Monday, 29 April 2024

All About Gag Grouper

Gag grouper are reef fish that live in the waters off the Southeastern United States, with a range that extends south throughout the Caribbean and along the coast of Brazil. They primarily eat fish, crabs and shrimp and can live for more than 30 years. They can weigh up to 80 pounds. Gag grouper are usually grayish brown and black, and some are called “copper bellies” due to darker patterns on their undersides. Gag grouper are known for distinct kiss-shaped markings on their sides in an adorable camouflage pattern.

Gag grouper are fascinating because they are hermaphrodites; they are all born female and some will change to male (protogynous). Sex reversal is very common in fish, but the dynamics that trigger the reversal are highly variable, and for gag, nobody yet knows what triggers the change! What we do know is that from birth as female, it takes nearly a decade before a gag grouper might transition to male. Many never transition though, making them even more mysterious.

Research has shown that gag grouper are also extremely dependent on specific habitats during different phases of their lives. In the Gulf of Mexico, juvenile gag (all female) live in seagrass flats and estuaries that serve as nurseries. As they age and grow, they migrate to deeper waters in nearshore reefs. In these nearshore reefs, females begin to mature and join spawning aggregations, to release eggs on offshore reefs. Some transition to male, and the males generally become residents and remain on offshore reefs. However, females visit these deeper offshore reefs to spawn, and then they may (or may not!) return to nearshore reefs. This specialized range makes them more vulnerable to environmental impacts and overfishing during some periods of their lives. For instance, harmful algal blooms have historically decimated juvenile populations in inshore waters.

Gag grouper are such interesting fish, but we have so much left to learn. But gag grouper are also in trouble—they are overfished (meaning the population is too low) and undergoing overfishing (meaning the catch rate is too high). In fact, the gag grouper has been identified as one of the most highly vulnerable fish stocks in the Gulf of Mexico.

Three things make them highly vulnerable:

Gag grouper are incredibly popular fish for both recreational and commercial anglers. They also form spawning aggregations which make locating large groups easier for anglers.
Because gag grouper are hermaphrodites, fishery managers must maintain a healthy balance of both males and females which is critical to the population’s survival.
Management is also challenging because gag grouper have specific ecosystem needs during various periods of their lives. Inshore fishing pressure on gag grouper can result in fewer gag grouper that make it to offshore reefs or transition to males.

We have much to learn from these impressive creatures, but what we do know is that gag grouper are remarkable fish that deserve more research, attention and protection. Ocean Conservancy is hard at work tracking gag landings, management actions and progress to rebuild the stock. We are working with you to protect the ocean from today’s greatest global challenges. We rely on evidence-based solutions for a healthy ocean and the wildlife and communities that depend on it.

Please donate to Ocean Conservancy today and make a difference for the future of our ocean.

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Friday, 26 April 2024

Why is This Sea Cucumber Called a Headless Chicken Monster?

My favorite creatures in the ocean are the weird ones. Those blobby, slippery, bizarre, alien-looking things that make you wonder “How does that live on our planet with us?” They remind me that the slice of nature I get to see is just a small fraction of the life out there. The Earth is a weird place, and that’s what makes it wonderful.

And that’s why it gives me such great pleasure to introduce you to one of these strange and glorious creatures: the swimming sea cucumber, also known as the headless chicken monster. This curious creature is a beautiful deep red color with fins that look like a fringed veil, giving it a vibe that might best belong in Dracula’s castle. These sea cucumbers are on the large side, averaging about nine inches in length, compared to their smaller fellow sea cucumbers. They can be found in the benthic zone, the sandy bottom of the ocean.

People who see these creatures have mixed reactions with some finding them beautiful, strange or terrifying. This mixed reaction is reflected in the many different names people have for them. Their scientific name is Enypniastes eximia which means the “dreamer sea cucumber.” Their common name is the swimming sea cucumber which reflects the fact that this species is unusually mobile compared to its other sea-cucumber cousins. They have unique webbed fin-like structures that not only help them move but make them look cool while doing so.

The other names for the swimming sea cucumber get a little weird, which is understandable when trying to find a title befitting such a peculiar creature. Some call the creature a Spanish dancer after the way it gracefully moves through the ocean with its red frills waving around (not to be confused with the Spanish dancer nudibranch, another swimming invertebrate). Others call it the pink sea-through fantasia due to its rosy hue and transparent body. The most shocking name this sea cucumber has earned is the “headless chicken monster.” This moniker came from ROV pilots who saw swimming sea cucumbers in the deep sea and thought they looked chickens right before going in the oven.

These sea cucumbers spend most of their time walking along the ocean floor. Their tentacles both move them and help them scoop up sand to allow them to eat the detritus they find there. Their transparent bodies mean that the food they eat can be tracked through their digestive systems. Just because they prefer to lie on the sandy bottom doesn’t mean they can’t move when needed; these swimming sea cucumbers can travel up the water column to find new food sources and to avoid predators.

As much as I’d love to tell you more about these chicken monsters, there aren’t many more known details because of where they live. It’s hard to study animals that can live miles below the ocean surface and well below the maximum depths human divers can reach. There have been only a few recorded sightings of these swimming sea cucumbers! They are incredible reminders of all the fascinating deep-sea creatures that live in our ocean and are only rarely seen like the blob fish or glass octopus. If you are curious about what else the ocean is hiding in its depths, you can explore more deep-sea creatures here.

The last place these mysterious ocean creatures were spotted were in the deep seas near Chile. Climate change affects all levels in the ocean, even the depths where these swimming sea cucumbers roam. We hope these weird and wonderful creatures spotlight why it is so important to take climate action now to protect our planet. Join Ocean Conservancy in protecting our ocean for all the creatures that live in it, even those we might not commonly see.

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Thursday, 25 April 2024

Let’s Talk About Tarpon

Nearly every night during our bedtime routine of reading countless books, my kids will ask me, “Why haven’t we met a dinosaur yet?” And, nearly every night, I begrudgingly admit that dinosaurs are extinct, and we probably won’t see one walking down the street anytime soon. But then I got to thinking … are they really extinct?

Sure, we don’t share morning commutes with pterodactyls or velociraptors. Still, I’d be remiss not to teach my kids about the fascinating prehistoric creatures that still live beneath our ocean’s surface. So let’s talk about tarpon.

Research of fossils has shown that the tarpon has inhabited our ocean since prehistoric times—dating back to more than 100 million years ago. Tarpon is of the genus Megalops, and just two tarpon species make up the family Megalopidae:Atlantic tarpon (M. atlanticus), those found in Atlantic waters from Virginia to Brazil, the Gulf of Mexico and throughout the Caribbean; and Indo-Pacific tarpon (M. cyprinoides), those found in the Indo-Pacific Ocean throughout Southeast Asia, Australia, Japan and Tahiti. Both species can be found in warmer marine habitats, around coral reefs, in freshwater habitats and sometimes in lakes and rivers.

The tarpon is an enormous fish with large flat, thick and silver scales that look like body armor. Atlantic tarpon make up the larger of the two species, with male tarpon reaching up to eight feet in length and weighing up to 280 pounds. Female Atlantic tarpon are even larger and can grow longer than eight feet and weigh as much as 300 pounds. The females can also live for more than 50 years and the males—particularly the smaller males—live for about 30 years. Due to its coloring and size, and the bright flicker that shines when it jumps out of the water, the Atlantic tarpon is nicknamed the “silver king,” but I’m inclined to change that to the “silver queen.”

Contrary to its large size, the tarpon’s teeth are incredibly small and tightly packed together. The tarpon typically feeds on fish, crustaceans like crabs and shrimp, zooplankton and insects, and it uses a protruding lower jaw to swallow its meals nearly whole.

One of the tarpon’s most unique characteristics is its modified swim bladder. Because of its large body and active underwater affairs, the tarpon needs a substantial amount of oxygen to maintain its lifestyle. The swim bladder has “lung-like” tissue and a duct connected to the esophagus so the tarpon can gulp air when at our ocean’s surface. This primes the tarpon for swimming, and even living, in waters with low oxygen levels and allows it to limit its interactions with predators.

If you’re a fan of fishing, it might come as no surprise that the Atlantic tarpon is one of Florida’s premier game fish due to its strength and stamina. Most recreational anglers practice tarpon catch-and-release fishing, since the tarpon is not considered to be of any food value.

While tarpon have been around for more than 100 million years, it’s on all of us to ensure that the ocean they rely on is protected for millions of years to come. Ocean Conservancy is on the front lines of ocean protection, and our work is not possible without generous donors like you—donate today and make a difference.

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Friday, 19 April 2024

Meet the Surgeonfish

Our ocean’s beloved coral reefs are home to many vibrant, unique and important marine animals. One of these creatures is none other than the surgeonfish, a fish that plays an important role in promoting healthy coral reefs.

When talking about these iconic fish, it’s only natural to begin with a reference to one of the most famous surgeonfish out there, Dory, the curious but forgetful blue tang from Disney’s Finding Nemo and Finding Dory. While we love this unmistakable blue fish, there are many more species of surgeonfish to admire and adore—not only for their wild characteristics and unusual anatomy but for their integral contributions to our marine ecosystems.

Read on as we explore the colorful world of surgeonfish.

Surgeonfish are fish in the family Acanthuridae and go by a couple of common names including doctor fish and tangs. They are typically found in tropical and subtropical ocean habitats throughout the world and, more specifically, around shallow coral reefs. There are about 75 surgeonfish species, which range widely in colors and patterns. This variety makes for amazing displays of colorful fish along coral reefs that are sure to wow any lucky snorkeler.

At this point I’m sure you’ve wondered where these fish got their unique name. Sadly, they aren’t licensed to perform fish surgeries as their name would suggest. Instead, surgeonfish get their name from a sharp spine on the base of their tails, or caudal fins, that are sharp like a surgeon’s scalpel. In some species, these sharp spines are venomous and are commonly used as secret weapons against their predators. When threatened, surgeonfish will extend their spines like a handy sword ready for battle. Although these beautiful fish may look cute, these sharp spines are reason enough to keep a safe distance.

Like so many amazing creatures of our ocean, surgeonfish play a vital role in maintaining a balanced ecosystem in their marine environments. Surgeonfish are primarily herbivores and act as a cleanup crew for their coral reef homes. These fish feed on the green and brown algae that grows along the reefs. This diet helps maintain the health of this environment. Algae also grow much faster than corals, so without the work of the surgeonfish and other herbivores, algae could become overgrown and negatively impact corals and other marine organisms. Undoubtedly, surgeonfish are vital inhabitants of our beloved coral reefs.

Surgeonfish are agile swimmers, using their slim shapes to weave around their rocky environments. This quality also comes in handy when competing during mating season. To spawn, some surgeonfish species mate in large groups while others form pairs. Some male surgeonfish display their colors and swim in patterns to garner the attention of a mate. Once the eggs are hatched, some males will guard these eggs till they hatch while other species end their role as parents after the eggs are hatched.

This colorful and impactful fish is clearly a staple in many coral reef ecosystems. Surgeonfish depend on their coral reef habitats for food just as the coral reefs depend on surgeonfish. Today, one of the biggest threats facing coral reefs are warming waters caused by our changing climate. Other stressors like pollution also trigger coral bleaching and cause further deterioration of these rainforests of the sea. By protecting these valuable ecosystems, we can protect animals like the amazing surgeonfish, keeping our ocean vibrant and full of life.

Ready to act for surgeonfish and all species that dwell in coral reefs? Take action and help Ocean Conservancy urge our leaders to act on climate change before it’s too late.

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Tuesday, 16 April 2024

How Many Species of Hammerhead Shark Are There?

Hammerheads are some of the most recognizable fish in the sea—their iconic “hammer” head is unlike the head of any other shark out there. But did you know there are actually several species of hammerhead?

Get the scoop on these spectacular sharks!

What is a hammerhead shark?

Let’s start with the basics. Hammerheads are elasmobranchs, which are cartilaginous fish—meaning they have skeletons made of cartilage rather than bone. Other elasmobranchs include rays, skates and other sharks.

More specifically, hammerheads are fish within the family Sphyrnidae, defined by their hammer-shaped head called a cephalofoil. The cephalofoil serves a few purposes, including making it easier for hammerheads to maneuver when going after prey (although, the downside is it might not be as hydrodynamic as previously thought). The wide shape of the cephalofoil also means more surface area for sensory organs called ampullae of Lorenzini, which detect electrical fields and help the sharks find prey, including ones buried in the sand.

How many species of hammerhead shark are there?

Within the hammerhead family, there are two genera, or subgroups: Sphyrna, which has eight species, and Eusphyrna, which has only one species. The smallest species within the hammerhead family reaches to about three feet long, where the largest can grow to 15 feet or more.

Read on for a spotlight on a few well-known—and some lesser-known—species of hammerheads.

Winghead shark (Eusphyra blochii)

Status: Endangered

Winghead sharks are the only species in the genus Eusphyrna, which is special already. If that wasn’t enough, they have one of the most dramatic cephalofoil shapes of all the hammerhead sharks—hence the “wing” in its name. They’re found in the Indo-Pacific region from China to Australia and can reach a maximum of six feet in length. They like to hang out in relatively shallow water and snack on small bony fish, crustaceans and cephalopods such as cuttlefish, octopus and squid.

Great hammerhead (Sphyrna mokarran)

Status: Critically endangered

Great hammerheads are the largest—and arguably most iconic—of the hammerheads. They are found in coastal and pelagic habitats in temperature and tropical regions around the world. They’re somewhat unusual among other coastal sharks because they will regularly go after other sharks and rays rather than primarily sticking to smaller bony fish or crustaceans. They will also go after larger prey and can consume prey about 25% their body size.

Scalloped hammerhead (Sphyrna lewini)

Status: Critically endangered

Scalloped hammerheads can be somewhat easily confused with the great hammerhead, but their cephalofoil is slightly “wavier”—hence the “scalloped” part of their name. Similar to greats, they are found around the world in tropical and temperate regions. During their seasonal migrations, they travel in large schools with hundreds of other scalloped hammerheads.

Bonnethead (Sphyrna tiburo)

Status: Endangered

The bonnethead is the smallest member of the hammerhead family, only reaching about four feet in length. They are found throughout the Western Atlantic, Eastern Pacific and Gulf of Mexico and are commonly seen in shallow bays, seagrass beds and sandy areas inshore. Unlike the other hammerheads, which are strictly carnivores, bonnetheads have been found to eat seagrass. One study found seagrass made up to 62% of a bonnethead’s stomach contents! That’s one shark that understands the importance of eating your veggies.

You might have picked up on something else these sharks have in common: All are considered endangered or critically endangered. Sharks like hammerheads depend on a sustainable ocean in order to thrive—visit Ocean Conservancy’s Action Center to see how you can take action to support a healthy ocean for all ocean animals.

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Watch Out for Nettles

Sometimes when you live in a big city like Baltimore, you forget that you are still living in a vibrant ecosystem. One of my favorite things to do with friends is to spot some of the incredible sea creatures that live in our harbor. One of my favorite animal neighbors is the Atlantic bay nettles, which were recently discovered to be a different species of sea nettle that lives in the Chesapeake Bay. You can commonly see these gorgeous jellyfish here in the summer and fall. They have beautiful long tendrils that dance around as they glide in a pulsing motion. But before you get too lured in by this mesmerizing façade, I should warn you: Atlantic bay nettles, and their other sea nettle relatives, can be dangerous.

Hidden in the beautiful frills and ribbons of a sea nettle’s tentacles and arms are stinging cells. For their prey these stings can result in paralysis and death. Once stunned the jellyfish will use its arms to move the unfortunate creature into its mouth for snack time. If you’re not a fish egg, worm or other sea nettle prey, that doesn’t mean you don’t still have to worry about its stings. In humans, a sea nettle sting can leave a rash with a painful and burning sensation.

What do you do if you’re one of the unlucky few who gets stung? Start by looking through your kitchen cabinets. Cleaning the sting with a mixture of ocean water and baking soda or meat tenderizer is the most common recommendation for sea nettle stings. If you don’t want to worry about storing these items in your beach bag, its best to check on the local conditions before you jump in. For fellow Chesapeake Bay residents, you can check this NOAA Map to see the probability of encountering our local Atlantic bay nettles at your local beach.

If you do encounter a sea nettle on the beach, remember to look, don’t touch. Jellyfish aren’t great swimmers so they aren’t going to aim for you, but they can’t easily swim out of the way either. The best way to share our water with them is to be aware of your surroundings and give them a wide berth.

There are actually a lot of pros to sharing our waters with sea nettles and other related sea nettles. They provide protection to some of the other animals around them. Pacific sea nettles give young cancer crabs a ride into shore as well as provide a snack as these crabs eat some of the mucus from their arms. When a predator scares a Pacific butterfish, they find safety in a sea nettle’s bell.

For my fellow residents of the Chesapeake Bay, we can thank our Atlantic bay nettles for protecting our oysters. Bay nettles eat comb jellyfish which are key predators for oyster larvae. In return, oyster beds offer a safe home for baby bay nettles to grow. Bay nettles can help our local oyster populations which in turn helps clean the waters in the bay. Oysters are filter feeders and can filter up to 50 gallons of water a day.

In the Pacific, brown sea nettles are the favorite food of the endangered leatherback sea turtle. These turtles journey to the west coast every spring and summer to find the very jellies we humans would prefer to avoid. These sea turtles don’t have to worry about getting stung, however. Their scales and shells protect them on the outside, and papillae, a layer of spines from their throat to their esophagus, protect their insides.

A sea turtle’s love for jellyfish can also be its downfall and is an important reminder of the other dangers of human interaction with our ocean. Floating plastic bags that end up in the ocean can easily be confused for jellyfish and eaten by turtles. Scientists have found plastics in all seven species of sea turtles on the planet. We can play an important role in protecting our beaches, beyond dodging sea nettles, by keeping our ocean free of plastics. Take action now to tackle the plastic pollution crisis.

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Wednesday, 3 April 2024

All About Echinoderms

Echinoderms constitute a unique group of animals that have me believing in the magic of our ocean. For a family of slow-moving creatures with no brains or bones, you’d expect echinoderms to really struggle for survival. But while there are several threats facing echinoderms, some species have been around for more than 500 million years. If you’ve never heard of echinoderms before, we’ve got you covered. While you’ve likely already heard of the group’s most famous members like sea stars, brittle stars, feather stars, sea urchins and sea cucumbers, there is so much more to know. Let’s dive in.

The phylum Echinodermata loosely translates from Ancient Greek to mean “spiny skin” since most echinoderms have a tough, spiny surface. These spines can range from incredibly short and dense (ex. sand dollar) to soft and much longer (ex. feather stars), to spikey and hard (ex. sea urchins). Some of these creatures, like sea cucumbers, don’t have spines at all. There is quite a bit of variety when it comes to these invertebrates, with approximately 7,000 species among five classes of echinoderms—all living exclusively in the ocean. And yet, there are some incredible features that all echinoderms have in common.

Radial Symmetry

All adult echinoderms have something called radial symmetry, which basically means their appendages point outward from the center of their bodies, like spokes jutting out from the center of a bicycle wheel. Similar to other unique items like snowflakes or even pizza, radial symmetry indicates that there are many lines across the objects in question that could divide them into matching halves. This allows for echinoderms to capitalize on food opportunities and detect threats from every direction, since their sensory receptors are evenly distributed throughout their bodies.

Their appendages are typically found in multiples of five, like the most popular sea star, and sometimes found in multiples of six. There are also exceptions, like the sunflower sea star, which has anywhere from 16 to 24 limbs. This radial symmetry is less obvious in echinoderms without appendages, like sea urchins and sand dollars from the Echinoidea class and sea cucumbers from the Holothuroidea class. While they may not have the same outward appendages, their internal anatomy still works off radial symmetry. Imagine, hypothetically, if a sea star were to wrap its arms up into a circle and cover itself with spikes—there you’d have something like a sea urchin.

Regeneration

Echinoderms possess the remarkable ability of regeneration—meaning their bodies can regrow parts that have been destroyed or removed. In fact, many echinoderms, like sea stars, can intentionally release a body part as a defense mechanism when it has sensed an attack from a predator. Sea urchins can regrow their pointy spines, and sea cucumbers can dispel their internal organs if they sense an attack, then grow them back slowly over time. While some species require the core of their bodies to be in one piece in order for limb generation to occur, others have been known to grow an entirely new body from just one detached arm.

Water Vascular System

Echinoderms have a unique water vascular system that allows for their movement. They can suck sea water up through their bodies and control its flow through several tiny tube feet, controlling how these feet expand and contract. With more water, the tube feet become stiff, which allows them to move on a conveyor-belt-like rotation of feet. Some echinoderms even use these tube feet as suckers to capture and hold on to their prey. Brittle stars can twist and bend their long arms to move, allowing them to move much faster than other echinoderms like sand dollars which actually use their tiny spines and tiny hairs called cilia to move slowly across the bottom of the sea.

As magical as echinoderms may seem, they need help, along with all the animals living in the ocean. Ocean Conservancy is working with you to protect the ocean from today’s greatest global challenges. Together, we create evidence-based solutions for a healthy ocean and the wildlife and communities that depend on it. Please donate to Ocean Conservancy today and make a difference for the future of our ocean.

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