Tuesday, 27 June 2023

The Unique Unicornfish

Sometimes, you can look at an animal and their name just makes sense. Tiger sharks have tiger-like stripes, sea slugs look like land slugs and blue whales are, well, quite blue. The same thing is true for the aptly named unicornfish.

As you can probably guess, the unicornfish gets its moniker from the unicorn-horn-like protrusion sticking out of its face. But what is that distinctive feature for? And what else is there to know about the unicornfish? Read on to have all your burning unicornfish questions satisfied.

What is a unicornfish?

Unicornfishes comprise a group of fish in the genus Naso, which is under the family Acanthuridae. You might know other fish in the family, including tangs and surgeonfishes (including the blue tang made famous by Dory in Finding Nemo). There are about 19 species within the genus Naso, but only some of them have the iconic “horn” protruding from their faces.

Where can you find unicornfish?

You can find unicornfishes in the tropical and subtropical regions in the Indo-Pacific seas (sorry Atlantic Coast residents, no unicornfish for you!) They typically find shelter in coral reef structures and can also be seen swimming over the top of the reef to feed. They are classified as diurnal planktivores, meaning they eat small plankton during the daylight hours. When they’re not feeding, they like to hide in nooks and crannies on the reef. Although it may look like they’re not up to much when they hide, unicornfish play an important role in the reef: Their waste helps provide nutrients to the corals. 

What’s the deal with the horn?

Only nine of the 19 species within Naso have the horn-like protuberances that give them their name. There are two types of “horns”—one that is actually shaped like a long horn and one that is more rounded.

Scientists aren’t entirely sure why unicornfishes have their horns, but there are some theories. One thought is that males use their horns as a way to signal to females that they are good mates. They also can change the color of their horns to “compete” against other males and stand out to females. Although both males and females have the protuberance, it appears that mostly males are the ones that change their horn color.

What’s the status of unicornfish?

Good news! According to the IUCN Red List, many species of unicornfish are considered of “least concern,” meaning we aren’t currently worried about them going extinct. But that doesn’t mean they’re out of the woods (or out of the seaweed, that is!): Like many species, unicornfishes rely on healthy, sustainable reef ecosystems. Coral reefs are currently under threat from climate change, and there is no healthy future for our reefs—and the animals who depend on them—unless we act now to reduce greenhouse gas pollution. Take action with Ocean Conservancy to urge policymakers to combat climate change before it’s too late.

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Friday, 23 June 2023

Is There a Difference Between Arms and Tentacles?

At Ocean Conservancy we love cephalopods AND we love being very specific about … well, everything. So, what better blog to dive into than one on specific terms and information about cephalopod appendages. This blog contains all the information you didn’t know you needed.

Arms, tentacles—the words are often used interchangeably because they are both types of appendages found on cephalopods. But, in reality, they are different, and each has their own unique characteristics and functions.

Similarities

As all cephalopods are invertebrates, cephalopod tentacles and arms both lack bones for structure. They are made from muscle fibers (much like your tongue). And, both tentacles and arms on cephalopods can regrow or regenerate. These arms and tentacles have strong suckers that work just like suction cups. While arms have suction cups the entire length of the limb, suction cups on tentacles are found only near the end of the limb.

What is a tentacle?

Tentacles are elongated structures, and they are generally longer than the length of the arms. Animals use their tentacles to catch or snatch prey from farther away through their ability to extend and retract. And typically, tentacles come in pairs.

Tentacles have suction cups only near the end of the limb. The suction cups on some squid species are shaped like sharp hooks to better grasp their prey. This makes them very efficient as underwater predators. The suction cup rings of squids are made of “suckerin” proteins that are similar in strength and structure to the protein found in spider’s silk.

What is an arm?

Arms have suction cups the entire length of the limb and can perform finer, more complex actions compared to tentacles. With eight sucker-lined arms and, in some cases, a pair of tentacles, a cephalopod has a really tight grip. But how a cephalopod maintains that grip differs between squid and octopus.

Squid mainly use their suckers mainly for grabbing food, whereas octopuses have figured out how to use their suckers for a wide variety of activities—including walking and handling objects.

Do the arms have their own brain?

Each of the octopus’s arms has a small cluster of nerve cells that controls movement, so technically octopuses have eight independent mini-brains along with a larger central brain.


Have you heard this joke before? Let’s laugh at it together…

How many tickles does it take to make an octopus laugh?

Ten tickles

And, the octopus laughs because… THEY DON’T HAVE ANY TENTACLES! They have arms.

Tentacles, Arms, Suckers

  • Octopuses have eight arms and no tentacles.
  • Cuttlefishes have eight arms and two tentacles.
  • Squids have eight arms and two tentacles.
  • Nautiluses have no arms and around 90 suckerless tentacles.
  • Coral have tentacles and no arms.
  • Jellyfish have tentacles and no arms.
  • Sea anemones have tentacles and no arms.

How can we help octopuses, squid and jellyfish?

There is still so much we can learn about the creatures living in the ocean—which is one of the many reasons that we should continue working together to protect their habitat.

Who knows what we will discover about them next?

We won’t find out if we don’t protect the ocean and the animals that dwell within it.

Join Ocean Conservancy today!

The post Is There a Difference Between Arms and Tentacles? appeared first on Ocean Conservancy.



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Thursday, 22 June 2023

2023 Photo Contest Winners Announced

Ocean Conservancy’s Annual Photo Contest has ended, and it’s safe to say that this was our best yet. Hundreds of you sent breathtaking ocean photos, and we are so impressed. Thank you for sharing your images with us—we are so grateful.

We are thrilled to announce our 2023 Photo Contest winners!

Judge’s Choice Winner:
Synchrony in Motion by Rachel Moore


A once-in-a-lifetime encounter with humpback whales in the crystal-clear waters of French Polynesia. While drifting miles offshore looking for whales this trio, mother, calf and male escort came in for a close pass in perfect synchrony.” — Rachel Moore

Born and raised by the sea, the ocean was Rachel’s first love. At just seven years old, she knew she wanted to become a diver and explore the world hidden below the surface. For the past seven years, Rachel has slowly been sailing around the world on her boat Agape, capturing the wild beauty of our planet to inspire others to protect and conserve our precious ocean. Follow along Rachel’s adventures on Instagram at @moore_rachel.

What Our Judges Had to Say

  • “What can be better than sharing the ocean with humpback whales? Likely very little. These three stacked humpbacks create an engaging moment of living art complete with sunbeams illuminating them like spotlights from above. I’m certain this was nothing short of a magical moment in time.” – Alex Rose
  • “Harmony, respect, fragility and the power of nature, generations embodied in an image, with how vast the ocean is but at the same time the great challenge of safeguarding it due to the impact that human beings have made.” – Karen Fuentes
  • “…the lighting and composition are incredible.” – David Coffey

Category Winners

The winners of our photo contest categories—Human Impact, Marine Wildlife and Spectacular Seascapes—were selected by ocean lovers like you who came out in droves to vote for their favorite photos. Thank you to everyone who voted and shared the contest with others.

Human Impact Winner:
Choked Up by Nicholas DeNezzo

“Bystanders crowd and look on at an entangled California sea lion. As a rescue professional, this scene is a part of our everyday life, in which we deal with the fishing gear, trash pollution and other human impacts affecting our local marine life.” — Nicholas DeNezzo

Follow Nicholas DeNezzo on his website, www.nicholasdenezzo.com, and Instagram, @nickipedia_.

Marine Wildlife Winner:
Climate Endurance by Jenny Wong

“Taken August 2, 2021 in Admiralty Inlet, just a short boat ride from the small hamlet of Arctic Bay. We were standing on top of a cliff with a 500mm lens, a polar bear mother and her two cubs swim by. Well adapted for the ocean, adult polar bears though taxing on energy is very well equipped to navigate the waterstheir young cubs not so much. As the open water season gets longer in the Arctic, mothers will struggle to not only feed herself but also her young, and long commutes to safety or better hunting grounds becomes an arduous journey for their future.” — Jenny Wong

Follow Jenny Wong on her website, www.JennWong.ca, and Instagram @jdubcaptures.

Spectacular Seascapes:
The Shallows by Maximilian Holba

“Simple bliss: On a calm early morning, when the reef awakens from its nightly slumber, and small fish are again swirling around and about, making you feel like you are in a tropical aquarium, you can be in the moment and soak in the wonderful cornucopia of marine life, to forget for just one brief moment, all the unfortunate truths of the climate’s peril and the ocean’s pollution…” — Maximilian Holba

Follow Maximilian Holba on his website, https://maxholba.com/, and on Instagram @maxbeyondthesea.

Thank you to our judges and to all who participated, voted, shared and submitted photos—you truly made this year’s contest a success. Congratulations to ALL our entrants, and we hope to see you next year for our 2024 contest.

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Thursday, 15 June 2023

Meet the Needlefish

If anyone in my family has a question about the ocean, I’m the first person they ask. While I was on vacation recently, my sister would constantly point at things swimming beneath the waves and ask me, “What’s that?” One of these creatures was a needlefish, and at the time I knew almost nothing about them. Who were these little swimming sword fighters who seem ready to joust on any occasion? It was eerie watching these long slender fish swim among humans enjoying the water. Would they challenge anyone to a duel? I had questions, and, honestly, my search for the answers led me down some dark paths. 

Am I now afraid of needlefish? Possibly. Do I think they are the villainous rogues of the ocean’s surface? Absolutely. You may look at that little fish and think nothing of it but I’m here to tell you: Think again. 

Where do you find needlefish? 

Just like that face that haunts your dreams, once you know what needlefish are, you’ll see them everywhere. They hang out in shallow waters or near the surface of the ocean. Most live in saltwater, though there are a few species that live in freshwater or brackish (mix of saltwater and freshwater) environments. Needlefish like warm water so you’ll often find them in tropical areas around the world. Wherever you might head on a relaxing vacation, a needlefish might be there lurking, just offshore. 

What’s that big pointy sword-looking thing for?

It’s clear how a needlefish got its name. In the front of its face is a long, narrow mouth that looks a bit like a needle. While that swordlike front is scary enough, it opens into a mouth with tons of small pointy teeth. These teeth are not for chewing but for making sure their prey does not escape. Which means a needlefish swallows their prey whole. 

What do needlefish eat?

Needlefish usually eat smaller fish, but how they digest them is a weirder story. That’s because needlefish don’t have stomachs. At some point in their evolution, they ditched that organ in favor of an acid-free approach to breaking down their meals. That means nothing turns a needlefish’s stomach because they’ve got no stomach to turn. 

Scarier still, needlefish are smart hunters that seem to take advantage of an underwater phenomenon called Snell’s window. If you have looked up when you were swimming underwater you might have noticed a cone of light that allows you to see up to the surface. That’s Snell’s window, which is caused by the way light refracts through water. While things inside the window are clear, everything around it is dark or distorted. A needlefish will use this disorientation to its advantage, allowing it to get very close to its prey without their being any the wiser. Waiting in the shadows for the right time to attack with your sword? A needlefish sounds like a rogue if I ever saw one.

How fast is a needlefish? 

A needlefish will make short jumps out of the water while hunting its prey. Needlefish can move up to 40 mph when they make their leaps. Needlefish move so fast that they can tail walk, where they appear to walk on the water straight up on their back ends. They’ll even skip along the surface like you might skip a stone, gliding along the waves. 

In their haste, they will often jump over low lying boats instead of swimming under. This can be dangerous for humans on those boats who can be struck by their sharp beaks at high speed. Swimmers, boaters, kayakers and windsurfers have been struck and seriously injured by needlefish. It is important to note, though, that these incidents are rare and accidental. Needlefish aren’t aggressive towards humans and usually avoid contact all together. While I won’t be signing up for a needlefish fan club anytime soon, these rapscallions are an important part of our ocean ecosystem. The truth is, they may have more reason to be afraid of us then we have to be afraid of them. In Pakistan, a needlefish was found dead trapped in a discarded plastic cup that had ended up in the ocean. Living closer to the shores means they also live in habitats polluted by our trash. No creature deserves to live in a dump. Take action with Ocean Conservancy to prevent plastic pollution now.

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We Need NOAA to Keep Fishing Communities Strong

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