due to shrinking sea ice forcing polar bears south, and rising land temperatures driving grizzly bears north. The two groups have been divided by habitat preferences over evolutionary time periods and each is a defined species in its own right.

bear fig

However, reports of hybrids (known as pizzly or grolar bears) are becoming increasingly frequent and recent research shows that these hybrids are actually fertile. Evolutionarily speaking, it makes sense for differing species to avoid interbreeding as this would reduce specialisation to local environments i.e. a growler bear is less adapted to icy environments than a polar bear and also less adapted to temperate forests than a grizzly bear so its chances of

survival are reduced. But technically are they different species? Well if we use the traditional definition then no, but ecologically speaking yes. Confused yet? (I sure am!)

Other issues with defining a species based on the traditional “breeding and producing fertile offspring” arise from species that don’t have sex (bacteria, some lizards/sharks/plants) and it is useless for fossil species. So in practise, biologists use a whole range of concepts to tease apart what makes a species.

So come on, how do we recognise a species? Traditionally, this involved classifying animals based on comparisons of body shape (morphology), but now this also includes behaviour, evolutionary history and genetics, and yes there are still frequent arguments among the scientific community as to what can be classed as what.

In terms of the sunfishes, there are currently four recognised, defined species

1) Mola mola (my favourite naturally!) also known as the ‘Ocean Sunfish’

Digital StillCamera

2) Mola ramsayi, a closely related group also called the ‘Southern Ocean Sunfish’


3) Masturus lanceolatus, the ‘Sharp-tailed Mola’


4) Ranzania laevis, ‘Slender Mola’


I will go into a more detailed overview of each of the above species in the follow blog posts (and *spoiler alert* this is by no means an exhaustive list!) Recent research suggests there might be up to 3 new species of Mola mola alone, indistinguishable to the eye, but genetically distinct… however these species have not yet been formally reviewed or named so watch this space!

Many thanks to Wikimedia Commons for providing the photographs used in this blog and as always, if you would like to get in touch or if you spot a sunfish (esp. a stranded specimen) please use the channels below:

Comments section on this blog

Twitter: @SunfishResearch