Big little lives
“it confirmed in my mind that this was indeed a new species.”
Delicate and diminutive, pygmy seahorses are some of the most enigmatic characters on the reefs they inhabit. With new species discovered in recent years, including the first in the Indian Ocean, big questions are being asked of these little creatures. In Issue 15 of Oceanographic, Dr Richard Smith shares his extraordinary discoveries.
Anticipation is always high when you’re set on looking for a particular species on a dive. You need the right conditions, broadly the right habitat and of course a little luck. People often ask how I find the well camouflaged pygmy seahorses that I study, particularly when they’re so tiny. I always say, it’s about having a mental image, and knowing where to look. After that, finding an animal just big enough to stretch across a US dime or a UK five pence coin in the great wide ocean is relatively easy! However, when you’re looking for a brand new species, that just one or two people may have seen before, that advice becomes rather redundant. So, as I descended in the nauseating South African swells, on a dive in search of the first pygmy seahorse sighted in the Indian Ocean my anticipation was completely through the roof.
Pygmy seahorses have become well known in the dive community, which is hardly surprising given their cheeky puckered lips, neon colours and incredible miniaturisation. Despite their notoriety, we actually know shockingly little about them. The original pygmy seahorses, that we now know of as Bargibant’s pygmy, were first spotted by a researcher at a museum in Noumea, New Caledonia. George Bargibant was bringing up a Muricella gorgonian for the museum’s collection and happened to notice a pair of tiny seahorses clinging cryptically to its surface. The species was named in his honour in 1970.
Over the next 25 years, there were very few reports of pygmy seahorses, until they began to be spotted by eagle-eyed divers in Papua New Guinea. Of course, this caused a flurry of excitement and these tiny fish became the celebrities of the coral reef. Divers began to realise that they lived exclusively on Muricella gorgonians and only certain ones of these. Later, pygmies began to be spotted living on other gorgonians, and those individuals tended to be smaller and slenderer. In 2003, these were described as Denise’s pygmy seahorses. The same year, a free-living pygmy was discovered at the remote Lord Howe Island, almost 500 miles northeast of Sydney, and named as Coleman’s pygmy seahorse.
Beyond the scientific naming process, which included only basic ecological information, there had never been any further biological research into the biology of pygmy seahorses until I began my PhD in 2007. I focused on the two gorgonian-living species, Bargibant’s and Denise’s pygmy seahorses. Among other things, I investigated how rare or common they might be, as well as their social and reproductive behaviours. I found plentiful healthy gorgonians to accommodate them, but fewer than 10% were inhabited. Generally, these two pygmies were the least abundant of all seahorses. I also revealed surprising behaviours among the social groups living together on a single gorgonian, such as males attempting to strangle each other and ordinarily monogamous female seahorses mating with multiple partners.
While writing up my thesis, several other new pygmies were added to the roster. In 2008, Pontoh’s and Satomi’s species were described. Both are free-living, preferring halimeda algae and hydroids in the case of the former, and soft corals and bushy gorgonians for the latter. The next year, 2009, they were joined by the Walea Soft coral pygmy seahorse, which lives on shallow soft corals only in Indonesia’s Tomini Gulf. As divers’ attentions around Southeast Asia moved towards smaller animals on the reef, the number of new pygmy discoveries was increasing. In fact, not only with pygmy seahorses, but many other creatures too. Around this time the tiny and hair-like thread pipehorse (Kyonemichthys rumengani) was also discovered, as well as other pipefishes, gobies and shrimps. Basically, almost any group of miniature habitat-specific creature you care to think of was burgeoning with new discoveries.
Soon after I was awarded my PhD, I went off to Okinawa, Japan to present some of my findings at the quadrennial Indo-Pacific Fish Conference. The conference was obviously an important part of my visit to Japan, but I must admit to an ulterior motive. Some years before, I had seen an image of an unusual pygmy seahorse that immediately looked different to me. It was superficially similar to Pontoh’s pygmy seahorse, but I was determined to find it for myself and investigate further. After the conference, and many months of preparation and planning (mostly with Google translate), I headed to Hachijo-jima, a small volcanic island 180 miles south of Tokyo. I had trawled the internet and managed to uncover a few pictures that had been taken of this seahorse from the island, so I decided this was the best place to go.
The first dive in Japan, I was sure would be my last. My amazing guide Kotaro had assured me that the best place to look for the pygmy would be a site called ‘Nazumado’, entry to which would require us basically repelling down a steep slope whilst holding onto a rope with one hand and my housed SLR in the other. At the end of the rope, you had to launch yourself off a small cliff into the water between crashing waves. As I negotiated my descent down the slope, I could hear the screams of people being wiped out by waves behind me. Finally, after the initial onslaught, we made it into some surprisingly calm water and headed off to look for the pygmy…
Read the full article, Big Little Lives, in Issue 15 of Oceanographic Magazine – available now worldwide.
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