Basking Shark
The basking shark is the second-largest shark species, and can reach lengths up to 30-40 feet. Weights for the basking shark have been estimated at 4-7 tons (about 8,000-15,000 pounds). They are filter-feeders who are often seen feeding near the surface with their huge mouths agape.
Basking sharks got their name because they are often seen “basking” on the surface of the water. It may appear the shark is sunning itself, but in fact it is often feeding on tiny plankton and crustaceans.
While it is at the surface, its prominent dorsal fin, and often the tip of its tail, can be seen, which may cause confusion with the Great White or other more threatening shark species when a basking shark is seen from land.
Basking sharks have been reported in all oceans of the world. They are found mainly in temperate waters but have also been seen in tropical areas. During the summer, they feed near on plankton near the surface in more coastal waters. It was once thought that basking sharks hibernated on the ocean bottom in the winter, but some research shows that they migrate to deeper waters offshore and also shed and re-grow their gill rakers, and a study published in 2009 showed that basking sharks traveled from Cape Cod, Massachusetts, all the way to South America in the winter.
Each basking shark has 5 pairs of gill arches, each with thousands of bristle-like gill rakers that are up to 3 inches long. Basking sharks feed by swimming through the water with their mouths wide open. As they swim, water enters their mouth and passes through the gills, where the gill rakers separate out plankton. The shark periodically closes its mouth to swallow. Basking sharks can strain up to 2,000 tons of salt water per hour.
Basking sharks have teeth, but they are tiny (about ¼-inch long). They have 6 rows of teeth on their upper jaw and 9 on their lower jaw, totaling about 1,500 teeth.
Basking sharks are ovoviviparous and give birth to 1-5 live young at a time.
Not much is known about the basking shark's mating behavior, but it is thought that basking sharks exhibit courtship behavior such as swimming parallel to each other and gathering in large groups. During mating, they use their teeth to hold on to their partner. The gestation period for the female is thought to be about 3 ½ years. The basking shark pups are about 4-5 feet long at birth, and they immediately swim away from their mother at birth.
Types of Marine Mammals
Cetaceans differ greatly in their appearance, distribution, and behavior. The word cetacean is used to describe all whales, dolphins and porpoises in the order Cetacea. This word comes from the Latin cetus meaning "a large sea animal," and the Greek word ketos, meaning "sea monster."
There are about 86 species of cetaceans. The term "about" is used because as scientists learn more about these fascinating animals, new species are discovered or populations are re-classified.
Cetaceans range in size from the tiniest dolphin, Hector's dolphin, which is just over 39 inches long, to the largest whale, the blue whale, which can be over 100 feet long. Cetaceans live in all of the oceans and many of the major rivers of the world.
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Sea Turtles
Sea turtles are reptiles that live in a marine or brackish environment. The flippers of sea turtles are long and paddle-like, making them excellent for swimming but poor for walking on land. Another characteristic that helps sea turtles swim easily is their streamlined carapace, or shell.
Kingdom: Animalia Phylum: Chordata Class: Reptilia Subclass: Anapsida Order: Testudines Family: Cheloniidae or DermochelyidaeSea turtles are classified in the Class Reptilia, Subclass Anapsida and Order Chelonii. There are seven recognized species of sea turtles, six of which are in the Family Cheloniidae (the hawksbill, green, flatback, loggerhead, Kemp's ridley and olive ridley turtles), with only one (the leatherback) in the family Dermochelyidae.
Sea turtles start their lives in eggs buried in the sand. After a two-month incubation, the young turtles hatch and run to the sea, facing attack by a variety of predators (e.g., birds, crabs, fish) along the way. They drift at sea until they are about a foot long and then, depending on the species, may move closer to shore to feed.
Sea turtles mature at around age 30. The males then spend their whole lives at sea, while females mate with the males at sea and then go to the beach to dig a hole and lay their eggs. Female sea turtles may lay eggs several times during a single season.
How Do Sharks Sleep
Even though sharks need to keep water moving over their gills to receive oxygen, some sharks need to keep moving to do this, while others don't. Either way, sharks, like other marine animals, don't seem to fall in a deep sleep like we do.
Some sharks have spiracles, a small opening behind their eyes, that force water across the shark’s gills so the shark can be still when it rests.
Other sharks do need to swim constantly to keep water moving over their gills and their bodies. These sharks have active periods, and restful periods, rather than undergoing deep sleep like we do. They seem to be “sleep swimming,” with parts of their brain less active, or "resting," while the shark remains swimming.
Baleen
Baleen is a strong, yet flexible material made out of keratin, a protein that is the same material that makes up our hair and fingernails. It is used by whales to filter their prey from the sea water.
Whales in the Suborder Mysticeti have several hundred plates of baleen hanging from their upper jaw. Like our fingernails, the baleen grows continuously. The baleen plates are about a quarter-inch apart and are smooth on the outer edge but have a hairy fringe on the inner edge. The fringe on the plates overlaps and creates a mesh-like strainer inside the whale's mouth. The whale uses this strainer to trap its prey (usually small schooling fish, crustaceans or plankton) while it filters out the sea water, which it cannot drink in large quantities.
Some baleen whales, like the humpback whale, feed by gulping large amounts of prey and water and then using their tongue to force the water out in between the baleen plates. Other whales, like right whales, are skim feeders, and move slowly through the water with their mouths open as the water flows in the front of the mouth and out in between the baleen. Along the way, tiny plankton are trapped by the right whale's fine baleen hairs.
Baleen is historically important as it was sought by whalers, who called it whalebone, even though it is not made of bone at all. The baleen was used in many things such as in corsets, buggy whips, and umbrella ribs.
Why Lobsters Turn Red
When you think of a lobster, you might think of a bright red creature, as that is what they look like when they're cooked. That's also the creature that the state of Maine had on their license plate until just a few years ago, making them the only state to have a dead animal on their license plate!
However, most lobsters are a brown to olive-green color in the wild, with only a reddish tinge. Lobsters are also occasionally unusual colors such as blue or even orange. When one of these curious creatures is caught by a lobsterman, it's usually big news, as these unusual colorations are a rarity.
Lobsters have a carotenoid pigment called astaxanthin in their shell, which provides a red coloring. However, in most lobsters, this reddish color is mixed with other colors to form the lobster's normal, often duller coloration. This coloration helps the lobster blend in well with its surroundings.
Astaxanthin is stable in heat, while the other pigments are not. This means that when a lobster is cooked, the other pigments break down, leaving only the bright red astaxanthin, thus a bright red lobster on your plate!
Open Ocean - Pelagic Zone
The open ocean, or pelagic zone, is the area of the ocean outside of coastal areas, and where you’ll find some of the biggest marine life species. The sea floor (demersal zone) is not included in the pelagic zone.
The pelagic zone is separated into several subzones depending on water depth:
Epipelagic zone (ocean surface to 200 meters deep)Mesopelagic zone (200-1,000m)Bathypelagic zone (1,000-4,000m)Abyssopelagic zone (4,000-6,000m)Hadopelagic zone (deep ocean trenches, greater than 6,000m).Guess the Creature, Part 2
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Phylum
The term phylum is one of seven major categories that are used to classify organisms. In order of broad to specific, these seven categories are: Kingdom, Phylum, Class, Order, Family, Genus, and Species. Carolus Linnaeus developed this system of classification in the 18th century.
Any organism that has been identified and scientifically described is put into each of the seven categories above. Studying an organism's classification can tell us what other organisms it is similar to.
Marine organisms are divided into many different phyla. All animals with a notochord (vertebrates) are in their own phyla, the Chordata. The rest of the animals are divided up into a very diverse array of invertebrate phyla. Some of the more well-known invertebrate phyla are include the: echinodermata, arthropoda, annelida, mollusca and Cnidaria.
Baleen vs. Toothed Whales
Female baleen whales are also larger than males of the same species.
Examples of baleen whales include the blue whale, fin whale, and humpback whale. Are generally smaller than baleen whales, although there are some exceptions (e.g., the sperm whale and Baird's beaked whale). The toothed whales include all species of dolphins and porpoises.Are active predators and have teeth that they use to catch their prey and swallow it whole. The prey varies depending on species, but can include fish, seals, sea lions or even other whales.Have a much stronger social structure than baleen whales, often gathering in pods with a stable social structure.Have one blowhole on top of their head.
Unlike baleen whales, males of toothed whales species are usually larger than females.
Examples of toothed whales include the beluga whale, bottlenose dolphin, and common dolphin.
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How Fast Can a Shark Swim
In a race among the sharks, the shortfin mako shark (Isurus oxyrinchus) would be the winner.
The robust, streamlined shortfin mako shark is reported to have been clocked at 22 mph, although some sources say it can reach up to 60 mph. This may be because it is capable of chasing even quicker fish, the sailfish and swordfish, which can reach speeds over 60 mph (when leaping). The mako can also perform giant leaps of up to 20 feet out of the water.
Sources:
10 Facts About Seahorses
After much debate over the years, scientists finally that seahorses are fish. They breathe using gills, have a swim bladder to control their buoyancy, and are classified in the Class Actinopterygii, the bony fish, which also includes larger fish such as cod and tuna. Seahorses have interlocking plates on the outside of their body, and this covers a spine made of bone. While they have no tail fins, they have 4 other fins - one at the base of the tail, one under the belly and one behind each cheek.
What is the Biggest Fish?
The whale shark is the world's biggest fish, maxing out at about 65 feet in length and weighing up to about 75,000 pounds.
The second-largest fish is the basking shark, which grows to about 40 feet and 8,000 pounds.
Even though their size may make them look fearsome and inshore appearances may cause alarm, there is nothing to fear. Both species are filter-feeders, and feed on tiny fish and plankton.
Ways to Help Marine Life
Global warming has been a hot topic in the ocean world, and it is because of ocean acidification, known as 'the other global warming problem.' As the acidity of the oceans increases, it will have devastating impacts on marine life, including plankton, corals and shellfish, and the animals that eat them.
But you can do something about this problem right now - reduce global warming by taking simple steps that will likely save money in the long run - drive less, walk more, use less electricity and water - you know the drill. Lessening your "carbon footprint" will help marine life miles from your home. The idea of an acidic ocean is scary, but we can bring the oceans to a more healthy state with some easy changes in our behavior.
Monofilament fishing line takes about 600 years to degrade. If left in the ocean, it can provide an entangling web that threatens whales, pinnipeds and fish (including the fish people like to catch and eat). Never discard your fishing line into the water - dispose of it responsibly by recycling it if you can, or into the garbage.
Maybe you work with marine life already, or are studying to become a marine biologist. Even if working with marine life isn't your career path, you can volunteer. If you live near the coast, volunteer opportunities may be easy to find. If not, you can volunteer on field expeditions such as those offered by Earthwatch as Debbie, our guide to insects, has done, where she learned about sea turtles, wetlands and giant clams!
Types of Cetaceans
There are about 86 species of whales, dolphins and porpoises in the Order Cetacea, which is further divided into two sub-orders, the Odontocetes, or toothed whales and the Mysticetes, or baleen whales. Cetaceans can differ greatly in their appearance, distribution, and behavior. Learn about and see photos of featured cetacean species.
Whale Shark
While its name may be deceiving, the whale shark is actually a shark, and the largest fish in the world. Whale sharks can grow to 65 feet in length and up to about 75,000 pounds in weight. Females are generally larger than males.
They are huge and streamlined, and have a beautiful coloration pattern on their back and sides that is made up of light spots and stripes over a dark gray, blue or brown background. They have a white underside.
Like the basking shark, whale sharks feed by filtering small organisms, such as plankton, crustaceans, tiny fish, and occasionally larger fish and squid. Unlike the basking shark, which moves water through its mouth by slowly swimming forward, the whale shark feeds by opening its mouth and sucking in water, which then passes through the gills. Along the way, organisms get trapped in the shark's dermal denticles (small, tooth-like structures) and the pharynx, which is a rake-like structure. A whale shark can filter over 1,500 gallons of water an hour.
Whale sharks are ovoviviparous and females give birth to live young that are about 2 feet long. Their age at sexual maturity and length of gestation is unknown. Not much is known about breeding or birthing grounds either, although in March 2009, a 15-inch long baby whale shark was rescued from a coastal area in the Philippines, where it had been caught in a rope. This may mean that the Philippines is a birthing ground for the species.
Whale sharks appear to be a long-lived animal. Estimates for longevity of whale sharks are in the range of 60-150 years.
The whale shark is listed as vulnerable on the IUCN Red List, because of hunting, its highly migratory nature, impacts of diving tourism and overall low abundance, which make it "vulnerable to exploitation."
Gulf of Mexico Marine Life
Fish species that live in the Gulf of Mexico include a number of sharks, such as the nurse shark, great white shark, shortfin mako, blue shark, scalloped hammerhead, stingrays (southern stingray, spotted eagle ray, cownose ray), and other fish species, some of which are sought by commercial and recreational fishermen. Other fish species include sawfish, moray eel, American eel, striped mullet, black drum, red drum, seatrout, tarpon, amberjack, Florida pompano, snook, crevalle Jack, cobia, tripletail, snapper, and sheepshead.
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Biggest Ocean Animal
Blue whales are thought to be the largest animal ever to live on the Earth. They reach lengths up to about 100 feet and weights of an amazing 100-150 tons.
Blue whales are a type of baleen whale known as a rorqual. Their skin is a beautiful gray-blue color, often with a mottling of light spots.
Blue whales are found in all the world's oceans. After the invention of the grenade-tipped harpoon in the late 1800's, blue whales were subjected to relentless hunting. The blue whale was given protection from hunting in 1966 by the International Whaling Commission and today there are an estimated 10,000-15,000 blue whales in the world.
How to Tell Whales Apart
Prior to the 1970s, knowledge about whales was gained primarily through the study of animals that were tagged or taken by whalers. Scientists eventually figured out that we can tell whales apart by their natural markings, meaning that whales don't need to be tagged or killed to study them - a simple series of photographs will do the trick.
A classic example of a whale that can be studied using its natural markings is the humpback whale?- humpbacks have a distinct black-and-white pattern on the underside of their tail (shown above), and this pattern can often be seen when the whale takes a deeper dive, enabling these whales to be easily photographed and cataloged.
Once a sighting record is established for an individual whale, researchers are able to study whale movements, migration, feeding patterns and life history (including age of maturity, calving interval and life span). Population estimates may also be obtained by tallying known individuals. Preferred feeding grounds can be noted as well, making it possible to identify locations as prime feeding areas and areas that may need protection.
Some species that can be studied using photo-identification, and how we can tell them apart:
Blue whales, which are identified using their mottled coloration pattern and dorsal fin shape Fin whales, which are identified using their dorsal fin shape, chevron pattern, and scarring Right whales, which are identified using the pattern of callosities on their headOrcas, which are identified using their dorsal fin and "saddle patch" behind the dorsal fin.Learn More:
Image: Three humpback whale flukes, showing the variation in tail patterns, ? Blue Ocean Society for Marine Conservation
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Do Whales Have Hair
There are over 80 species of whales, and hair is only visible in some. Whales have hair on their heads as fetuses, but they don't always keep it. Some of the larger baleen whales have visible hair. One great example is the humpback whale, which has golf ball-sized bumps on its head. Within each of these bumps, called tubercles, there is a hair follicle.
Other examples include the right whale, which has hairs on its chin and upper jaw, and the bowhead whale, which has hairs on its lips, chin, snout and behind its blowhole.
Since hair is not needed for warmth, scientists think the hair serves as a sensory structure, and may be used in social or sexual situations, or for calves communicating a need to nurse.
Baleen whales also have hairlike structures in their mouth called baleen, which is made of keratin, a substance found in hair and nails.
9 Facts About Lobsters
When you think of a lobster, you might think of a bright red creature. Most lobsters are a brown to olive-green color in the wild, with only a reddish tinge.
Lobsters have a carotenoid pigment called astaxanthin in their shell, which provides a red coloring. However, in most lobsters, this reddish color is mixed with other colors to form the lobster's normal coloration. Astaxanthin is stable in heat, while the other pigments are not. This means that when a lobster is cooked, the other pigments break down, leaving only the bright red astaxanthin, thus a bright red lobster on your plate! More on lobster coloration.
How To Sex a Lobster
Lobsters have feathery appendages called swimmerets, or pleopods, underneath their tail. These swimmerets help a lobster swim and are also where a female lobster carries her eggs. Swimmerets also can clue you in to the sex of a lobster. The first pair of swimmerets (the pair closest to the head) are soft on a female, but hard and bony on a male.
Also, the female has a rectangular shield between her second pair of walking legs, which she uses to store sperm after mating with a male. This is where the male inserts those hard swimmerets during mating, releasing sperm that the female stores and later uses to fertilize her eggs.
Shark Week is Here
Discovery Channel's Shark Week started last night (7/31), so you can expect lots of programming about sharks on that channel this week. Do you eagerly anticipate Shark Week each year? Or do you prefer to get information on sharks from other sources? What do you think about Shark Week? Leave your comments below!
Image: Great white shark, Stephen Frink / Getty Images
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10 Facts About Sharks
The term “cartilaginous fish” means that the structure of the animal’s body is formed of cartilage, instead of bone. Unlike the fins of bony fishes, the fins of cartilaginous fishes cannot change shape or fold alongside their body. Even though sharks don't have a bony skeleton like many other fish, they are still categorized with other vertebrates in the Phylum Chordata, Subphylum Vertebrata, and Class Elasmobranchii. This class is made up of about 1,000 species of sharks, skates and rays.
Guess the Creature Answer
There were lots of great (and correct) guesses to this Guess the Creature feature - the creature is a small-toothed sawfish, one of two species of sawfish that live in the U.S. ?Learn more about sawfish here.
Image: NOAA
Intertidal Zone
The intertidal zone is the area where land and sea meet. This habitat is covered with water at high tide, and exposed to air at low tide. The land in this zone can be rocky, sandy or covered in mudflats.
The intertidal zone is divided into several zones, starting near dry land with the splash zone, an area that is usually dry, and moving down to the littoral zone, which is usually underwater. Within the intertidal zone, you’ll find tide pools, puddles left in the rocks as water recedes when the tide goes out.
The intertidal is home to many species of animals and plants. Many of the animals are invertebrates (animals without a spine), which comprise a wide group of organisms.
Some examples of invertebrates found in tide pools are crabs, urchins, sea stars, sea anemones, barnacles, snails, mussels and limpets. The intertidal is also home to marine vertebrates, some of whom prey on intertidal animals, such as fish, gulls and seals.
Class Gastropoda
The Class Gastropoda includes snails, slugs, limpets and sea hairs - all animals referred to as 'gastropods.' Gastropods are mollusks, and a extremely diverse group that includes over 40,000 species. Envision a sea shell, and you're thinking about a gastropod, although this class contains many shell-less animals as well.
Examples of gastropods: whelks, conchs, periwinkles, limpets, nudibranchs
Many gastropods, such as snails and limpets, have one shell. Sea slugs, like nudibranchs and sea hares, do not have a shell, although they may have an internal shell made of protein. Gastropods come in a wide variety of colors, shapes and sizes.Such a diverse group of organisms has diverse feeding mechanisms. Some are herbivores, some carnivores. Most feed using a radula. The whelk, a type of gastropod, use their radula to drill a hole into the shell of other organisms for food.
Food is digested in the stomach. Because of the torsion process described earlier, the food enters the stomach through the posterior (back) end, and wastes leave through the anterior (front) end.
Some gastropods have both sexes; some are hermaphroditic. One interesting animal is the slipper shell, which may start out as a male and then change to a female.
Depending on the species, gastropods may reproduce by releasing gametes into the water, or by transferring the male's sperm into the female, who uses it to fertilize her eggs.
Once eggs hatch, the gastropod is usually a planktonic larvae called a veliger, which may feed on plankton or not feed at all. Eventually, the veliger undergoes metamorphosis and forms a juvenile gastropod.
Photo-Identification Research
Studying Individual Whales
Prior to the 1970s, knowledge about whales was gained primarily through the study of animals that were tagged or taken by whalers.
Since the 1970s, photo identification has become a primary method for studying whales. By photographing unique physical characteristics of the whale, such as dorsal fin shape and body coloration patterns, researchers are able to tell many individuals apart within a population of a particular species.
How to Tell Whales Apart
Each whale species has a set of distinctive features, which scientists use to identify individuals. One whale species that is fairly easy to distinguish is the humpback whale. Every humpback has a unique pattern on the underside of its tail, which is just like our fingerprint. The pattern ranges from all black to all white. A humpback whale will often lift its tail, or fluke, up when it dives, allowing a researcher to photograph this pattern.
Some whales do not life their tails up when they dive, or do not have a pattern on the underside of their tails. In this case, researchers have other methods to tell them apart. These may include distinguishing the whales by the shape of their dorsal fin, pigmentation patterns on their bodies, or by unique scars or markings on the whale.
Examples of other species that are studied using photo-identification are: Blue whales, which are identified using their mottled coloration pattern and dorsal fin shape Fin whales, which are identified using their dorsal fin shape, chevron pattern, and scarring Right whales, which are identified using the pattern of callosities on their headOrcas, which are identified using their dorsal fin and "saddle patch" behind the dorsal fin.
What Can Photo-Identification Tell Us?
Once a sighting record is established for an individual whale, researchers are able to study whale movements, migration, feeding patterns and life history (including age of maturity, calving interval and life span). Population estimates may also be obtained by tallying known individuals. Preferred feeding grounds can be noted as well, making it possible to identify locations as prime feeding areas and areas that may need protection.
Names for Whales
Researchers may see the same individuals year after year and many of the whales have been given names. The names usually relate to a marking on the whale so that the researchers will have an easier time remembering the name when they see the whale out on the water.
Using photo-identification, thousands of whales have been cataloged. In the Gulf of Maine, for example, many whales have "family trees" showing their lineages. One of the first whales identified in the Gulf of Maine was "Salt," a female whose dorsal fin is speckled white. Salt was first photographed in 1976 and has been seen nearly every year since. In 2008, she returned to the Gulf of Maine with her eleventh calf. Salt's family tree is extensive, and information such as this allows researchers to learn much about the life history of whales, such as calving intervals, if calves return to the same feeding and breeding grounds as their mothers, and how often they associate with their relatives.
Green Sea Urchin (Strongylocentrotus drobachiensis)
The green sea urchin has one of the longest, most awkward scientific names, Strongylocentrotus drobachiensis. The genus Strongylocentrotus loosely translates to "round, pointed" and drobachiensis comes from the city of Drobach, Norway (Source: Woods Hole MBL).
Despite their immobile appearance, sea urchins can move quite quickly using their long, clear tube feet, and they are fascinating to watch. Sea urchins use their spines for protection and also may camouflage themselves by trapping pieces of algae with their spines. In a tide pool, sea urchins are often found in clusters underneath rocks.
These echinoderms feed on algae using a unique feeding apparatus on their underside called the "Aristotle's lantern," which is comprised of five calcium plates, muscles and connective tissue that allow the urchin not only to scrape algae, but to chew it into tiny bits.
Cetaceans
The word cetacean is used to describe all whales, dolphins and porpoises in the order Cetacea. This word comes from the Latin cetus meaning "a large sea animal," and the Greek word ketos, meaning "sea monster."
There are about 86 species of cetaceans. The term "about" is used because as scientists learn more about these fascinating animals, new species are discovered or populations are re-classified.
Cetaceans range in size from the tiniest dolphin, Hector's dolphin, which is just over 39 inches long, to the largest whale, the blue whale, which can be over 100 feet long. Cetaceans live in all of the oceans and many of the major rivers of the world.
Cetaceans are thought to have evolved from hooved land mammals that lived about 50 million years ago.
There are many types of cetaceans, which are divided largely according to how they feed.
The order Cetacea is divided into two sub-orders, the Mysticetes (baleen whales) and the Odontocetes (toothed whales). The Odontocetes are more numerous, comprising 72 different species, compared to 14 baleen whale species.
The Mysticetes include species such as the blue whale, fin whale, right whale and humpback whale.
Mysticetes have hundreds of comb-like plates of baleen hanging from their upper jaw. Baleen whales feed by gulping large amounts of water containing hundreds or thousands of fish or plankton, then forcing the water out in between the baleen plates, leaving the prey inside to be swallowed whole.
Odontocetes include the sperm whale, orca (killer whale), beluga and all of the dolphins and porpoises. These animals have cone-shaped or spade-shaped teeth and usually capture one animal at a time and swallow it whole. Odontocetes feed mostly on fish and squid, although some orcas prey on other marine mammals.
Cetaceans are mammals, which means they are endothermic (commonly called warm-blooded) and their internal body temperature is about the same as a human's. They give birth to live young and breathe air through lungs just like we do. They even have hair.
Unlike fish, which swim by moving their heads from side-to-side to swing their tail, cetaceans propel themselves by moving their tail in a smooth, up-and-down motion. Some cetaceans, such as the Dall's porpoise and the orca (killer whale) can swim faster than 30 miles per hour.
When a cetacean wants to breathe, it has to rise to the water surface and exhale and inhale out of the blowholes located on top of its head. When the cetacean comes to the surface and exhales, you can sometimes see the spout, or blow, which is the result of the warm air in the whale's lungs condensing upon reaching the cool air outside.
Whales do not have a coat of fur to keep warm, so they have a thick layer of fat and connective tissue called blubber underneath their skin. This blubber layer can be as much as 24 inches thick in some whales.
Whales have a poor sense of smell, and depending on where they are, they may not be able to see well underwater. However, they have excellent hearing. They do not have external ears, but have tiny ear openings behind each eye. They can also tell the direction of sound underwater.
Baleen
Baleen is a strong, yet flexible material made out of keratin, a protein that is the same material that makes up our hair and fingernails. It is used by whales to filter their prey from the sea water.
Whales in the Suborder Mysticeti have several hundred plates of baleen hanging from their upper jaw. Like our fingernails, the baleen grows continuously. The baleen plates are about a quarter-inch apart and are smooth on the outer edge but have a hairy fringe on the inner edge. The fringe on the plates overlaps and creates a mesh-like strainer inside the whale's mouth. The whale uses this strainer to trap its prey (usually small schooling fish, crustaceans or plankton) while it filters out the sea water, which it cannot drink in large quantities.
Some baleen whales, like the humpback whale, feed by gulping large amounts of prey and water and then using their tongue to force the water out in between the baleen plates. Other whales, like right whales, are skim feeders, and move slowly through the water with their mouths open as the water flows in the front of the mouth and out in between the baleen. Along the way, tiny plankton are trapped by the right whale's fine baleen hairs.
Baleen is historically important as it was sought by whalers, who called it whalebone, even though it is not made of bone at all. The baleen was used in many things such as in corsets, buggy whips, and umbrella ribs.
Common Periwinkle (Littorina littorea)
Periwinkles are sea snails classified in the Phylum Mollusca and Class Gastropoda.
Periwinkles have a dark brown to brownish-gray shell that is up to about 1 inch long. While this species is a common sighting along the eastern coast of the U.S. and Canada, it is an invasive species that originally hailed from Europe and is thought to have been introduced by ballast water in the 1800's.
Periwinkles feed on algae, which they scrape off of rocks using their radula. They are edible snails, and are often called the 'edible periwinkle'. While they are not a common meal in the U.S., they are eaten in Europe, Africa and Asia.
Types of Sirenians
There is one dugong species living today, which is simply called the dugong. Dugongs live in warm waters along the coasts from East Africa to Australia. This range spans at least 48 countries. They can grow to lengths of 8-10 feet and weights of up to 1,100 pounds. Dugongs are gray or brown in coloration and have a whale-like tail. Like Manatees, dugongs are sirenians and feed on aquatic plants.
Dugongs are listed as vulnerable on the IUCN Red List. Threats include coastal development and hunting by indigenous peoples.
Dorsal Fin Collapse
A male killer whale's dorsal fin can grow to as much as 6 feet tall. Despite the fact that the dorsal fin is very straight, it is primarily made of cartilage. A wild orca often travels far, and quickly, in deep water. The water provides pressure to the fin, keeping the tissues inside healthy and straight.
In captivity, a killer whale is usually confined to a small pool, where it spends much time at the surface and often has to swim in a circle. Consequently, the tissue in its dorsal fin doesn't get much of a workout, and starts to atrophy (wastes away due to lack of use), and it falls over. The same thing can happy to the whale's tail flukes, which often flop over at the ends.
According to SeaWorld, dorsal fin collapse "isn't an indicator of the animal's health or well-being," but it's certainly not natural. Dorsal fin collapse is very rare in wild killer whales.
Do you think whales and other marine life should continue to be held in captivity? Share Your Opinion.
Marine Conservation
Marine conservation is the protection of marine species and ecosystems in oceans and seas worldwide. It involves protection and restoration of species, populations and habitats and mitigating human activities such as overfishing, habitat destruction, pollution, whaling and other issues that effect marine life and habitats.
Marine conservation work can be done by enforcing and creating laws, such as the Endangered Species Act and Marine Mammal Protection Act. It can also be done by establishing marine protected areas, studying populations through conducting stock assessments and mitigating human activities with the goal of restoring populations.
Current and emerging issues in marine conservation include:
10 Facts About Seahorses
After much debate over the years, scientists finally that seahorses are fish. They breathe using gills, have a swim bladder to control their buoyancy, and are classified in the Class Actinopterygii, the bony fish, which also includes larger fish such as cod and tuna. Seahorses have interlocking plates on the outside of their body, and this covers a spine made of bone. While they have no tail fins, they have 4 other fins - one at the base of the tail, one under the belly and one behind each cheek.
How Do Sharks Sleep
Even though sharks need to keep water moving over their gills to receive oxygen, some sharks need to keep moving to do this, while others don't. Either way, sharks, like other marine animals, don't seem to fall in a deep sleep like we do.
Some sharks have spiracles, a small opening behind their eyes, that force water across the shark’s gills so the shark can be still when it rests.
Other sharks do need to swim constantly to keep water moving over their gills and their bodies. These sharks have active periods, and restful periods, rather than undergoing deep sleep like we do. They seem to be “sleep swimming,” with parts of their brain less active, or "resting," while the shark remains swimming.
Kemp's Ridley Sea Turtle
The Kemp's Ridley sea turtle weighs about 100 pounds, on average. This sea turtle has a rounded, grayish-greenish carapace that is about 2 feet long. Its plastron (bottom shell) is yellowish in color.
Kemp's ridley sea turtles live from the Gulf of Mexico, along the coast of Florida and up the Atlantic coast through New England. There are also records of Kemp's ridley sea turtles near the Azores, Morocco and in the Mediterranean Sea.
Kemp's ridley sea turtles primarily eat crabs, but also eat fish, jellyfish and mollusks.
Kemp's ridley sea turtles are endangered. Ninety-five percent of the Kemp's ridley turtles nest on beaches in Mexico. Egg harvesting was a major threat to the species until the 1960's, when egg harvesting became illegal. The population appears to be slowly recovering.
Get a Marine Internship
As a person who has worked in internships related to marine biology, and someone who now reviews applications, interviews and hires interns, I've learned some tips and tricks that might help you land a marine biology internship at the organization of your choice.
From applying for the internship to following-up with your interviewer, following these steps will put you in the running. As for your enthusiasm and qualifications, those are up to you. Good luck and let me know if you have any feedback!
Marine biology is a competitive field and you are often up against many other stellar applicants. Don't let that discourage you, though.
When putting your application together, follow instructions exactly and pay attention to detail. Be honest and thoughtful in your answers. Review the organization's web site beforehand to know what qualifications they're looking for and use those to highlight your relevant skills. Write a stellar resume and cover letter. Proofread your application twice before submitting it.
Many marine biology internship applicants hail from far and wide, making it difficult for an in-person interview. Hence, some organizations will offer a phone interview. Wherever possible, make the effort to meet for an in-person interview.
Scheduling an in-person interview has several benefits: you'll show that you're interested enough in the position to make the effort to visit the organization, plus, you'll get to check out the place where you'll be working and the area you'll be living in if you're lucky enough to get accepted. You might also find that you don't like the area at all and it's not the right fit for you.
Applicants are often too nervous, or unprepared, to ask questions about the position. To an interviewer, you'll likely just appear disinterested. Put yourself in the interviewer's shoes and compare an applicant who simply answers all the interview questions, to one who enthusiastically answers questions and engages the interviewer in a discussion about different aspects of the position and clearly wants to know more about the organization.
You'll likely be working closely with your interviewer, especially in a small organization. Ask how long they've worked there, what they like and don't like about their job, and about the organization's current and future work.
The dreaded question..."Is there anything else you'd like to tell me about yourself?", also known as "Anything else we should know?" or "Do you have any other questions?"
When the interviewer asks that question...say something - anything! This is your chance to make a last - and lasting - impression. Highlight your best qualities or if all else fails, simply say, "Thank you so much for taking the time to interview me. I'm really interested in this position and would love the opportunity to work with you."
Humpback Whale
Humpback whales are a baleen whale, meaning they filter-feed on small fish and krill using baleen plates in their mouth. Humpbacks are known for spectacular breaching and feeding behaviors.
Humpback whales in New England have 15-foot long, white flippers, or pectoral fins. The first humpback to be scientifically described was in New England, and was christened Megaptera novaeangliae, or “big-winged New Englander,” by German naturalist Georg Borowski.
Humpbacks have developed a number of spectacular behaviors. These behaviors include bubble-net feeding and lunge-feeding, and “breaching,” or leaping out of the water. At average weights of 20-30 tons and lengths of 50 feet, this is a spectacular sight.
Most humpback populations are migratory. Humpback whales spend their summers feeding in temperate and polar waters and winters mating and calving in tropical waters.
During the breeding season, humpbacks are thought to eat little, if at all. Mating occurs in the winter and the gestation period for the female humpback is about 11 ¼ months. Females give birth in the winter to calves that are about 10-15 feet long and weigh 2,000 pounds. Calves nurse for about a year on their mother’s rich, fatty milk and then begin to feed on smaller fish when they are about a year old.
One of the most interesting facets of humpback behavior is their sounds. Males sing complex “songs” on the breeding ground that are thought to be part of a mating behavior. All of the humpbacks in the same population sing the same song, and the song evolves in complexity throughout the breeding season.
In addition to these “songs,” both males and females make a variety of sounds to communicate. Researchers in Australia recently identified over 30 different types of sounds made by humpbacks.
BP Oil Spill in Gulf of Mexico
Fire boats battle a fire at the off shore oil rig Deepwater Horizon April 21, 2010 in the Gulf of Mexico off the coast of Louisiana.US Coast Guard via Getty Images On April 20, 2010, the oil rig Deepwater Horizon exploded off off the coast of Louisiana in the Gulf of Mexico, killing 11 crew members. The rig sank two days later. The oil rig is owned by Swiss company Transocean but was being operated by British company BP as it searched for oil about 40 miles off the Louisiana coast. The impacts of the spill on marine life, habitats and the economy in the area are already huge.
Read the latest news below - and you can also share news and your experiences here.
Juvenile Tuna Impacted By Oil Spill
October 20, 2010
Research conducted by the Ocean Foundation has led researchers to estimate that juvenile bluefin tuna may have been reduced by as much as 20 percent due to the effects of the BP/Deepwater Horizon oil spill...read more.
Oil Spill Could Be Disastrous For Whale Sharks
September 26, 2010
Whale sharks are the world's biggest fish. One location where you can find whale sharks is in the Gulf of Mexico, and unfortunately, 1/3 of the Gulf's whale sharks, a species listed as vulnerable on the IUCN Red List, live in the area affected by the oil spill that occurred starting in April 2010. Recent reports indicate the oil spill could be disastrous for the Gulf's whale shark population...read more.
Relief Well May Be Completed This Week
August 16, 2010
BP said in a press release that the leaking oil well has been capped, and no new oil has flowed into the Gulf of Mexico since July 15, 2010. However, the company is still drilling a relief well, and that is expected to be completed this week.
There is concern that about 1,000 barrels of oil may be trapped between the rock and the concrete blocking the top of the well, and drilling the relief well in the wrong place could release that oil into the ocean. But Thad W. Allen, the retired U.S. Coast Guard commander who is leading the response effort, said that the relief well would be completed and is necessary to complete the procedures to plug the leak.
Meanwhile, the efforts to collect oil at sea and clean up beaches continues, with over 5,000 vessels and dozens of aircraft involved in the effort...read more.
The Oil Spill's Toll On Wildlife
August 13, 2010
The site Treehugger posted an article about the BP oil spill, noting that 4,500 animals have been affected by the spill so far. The article refers to the Deepwater Horizon Response Consolidated Fish and Wildlife Collection Report, which lists the numbers of marine mammals, reptiles and birds collected and released since the Deepwater Horizon exploded in April 2010.
The report is disturbing, but must be read with a skeptical eye, as not all the animals may have died from the spill. What you can tell from the report, in black and white, is that 1,869 birds and 440 sea turtles were collected alive with visible oiling (meaning they must have experienced some effects of oil), and only 773 birds and 127 adult sea turtles have been released, so there is still a lot of work ahead for the rehab centers...read more.
Sea Turtle Nests Relocated
July 24, 2010
A Kemp's Ridley sea turtle nest at the Gulf Islands National Seashore in Florida has been dug up for relocation to an area less affected by the Deepwater Horizon oil spill in the Gulf of Mexico. The eggs will be transported to a NASA incubation facility near Cape Canaveral...read more.
The Leak Has Stopped - For Now
July 15, 2010
After 85 days of oil flooding the Gulf of Mexico, the leak has been stopped. BP reported today that the well was closed off and had passed integrity tests so far.
Despite this good sign, BP and others working on the response were cautious....read more.
Big Week For Oil Spill Response?
July 12, 2010
BP is attaching a new, tighter cap onto the well, which will include funneling additional oil to the surface ship Helix Producer until a relief well can be drilled, which is estimated to be finished by mid-August...read more.
Federal Judge Blocks Moratorium on Drilling
June 22, 2010
Judge Martin Feldman blocked a 6-month ban on offshore drilling on June 22. The White House said it would appeal the decision. Read more.
Dead Sperm Whale Seen In Gulf of Mexico
June 17, 2010
NOAA reported this week that a dead sperm whale was seen 77 miles from the Gulf of Mexico oil spill site. Cause of death has not yet been determined. In addition, 45 dolphins have stranded, and two have evidence of external oil, but it's not known whether the oil was on them before they died. The total of sea turtles with evidence of external oiling is up to 82...read more.
Sea Turtles Affected By Oil Spill
June 10, 2010
According to the NOAA response web site, 7 sea turtle strandings were verified between June 7 and June 8, four in Mississippi, two in Louisiana, and one in Alabama, and all the turtles were dead. Only one (from Louisiana) had visible oil. Oil can affect sea turtles in several ways...read more.
BP Containment System Begins Siphoning Oil
June 6, 2010
Last last week, the cap containment system installed by BP began siphoning oil out of the leaking well in the Gulf of Mexico. BP is working to increase the amount of oil contained by the cap system, while continuing to drill two relief wells. It is expected to take another 3 months to complete the relief wells... read more.
'Top Kill' Procedure Unsuccessful
May 31, 2010
BP reported that despite pumping over 30,000 barrels of heavy mud into the well in the Gulf of Mexico, the 'Top Kill' procedure didn't work.
Oil Affecting Louisiana Marshes and Marine Life
May 24, 2010
The Associated Press reported that oil from the Deepwater Horizon spill is now at least 12 miles into Louisiana's marshes and has affected at least 2 major pelican rookeries. ...read more.
Marine Life Affected By the Oil Spill
May 21, 2010
It's been difficult to determine exactly how many marine animals have been impacted by the Gulf of Mexico oil spill. This will likely be a number that we never know, as the impacts may be far-reaching and undetectable in some cases. ...read more.
Have you been impacted by the oil spill? Or have you heard news not covered on this site? Share it here.
Fish Anatomy
Depending on where they are located, a fish's fins may be used for stability and hydrodynamics (e.g., the dorsal fin and anal fin), propulsion (e.g., caudal fin), and/or steering (e.g., the pectoral fins)
Facts About Sawfish
With their very distinctive, flattened snout, sawfish are intriguing animals. What is their "saw?" How is it used? Where do sawfish live? Learn the answers to these questions and more below.
The "teeth" on the sawfish's snout are not true teeth, but modified scales. A sawfish's real teeth are located inside its mouth, which is on the fish's underside.
There is some debate over the number of sawfish species, especially since sawfish are relatively understudied. According to the World Register of Marine Species, there are 4 species of sawfish. The largetooth sawfish and the smalltooth sawfish occur in the U.S.
Sawfish can reach lengths over 20 feet. The smalltooth sawfish might be small in teeth size, but not in length. According to NOAA, the maximum length of a smalltooth sawfish is 25 feet. The green sawfish, which lives off Africa, Asia and Australia, can reach lengths of at least 24 feet.
Sawfish eat fish and crustaceans, which they can find using the sensory capabilities of their saw, and which they can kill by slashing their saw back and forth. The saw may also be used to detect and dislodge prey on the ocean bottom.
Delphinidae
Delphinidae is the family of animals commonly known as the dolphins. The animals in the delphinidae are some of the most recognizable species of marine life, and includes species such as the bottlenose dolphin and (perhaps surprisingly) the killer whale (orca). Cetaceans in the Family Delphinidae are Odontocetes, or toothed whales. There are 36 species in this family.
The Delphinidae are generally fast, streamlined animals, and have cone-shaped teeth, an important characteristic that distinguishes them from porpoises. According to the Encyclopedia of Marine Mammals, the Delphindae can range in size from about 5 feet (e.g., the spinner dolphin) to about 30 feet in length (the killer whale, or orca).
Delphinids have a wide range of habitat, from coastal to pelagic areas. The Family Delphinidae includes these species: the bottlenose dolphin, the killer whale (orca), the Atlantic white-sided dolphin, Pacific white-sided dolphin, spinner dolphin, common dolphin, and pilot whales.
Do Whales Sleep?
The way a cetacean sleeps is surprising. Quite unlike us, whales "sleep" by resting one half of their brain at a time. While one half of the brain stays awake to make sure the whale breathes and alerts the whale to any danger in its environment, the other half of the brain sleeps.
We humans are involuntary breathers, meaning we breathe without thinking about it and have a "breathing reflex" that kicks into gear when we're sleeping or are knocked unconscious.
Whale sleep is complex and still being studied. One interesting finding, or lack thereof, is that whales do not appear to have REM (rapid eye movement) sleep that is characteristic of humans. This is the stage in which most of our dreaming occurs.
Where cetaceans sleep differs among species. Some rest at the surface, some are constantly swimming, and some even rest far below the water surface (for example, captive dolphins have been known to rest at the bottom of their pool for a few minutes at a time). I've seen large baleen whales such as humpbacks resting at the surface for sometimes half an hour at a time. These whales take slow breaths that are less frequent than a whale that's active. They are so relatively motionless on the surface that we refer to this behavior as "logging," because they look like giant logs floating on the water.
Sources:
Lyamin, O.I., Manger, P.R., Ridgway, S.H., Mukhametov, L.M., and J.M. Siegal. 2008. "Cetacean Sleep: An Unusual Form of Mammalian Sleep." (Online). Neuroscience and Biobehavioral Reviews 32:1451–1484.Mead, J.G. and J.P. Gold. 2002. Whales and Dolphins in Question. Smithsonian Institution.Ward, N. 1997. Do Whales Ever...? Down East Books.Cephalopods
All cephalopods have a ring of arms surrounding their head, a beak made of chitin, a shell (although only the nautilus has an exterior shell), a merged head and foot, and eyes that can form images.
Cephalopods are intelligent, with relatively large brains. They are also masters of camouflage, changing their color and even pattern and texture to match their surroundings. They range in size from less than 1/2 an inch long to about 30 feet long.
10 Facts About Sharks
The term “cartilaginous fish” means that the structure of the animal’s body is formed of cartilage, instead of bone. Unlike the fins of bony fishes, the fins of cartilaginous fishes cannot change shape or fold alongside their body. Even though sharks don't have a bony skeleton like many other fish, they are still categorized with other vertebrates in the Phylum Chordata, Subphylum Vertebrata, and Class Elasmobranchii. This class is made up of about 1,000 species of sharks, skates and rays.
10 Facts About Scallops
You may have eaten a scallop, but do you know exactly what you were eating? You also may have found a brightly-colored scallop shell on the beach. Here you can learn more about this popular seafood - where scallops live, how big they get and how they feed and reproduce.
Unlike other bivalves like mussels and clams, most scallops are free-swimming. They swim by clapping their shells quickly, which moves a jet of water past the shell hinge, propelling the scallop forward. Click here to see a video of a swimming scallop.
Acadian Hermit Crab (Pagurus acadianus)
Hermit crabs are in the Phylum Arthropoda and Class Crustacea. They are usually found scurrying across the ocean floor or hiding under rocks.
Acadian hermit crabs are reddish-brown in color. The crab has a soft abdomen about 1 inch long. Because the abdomen has no exoskeleton, the crab keeps it hidden in a shell. Usually the shells are empty periwinkle, moon snail or whelk shells that the crab has found, although they sometimes compete for shells with other crabs. When the hermit crab outgrows its shell, it needs to find a new one.
Olive Ridley Sea Turtles
At nesting time, olive ridley turtles gather in large groups offshore of their nesting grounds, then come ashore in arribadas (which means "arrival" in Spanish), sometimes by the thousands. It is unknown what triggers these arribadas, but possible triggers are phermones, lunar cycles, or winds. Although many olive ridleys nest in arribadas (some beaches host 500,000 turtles), some olive ridleys nest singly, or may alternate between solitary and arribada nesting.
Olive ridleys will lay 2-3 clutches of about 110 eggs each. They nest every 1-2 years, and may nest during night or day. The nests of these small turtles are shallow, making the eggs especially vulnerable to predators.
In Ostional, Costa Rica, a limited legal harvest of eggs has been allowed since 1987 to satisfy demand for eggs and economic development, in a supposedly controlled manner. Eggs are allowed to be taken during the first 36 hours of an arribada, then volunteers monitor the remaining nests and maintain the nesting beach to assure continued nesting success. Some say this has decreased poaching and helped turtles, other say that there isn't enough reliable data to prove that theory.
Hatchlings emerge from eggs after 50-60 days and weigh .6 oz at when they hatch. Thousands of hatchlings may go to sea at once, which may have the effect of confusing predators so that more hatchlings survive.
Not much is known about the early live of olive ridleys, but it is believed that they mature in 11-16 years.
Brief History of Cod Fishing
The cod's importance to American history is undeniable. It was cod that attracted Europeans to North America for short-term fishing trips, and eventually enticed them to stay.
The cod became one of the most sought-after fish in the North Atlantic, and it was its popularity that caused its enormous decline and precarious situation today.
Long before Europeans arrived and "discovered" America, Native Americans fished along its shores, using hooks they made from bones and nets made from natural fibers.
Cod bones such as otoliths (an ear bone) are plentiful in Native American middens, indicating they were an important part of the Native American diet.
The Vikings and Basques were some of the first Europeans to travel to the coast of North America and harvest and cure cod. Cod was dried until it was hard, or cured using salt, so that it was preserved for a long period of time.
Eventually, explorers such as Columbus and Cabot "discovered" the New World. Descriptions of the fish indicate that cod were as big as men, and some say that fishermen could scoop the fish out of the sea in baskets. Europeans concentrated their cod fishing efforts in Iceland for awhile, but as conflicts grew, they began fishing along the coast of Newfoundland and what is now New England.
In the early 1600's, John Smith charted out New England. When determining where to flee, the Pilgrims studied Smith's map and were intrigued by the label "Cape Cod." They were determined to profit from fishing, although according to Mark Kurlansky, in his book Cod: a Biography of the Fish That Changed the World, "they knew nothing about fishing," (p. 68) and while the Pilgrims were starving in 1621, there were British ships filling their holds with fish off the New England coast.
Believing they would "receive blessings" if they took pity on the Pilgrims and assisted them, the local Native Americans showed them how to catch cod and use the parts not eaten as fertilizer. They also introduced the Pilgrims to quahogs, "steamers," and lobster, which they eventually ate in desperation.
Negotiations with the Native Americans led to our modern-day celebration of Thanksgiving, which would not have occurred if the Pilgrims did not sustain their stomachs and farms with cod.
The Pilgrims eventually established fishing stations in Gloucester, Salem, Dorchester, and Marblehead, Massachusetts, and Penobscot Bay, in what is now Maine. Cod was caught using handlines, with larger vessels sailing out to fishing grounds and then sending two men in dories to drop a line in the water. When a cod was caught, it was pulled up by hand.
Fish were cured by drying and salting, and marketed in Europe. Then a "triangle trade" developed linking cod to slavery and rum. High-quality cod was sold in Europe, with the colonists purchased European wine, fruit and other products. Then traders then went to the Caribbean, where they sold a low-end cod product called "West India cure" to feed the burgeoning slave population, and bought sugar, molasses (used to make rum in the colonies), cotton, tobacco, and salt.
Eventually New Englanders also transported slaves to the Caribbean.Cod fishing continued and made the colonies prosperous.
In the 1920's-1930's, more sophisticated and effective methods, such as gillnets and draggers were used. Commercial cod catches increased throughout the 1950's.
Fish processing techniques also expanded. Freezing techniques and filleting machinery eventually led to the development of fish sticks, marketed as a healthy convenience food. Factory ships started catching fish and freezing it out at sea.
Technology improved and fishing grounds became more competitive. In the U.S., the Magnuson Act of 1976 prohibited foreign fisheries from entering the exclusive economic zone (EEZ) - 200 miles around the U.S.
With the absence of foreign fleets, the optimistic U.S. fleet expanded, causing a greater decline in fisheries. Today, New England cod fishermen face strict regulations on their catch.
The commercial cod catch has decreated greatly since the 1990's due to strict regulations on cod fishing. This has led to an increase in cod populations. According to NMFS, cod stocks on Georges Bank and the Gulf of Maine are rebuilding to target levels, and the Gulf of Maine stock is no longer considered overfished.
Still, the cod you eat in seafood restaurants may no longer be Atlantic cod, and fish sticks are now more commonly made of other fish such as pollock.
Bowhead Whale
The bowhead whale, also known as the Greenland right whale, is about 45-60 feet long and weighs 75-100 tons when full-grown. They have a stocky appearance.
Bowheads are mostly blue-black in coloration, but have white on their jaw and belly, and a patch on its tail stock (peduncle) that gets whiter with age. Bowheads also have stiff hairs on their jaws. Bowheads have broad, paddle-shaped, 6-foot long flippers and a huge, notched fluke (tail) that can be 25 feet across from tip to tip.
The bowhead's blubber layer is over 1 1/2 feet thick, which provides insulation against the cold waters of the Arctic.
Bowhead whales are a baleen whale, meaning they filter their food, which includes planktonic crustaceans such as copepods, plus small invertebrates and fish from the seawater.
Bowheads have about 600 baleen plates that are up to 14 feet long, illustrating the immense size of the whale's head.
The bowhead's breeding season is in late spring/early summer. Once mating occurs, the gestation period is 13-14 months long, after which a calf is born. Calves are 11-18 feet long and 2,000 pounds in weight when born. The calf nurses for 9-12 months and isn't sexually mature until it is 20 years old.
The bowhead is considered one of the world's longest-living animals, with evidence showing some bowheads may live to over 200 years.
The bowhead whale is listed as species of least concern on the IUCN Red List, as the population is increasing. However, the population, currently estimated at 7,000-10,000 animals, is far lower than the estimated 35,000-50,000 whales that existed before they were decimated by commercial whaling. Only about 3,000 bowheads existed by the 1920's. Due to this depletion, it is still listed as endangered by the U.S.
Placoid Scales
Placoid scales (dermal denticles) are tough scales that cover the skin of elasmobranchs (sharks and rays). Even though placoid scales are similar to the scales of bony fish, they are really modified teeth and are covered with a hard enamel. Placoid scales are packed tightly together and grow with their tips facing backwards. This gives the fish's skin a rough feel. The function of these scales is for protection against predators, although in some sharks, they may also have a hydrodynamic function.
Like our teeth, placoid scales have an inner core of pulp (made up of connective tissues, blood vessels, and nerves), which is covered by a layer of dentine (hard calcareous material). This dentine is covered by enamel-like vitrodentine.
Scales in bony fish grow as the fish gets larger, but placoid scales stop growing after they reach a certain size, and then more scales are added as the fish grows.
Whale Watching Tips Roundup
Learn about whale watching from other readers - hear their stories, see great whale watching photos and come back and share your own! I'd love to hear about your trip - the first whale you saw, your favorite memory, your trip experience - and see your photos!
American Lobster
Some think of lobster as a bright red delicacy served up with a side of butter. But the American lobster (often called the Maine lobster), while a popular seafood, is also a fascinating animal with a complex life. Lobsters have been described as aggressive, territorial, and cannibalistic, but you may be surprised to know they've also been referred to as "tender lovers".
American lobsters are generally a reddish-brown or greenish color, although there are occasionally unusual colors, including blue, yellow, orange or even white. American lobsters can be up to 3 feet long and weigh up to 40 pounds.
Lobsters have a hard carapace. The shell does not grow, so the only way the lobster can increase its size is by molting, a vulnerable time in which it hides, "shrinks" and withdraws from its shell, and then its new shell hardens over a couple months. One very noticeable feature of the lobster is its very strong tail, which it can use to propel itself backwards.
Lobsters were once thought to be scavengers, but recent studies have revealed a preference for live prey, including fish, crustaceans and mollusks. Lobsters have two claws - a larger "crusher" claw, and a smaller "ripper" claw (also known as the cutter, pincher, or seizer claw). Males have larger claws than females of the same size.
Mating occurs after the female molts. Lobsters display a complex courtship/mating ritual, in which the female picks a male to mate with and approaches his cave-like shelter, where she produces a pheromone and wafts it in his direction. The male and female then engage in a "boxing" ritual, and the female enters the male's den, where she eventually molts and they mate before the female's new shell hardens. For detailed descriptions of a lobster's mating ritual, see the Lobster Conservancy or the Gulf of Maine Research Institute.
The female carries 7,000-80,000 eggs under her abdomen for 9-11 months before larvae are hatched. The larvae have three planktonic stages during which they are found at the water's surface, and then they settle to the bottom where they remain for the rest of their lives.
Lobsters reach adulthood after 5-8 years, but it takes about 6-7 years for a lobster to reach the edible size of 1 pound. It is thought that American lobsters can live for 50-100 years or more.
The American lobster is found in the North Atlantic Ocean from Labrador, Canada, to North Carolina. Lobsters can be found both in coastal areas and offshore along the continental shelf.
Some lobsters may migrate from offshore areas during the winter and spring to inshore areas during the summer and fall, while others are "long-shore" migrants, traveling up and down the coast. According to the University of New Hampshire, one of these migrants traveled 398 nautical miles (458 miles) over 3 1/2 years.
Some accounts, such as that in Mark Kurlansky's book Cod say that early New Englanders did not want to eat lobsters, even though "the waters were so rich in lobsters that they were literally crawling out of the sea and piling up inhospitably on the beaches." (p. 69)
It was said that lobsters were considered a food fit only for poor. Evidently New Englanders eventually developed a taste for it.
The lobster's biggest predator is humans, who have seen lobster as a luxury food item for years. Lobstering has increased greatly over the last 50 years. According to the Atlantic States Marine Fisheries Commission, lobster landings increased from 25 million pounds in the 1940's and 1950's to 88 million pounds in 2005. Lobster populations are considered stable throughout much of New England, but there has been a decrease in catch in Southern New England.
In addition to harvesting, lobsters are threatened by pollutants in the water, which can accumulate in their tissues. Lobsters in highly-populated coastal areas are also prone to shell rot or shell burn disease, which results in dark holes burned into the shell.
Coastal areas are important nursery areas for young lobsters, and young lobsters could be affected as the coast is developed more heavily and population, pollution and sewage runoff increases.
Brown Algae
Brown algae is the largest, most complex type of algae. This type of marine algae is brown, olive or yellowish-brown in color. Brown algae contains contains chlorophyll a and c and a pigment called fucoxanthin, which gives it its color.
Fucoxanthin is not found in other algae or plants. Unlike red and green algae, brown algae are in the Kingdom Chromista.
Like other algae, the distribution of brown algae is broad, from tropical to polar zones. Brown algae can be found in intertidal zones, near coral reefs and in deeper waters, with a NOAA study noting them at 165 feet in the Gulf of Mexico.
There are about 1,800 species of brown algae. The largest, and one of the most well-known, is kelp. Other examples of brown algae include seaweeds in the genus Fucus commonly known as "rockweed," or "wracks," and the genus Sargassum, which form floating mats and are the most prominent species in the area known as the Sargasso Sea, which is in the middle of the North Atlantic Ocean.
Brittle Stars and Basket Stars
This is a collection of aptly-named animals. Brittle stars have very fragile-looking, worm-like arms and basket stars have a series of branching arms resembling a basket. Brittle stars and basket stars are echinoderms that belong to the Class Ophiuroidea, which contains thousands of species. These animals are sometimes referred to as ophiuroids.
These marine invertebrates are not 'true' sea stars, but have a similar body plan, with 5 or more arms arranged around a central disc. The central disk of brittle stars and basket stars is very obvious, since the arms attach to the disc, rather than joining to each other at the base like they do in true sea stars.
The central disk of brittle stars and basket stars is usually relatively small, under one inch, and the whole organism itself may be under an inch in size. The arms of some species can be quite long, though, with some basket stars measuring over 3 feet across when their arms are extended (Source: Coral Reefs: An Ecosystem in Transition). These very flexible animals can curl themselves into a tight ball when they are threatened or disturbed.
Depending on the species, basket stars and brittle stars may be predators, actively feeding on small organisms, or may filter-feed by filtering organisms from the ocean water. They may feed on detritus and small oceanic organisms such as plankton and small mollusks.
The mouths of brittle stars and basket stars are located on their underside. They have no anus, so wastes are also expelled through the mouth.
Chordata
Chordata is the phylum that includes all the animals that have a notochord, or nerve cord, at some stage of their development. Animals in this phylum are known as chordates. The most well-known chordates are the vertebrates - animals that have a spine.
Marine chordates include cetaceans, pinnipeds, sirenians, fish and tunicates (ascidians).
Lobster Information
I aim to answer all your marine life questions here, and this is an interesting one, with an answer that is simpler than you might think. Learn why lobsters are a greenish brown in the wild but end up bright red on your plate.
Shark Attack Tips
Even though you're more likely to die from a lightning strike, alligator attack or on a bicycle than from a shark attack, sharks do sometimes bite humans. According to the International Shark Attack File there were 59 cases of unprovoked shark attacks worldwide in 2008. Forty-one of these unprovoked attacks were in U.S. waters, and 32 of these were in Florida.
There are many ways (most of them common-sense) that you can avoid a shark attack. Below is a list of what not to do if you'll be swimming in waters where sharks might be present, and techniques for getting away alive if a shark attack really does happen.
Don't swim alone.Don't swim during dark or twilight hours.Don't swim with shiny jewelry.Don't swim if you have an open wound.Don't swim too far offshore.Ladies: don't swim if you're menstuating.Don't splash excessively or make erratic movements.Keep pets out of the water.Don't swim in areas where there are sewage (for other obvious reasons!) or pinnipeds that are hauled-out. Both areas can attract sharks.Don't swim in areas being used by fishermen, as their bait could attract sharks.Don't push your luck - never harass a shark. Get out of the water if one is spotted.Ocean Acidification
It's no secret that global warming is a major issue. A main cause of global warming is our release of carbon dioxide, primarily through the burning of fossil fuels and the burning of vegetation. Over time, the oceans have helped this problem by absorbing excess carbon dioxide. According to NOAA, the oceans have absorbed nearly half of the fossil fuel emissions we've generated over the past 200 years.
As the carbon dioxide is absorbed, it reacts with the ocean water to form carbonic acid. This process is called ocean acidification. Over time, this acid causes the pH of the oceans to decrease, making ocean water more acidic. This can have drastic consequences on corals and other marine life, with cascading impacts on the fishing and tourism industries.
The term pH is a measure of acidity. If you've ever had an aquarium, you know that pH is important, and pH needs to be adjusted to optimal levels for your fish to thrive. The oceans has an optimal pH, too. As the ocean becomes more acidic, it becomes more difficult for corals and organisms to build skeletons and shells using calcium carbonate.
In addition, the process of acidosis, or buildup of carbonic acid in body fluids, may affect fish and other marine life by compromising their ability to reproduce, breathe and fight diseases.
On a pH scale, 7 is neutral, with 0 the most acidic and 14 the most basic. The historical pH of sea water is about 8.16, leaning on the basic side of the scale. While it doesn't seem like this is a problem, the pH of our oceans has fallen to 8.05 since the beginning of the Industrial Revolution, a change greater in magnitude than any time in the 650,000 years before the Industrial Revolution. The pH scale is also logarithmic, so that slight change in pH results in a 30 percent increase in acidity.
Another problem is that once the oceans get their "fill" of carbon dioxide, scientists think the oceans could become a carbon dioxide source, rather than a sink. This means the ocean will contribute to the global warming problem by adding more carbon dioxide to the atmosphere.
Lowering our emissions will help the ocean acidification problem, even if that just slows the impacts long enough to give species time to adapt. Read the Top 10 Things You Can Do to Reduce Global Warming for ideas on how you can help.
Scientists have acted swiftly on this issue. The response has included the Monaco Declaration, in which 155 scientists from 26 countries declared in January 2009 that:
Ocean acidification is accelerating and severe damages are imminent;Ocean acidification will have broad socioeconomic impacts, affecting marine food webs, causing substantial changes in commercial fish stocks and threatening food security for millions of people;Ocean acidification is rapid, but recovery is slow;Ocean acidification can be controlled only by limiting future atmospheric carbon dioxide levels.The scientists called for intense efforts to research the problem, evaluate its impacts and cut emissions drastically to help curb the problem.
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Great Pacific Garbage Patch
The North Pacific Subtropical Gyre circulates in a clockwise pattern and this tends to focus marine debris, particularly tiny plastic particles, into the center of the gyre. The Pacific Garbage Patch is said in the book World Ocean Census to be as large as Africa.
While it's easy to visualize a giant pile of plastic and other debris accumulated in the ocean, this isn't exactly what the Great Pacific Garbage Patch looks like. It looks more like a "soup" of tiny plastic particles and other marine debris. These particles float, but are not necessarily all gathered at the surface. Research on the plastic in the gyre usually involves taking samples using large plankton nets. These do a great job of straining out the water, leaving behind whatever organisms, or plastic, are in the ocean at that location.
The North Pacific Gyre is one of 5 major oceanic gyres. The other four are the South Pacific Subtropical Gyres, the North and South Atlantic Subtropical Gyres, and the Indian Ocean Subtropical Gyre. Increasingly, there is evidence that each gyre has its own garbage patch.
Garbage doesn't just collect in these gyres - debris can concentrate in other areas such as convergence zones, eddies, meanders and Langmuir circulation (surface currents usually caused by wind).
The North Pacific Subtropical Convergence Zone is an area identified as of high concern by NOAA because of its presence of "high productivity, pelagic species feeding and migration, and documented marine debris concentration." This area is a primary means of transport of marine debris onto the Hawaiian Islands.
Although various cleanup scenarios have been proposed, most researchers seem to agree that the only solution is prevention. Due to the widespread nature of the plastic particles and a cleanup operation's impact on marine life, we can't simply go out and scoop up all the debris. And it will continue to accumulate unless we stop using so much plastic, stop using so many disposable items and start disposing of our waste responsibly.
Human Uses For Algae
The agar found in red algae is used as a culture medium in microbiology research. Algae is also used in a variety of other ways, and research continues on the benefits of algae for medicine. Some claims about algae include the ability of red algae to improve our immune system, treat respiratory ailments and skin problems, and cure cold sores. Algae also contains abundant amounts of Iodine, an element required by humans and necessary for proper thyroid functioning.
Both brown (e.g., kelp and Sargassum) and red algae are used in Chinese medicine. Uses include treatment for cancer and for treating goiters, testicular pain and swelling, edema, urinary infections and sore throat.
Spider Crab
Like other crabs, spider crabs are in the Class Crustacea. Their Family, Madijae, contains over 700 species of crabs. The common name "spider crab" refers to several species of spider crabs, which are found in both the Atlantic and Pacific Oceans.
Spider crabs have long legs, and spines on their legs and carapace. They are scavengers, eating dead sea stars and fish.
The deep sea spider crab (Macroregonia macrochira) shown here can inhabit depths over 9,000 feet, and doesn't exist in waters shallower than 3,000 feet. The deep sea spider crab's legs are thin and over 1.5 feet long. This crab species is found across the North Pacific Ocean, and was discovered in waters off Alaska for the first time in 2001.