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Habitat – Tropical seas (reefs and shallows)

Niche – Ambush predator

Favorite Food – small fish like wrasses

Length – up to 3 feet

Status – locally common

Among the residents of the warm waters of the Caribbean, trumpetfish are both conspicuous and anything but. Relatives of seahorses and pipefish, their flattened tube-like bodies are truly bizarre to behold, provided you can find them. Most of their lives are spent hiding on the seafloor or drifting in the currents as inconspicuous as a piece of seaweed.

Trumpetfish are ambush predators, using stealth are trickery to remain unseen until the moment of strike. They often hover vertically alongside sponges, thin corals, and gorgonian weeds, swaying in tune with the currents. Other times they’ll swim alongside large fish in order to cloak themselves from schools of wrasses on the other side. If an unsuspecting fish gets too close, the trumpetfish will dart at it, flaring its mouth open like the end of a trumpet. Like other fish that hunt by ambush, they suck in a volume of water with lightning speed during an attack, vacuuming small fishes into their mouths.





Trumpetfish are still locally common in many parts of the Caribbean and Gulf of Mexico, but like any resident of a reef system, they’re vulnerable to even slight disruptions. Something like a giant oil slick could have unwelcome consequences for these and thousands of other species living in the warm waters off the Americas.

*filmstrip photo provided courtesy of JennyHuang on Flickr Creative Commons

Home

Habitat – Coasts, estuaries

Niche – Filter feeder

Favorite Food – microscopic food particles

Length – up to 3 inches

Also called common mussels, blue mussels are a familiar sight on the shores of most temperate and cold seas in the western hemisphere. Anyone who’s climbed over beach rocks knows to be careful where they step, lest they cut themselves on sharp clusters of black and blue shells.

Mussels are delicious relatives of clams in a class of ocean creatures called bivalves. A hinged shell is their primary protection, opening while the animals are feeding, and closing when they’re threatened by predators or receding tides. Mussels anchor themselves to rocks with fibrous tissue made of filaments called byssal threads, which taken together are five times stronger than human tendon. The threads make it nearly impossible for mussels to be nipped away or pounded off the rocks by waves, inching them one step closer to living life happy as a clam, so to speak.

Because they rarely move, mussels need their food to come to them. They are filter feeders, capturing tiny bits of food floating in the currents with their feathery gills. They also obtain oxygen in the same way, and can process nearly 20 gallons of water a day, consuming most everything in it. As far as filter feeders go, blue mussels are among the most successful in the ocean.





Unlike their cousins, the freshwater zebra mussels, blue mussels are economically important and are a staple seafood dish worldwide. Because of their high rate of reproduction, wide range, and lack of many natural predators, blue mussels are still common. However, like anything else in the ocean, they’re prone to changes in currents, availability of food, and especially pollution. When an animal lives by sucking water into its body, it won’t live long if there’s crap in the water. So long as we respect that notion, we’ll likely continue to see the shores littered with thousands of those black and blue shells.

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Habitat – ocean surface

Niche – passive predator

Favorite Food – small fish

Length – up to 100 feet

Status – Common

Notable Feature – the whole is composed of thousands of individual organisms

Although it looks like a jellyfish, the Portuguese Man-o-War is actually a colony of living organisms that band together to form a highly efficient killing machine. These organisms, called polyps, each perform a specialized role in order to keep the whole outfit floating, killing, eating, digesting, and reproducing in the world’s oceans.

The Portuguese Man-o-War is so named because of the projection on its float bladder that resembles the sail of a centuries-old warship. This sail catches wind on the surface of the ocean, which is the only way the colony can move. The Man-o-War has no means of locomotion and can only float. It’s at the mercy of the sea breeze and ocean currents, and if either of these forces drives it onto the seashore, it’s done for. However, as long as it remains at sea, it is a formidable predator.

Although it’s not technically a jellyfish, the Portuguese Man-o-War nonetheless hunts like one. It boasts dozens of dark purple tentacles that can trail behind the bladder in the water for over 60 feet. Like a net trolling behind a boat, these tentacles are used to kill and ensnare prey. Each one is studded with tiny cellular weapons called nematocysts. Each contains a trigger mechanism, a coiled spring, and a deadly barb. When an unsuspecting fish brushes up against one of the Portuguese Man-o-War’s tentacles, it flicks the trigger and the trap is sprung. The coiled spring unfurls in a fraction of a second, driving the venomous barb deep into the fish’s body at high velocity. Toxins in the barb attack the fish’s nervous system, paralyzing it. The polyps specializing in digestion take over, secreting powerful enzymes to break down the fish for the good of the colony.





Although it can’t run, fly, or even swim, the Portuguese Man-o-War is nonetheless one of the most feared hunters in the temperate and tropical seas of earth, delivering stings powerful enough to land an unwary diver in agony. They are also prime examples of the fascinating possibilities of working together in the natural world.

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Niche – predator

Favorite Food – deepwater fish

Length – up to 4.5 feet

Weight – up to 200 pounds

Status – Least Concern for Extinction

Threats – pollution, overfishing

The Baikal seal is the only exclusively freshwater seal in the world, living in the cold waters of Lake Baikal in Russia. Being the only large predatory mammal in a giant lake has its advantages, especially in terms of food. Because of their ability to hold their breath for long stretches, Baikal seals dive for fish in the deeper regions of the massive lake and have heavy claws on their forepaws for keeping holes open in the winter ice.

Although Baikal seals resemble most other true seals in appearance, they are much more solitary and are generally monogamous when it comes to mating. Female Baikal seals have been shown to mature earlier when populations are reduced. This adaptation can give ailing populations a fighting chance at rebounding if more females are available to mate. Baikal seals also live longer than many seals, and lucky adults can reach 55 years old or more. The combination of these factors has helped to maintain populations above the threshold for conservation concern.

Baikal seals run into the problem of finding a place to raise their young on a lake that can freeze over completely in winter. In response, pregnant Baikal seals dig burrows called “snow caves” under the snow cover on the lake during the cold months. Pack ice on the lake’s surface is prone to buckling, and where the ice buckles, the snow piles higher, allowing space for a den. The snow cave allows a place for the mother protect her pup and have ready access to the cold waters under the ice without needing to dig or search for other openings. A single pup is born and raised in the snow cave for up to 10 weeks before it is strong enough to start hunting for its own food. Baikal seal pups are extremely cute, sporting soft white fur for several weeks before shedding it to reveal the characteristic gray coats of the adults.

Lake Baikal’s size and relative isolation in the wastes of Siberia has long protected the Baikal seal and scores of other animals found nowhere else on earth. However, industrial activity and human development have been on the rise in recent years and the lake is not immune from the horrors of pollution. The future is open.

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Habitat – coral reefs, rocky coastal shelves

Niche – ambush predator

Favorite Food – small fish

Length – up to two feet

Status – Endangered

Threats – habitat destruction, exotic fish trade, bottom trolling fishing practices

Notable Feature – highly venomous

The estuarine stonefish is one of five species of synanceia, a group of unusual scale-less fishes that inhabit tropical waters. However, this species is commonly known just as the stonefish. These grotesque fish are both masters of camouflage and killing in their underwater lair.

Stonefish are the most venomous fish in the world, delivering a powerful toxin through sharp spines on their dorsal fins. What makes the stonefish so terrifying is that it’s nearly impossible to see when it’s sitting motionless on the sea floor. As an ambush predator, it relies on its ability to blend in with its surroundings. Many divers have discovered the sinister nature of this fish the hard way, in excruciating pain after stepping on what they thought was a stone. If the antivenin is not promptly administered to reverse the effects of the deadly toxin, what started as an unfortunate accident could quickly turn fatal.

Stonefish don’t use their venom for hunting because they don’t need it. Few fish even know of a stonefish’s presence before they’re gobbled up. The stonefish has eyes set on the top of its head, so it can remain completely motionless piled in sand and mud until its victim is practically touching its body. It then strikes with lightning speed, sucking the unfortunate fish into its huge mouth.





Although stonefish encounters can prove deadly, the number of those encounters in the wild is steadily decreasing. Destruction of their rocky reef habitats, collection as exotic aquarium fish, and bottom trolling fishing has devastated populations in the South Pacific. They are now an endangered species.