Creature Feature: The Lionfish

lionfish evolution diving resort malapascua

A common fish with the coolest name!

It’s easy for seasoned divers to dismiss lionfish as a ‘seen it’ item on their dives, but did you know Malapascua has 5 species of lionfish? Unlike their cousins in the Caribbean, the lionfish around our island are actually indigenous.

Thought to be transported in ships’ ballast or releases from the aquarium trade, lionfish have become an accidental invader of other ecosystems. Without a natural predator they are able to reproduce at an alarming rate resulting in a devastating environmental threat, as local species have not evolved defenses against these deadly predators. In some places you can even train to become an underwater assassin to control the threat with a Hawaiian sling.  In Columbia lionfish are encouraged as must eats on Fridays and religious holidays by the Church authorities in an attempt to control the populations and reduce the strain on other over-fished species.

philippines lionfish malapascua

With a flamboyant display, lionfish make for an exciting sight on training dives but experienced divers can also find something interesting in their behaviour, and learning to identify the different species.  If you get too close, the lionfish will fan out its pectoral fins in a warning display, thus employing an evolutionary technique called aposemitism, where a creature uses bright colours or displays to warn would-be predators that getting too close would result in a very bad day.

Lionfish are skilled hunters, and usually swallow smaller prey whole.  They are able to adjust their centre of gravity, which, combined with their large pectoral fins, enables masterful control in the water.  When approaching a victim they also blow jets of water towards them to disorientate the fish. Since most smaller fish choose to swim into the current when evading prey this can result in smaller fish swimming straight for the lionfish’s mouth.

philippines lionfish malapascua evolution diving

Around Malapascua island we are fortunate to have 5 different species, which are easy to distinguish if you know how.  The first thing to note is the pectoral fins – you don’t have to be too close for the fins to be fanned out in a warning. If the fan like fins are quite ‘feathery’ with no webbing connecting them then you’re looking at the common lionfish.  The juvenile of this species is often mistaken for a different species, coloured black all over and looking a bit ‘spidery’.

The other species will all have some webbing connecting the pectoral fins. If this only extends halfway up the fin and is decorated with blue spots, then it’s the bluespot/spotfin lionfish.

Webbing all the way to the tips is usually a zebra lionfish, although the dwarf lionfish is similar, but usually smaller, more red in colour, and more often seen on night dives.

Finally, our most uncommon species is the two-spot lionfish which unsurprisingly has 2 distinctive spots clearly marked on the tail fin.

So next time you’re diving, don’t dismiss the amazing lionfish.  Check out its behaviour, maybe its hunting. And try to identify the species for your post dive log.

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