5 ocean-themed kid costumes from Etsy

It’s not too late to find a costume for your little one to show-off a growing love of the ocean for this Halloween! Here are five adorable costumes I found on Etsy that are worth some serious consideration. (The only reason I was looking was because I keep checking to see if anyone has made a horseshoe crab costume yet, no luck.)

Anglerfish from Pip and Bean

Fish from Laurie’s Gift

Orca from Pip and Bean

Tiger shark from Laurie’s Gift

Shark from Cute and Comfy Costumes

… and 2 bonus costumes for the canine family member.

Dog seahorse from hatzforbratz

Dog shark from Sew Dog Gone Creative

Myth debunked: Delaware Bay not an annual pit stop for all shark species

A fan of Beach Chair Scientist on Facebook recently asked me to demystify a rumor she had heard. This is what she wanted to know: “I was told that over the course of a year, at least one of every species of shark can be found in the Delaware Bay. Do you know if this is true?” I asked Jim Wharton, frequent BCS guest blogger and shark expert, to tackle this one. This is his response.

Sadly, it is not true. There are at least 500 species of sharks in the ocean. They range in size from six inches to sixty feet. They can be found in water ankle deep to the abyssal depths … from the tropics to polar ice caps. To find a nexus point like this anywhere in the ocean would miraculous. Sharks are just too diverse.

Still, there are sharks in Delaware Bay. Anglers might encounter sand tigers, sandbar (brown) sharks, smooth dogfish, and spiny dogfish with other occasional visitors (including at least one record of a juvenile white shark). In fact, the National Marine Fisheries Service has identified the Bay as ‘Essential Fish Habitat’ for several species of Federally protected ‘Highly Migratory Species’ including sandbar sharks, sand tigers, and smooth dogfish. This designation recognizes the critical foraging and nursery habitat the Bay provides for these important species.

Sand tiger shark at the Georgia Aquarium. Image (c) Underwater Times

Dr Dewayne Fox’s lab at Delaware State University is working to create a conservation plan for the sand tiger sharks in the Bay. These distinctive, snaggletoothed sharks are very popular in public aquariums. Despite their fearsome appearance, they rarely interact with people. Sand tigers are top predators and represent a critical keystone species in the ecology of Delaware Bay. Dr. Fox and his students are implanting passive acoustic transmitters inside sharks to better understand their movement patterns. The transmitters emit an identifiable ‘ping’ that is collected by strategically located listening stations to help researchers track the animals in the Bay. Understanding how the sharks use the Delaware Bay is essential to identifying critical habitat for protection. You can learn more about Dr. Fox’s work here.

Sand tigers, by way, are freakish and fantastic creatures that are well-worth saving. No sharks have swim bladders, but sand tigers gulp air at the surface to make themselves neutrally buoyant. Sand tigers are one of many species that explode the myth of the shark in constant motion, frequently found lying near-motionless on the sandy bottom. Sand tigers are fish-specialists, with more-than-a-mouthful of narrow, prong-shaped teeth for grabbing slippery prey. They like to hang-out in large aggregations and may actively cooperate to herd schools of fish. Most fantastic of all…baby sand tigers are “embryonic cannibals.” Sand tiger embryos quickly exhaust their meager yolk sacs and start in on the undeveloped eggs…but they don’t stop there. The largest embryo in each uterus (yes, sharks have two) attacks and consumes its brothers and sisters in the ultimate form of sibling rivalry.

Good references for more on sand tigers:

  • Castro, J. I. (2011). The sharks of North America. Oxford: Oxford University Press.
  • Compagno, L. J. V., Dando, M., & Fowler, S. L. (2005). Sharks of the world. Princeton: Princeton University Press.

Thanks for sharing you knowledge, Jim! Check out his other BCS posts on sharks here.

10 fish you don’t see during Shark Week

I confess. I’ve given up on Shark Week. It took 25 years to shake me, but for the first time I can remember, I won’t be watching. When I was 16, you couldn’t schedule enough great white and shark attack programming to satisfy me. Danger Beach, Vic Hislop, Air Jaws … it was all good. It’s obviously a winning formula for Discovery, but for me, it’s just not enough any more.

There are 500 species of sharks out there. Probably more. There are so many stories to tell. Here are ten you (probably) won’t see this year during Shark Week:

1. Ocean giants. The two largest fishes on Earth are sharks. Thirty-foot, plankton-eating basking sharks can filter a swimming pool of seawater every hour through sieve-like gill rakers in their throats. Whale sharks grow bigger than school buses, and gather by the hundreds in the waters off Mexico’s Isla Holbox and other global hotspots for seasonal feasts of zooplankton or fish eggs. Despite surviving on this surface-dwelling diet, researchers have also tracked whale sharks to depths of more than 6,000 feet. Why?

2. Glowing deepsea sharks. Lantern sharks glow in the dark and hide in the light. Many species of deepwater sharks, including the lantern sharks, are bioluminescent (i.e., they create their own light). Some of these sharks can even project light from their bellies that closely matches the light filtering down from above, erasing their silhouette. They also happen to be beautiful little creatures with fantastic names, like the velvet belly shark, the taillight shark, and the splendid lantern shark. Wouldn’t you like to meet a splendid lantern shark?

3. Cookie cutters. Shark geeks know all about the cookie-cutter shark, but I always forget that they’re not exactly famous…yet. A big cookie-cutter is less than two feet long and yet they’ve been known to feed on tuna, seals, dolphins, and whales…yes, whales. It’s a neat trick. The cookie-cutters sneak up on large prey, attach themselves with fat, sucking lips and twist and thrash until they pull free a round plug of flesh. These little sharks have a remarkable set of jaws with positively enormous teeth. In fact, the cookie-cutters have the largest tooth-to-body-length ratio of any shark (including the great white).

4. Wobbegongs. Can I interest you in a flat shark with patterns like bad 70’s wallpaper and a mustache that would put Tom Selleck to shame? Wobbegongs are bottom-dwelling masters of camouflage with ornate, branching lobes hanging from their upper jaws that look enough like algae or kelp to attract unsuspecting fishes and crustaceans. Wobbegongs lie in wait until their prey gets just a little too close, then erupt in an explosion of tassels and teeth.

5. Hammers and saws. You may have seen hammerheads during Shark Week, but have you ever seen a winghead shark? Wingheads have ‘hammers’ nearly half their total body length. To what benefit? Don’t know. What’s stranger than a hammerhead? How about a sawshark? Imagine a shark, with a chainsaw blade attached to its face and two long noodle-like nasal barbels for detecting buried prey. You can’t make this stuff up.

6. Here be goblins. All sharks have protrusible jaws. Their choppers are loosely attached to their skull, which allows them to push their jaws forward to get a little extra reach, or to create suction. Goblin shark jaws aren’t just extendable, they’re spring-loaded. Elastic ligaments are stretched taught when the shark’s mouth is closed and slingshot the jaws forward as they open. Goblins may need the extra reach to get out from under their long, wide rostrum…which looks a little like an ironing board (at least to me).

7. Helicoprion. You’ll hear plenty about the mega-monstrous megalodon this week, but I’d rather hear a little more about a real pre-historic elasmobranch enigma. Helicoprion had a strange spiral tooth whorl that early paleontologists had no idea what to do with. Some placed it in the sharks’ mouth, some on their dorsal fin. Some suggested it shot out like a frog’s tongue to ensnare their prey. Though speculation seemed to have settled on a lower jaw placement, at least one author suggests the teeth may have resided in Helicoprion’s throat.

8. The shark that walks like a dog. One of my favorites is the epaulette shark, a charming little carpet shark with a distinctive ocellated spot on its flank and a peculiar habit of locomotion. Epaulettes scamper across the reef on large pectoral and pelvic fins. Truthfully, these sharks look more like salamanders than dogs as they wriggle over complex coral reef habitats…and maybe a little like pigs as they root around in the substrate searching for food with their nasal barbels.

9. The sharks who’re named for cats. The catsharks are the largest family of sharks, and boast some of the strangest and most beautiful sharks in the sea. Some catsharks sport snappy colors and patterns like the striped pajama catshark and the chain dogfish (which is actually a catshark). Others are just bizarre, like the spatulasnout and lollipop catsharks, two hyper-specialized deepsea rarities. The aptly named swell shark gulps seawater (or air) and inflates like a pufferfish when threatened.

10. Sleepers. There’s not only diversity in size, shape, and appearance; there is also surprising variety in the ranges and habitats of sharks. Would you expect to find sharks beneath arctic ice sheets? Greenland sharks and Pacific sleepers are lumbering, flabby, but impressive beasts, surviving and thriving where you’d least expect. Stomach contents range widely from giant squid to halibut to seal and whale blubber to at least one (probably apocryphal) account of an entire reindeer.

That’s ten, but I’m still ignoring that other elusive plankton-feeding giant, the megamouth shark, not to mention the long-tailed threshers, the surrealistic rough sharks, frilled sharks, cowsharks, spotted zebra sharks, and puffadder shysharks. I won’t be watching, so if you hear more than a gee-whiz sound bite on any of these sharks, you’ll have to leave a comment to let me know and my faith will be restored.

I will credit Shark Week for creating a lot of excitement about sharks once a year. Some of the kids thrilled by the antics of bait-addled and target-tempted whites, tigers and other super predators will go on to become scientists, conservationists and marine educators…but many others will merely have tired shark stereotypes newly instilled or freshly reinforced. The challenge falls to educators, researchers, and shark enthusiasts to pick up the gauntlet and fill in the blanks for those viewers who just don’t know what they’re missing when it comes to the unappreciated (but critically important) diversity of sharks.

This post was contributed by Jim Wharton, Director of Conservation and Education at the Seattle Aquarium.

What is shark finning?

There has been a lot in the news recently about shark finning. It’s the inhumane practice of capturing a shark, slicing its fins off (shark fin soup is an expensive delicacy popular at Chinese weddings and Chinese New Year celebrations), and tossing the rest of the animal overboard to bleed out a die.

As noted on the Save Our Seas Foundation website, “Compared to other commercial fisheries, the shark-fin industry is opaque, secretive, and often operates in a legal grey area, exploiting loopholes in anti-finning laws and keeping few records. In addition to this, reporting can be unreliable and misleading, as member countries of the UN Food and Agriculture Organisation (FAO) report shark catches with varying degrees of detail and accuracy”. There is some forward momentum. A ban has been put in place in California, Hawaii, Oregon, and Washington to end the practice. California will also implement a ban on the importation of fins starting January 1, 2013. Although, as the LA Times writes, it is still an uphill battle in China.

Wildaid, in conjunction with artist Kiki Karpus, created this powerful “What is shark finning?” infographic as a way to understand more on the harmful effects the practice has on the entire ocean ecosystem.

How do fish give birth?

There are three general ways fish in the sea give birth to a new generation.

I will start off explaining what is most familiar to us, fish that give birth to live young. This is called being viviparous. There is a structure similar to the placenta that connects the embryo to the mother’s blood supply. Some shark species are viviparous. In fact, in some shark species such as the shortfin mako, the embryo has been known to eat other eggs developed by the mother.

Next is something similar called giving birth oviviparously. This is when the embryo develops inside of an egg that is inside the mother. The difference between this and viviparity is that the embryo gets no nourishment from the mother. Nutrients are taken from within the egg. Coelacanths are a type of oviviparious fish.

Lastly, I will go over how 97% of fish species reproduce. These are the fish that lay many, many eggs and hide them in a dark corner so predators can’t get to them. This is called being oviparous. With most oviparous fish species fertilization takes place outside the body. But with many types of skates and rays (pictured right) the male will use his claspers to internally fertilize the female eggs before she lays them.

Image (c) www.gma.org

15 facts about sharks

1.) Sharks are divided into 8 orders.
2.) Sharks are again divided into 34 families.
3.) There are over 360 shark species.
4.) The largest meat eating shark is the great white shark (37 feet).
5.) The largest shark is the whale shark (and largest fish overall), a filter feeder.
6.) The second largest shark (and fish) is also a filter feeder, the basking shark.
7.) Dwarf laternfish (7 1/2 -8 inches), the spined pygmy shark (8 inches) and the pygmy ribbontail catshark (7-7 1/2/ inches) are among the smallest of the sharks.
8.) The fastest swimming fish are the mako and blue sharks which can swim upwards to 60 miles per hour.
9.) The shark with the strongest bite is the dusky shark with a jaw of 132 pounds of force.
10.) The dogfish is the most common shark species.
11.) The deepest diving fish is the Portuguese shark.
12.) The shark with the longest migration has been found to be the blue shark.
13.) Megalodon was an ancient shark that may have been 2 or 3 times as long as a great white shark.
14.) Megalodon means “giant tooth”.
15.) The fossilized teeth of a megalodon are as large as an adult’s hand.

Do sharks have bones?

No sharks do not have bones.

Sharks do have skeletons, but they’re made of cartilage rather than bone. Cartilage is the flexible stuff in the tip of your nose. A cartilage skeleton has its advantages. It’s light, flexible, and it heals faster than bone. In some spots though, sharks need a little extra strength. Their skulls, jaws, and spine are fortified with calcium salts, making them much thicker and stronger. Can you think of why a shark would need strong jaws, skulls, and spines?

by Jim Wharton
Vice President, Education Division, Director, Center for School and Public Programs, Mote Marine Laboratory

Do you have another great question? Email info@beachchairscientist.com.

Are stingrays related to sharks?

English: Various types shown. Taken at Mote Ma...

Image via Wikipedia

Stingrays and sharks are very closely related. They belong to a group of fishes called the elasmobranchs. All elasmobranchs have 1) skeletons made of cartilage (the flexible material that makes up the tip of our nose and ears) and 2) 5-7 gill slits. Elasmobrachs includes sharks, rays, and skates.

It’s not entirely incorrect to think of stingrays as flattened sharks. On the inside, they’re just about the same. There are some animals that blur the lines between the two. Angel sharks and wobbegongs are flat, but they’re not rays. Then there are sawfish (which are rays) and sawsharks (which are sharks). Sharkrays are just plain confused. As a general rule, if the gill slits are on the bottom, it’s a ray. If they’re on the side, it’s a shark.

Jim Wharton
Vice President, Education Division, Director, Center for School and Public Programs, Mote Marine Laboratory

Do you have another great question? Email info@beachchairscientist.com!

How do fish float?

wikifishblutangThere are a few different answers – depending on what type of fish we are asking about.

The most sophisticated types of fishes – bony fishes – have a swim bladder. These fish can inflate their swim bladder with gas from a special gas gland. The gas is basically oxygen from the fish’s blood. Bony fishes that spend most of their lives on the bottom of the ocean floor (e.g., flounder) don’t have a strong swim bladder – therefore, don’t float.

Sharks, skates, and rays are all types of fish. However, these fishes are more primitive – lacking bones. They stay afloat with a liver filled with oil. They use long pectoral fins for balance in mid-waters while maintaining a light framework. The ‘light framework’ is made up of cartilage (the same material found in our nose and ears).

Image (c) wiki-fish.com. (Yellow Tang – a true bony fish)

Do you have another great question? Email info@beachchairscientist.com.

What is the biggest fish in the sea?

Picture taken at Georgia Aquarium, pictured is...

Image via Wikipedia

The whale shark is the biggest fish on the planet. The largest whale shark measures about 66 feet long and 74,957 pounds.

Not to be confused with the blue whale, a mammal, which is the largest animal on the planet. The largest blue whale measured about 110 feet and up to 400,000 pounds!

The whale shark got its name because the shark’s mouth is shaped just like baleen whales. Baleen whales and whale sharks both munch on krill. For being the largest fish in the sea the whale shark is surprisingly affable to divers and known as a relaxed fish.

How are ‘whale sharks’ and ‘whales’ different?

Whales are mammals, just like people, and must breathe air. Dolphins, seals, porpoises, otters (and some people say, polar bears) are mammals that live in the ocean (ie., marine mammals).

Another difference is that mammals raise their young. Whale sharks give live birth like mammals, but, move on right after and don’t raise them. Most other fish do lay eggs.

Fish also have gills to breathe underwater, unlike mammals that must come up to the surface of the ocean and breathe air.

Have another great question for me? Just shoot me an email at info@beachchairscientist.com. Thanks!