Americans fondness for outdoor recreation at the beach means they come face to face with many of the ocean animals that share the same space.
It’s often the case that a stroll down the boardwalk on any sandy beach along the East Coast brings the visitor face to face with nesting sea turtles or resident crab species. A stroll closer to the shoreline at low tide often reveals the jellyfish and starfish hanging out, waiting for the tide to come in.
The types of ocean animals present in the inter-tidal zone in any give place, often depends on the type of inter-tidal zone in question, rocky or sandy. Sand dollars, for example, are found along sandy beaches at low tide, while chiton are typically found on rocky beaches along the rocky inter-tidal zone. We learn very quickly that the oceans teem with both animal and plant life, some very familiar, some strange.
Ocean Animals: Sea Snails
Sea shells fall into the familiar category. In fact, coastal outdoor recreation activities commonly include sea shell collecting. Conch shells and whelk shells fit the bill for collectors who go by the moto the larger the better. Both types of seashells belong to large sea snails, and they are commonly found along Atlantic Coast and Gulf Coast beaches.
The picture shows a Florida Fighting Conch with a Giant Hermit Crab in residence. Found near shore, from coastal North Carolina to the Gulf of Mexico, they tend to live in large colonies, and contrary to the name, are not known to pick fights with one another.
Their shells grow to an average length of four or five inches. Smaller species are popular aquarium species.
The term whelks usually refers to two genera of sea snails (Busycon and Busycotypus) found in near shore areas, mostly along the East Coast and Gulf of Mexico. Diet differentiates the whelks the conchs. While conchs are vegetarian filter feeders, whelks are carnivores, feeding on both living and dead local mollusk species.
Over the past thirty years, commercial whelk harvest has spread along the Atlantic and Gulf Coasts, mostly for export to Europe and Japan.
While the shell is worn, the picture probably shows the Pear Whelk (busycotypus spiratus), a medium sized species (3-5 inches) that lives in coastal waters from North Carolina, south into the Gulf of Mexico.
The Busycon species, the larger of the two American whelk genera, grows up to nine inches in length, with a shell that opens to the right.
In many coastal areas, a trip to the beach means a trip to a beach lined with the shells of living animals and the remnant shells of once living animals. Mostly the types of sea shells fall into either one of two common categories, the bivalves like mussels and oysters with two symmetrical shells that close together. Sea snails represents the single shelled animals by and large.
The black shell of the Black Turban snail makes it an easily identified marine snail in the upper inter-tidal zone. They are medium sized snails, measuring a little over one inch in diameter. They spend their time roaming the rocky coastline, consuming algae. Finding them can be easy. During low tide they gather in large numbers.
A handful of mollusks go by the name slipper shells. More specifically the term refers to two genera of sea snails, more commonly called the cup and saucers and slipper shells. Crepidula species can be found on both coasts, while Crepipatella are West Coast species.
The picture, an Atlantic Slipper Shell, pretty much explains the name slipper shell. Unlike bivalves, slipper shells are medium sized, one shelled, snails. Rather than having the circular, tightly coiled shell home, they have a more open shell with a ledge built into the bottom to hold the snail.
They tend to behave more like barnacles than snails. As larvae, they attach themselves to an object, including the shells of other nearby animals and other slipper shells, and they spend their lives filter feeding from that spot. Their gender changes over time, with young slipper shells being male and transforming into females as they age.
Shells from most sea snail species also make popular hermit crab homes. The story of the Channeled Dogwhelk explains the competitive environment all the small beach animals face.
It’s another common West Coast marine snail, a predatory sea snails in the rock snail family, Muricidae that inhabits both rocky and muddy areas along the inter-tidal zone. They prey on mussels and barnacles by drilling holes in their shells, injecting an enzyme, and then siphoning up the liquid remains. They need to be careful, because their home range also hosts their predators, crabs and starfish.
A variety of freshwater and salt water bivalve mollusks go by the name of mussels. Formally the term sea mussels often loosely refers to either all members of the Mytilidae family, or one genera such as Mytilus. However defined, most people recognize them as the edible, pear shaped mollusks that form large colonies along rocky shorelines around the world.
Their edibility makes them a popular research subject, especially because of the fact that they also collect near shore pollutants which can endanger the health of people who consume them.
Mussel Watch, a long term coastal monitoring program, in order to analyze “sediment and bivalve tissue chemistry for a suite of organic contaminants and trace metals”.
A recent twenty year program review shows, scientists have discovered a trend of increased levels of arsenic in Eastern Gulf Coast Oysters, although sample measures fall well short of FDA prescribed danger levels. Of all the regions measured for mercury levels, the Middle Atlantic region shows the only increasing trend, due largely to contamination from Midwest coal generated power plants.
More often than not, mussel harvesting areas get closed down because of outbreaks of harmful algal blooms (HABs) that produce toxic substances ingested by the mussels.
Crustaceans: Anthropods of the Ocean
Formal classification of ocean animals follows the same rules as applied to other animals. Moving to the top of the biology classification listing to the level of phyla reveals some interesting facts. Arthropods, for example, are a large group of hard-shelled animals that consists of many smaller groups such as the order of ten legged creatures (decopods) such as crabs, as well as the whole class (Insecta) of six legged animals known as insects.
Human interest in the world’s crustaceans such as crabs and lobsters tends to be culinary oriented. Seafood continues to satisfy human pallets world wide. Nonetheless, other interesting arthropods, such as the Horseshoe crab, also add spice to ocean animal diversity, regardless of their potential as a dinner plate item.
Most people’s familiarity with crabs extends from a typical beach vacation to the kitchen table. That knowledge barely scratches the surface of the world’s true crabs that currently count about seven thousand species in almost one hundred genera.
True crabs often get divided into geographically based species such as fresh water crabs, land crabs and marine crabs.
Marine crabs dominate the West Coast, East Coast and Gulf Coasts. They can breathe underwater using gills, and as anyone who has done recreational crabbing, they are scavengers that eat most any bait thrown their way. Absent bait, their diet includes other benthic creatures such as consists of worms, clams, mussels and other invertebrates.
Some of those crabs live near shore a least part of he year and wind up on the beach. The crab pictures and identification tips presented here address these crab species.
Describing crabs always starts with a few basic facts such as they have ten legs with the first set of legs often described as pincers or claws. Marine crabs breathe underwater using gills. Marine crabs are scavengers. Their diet primarily consists of worms, clams, mussels, other crabs, and other invertebrates.
In the East, a family of crabs called swimming crabs get their name because of the presence of a pair of back flippers as legs that help them swim in their near shore environment. The Atlantic Blue Crab, pictured above, the most prominent swimming crab, is also the most commercially popular species. The blue on the claws stand out in many specimens.
Depending on the location along the Atlantic and Gulf Coast shoreline, they also are called the Chesapeake Blue Crab.
Speckled crabs also live along the Atlantic and Gulf Coasts. They grow smaller than the Blue Crabs and the picture highlights the speckles on the shell.
The colorful shell of the Lady Crab outmatches its relative the Speckled Crab. They are medium sized crabs that live near shore along the Atlantic and Gulf coast.
The swimming crab family also includes a species not very welcome on the East Coast, the European green crab. This is a much smaller species native to the other side of the Atlantic pond. The crab is an effective predator, adept at opening bivalve shells, and has been blamed for harming the soft shell clam industry.
Nothing says crabs on the Coast like the Rock Crabs including the commercial king, the Dungeness Crab.
Even the formal name for Rock crabs (genus Cancer) personifies concept of crab for many people. They tend to grow smaller than the major commercial crabs such as the Atlantic Blue Crab and Pacific Dungeness. However, shell sizes of six inches in length make they commercially viable in many local market.
The common name rock refers to their preferred habitat, rocky shores on both coasts.
They are also hard shelled and the sawtoothed form of the shell as shown in the picture of the Pacific Rock crab, is a good field identification clue.
Seafood Watch reports that over the past few decades the Atlantic Rock Crab has been highly over harvested and undermanaged.
Crab pictures might be incomplete with the fiddler crabs and ghost crabs. Sandy beaches are their preferred habitats, making them highly visible to people on a beach holiday. The Atlantic Ghost Crab represents the genera i the United States. Dark eyes on a small light colored body catch the eye as they scamper above the tide line.
Interestingly enough, fiddler crabs are also an primarily East Coast species. Recently a second fiddler crab species has been identified on the West Coast in Southern California.
Fourteen different species have been documented along the East and Gulf Costs. species of fiddler crab to be found along the Pacific coast of the USA. In contrast, 14 species are found on the Atlantic and Gulf of Mexico.
The single large claw of the male is the key identification clue.
Many areas of the Atlantic Coast host the Common Spider Crab, also called the the Portly Spider Crab. One look at the spikes on the shell makes it very easy to identify. Males can have shells that reach six inches in length. The long legs give it the spider moniker.
Best known of the spider crabs is the monster Japanese spider crab. The legs can extend up to eighteen feet in length.
Smaller and less conspicuous members of the family, the Kelp crabs survive on the kelp forests. They can often be found in the intercoastal zones along the Pacific Coast that host kelp forests. They don’t grow very big. Males might have a shell less than four inches in length. Females are smaller.
Marsh and Mangrove crabs are small crabs with square bodies that inhabit near shore areas of the East Coast and Gulf Coast.
As the name suggests the Mangrove Tree crab, pictured, limits it habitat to Mangroves of Florida and is the least ranging of the two species. It’s an omnivore that often feeds on Mangrove leaves. As the picture highlights, you can often find it walking on the tree trunk.
The marsh crabs, also small shelled has, range in color from light brown to olive green. Its small size means it limits its range to shallow waters of bays and marshes along the coast.
The last of the crab pictures present shore crabs. They are mostly a West Coast group and as the common name suggests, they live along rocky coastal areas. As the picture of the Striped shore crab shows, looking between the corner of two rocks along the beach often produces one.
Here’s the purple shore crab.
Jellyfish
A day at the beach without meeting up with a jellyfish normally gets counted as a good beach day.
The name jellyfish refers to the animal’s jelly-like bell, or box shaped body. The accompanying tentacles suit their carnivorous diet by paralyzing prey with toxic substances.
While most jellyfish sting, not all jellyfish stings are deadly to humans. The Portuguese man-of-war, pictured above, and various box jellyfish are probably the two most dangerous jellyfish found along the coastal waters of the United States.
Prevention is worth an ounce of cure, and knowing which jellyfish to avoid is the best way to prevent jellyfish stings.
Other native jellyfish such as sea nettles and purple-striped jellyfish are also known to cause painful stings. The picture shows the rust colored marks of the Sea Nettle Jellyfish and East Coast species.
Cannonball Jellyfish are one of the most common jellyfish species along the Mid-Atlantic and Southeast Atlantic Coast.
The bell grows about a foot in diameter. Their sting is fairly mild.
Reputed to be the world largest Jellyfish, Lion’s Mane jellyfish swim in all the world’s oceans. Sometimes they wash ashore, and when the larger ones, with caps up to eight feet in diameter, they cause quite the scene.
The tentacles reach even longer. The national aquarium says the world record is over one hundred feet.
The sting from the tentacles can cause severe pain. Just a friendly reminder that it’s always a good idea to wear some type of foot covering while walking on a beach with washed up jellyfish.
Pacific Sea Nettles are found all along the West Coast of the United States. The bell can reach over a foot in diameter and is typically tinted red.
Like their East Coast counterpart, their sting hurts.
The yellow color in the middle of the bell explains the name of another fairly common West Coast species, the Egg Yolk Jellyfish.
Their bell can grow two feet in diameter and the sting of the tentacles is reported to be more annoying rather than dangerous.
A few species of Moon Jellyfish live in all the waters of the United States. The clear bell with four almost circular spots in the middle, plus the lack of long tentacles are the defining characteristics of the species.
They tend to swim close to the top of the water. Their sting is considered fairly mild.
Avoiding jellyfish stings can also be as simple as checking local beach reports about areas where large numbers of jellyfish (often called blooms) have been cited. Avoiding any jellyfish that wash up on the beach also helps.
Sea Anemones share similar feeding habits with jellyfish, their tentacles contain a toxin that can paralyze small fish and other creatures that come into contact with it.
Sea anemone habitat varies. Many species around the world live along the rocks in coastal tide pools. When the tide goes out it is often easy to walk around the area in search of them. They come in a variety of colors and sizes, with approximately one thousand species documented world wide. Of those, about ten species live in harmony with fish, specifically clown fishes.
Look, but don’t touch, represents a rule of thumb for anyone who crosses paths with them. Many species have stings that produce ill effects on humans.
Physical features explain the name Seahorse (genus Hippocampus). Swimming vertically with bent head and tail, gives it the appearance of a horse.
Notwithstanding looks, the seahorse is a true fish that lives in tropical or semi-tropical waters around the world.
Most experts currently identify around thirty five seahorse species, with expectations of new discoveries. However, seahorse popularity and their exploitation for medicinal uses, aquarium pets and souvenirs, has placed great stress on population levels. Experts estimated population declines of anywhere from 25% to 75%, depending on species.
Marine Mammals
Often times a trip to the beach translates into the average American crossing paths with a seal or sealion. It comes as no surprise that more often than not, Americans associate the types of marine mammals present in their local ecosystem with them.
With a bit of nudging, the average American also vaguely associates marine mammals with a Florida favorite, the manatee. In fact, some Floridians also cross paths with them on a daily basis. And while three different manatee species (family Trichechidae) swim in the temperate and sub-tropical fresh salt waters of the Atlantic ,Ocean, the West Indian Manatee (Trichechus manatus) inhabits the warm coastal waters of Florida, the Caribbean Sea and the Atlantic Ocean along the coast of eastern South America.
Known as gentle animals, Florida Manatees, a subspecies of the West Indian Manatee, live along both of Florida’s coasts. On average, they can grow over ten feet long and weight about one thousand pounds. That means the manatee, an herbivore, must invest most of its time consuming large amounts of local grass and plant. Experts estimate that a manatee can eat one hundred pounds of feed each day.
The manatee’s preference for the warm coastal and river waters around Florida means they compete with Florida’s boaters for water space. The competition often turns deadly because the manatee’s soft body usually can not stand up to contact with a boat’s propellers.
Florida wildlife experts estimate that over one-quarter of manatee deaths are caused by boating accidents, and they constantly monitor manatee migrations in order to provide boaters with warnings of their presence.
Most beach goers care little about differences between seals and sealions. However, for clarity sake, seals and Sealions divide into two families, the eared and earless.
Fur Seals and Sea Lions constitute the eared seals, and two species, the Stellar Sea Lion and the California Sea Lion represent the eared species domestically.
Stellar sea lions, also called Northern sea lions, the largest eared seals, inhabit cold ocean water and rocky beaches typical of many areas of the West Coast from Northern California to Alaska.) Males can grow over ten feet long and weigh well over a ton (2,000 pounds). Calling them Northern sea lions helps identify them as the cold water sea lions. A dramatic population decline led to their being listed as a threatened species under the Endangered Species Act in 1990.
California Sea Lions, warm water marine mammals, breed along coastal areas. During nonbreeding season, they migrate as far north as Alaska in search of food. Social animals, they often congregate in large groups.
Earless seals formally fit into the family Phocidae, and are considered top notch swimmers.
Formally nineteen species represent the group, and in the United States. Earless seal often means Harbor seal, the most common species.
Sometimes called sea dogs, their disposition appears that of a family pet, You often find them fishing close to shore or around harbors and other areas where fishermen bring home their catch of the day.
Elephant seals, the largest Phocidae, consist of two species, the northern elephant seal (Mirounga angustirostris) and the southern elephant seal. While size may partially account for their name, the male’s extended nose, which resembles an elephant’s trunk, better explains the elephant name.
When the talk turns to Walrus often it gets introduced by mention of the three subspecies that live in the cold water oceans in and around the Arctic Ocean. The scientific name means tooth-walking sea-horse, referring to tusks present on both males and females. The tusks serve a variety of purposes such as helping them navigate on ice and land. Males also use their tusks for territorial defense.
The walrus’s great size and tusks have long served as a source of food and trophy for both native Eskimo and non-native hunters.
Pacific Walrus males, the largest walrus, can grow twelve feet long and weigh up to eight hundred pounds. Their tusks can grow over three feet in length.
From the seventeenth century to the mid-twentieth century, walrus hunting, along with whale hunting, occupied a substantial portion of most large-scale western commercial fleets.
Today the Atlantic population remains at low levels, and concerns are voiced that melting Arctic Sea Ice, the traditional Walrus breeding ground, could place stress on an otherwise recovered Pacific population.