i touch, i taste, i am
Catfishes are the most hipster fish.
You’ve probably never heard of them.
They grow elaborate mustaches, also known as barbels. A catfish’s most prominent barbels are maxillary, protruding from the sides of their mouths. Another hipster fish donning barbels is the sturgeon. A sturgeon’s four barbels are mandibular, protruding from their chins. Goatfish rock goatee barbels. Zebrafish have tiny ones. Wobbegong sharks, I can’t even.
These whisker-like extensions are more than an expression of individualism – they are sensory marvels.
Barbels are associated with a benthic lifestyle – fishes that hang out on the bottom of rivers and reefs, critiquing the consumerist lifestyle of pelagic fishes. Benthic fish feed on invertebrates (exclusively local and organic, of course) that are hidden beneath the murky plumes of mud and sand. Vision, even when enhanced with thick-framed glasses, is not the sense to rely on for finding brunch under these conditions.
Well wouldn’t you know, barbels have taste buds. Way back when, neurologist Charles Judson Herrick discovered that catfish can sense taste through buds on the body, fins, and barbels. Barbels can also be sensitive to touch. So, while these legit-looking fish cruise along the bottom, their barbels act as “feelers” detecting objects and tasting them to confirm they are food.
– sent from my iPhone
on the brink
Where do I even begin for this fish? In mangrove forests, I suppose. Mudskippers can be found there performing the following remarkable stunts:
1. The Anti-Fish
For this act, mudskippers emerge from the water, perch on air-exposed roots and breathe through their skin (a.k.a. cutaneous air breathing).
2. The Skip-To-My-Lou
Yes, mudskippers skip on mud. They skip along the intertidal areas of mangroves and mudflats. Skipping is made possible by the unique morphology of their pectoral fin – it is shaped like a bent arm.
3. The Angry Mime
When tempers flare, a mudskipper’s skips turn into acrobatic lunges. Fighting males heroically (and hilariously) leap at each other while silently yelling. What’s all the fuss about? Maybe access to the best hole in the mud. Mudskippers live in muddy burrows and females lay their eggs there.
4. The Googly Eye
Mudskippers have to make sure no part of their body dries out. To keep eyes moist, the eyeballs are popped back into their water-filled eye sockets.
5. The Tongue Twister
Under water, fish normally suck in water to capture prey. So how does a fish feed on land? A magical water tongue! Mudskippers bubble out stored water from their mouth onto the food, slurp the water and food back into their mouth and then swallow.
of oxidizing copper
tide up, tide down
Mangroves, the salt savvy plants that live along the shoreline battling high and low tides. From the sky, mangroves can look like mazes of broccoli. From the ground, mangroves are an army of dichotomous statues – spidery, bronzed roots crowned with emerald foliage.
The roots are, well, amazing. They block salt from entering the tree and can breathe when exposed during low tide. The leaves are pretty tough, spitting out any salt that enters.
Mangroves are multitaskers. When tropical storms strike, mangroves buffer the coast from attacking waves, reducing damage. Mangroves are prime real estate for oysters and an all-you-can-eat invertebrate buffet for egrets, ibis and the magnificent spoonbill. The winding channels are a chill-out place for dugongs. Mangroves are also underwater meccas and important nurseries for young fish.
From coastal USA, the Bahamas, and Brazil to Thailand, Africa and Australia, mangrove forests presently cover 137,760 km² on this planet – an area comparable in size to the country of Greece or 27 million tennis courts.
But mangroves face the same grave and uncertain future as their fellow terrestrial (e.g. rainforests) and aquatic (e.g. coral reefs) habitats. Due to the usual suspects (i.e. human development/rising seas and water temperature), mangrove forests are in precipitous decline.
Nature could really use a feel-good story right about now.
i’ll take a breath
because there are few rules
i’ll take a plunge
I saw one of Evolution’s ridiculous marvels in the wild – the platypus (Ornithorhynchus anatinus)! I’m not sure why but my childhood understanding of the platypus had me expecting it to be the size of a dugong. They are tiny swimmers though, measuring in at a little over a foot.
Let’s explore this animal’s myriad curiosities.
The duck-bill; an electrified hunting shovel, similar to that of a paddlefish. The bill contains sensors that detect changes in electrical fields to hone in on prey. A handy tool since a platypus’ other senses are rather useless underwater when its eyes, ears and nostrils are closed!
The hats; because the internet.
The hair; it’s very dense, like on otters.
The eggs; a “WTF evolution” moment for sure. Yes, platypus are an egg-laying mammal. They also lactate without nipples.
The webbed feet; because the duck-bill wasn’t ducky-enough. Webbed feet are certainly appropriate for the platypus’ aquatic life. The claws apparently make for decent ability to walk on grass.
The venom; because platypus wanted to be like reptiles. Males have a particularly nasty spur on their back feet that secretes a venom.
The beaver tail; because Australians like visiting Canada.
So platypus are really just an egg-laying-paddlefish-duck-otter-venomous-reptile-lactating-mammal-beaver hybrid. And if modern day platypus aren’t intriguing enough, imagine if they were the size of dugongs!
yet, ecological keystone
Once upon a time there was a starfish. She was a rather beastly organism with over a dozen arms covered in toxin-riddled thorns. Hence her name, crown-of-thorns starfish (Acanthaster planci). She had an insatiable appetite that rivaled that of Cookie Monster’s. Her meal of choice: coral. Living in the waters of the Great Barrier Reef, she fed on fast-growing corals allowing slow-poke corals to grow, diversifying the spectacular reef. The starfish and the corals lived happily ever after.
Except, they most definitely did not.
Also known as COTS, when populations of this starfish explode the reef succumbs to a ravenous “plague”. Swarms of COTS devour corals at alarming rates. Vibrant reefs rich in diversity are converted to abysmal, colourless masses. COTS can be as damaging as cyclones, and thought to be responsible for ~40% of coral decline.
What causes a COTS outbreak?
There is no smoking gun. Maybe a perfect storm of factors. First, fluctuations in COTS population size occur naturally. But there has been over-harvesting of COTS’ natural predators including the Triton’s trumpet. Then there is urban and agricultural run-off increasing the nutrient-richness of river water entering the reefs, which could enhance larval COTS survival.
What can be done to mitigate outbreaks?
Physically removing COTS is tedious and getting pricked by the venomous spines is not ideal. A single injection of the chemical goop thiosulfate-citrate-bile-sucrose causes an allergic reaction and 24 hours later you’ve got dead COTS. The smell of their triton enemy causes COTS to run scared. Predator odour could be used to push COTS out of reefs. [update: injection of lime juice or vinegar also kills COTS!]
It remains a challenge predicting what conditions will cause an outbreak, and when and where an outbreak will occur.
This starfish and coral story is to be continued.
is lush, protected
Behold, the dugong (Dugong dugon) – whose name translates to “lady of the sea” in indigenous languages.
So dugongs are not manatees. An easy way to tell the creatures apart is by their tail – a dugong’s tail is forked whereas manatees have a paddle.
Australia is home for populations of this seagrass snarfing marine mammal. The country also produces some fascinating research on dugongs. Hormones in dugong poop can be measured to determine if a female is pregnant. Dugongs are being tracked by blimps, drones and GPS. Similar to fish otoliths, counting the layers visible on a dugong’s teeth estimates its age.
Dugongs are protected under Australia’s Environment Protection and Biodiversity Act. This animal is also a “cultural keystone species” for the Aboriginal people living on the islands of the Torres Strait. Dugongs are hunted for food and traditional ceremonies. For ~20 years interactions among the government, scientists and the Aboriginal Australians have attempted to ensure sustainability of both dugongs and indigenous culture.
There are concerns of over-hunting. Distinguishing dugongs from manatees is relatively simple, but estimating their global and local population sizes is a challenge. Without accurate population sizes, the issue of over-hunting remains in flux and controversial.
secrets roaming as
connect the dots
Manta rays are often referred to as the ocean’s giants. Also sea pancakes.
You’d expect it to be rather cumbersome maneuvering a 20 ft (6 m) wide body. Except the behavioural repertoire of manta rays is quite spectacular.
They leap into the air for reasons unknown. They dive to depths beyond 150 m. They somersault when feeding. They patiently pose while being preened of parasites by small fishes. Males “train” behind females and bite their fins during courtship.
Like the leafy seadragon, these fish can be identified by unique markings. Distinct spots and smears on a manta ray’s belly are used like a fingerprint to determine who’s who. Citizen science initiatives using “automated animal recognition technology” are helping build databases of manta ray photos.
And for those wondering; yes, manta rays even make pooping look graceful.
the currents arc
i think i’ll wear a mask today
Greetings from Australia! Over the next few months I will be highlighting aquatic creatures of Terra Australis.
First up, the leafy seadragon (Phycodurus eques); part leaf, part dragon. Leafy seadragons (or leafies) are officially members of the Syngnathidae family and relatives of pipefish and seahorses.
The epitome of stealth, leafy seadragons look and move like seaweed. Leafy appendages branch out from the animal’s body. Never in a hurry, leafy seadragons amble about using pectoral fins on their neck and a dorsal fin along the tail.
Their snouts hoover up tiny crustaceans, and also bear distinct markings. Researchers can follow individuals in the wild based on unique facial patterns. Turns out these foot-long slowpokes manage to have home ranges up to 5 hectares in size!
Where there are leafies, there are weedies! Weedy seadragons (Phyllopteryx taeniolatus) are also endemic to Australia – so are the newly discovered ruby seadragons!
unknowing they swim
i’m a hovering sniper
scissored and swoop
They poise grandly above their mark. They wield a mighty dagger. They strike with precision. They abolish prey which are swallowed whole. They are king of the fishers.
Kingfishers also look as if they will topple forward at any moment. Their bills are characteristically long, sharp and strong – ultimately designed for piercing through water and spearing into a fish.
The colours and patterns of kingfishers could easily fill a Milan runway show. Kingfishers are collared, striped, green-backed, crested, spotted, white-rumped, belted, ringed, blue-breasted and moustached.
Kingfishers are popular among animal behaviour researchers. Stuffed models and cutout silhouettes of the bird are “flown” in the lab to understand predator avoidance and schooling in fishes. It’s always a good thing when science and crafting mix!
P.S. Some kingfishers have compressed bills and don’t fish. The elusive shovel-billed kingfisher (Clytoceyx rex) prefers to nom nom on beetles and snails.
cloaked along the earth’s crust
then – flurried sand
The life of a flatfish (e.g., sole, flounder, halibut) is the opposite to that of the ugly duckling. Flatfish start life cute as a button – swimming about upright with an eye on each side of their heads. Then a metamorphosis occurs and the darling fry turn into flattened, asymmetrical “Picasso” fish with both eyes on one side of the body.
The side of the body with both eyes faces upward and is mottled, usually in drab colours that camouflage well with the ocean sediment. The other side of the body faces downward and is devoid of eyes and colour. Flatfish slink along the ocean bed, their bodies rippling like a windblown flag. A flatfish’s mouth ranges from a European flounder’s goofy smile to the toothy sneer of a California halibut waiting to snatch up an unsuspecting small fish for dinner.
What’s the deal with a flatfish’s eye meandering from one side of the body to the other as it gets older?
Paul Myers suggests flatfish are simply transforming from juvenile to adult form like many marine fishes, but in an exaggerated and peculiar way.
Initially larval fish (including larval flatfishes) drift in the pelagic zone (i.e., not the bottom, not the coast) eating zooplankton. Upright swimming and normal eye placement seems appropriate for this life stage. Eventually larvae settle down on their new homes, perhaps a coral reef, and metamorphose into miniature versions of adult fish. Flatfish will literally settle down onto the seafloor. As upright swimming is abandoned and pancake mode is engaged, normal eye placement may be a problem. An adult flatfish with two eyes on one side of the body would probably have better success hunting and hiding than an adult with only one eye.
I suppose now that I’ve looked at so many images of flatfishes, they aren’t that ugly. After all, my two eyes are also on one side of my body.